There are many valuable people who have helped create CCXML. Please see the complete list in the Acknowledgments section at the rear of the specification.
Please refer to the errata for this document, which may include some normative corrections.
This document describes CCXML, or the Call Control eXtensible Markup Language. CCXML is designed to provide telephony call
control support for dialog systems, such as VoiceXML [VOICEXML]. While
CCXML can be used with any dialog systems capable of handling media, CCXML has been designed to complement and integrate with a
VoiceXML interpreter. Because of this there are many references to VoiceXML's capabilities and limitations. There are also
details on how VoiceXML and CCXML can be integrated. However, it should be noted that the two languages are separate and are
not required in an implementation of either language. For example, CCXML could be integrated with a more traditional
Interactive Voice Response (IVR) system or a 3GPP Media Resource Function (MRF), and VoiceXML or other dialog systems could be
integrated with other call control systems.
Status of this Document
This section describes the status of this document at the time of its publication. Other documents may supersede this
document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
This is the 05 July 2011 Recommendation of "Call Control eXtensible Markup Language
(CCXML) Version 1.0". There were no changes since the Proposed Recommendation document.
This specification describes the Call Control XML (CCXML) markup language that is designed to provide telephony call control
support for VoiceXML or other dialog systems.
During the Candidate Recommendation phase, four independently developed implementations were evaluated. The entrance criteria for the Proposed Recommendation phase requires a minimum of two independently developed interoperable implementations for each required feature, two or more implementations of optional features that would impact interoperability, and a minimum of one implementation for each optional feature that has no impact on interoperability. These requirements were met. For further details and complete results please see section 7 of the CCXML Implementation Report. Comments received during the Candidate Recommendation period can be found in the Disposition of Comments.
This document has been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and is endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited from another document. W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web.
In this document, the key words "must", "must not", "required", "shall", "shall not", "should", "should not", "recommended",
"may", and "optional" are to be interpreted as described in [RFC2119] and indicate
requirement levels for compliant CCXML implementations.
This document describes CCXML, the Call Control eXtensible Markup Language. CCXML provides declarative markup to describe
telephony call control. CCXML is a language that can be used with a dialog system such as VoiceXML [VOICEXML].
CCXML can provide a complete telephony service application, comprised of Web server CGI compliant application logic, one or more CCXML documents to declare and perform call
control actions, and to control one or more dialog applications that perform user media interactions
Since platforms implementing CCXML may choose to use one of many telephony call control definitions (JAIN Call Control
[JSR021], ECMA CSTA [CSTA], S.100 [S.100], etc.), the call control model in
CCXML has been designed to be sufficiently abstract so that it can accommodate all major definitions. For relatively simple
types of call control, this abstraction is straightforward. The philosophy in this regard has been to "make simple things
simple to do." Outdial, transfer (redirect), two-party bridging, and many forms of multi-party conferences fall within this
classification.
Figure 1 shows the architecture of a telephony implementation consisting of four primary components:
a caller (along with the telephone network),
a dialog system (e.g. a VoiceXML implementation),
a conference server used to mix media streams,
and the CCXML implementation which manages the Connections between the first two components.
The Telephony Web Application may or may not be integrated with the Voice Web Application.
The Telephony Control and Dialog Control Interfaces may be implemented as an API or protocol.
The components as shown in the figure below represent logical functions, and are not meant to imply any particular
architecture.
Figure 1
2: Motivation (Informative)
CCXML is designed to complement dialog systems such as VoiceXML by providing advanced telephony functions. It also can be
used as a third-party call control manager in any telephony system. This document contains references to VoiceXML's
capabilities and limitations, as well as details on how VoiceXML and CCXML can be integrated.
The CCXML specification originated from the desire to handle call control requirements that were beyond the scope of the
VoiceXML specification. The following requirements are addressed by this specification:
Support for multi-party conferencing, with advanced conference and audio control. A conferencing application involves
multiple participants, and is dependent upon call control to establish relationships between those participants.
The ability to give each active call leg its own dedicated VoiceXML interpreter. For example, in VoiceXML, the second leg
of a transferred call lacks a VoiceXML interpreter of its own, limiting the scope of possible applications.
Sophisticated multiple-call handling and control, including the ability to place outgoing calls.
Handling for a richer class of asynchronous events. Advanced telephony operations involve substantial amounts of signals,
status events, and message-passing. VoiceXML 2.0 does not integrate asynchronous "external" events into its event-processing
model.
VoiceXML lacks the external interfaces required to interact with an outside call queue, or place calls on behalf of an
external document server
CCXML and VoiceXML implementations are not mutually dependent. A CCXML implementation may or may not support voice dialogs,
or may support dialog languages other than VoiceXML.
3: Concepts and Architecture
A CCXML application consists of a collection of CCXML documents that
control and manage the objects listed below:
CCXML Session: A CCXML session is comprised of an executing
CCXML document, or sequence of CCXML documents; each concurrently executing CCXML document is a separate session, and can be
uniquely identified and referenced.
Connection: Connections can be "call legs" (real-world
phone connections) or system resources to facilitate interaction with a voice dialog.
Media streams between Connections, or between Connections and Conference objects, need to be tracked by the CCXML interpreter and will take real system resources, but do not need a dedicated
identifier because they are identified by their endpoints. Ownership of Connections can be moved from one session to another using <move>.
Conference object: A Conference Object models a resource
for mixing media streams. In order to accommodate the widest range of underlying telephony call control definitions, CCXML
assumes a separate Conference Object, realizing that this abstraction may not have
a direct counterpart in all telephony platforms. See <createconference> and
<destroyconference> for further information.
Dialog: When active, a Dialog may interact with other Connections or Conferences using one-way or two-way
media streams, often under the control of dialog environment such as VoiceXML.
CCXML programs manipulate these entities through elements defined in the CCXML language. They can also send and/or receive
asynchronous events associated with these entities.
CCXML programs directly manipulate Connection Objects and Conference Objects with various elements in the language, such as
<accept>, <createconference>, and <join>. CCXML may also receive
events from Connection and Conference
Objects, in the case of line signaling, line-status informational messages, or error and failure scenarios.
CCXML programs can start and kill Voice Dialogs using language elements. It can
receive events from Voice Dialogs, which may be standardized events such as
dialog.exit, or application-specific ones. CCXML can support sending of an event to a Voice Dialog.
CCXML programs can create other CCXML sessions using
<createccxml>. This is the only guaranteed control mechanism a CCXML
Session ever wields over another. Any other interaction takes place through the event mechanism. CCXML Sessions can both send and receive events between one another.
3.1: Event Processing
Telephone applications need to receive and process large numbers of events in real-time. These events arrive from outside
the program itself - either the underlying telephony platform, or from other sources of events.
A CCXML program includes event handlers which are executed when certain events arrive. There are mechanisms for passing
information back and forth between Voice Dialogs (such as VoiceXML) and CCXML, but the
important points are that CCXML:
lives on its own thread, and
carries the burden of rapid asynchronous event handling
Note: References to threads are meant as logical threads and do not imply any specific platform implementation.
3.2: Conferencing
CCXML provides a powerful and flexible method of creating multi-party calls based on the following concepts:
Call legs are audio sinks and sources which can be combined to form arbitrary networks.
A conference is an audio stream that mixes together all the speakers' audio outputs. CCXML conference networks allow for
conference objects, which mix inputs into a single output channel.
A conference's architecture may be modified dynamically, thus allowing for moderation, floor control, mute, etc.
Media splitters, which take a single input channel and emit it over several outputs, may be used by an implementation to
realize the CCXML model in a given network environment.
Conferencing technology is implementation-dependent. CCXML implementations may not support all conferencing features
mentioned above.
3.3: Scripting
The computational semantics of CCXML language is based on the ECMAScript Compact Profile (ES-CP, also known as ECMA-327)
[ECMA327]. ES-CP is a strict subset of the third edition of ECMA-262
[ECMASCRIPT]. Execution efficiency is a primary goal of CCXML
implementations, and ES-CP was chosen to ensure that CCXML implementations can operate in a variety of execution environments
and without excessive execution overhead.
The ES-CP document specification states:
'ECMAScript Compact Profile is a subset of ECMAScript 3rd Edition tailored to resource-constrained devices such as battery
powered embedded devices. Therefore, special attention is paid to constraining ECMAScript features that require
proportionately large amounts of system memory (both for storing and executing the ECMAScript language features) and
continuous or proportionately large amounts of processing power.'
While CCXML implementations are not necessarily intended for battery powered embedded devices, it is intended to be used in
large, real-time telephony platforms managing thousands of lines. The constraints of ES-CP emphasize CCXML's ongoing concern
for execution efficiency.
Even though ES-CP tends to be implemented using interpreters, CCXML does not require an interpretive implementation. ES-CP
can be compiled to a target language such as C, and thus in turn to machine code, so that CCXML documents which are static can
be rendered once in machine code. For example, a CCXML implementation, for optimization purposes, could translate and compile
frequently used CCXML documents on their way from the document server to the CCXML execution environment in order to avoid
multiplying interpretive overhead by the number of lines that execute the same document.
The emphasis on efficiency in CCXML language is also shown by the avoidance of requirements which can only be implemented
either by interpretation or by run-time evaluation.
The choice of an implementation strategy is up to the CCXML implementer and CCXML language is aimed to allow a range of
design choices in order to accommodate implementations on a wide variety of platforms.
A CCXML implementation MUST support the ECMAScript Compact Profile.
3.3.1: Implementation Note: Line by line vs Batch ECMAScript execution
CCXML implementations MAY provide different
levels of optimization in their ECMAScript interpreters and are expected to be deployed in performance critical environments. One such level of
optimization could be a decision to execute all the executable items
in a <transition> as if they were a single script instead of processing them
line by line as is the normal mode of execution. An example of this is the
following bit of CCXML Code:
<assign name="x" expr="3"/>
<var name="x"/>
In the case where the platform executes CCXML line by line the <assign> statement
will fail with an error.semantic event due to trying to assign to
an undefined variable. However on a platform where the actions are optimized into a single
ECMAScript execution block something like the following code would actually be executed instead:
x=3;
var x;
Due to how ECMAScript var statements work, declarations are applied before
assignments no matter where they are placed in the code. This script
is actually allowed and the assignment to x will be completed without error.
Due to this difference in behavior between line by line vs batch execution application developers
SHOULD NOT depend on the ability to declare variables out of document order
and SHOULD write code such that its behavior is the same whether executed line by line or in a batch.
A more complex situation can arise if you use the <var> element to declare
transition scoped variables by the same name as session or application
scoped variables inside of an <if> statement. An example of this would be:
If executed line by line this would end up executing every line in the script and declaring a transition scoped variable named id with a value of 2.
The <if> statement would evaluate to true due to auto scope searching when resolving the id reference into a session scoped variable
and the next line would assign a new transition scoped variable by the name id.
However, if the CCXML implementation were to optimize this into a single
ecmascript chunk you may get something like the following scriptlet:
if(id==session.id) {
var id = '2';
}
Due to the way ECMAScript treats var
declarations the initial ID will evaluate as undefined as ECMAScript adds
a implicit var declaration to the top of the script and changes the var
to an assignment leaving you with something that is executed as if it was written like this:
var id;
if(id==session.id) {
id = '2';
}
This causes a different flow of execution and could cause unexpected program behavior as id in the if statement
will now be undefined instead of being equal to session.id.
Application developers SHOULD consider this bad programing practice and avoid creating scenarios where
applications create and depend on ambiguously scoped variables that use assignments inside conditional blocks with variable names
that are already in use by parent scopes.
Based on years of implementation experience the CCXML working group believes that CCXML
application code that would be affected by these scenarios is very rare. Any such code
likely relies on unusual ordering of variable declarations and assignment statements or
the use of confusing variable names and scopes; such code is discouraged due to its potential
for producing unintended results.
3.4: Definitions
The following terms, which are used throughout this specification, are defined as:
ECMAScript left-hand-side expression - defined in ECMA-262 [ECMASCRIPT] 11.2; this is an expression which produces a result to which a value can be assigned; an
expression which is valid as the left hand operand of an assignment (=) operator;
Several examples of left-hand-side expressions are as follows (left-hand-side expression in red):
ECMAScript expression - defined in ECMA-262 [ECMASCRIPT] 11.1; this is an expression which produces a value; an expression which is valid on the right
hand side of an assignment operator;
Several examples of ECMAScript expressions are as follows (ECMAScript expression in red):
<?xml version="1.0" encoding="UTF-8"?>
<ccxml version="1.0" xmlns="http://www.w3.org/2002/09/ccxml">
<script>
var simpleVar;
var aaVar = Object();
simpleVar = 'hello world'; // simple string expression
simpleVar = 'hello world'.length; // Calling a method that returns a
// number on the simple string object
simpleVar = 5; // Simple number expression
simpleVar = aaVar[0]; // Associative Array position expression
simpleVar = aaVar['key']; // Associative Array named value expression
simpleVar = myCoolFunction(); // Function return expression
</script>
</ccxml>
ECMAScript variable name - defined in ECMA-262 [ECMASCRIPT] 7.6; this is any valid sequence of characters, known as an identifier, which can be used as a
variable name, a property name, or a function name; this does not include any qualifiers, such as array or property
accessors;
Several examples of ECMAScript variable names are as follows (ECMAScript variable name in red):
Empty ECMAScript object - an object returned by the new Object() ECMAScript expression; an
object with no properties.
CCXML variable name - a variable name, with optional dot separated qualification, declared in a CCXML
<var> element or defined within ECMAScript code using the var keyword.
Scope element - a CCXML element which defines a variable scope; <ccxml> and
<transition> are CCXML scope elements. Variables which are defined within a scope element are not visible
to variables defined in other scope elements.
Time interval - CCXML uses the Cascading Style Sheets, Level 2 [ CSS2 ] time format. Time designations consist of a non-negative real number followed by a time unit
identifier. The time unit identifiers are:
ms : milliseconds
s : seconds
Examples include: "3s", "850ms", "0.7s", ".5s" and "+1.5s".
CCXML Application/Program - A collection of CCXML documents that together
create a complete application/program.
CCXML Interpreter - The software that processes CCXML documents, executes
commands and dispatches events. Also referred to as the "CCXML Platform".
CCXML Platform - An implementation of CCXML for a specific network and
environment, generally including a CCXML Interpreter as a component.
CCXML Session - A single instance of a CCXML application. It can span multiple documents and phone
calls. See Section 3.5 Session Life-Cycle for details.
CCXML Parent Session - The CCXML session that created the currently running session using the
<createccxml> element.
Event - An action or occurrence to which an application can respond. Examples of events are incoming
phone calls, dialog actions or user defined events. Events in CCXML are modeled as ECMAScript objects and can contain complex
values. All events in CCXML have a standard set of properties as defined in section 9.4.2: Standard Event
Attributes.
Associative array - An associative array (also known as a map, lookup table, or dictionary) is an
abstract data type composed of a collection of keys and a collection of values, where each key is associated with one value.
Associative arrays in ECMAScript are implemented using an Object with sub properties.
Class - CCXML Classes are ECMAScript Constructor objects (see section 4.2.1 of the ECMAScript
specification for more information) to help in creating the appropriate type of object instances (such as connection,
conference and dialog). The Constructor object may contain properties that are not inherited by children objects (such as
Connection.states). The constructor object MAY also contain a Prototype property to allow properties
that are inherited. Platforms MAY choose to add properties to classes. By convention, the properties
MUST begin with an underscore, "_", to identify them as platform-dependent. All defined objects in
this specification must be initiated via one of these classes. An example would be 'MyConnection = new
Connection()'.
The Connection class MUST initiate connection objects, the Dialog class
MUST initiate dialog objects and the Conference class MUST initiate
conference objects.
3.5: Session Life-Cycle
3.5.1: Startup
A CCXML session can be started for the following reasons:
A new incoming phone call coming into the platform.
A CCXML application executing a <createccxml>.
An external session launch request coming into the platform.
To create a CCXML session, the URI for the initial CCXML document must be known, along with any fetching parameters
affecting how that CCXML document is retrieved. For incoming calls, the selection of the initial URI and fetching parameters is
platform-dependent, and MAY be based on information from the incoming call. Sessions created via
<createccxml> and the session creation event I/O processor determine the initial URI and fetching parameters
as stated in this specification.
When a session is started due to an incoming call it has ownership of the new Connection that caused it to be created. The
new CCXML session will be responsible for processing the Connection state events and performing the Connection actions. If the
session was started because of a <createccxml>, it will start without ownership of any event endpoints. In
the case of an external session launch the session will not own any event endpoints.
A CCXML application can determine the reason its session was started by evaluating the contents of the
session.startupmode session variable that is defined in the Session
Variables section.
3.5.2: Shutdown
A CCXML session can end in one of the following ways:
The CCXML application executes an <exit>.
An unhandled "error.*" event.
An unhandled "ccxml.kill" event.
A "ccxml.kill.unconditional" event.
When a CCXML session ends, all active connections, conferences and dialogs that are owned by that session are automatically
terminated by the platform.
3.5.3: Session Life-Cycle Diagrams
The following diagrams illustrate the session life-cycle of several different scenarios. These diagrams do not show all
possible scenarios but rather show some of the most common ones that CCXML applications may encounter.
3.5.3.1: session can live before and after active connections (or no connections at
all)
A CCXML session does not necessarily need to have any connections associated with it. After starting, a session may acquire
connections as a result of <createcall> or <move> requests.
3.5.3.2: connection life shorter than session
In this example, the session is started due to an incoming call. A connection is typically shorter than a session. A session
does not end when a connection terminates.
3.5.3.3: session ends, kills all active connections
When a session ends, any resources, including connections owned by that session are terminated.
3.5.3.4: session can have multiple sequential connections
A session can have multiple sequential connections
3.5.3.5: session can have multiple sequential connections and multiple concurrent
connections
In addition to having multiple sequential connections, a session can have multiple concurrent connections.
3.5.3.5: move a connection to a newly created session
A connection can be moved from one CCXML session to another session. In the figure below, CCXML session (1) creates a new
CCXML session (2) via <createccxml>. Then, the connection is moved from the original CCXML session to the
new session.
3.5.3.7: move a connection to a "master" session
A connection can be moved from one CCXML session to another session, such as a "master" session.
3.5.3.8: optional "master" session for inbound call handling
Implementations MAY, as a platform-specific optimization, choose to deliver more than one inbound
call to a single "master" session. This can be viewed as equivalent to sessions handling incoming calls performing a
<move>, as described in 3.5.3.7, of the new Connection (including the connection.alerting
event) to the single "master" CCXML session.
The default inbound call handling behavior for CCXML implementations is to create a new CCXML session and deliver the
connection.alerting event to it. If a platform supports delivery of multiple inbound calls to a single session,
the way this is configured is implementation specific.
3.5.3.9: ccxml.kill.unconditional event raised
If at anytime a ccxml.kill.unconditional event is raised by the underlying implementation, the CCXML session is
immediately terminated and all active connections, conferences and dialogs that are owned by that session are automatically
terminated by the platform.
3.5.3.10: Normal session shutdown requested by the platform
If at anytime the platform wishes to terminate a CCXML session it MUST raise a
ccxml.kill event to inform the CCXML application. The normal response to this event is for the CCXML application
to perform any clean up and termination of current active connections, conferences or dialogs and then execute an
<exit> element.
If the CCXML application does not respond to the ccml.kill event in a timely manner the platform MAY then raise a ccxml.kill.unconditional event to immediately terminate the CCXML session and all
active connections, conferences, and dialogs that are owned by the session.
4: Simple Examples
4.1: Hello World
This simple CCXML document shows an example of a "hello world" application that is started due to an incoming call where the
application simply assigns a value to a variable, prints a message to the platform log and exits:
<?xml version="1.0" encoding="UTF-8"?>
<ccxml version="1.0" xmlns="http://www.w3.org/2002/09/ccxml">
<eventprocessor>
<transition event="connection.alerting">
<var name="MyVariable" expr="'This is a CCXML Variable'"/>
<log expr="'Hello World. I just made a variable: ' + MyVariable"/>
<log expr="'Lets hang up on this incoming call.'"/>
<exit/>
</transition>
</eventprocessor>
</ccxml>
4.2: Accept or Reject a Call
This CCXML document shows an example of how to process a incoming call event and answer or reject the call based on the
phone number of the calling party:
<?xml version="1.0" encoding="UTF-8"?>
<ccxml version="1.0" xmlns="http://www.w3.org/2002/09/ccxml">
<eventprocessor>
<transition event="connection.alerting">
<log expr="'The number called is' + event$.connection.remote + '.'"/>
<if cond="event$.connection.remote == 'tel:+18315551234'">
<log expr="'Go away! we do not want to answer the phone.'"/>
<reject/>
<else/>
<log expr="'We like you! We are going to answer the call.'"/>
<accept/>
</if>
</transition>
<transition event="connection.connected">
<log expr="'Call was answered,Time to disconnect it.'"/>
<disconnect/>
</transition>
<transition event="connection.disconnected">
<log expr="'Call has been disconnected. Ending CCXML Session.'"/>
<exit/>
</transition>
</eventprocessor>
</ccxml>
4.3: Simple Dialog
This is an example of running a simple VoiceXML dialog from CCXML. The application answers an incoming phone call and then
connects it to a VoiceXML dialog that returns a value that is then logged to the platform:
dialog.ccxml:
<?xml version="1.0" encoding="UTF-8"?>
<ccxml version="1.0" xmlns="http://www.w3.org/2002/09/ccxml">
<!-- Lets declare our state var -->
<var name="state0" expr="'init'"/>
<eventprocessor statevariable="state0">
<!-- Process the incoming call -->
<transition state="init" event="connection.alerting">
<accept/>
</transition>
<!-- Call has been answered -->
<transition state="init" event="connection.connected">
<log expr="'Houston, we have liftoff.'"/>
<dialogstart src="'dialog.vxml'"/>
<assign name="state0" expr="'dialogActive'" />
</transition>
<!-- Process the incoming call -->
<transition state="dialogActive" event="dialog.exit">
<log expr="'Houston, the dialog returned [' + event$.values.input + ']'" />
<exit />
</transition>
<!-- Caller hung up. Lets just go on and end the session -->
<transition event="connection.disconnected">
<exit/>
</transition>
<!-- Something went wrong. Lets go on and log some info and end the call -->
<transition event="error.*" >
<log expr="'Houston, we have a problem: (' + event$.reason + ')'"/>
<exit/>
</transition>
</eventprocessor>
</ccxml>
A CCXML session begins with the execution of a CCXML document. The flow of the execution can be changed with the help of
<if>, <elseif>, <else>, <fetch>, and
<goto>. Most of a CCXML session's execution will take place within an <eventprocessor>,
which processes a stream of incoming events.
A CCXML session can consist of multiple CCXML documents, traversed by use of <goto> and
<fetch>.
A new CCXML session has a new session object (session.*). A CCXML session can contain multiple active
connections.
A CCXML session may launch a new CCXML session using <createccxml>. The new CCXML session executes in an
independent context and variable space from the original CCXML session, completely independent of the lifetime of the original
session. Sessions can communicate by sending messages via <send>.
This media type should be used for a XML document containing CCXML content, see Appendix M.
6.2: Elements
This section details the CCXML elements for control flow and execution.
6.2.1: <ccxml>
6.2.1.1: Overview
This is the parent element of a CCXML document and encloses the entire CCXML script in a document. When a
<ccxml> is executed, its child elements are collected logically together at the beginning of the document
and executed in document order before the target <eventprocessor>. This is called document
initialization.
The <ccxml> can designate the CCXML namespace. This can be achieved by declaring an xmlns
attribute or an attribute with an " xmlns " prefix. See [XMLNS] for details.
Note that when the xmlns attribute is used alone, it sets the default namespace for the element on which it
appears and for any child elements. The namespace URI for CCXML is "http://www.w3.org/2002/09/ccxml".
6.2.1.2: <ccxml> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
version
true
string
none
1.0
The version of this CCXML document. The initial version number must be 1.0.
xml:base
false
valid URI
none
A valid URI
The base URI for this document as defined in [XML-BASE]. As
in [HTML], a URI which all relative references within the document take as their base.
6.2.2: <meta>
6.2.2.1: Overview
The <metadata> and <meta> are containers in which information about the document can be placed. The
<metadata> provides more general and powerful
treatment of metadata information than <meta> by using a
metadata schema.
A <meta> declaration associates a string
to a declared meta property or declares " http-equiv " content. Either a name
or http-equiv attribute is REQUIRED. It is an error to provide both
name and http-equiv attributes. A content attribute
is REQUIRED. The http-equiv attribute has a special significance when
documents are retrieved via HTTP. Although the preferred method of
providing HTTP header information is by using HTTP header fields, the " http-equiv " content MAY be used in situations where the CCXML document author is unable to configure HTTP header fields associated with their document on the origin server, for example,
cache control information. Note that, as with <meta> in HTML documents [HTML], HTTP servers and caches are NOT REQUIRED to introspect the contents of <meta> in CCXML documents and thereby override the header values they would send otherwise.
Informative: This is an example of how <meta> can be
included in a CCXML document to specify a resource that provides additional metadata information and also indicate that the
document MUST NOT be cached.
This attribute must not be specified in conjunction with the http-equiv
attribute
NMTOKEN
none
The NAME of the metadata property.
http-equiv
false
This attribute must not be specified in conjunction with the name
attribute
NMTOKEN
none
A valid HTTP header
The NAME of an HTTP response header.
This attribute has special significance when documents are retrieved via HTTP. The http-equiv content may be
used in situations where the CCXML document author is unable to configure HTTP header fields associated with their document
on the origin server.
content
true
string
none
The value of the metadata property.
6.2.3: <metadata>
6.2.3.1: Overview
<metadata> is a container in
which information about the document can be placed using a metadata language. Although any metadata language can be used within
<metadata>, it is recommended that the Resource Description Format [RDF] be used in conjunction with the general metadata
properties defined by the Dublin Core Metadata Initiative [DC].
RDF [RDF-SYNTAX] is a declarative language and provides a standard way for using
XML to represent metadata in the form of statements about properties and relationships of items on the Web. A recommended set of generally applicable metadata properties (e.g., " title ", "
creator ", " subject ", " description ", " copyrights ", etc.) is the
Dublin Core Metadata Element Set [DC], used in the example below.
Document properties declared with <metadata> can
use any metadata schema.
Informative: This is an example of how <metadata>
can be included in a CCXML document using the Dublin Core version 1.0 RDF schema [DC]
describing general document information such as title, description, date, and so on:
The following CCXML elements can occur within the content of <metadata> : none .
6.2.3.2: <metadata> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
none
none
none
6.2.4: <if>
6.2.4.1: Overview
<if> is a container for conditionally executed elements. <else> and
<elseif> can optionally appear within an <if> as immediate children, and serve to
partition the elements within an <if>. <else> and <elseif> have no
content. <else/> is a synonym for <elseif cond="true"/>.
Each partition within an <if> is preceded by an element having a cond attribute. The initial
partition is preceded by the <if> and subsequent partitions by <elseif>s (or
<else>s). The first partition in document order with a cond that evaluates to true
is selected. <else> always evaluate to true. A partition MAY be
empty.
If an <if> has no immediate <elseif> or <else> children, the full
contents of the <if> will be selected when the cond attribute is true.
<else> was chosen to match similar concepts in other languages, and supports examples such as
<if cond="...">
<!-- selected when <if cond> is true -->
<else/>
<!-- selected when <if cond> is false -->
</if>
However, <else> is a synonym for <elseif cond="true"/>, so an example such as
<if cond="...">
<!-- selected when <if cond> is true -->
<else/>
<!-- selected when <if cond> is false -->
<else/>
<!-- never selected -->
</if>
is also possible and MUST be interpreted as
<if cond="...">
<!-- selected when <if cond> is true -->
<elseif cond="true"/>
<!-- selected when <if cond> is false -->
<elseif cond="true"/>
<!-- never selected -->
</if>
With this definition for <else>, CCXML provides familiar if/elseif/else semantics, but conforms to the
rules of valid XML [XML] documents.
6.2.4.2: <if> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
cond
true
ECMAScript Expression
none
A valid ECMAScript expression
An ECMAScript expression which can be evaluated to true or false.
6.2.5: <elseif>
6.2.5.1: Overview
An <elseif> partitions the content of an <if>, and provides a condition that
determines the selection of the partition it begins. <elseif> can appear optionally as an immediate child of
an <if>.
6.2.5.2: <elseif> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
cond
true
ECMAScript Expression
none
A valid ECMAScript expression
An ECMAScript expression which can be evaluated to true or false.
6.2.6: <else>
6.2.6.1: Overview
<else> is a synonym for <elseif cond="true"/>.
6.2.6.2: <else> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
none
none
else is a synonym for elseif cond="true".
6.2.7: <fetch>
6.2.7.1: Overview
<fetch> is used to asynchronously fetch content identified by the attributes of the
<fetch>. The fetched content may be a CCXML document, script content or other document types supported by
the CCXML platform. Content that has been acquired using <fetch> is accessible through other elements
defined by CCXML and via the content attribute of the fetch.done event. Execution returns from the element
immediately, and the CCXML application can continue on while the platform works to fetch the identified resource. When the
fetch request has been completed, an event is generated against the session that initiated the fetch. If the requested content
was fetched successfully, and in the case of CCXML content, was successfully parsed and validated, a fetch.doneMUST be generated. If the requested content failed to be fetched, an error.fetchMUST be generated. Note that even if content is successfully fetched, errors in processing fetched
content (for instance, a CCXML document with a syntax error) may result in an error.fetch being thrown.
The fetch request is local to the session that initiated the <fetch>, and is referenced through a unique
identifier generated by the CCXML platform. The application may obtain the unique identifier for a fetch request by providing
an ECMAScript left-hand-side expression in the fetchid attribute when the fetch is performed. The fetch identifier
can also be obtained as a property of the fetch.done event. The application uses the fetch identifier in any CCXML
elements that reference fetched content, currently <goto> and <script>.
Fetched content that could be referenced via a fetchid (eg, a CCXML or ECMAScript Document) that was fetched in
processed mode has a lifetime that is limited to that of the document in which it is fetched. Therefore, following
a transition to a new CCXML document using <goto>, content fetched in the scope of the current document is
no longer accessible. Note that this should not be taken to preclude platform-level optimizations or caching of resources that
are fetched multiple times.
All other content is only accessible via the content attribute of the fetch.done event. If the application
needs access to the content outside of the fetch.done event transition it is the responsibility of the application
to save a reference in an appropriately scoped variable.
Content referenced via fetchid (for example via <script> or <goto>)
MUST be fetched using processed mode.
The use of <fetch> to obtain content does not compel the application to make use of that content.
However, it is wasteful of system resources to fetch resources that are not used. Platforms are responsible for clearing out
unused fetch resources, and may impose limits on the resources that can be fetched by a single session.
The "http" URI scheme MUST be supported by CCXML platforms, the "https" protocol should be supported and other URI protocols may be supported.
If the platform does not support the content type returned from a <fetch> request but the fetch does
successfully complete (for example HTTP 2xx response code) the platform MUST still throw a
fetch.done event for the fetchid.
If the platform implements a security model (such as Access Control for Cross-site Requests [ACCESS-CONTROL]) and the request is denied due to the security model an error.notallowed event
MUST be thrown.
INFORMATIVE NOTE: It is expected in future versions of CCXML additional forms of processed fetch modes will be added.
Examples of these could be dom or e4x mappings of raw XML content.
6.2.7.2: <fetch> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
next
true
ECMAScript Expression
none
must evaluate to a valid URI
An ECMAScript expression which returns the URI of the resource to be fetched.
type
false
ECMAScript Expression
In processed mode "application/ccxml+xml". In raw mode "*/*".
MIME Types formatted as per HTTP Accept header [RFC2616]
An ECMAScript expression which returns a character string setting the value of the HTTP
Accept header to tell the application server what content type the application wishes to have returned.
namelist
false
Var List
none
List of ECMAScript Variable names
A list of zero or more whitespace separated CCXML variable names. These variables must be
submitted to the web server, with the same qualification as used in the namelist. When an ECMAScript variable is submitted
to the web server, its value must be first converted into a string before being submitted.
If the variable is an ECMAScript Object, the mechanism by which it must be submitted is not currently defined. Instead of
submitting ECMAScript Objects directly, the application developer may explicitly submit the properties of an Object. e.g.
"date.month date.year".
method
false
ECMAScript Expression
get
get
post
An ECMAScript expression which returns a character string that indicates the HTTP method to use. Values defined by the
specification are:
get
This indicates that the "GET" method must be used to fetch the URI
post
This indicates that the "POST" method must be used while submitting the URI to the web server.
fetchid
false
ECMAScript Left Hand Side Expression
none
ECMAScript Variable
An ECMAScript left hand side expression evaluating to a previously defined variable. The
value of the attribute must receive an internally generated unique string identifier to be associated with the completion
event. This identifier can be tested by the fetch completion event handler to distinguish among several outstanding fetch
requests.
If this attribute is not specified, the fetch identifier can be acquired from the fetch completion event. Every fetch
request must receive a unique fetch identifier, even if the request is for the same URI
timeout
false
ECMAScript Expression
none
An ECMAScript expression which returns a character string in CSS2 [CSS2] format
The character string returned must be interpreted as a time interval. This interval
begins when the fetch is executed. The fetch must fail if not completed at the end of this interval. A failed fetch must
return the error.fetch event.
maxage
false
ECMAScript Expression
none
An ECMAScript expression which returns a valid time value for the HTTP 1.1 request
[RFC2616]
The character string returned must be interpreted as a time interval. This indicates that
the document is willing to use content whose age must be no greater than the specified time in seconds (cf. 'max-age' in
HTTP 1.1 [RFC2616]). The document is not willing to use stale content, unless maxstale is also
provided.
maxstale
false
ECMAScript Expression
none
An ECMAScript expression which returns a valid time value for the HTTP 1.1 request
[RFC2616]
The character string returned must be interpreted as a time interval. This indicates that
the document is willing to use content that has exceeded its expiration time (cf. 'max-age' in HTTP 1.1 [RFC2616]). If maxstale is assigned a value, then the document is willing to accept content that has
exceeded its expiration time by no more than the specified number of seconds.
enctype
false
Valid only when the value of the method is "post", otherwise ignored.
ECMAScript Expression
application/x-www-form-urlencoded
valid media encoding type
An ECMAScript expression which returns a character string that indicates the media encoding type of the submitted
document (when the value of the method is "post"). Values defined by the specification are:
application/x-www-form-urlencoded
This indicates that the ccxml variables specified in the namelist must be url encoded.
mode
false
ECMAScript Expression
processed
processed, raw
Controls what the CCXML platform should do with fetched content. If set to
processed (the default) the CCXML platform MUST attempt to parse and validate the
returned content. If set to raw the platform MUST NOT attempt to process the data and
MUST leave processing of the content to the application who can do what it wishes with the content
via the content attribute of the fetch.done event
6.2.8: <goto>
6.2.8.1: Overview
<fetch>, in conjunction with <goto>, is used to transfer execution to a different
CCXML document in a multi-document CCXML application. The <fetch> tells the platform to find, load, and
parse a given CCXML document. After the fetch completes, the CCXML application can then issue a <goto> to
execute the now-fetched document.
Below is a small snippet of code from the CCXML application's event handler. We execute a <fetch>
operation, and continue on to assign to a state variable, and maybe handle more events. Eventually, the fetch completes, the
CCXML platform services the event, and the application performs the <goto>.
A <goto> transfers control to the document obtained through a fetch request, using the platform-generated
unique identifier associated with that fetch request. The fetch completion event MUST have arrived
before the <goto> is executed, otherwise, an error.semantic event is generated. If the fetched
content referenced by the fetch identifier is not a CCXML document, or the fetch identifier is invalid and does not correspond
to any fetch request, this also results in an error.semantic event.
When a <goto> is executed, the target document replaces the current document in its session. Event
sources associated with this session are inherited by the target document. Execution of the current document terminates.
6.2.8.2: <goto> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
fetchid
true
ECMAScript Expression
none
A valid fetch id
An ECMAScript expression which returns the fetch identifier of a completed fetch request
acquired either in a fetch with the fetchid attribute, or from the fetchid attribute of a fetch.done event.
If the attribute value is invalid, an error.semantic event must be thrown.
6.2.8.3: <fetch> and <goto> Example
The following code shows the use of the <fetch> and <goto> elements along with the
fetchid attribute to handle more complex fetching situations:
<?xml version="1.0" encoding="UTF-8"?>
<ccxml version="1.0" xmlns="http://www.w3.org/2002/09/ccxml">
<!-- var to hold the value of the fetch
identifier that we care about -->
<var name="myGoodFetchID"/>
<eventprocessor>
<transition event="ccxml.loaded">
<!-- stick the value of the fetch
identifier in the myGoodFetchID var -->
<fetch fetchid="myGoodFetchID"
next="'http://www.example.com/goodfetch.ccxml'"/>
<!-- do not bother saving the fetch id's for these,
we would just ignore them anyway -->
<fetch next="'http://www.example.com/fakefetch1.ccxml'"/>
<fetch next="'http://www.example.com/fakefetch2.ccxml'"/>
</transition>
<transition event="fetch.done">
<if cond="myGoodFetchID == event$.fetchid">
<!-- only matched if we have fetched
http://www.example.com/goodfetch.ccxml -->
<goto fetchid="event$.fetchid"/>
</if>
</transition>
<transition event="error.fetch">
<!-- Ignore bad fetches in this example -->
</transition>
</eventprocessor>
</ccxml>
6.2.9: <createccxml>
6.2.9.1: Overview
<createccxml> is used to create another CCXML session, which begins execution with the document
identified by this element. The new CCXML session has no relation to its creator once spawned, and has a wholly separate
lifetime and address space.
Execution returns from the <createccxml> element immediately, and the CCXML interpreter can continue on
while the new CCXML session is established and loads its initial document. If the new session is successfully established or a
failure occurs an event is generated and is delivered to the session that executed the <createccxml>
element.
6.2.9.2 <createccxml> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
next
true
ECMAScript Expression
none
a valid URI
An ECMAScript expression which returns the URI of the resource to be fetched.
namelist
false
Var List
none
List of ECMAScript Variable names
A list of zero or more whitespace separated CCXML variable names. These variables must be
submitted to the web server, with the same qualification as used in the namelist. When an ECMAScript variable is submitted
to the web server, its value must be first converted into a string before being submitted.
If the variable is an ECMAScript Object, the mechanism by which it must be submitted is not currently defined. Instead of
submitting ECMAScript Objects directly, the application developer may explicitly submit the properties of an Object. e.g.
"date.month date.year".
fetchparam
false
ECMAScript expression
'none'
'none', 'session-id', 'session'
Specifies parameters, in addition to those specified via 'namelist' (if present), that will be passed to the web server
when fetching the CCXML document for the new session. Three values are legal for this attribute:
none - No additional parameters should be passed with the fetch;
session-id - The 'session.id' property of the newly created session will be included when fetching the
initial document;
session - The 'session.id' property and all properties of 'session.values' will be included when
fetching the initial document. The evaluation of 'session.values' will occur after it has been populated as per the
'parameter' attribute above, providing developers with a simple means of passing data both to the new CCXML session and
to the web server.
parameters
false
Var List
none
List of ECMAScript Variable names
A list of zero or more whitespace separated CCXML variable names. Each named variable
will be created as a property of 'session.values' in the newly created session. For instance, passing a variable named
'foo' with value '123' will result in the 'session.values.foo' property evaluating to '123'; similarly, passing a variable
named 'foo.bar' would result in a 'session.values.foo.bar' property. Variable values are passed in string form; the passing
of ECMAScript objects is not currently defined.
method
false
ECMAScript Expression
get
get
post
An ECMAScript expression which returns a character string that indicates the HTTP method to use. Values defined by the
specification are:
get
This indicates that the "GET" method must be used to fetch the URI
post
This indicates that the "POST" method must be used while submitting the URI to the web server.
sessionid
false
ECMAScript Left Hand Side Expression
none
ECMAScript Variable
An ECMAScript left hand side expression evaluating to a previously defined variable. The
value of the attribute must receive an internally generated unique string identifier which identifies the newly created
session.
timeout
false
ECMAScript Expression
none
An ECMAScript expression which returns a character string in CSS2 [CSS2] format
The character string returned must be interpreted as a time interval. This time interval
must be interpreted by the new CCXML session as the maximum time it may wait for the completion of the fetch for the
initial document specified by the next attribute. If the new CCXML session is unable to fetch the initial document
within the timeout interval, an error.createccxml event must be thrown.
maxage
false
ECMAScript Expression
none
An ECMAScript expression which returns a valid time value for the HTTP 1.1 request
[RFC2616]
The character string returned must be interpreted as a time interval. This indicates that
the document is willing to use content whose age must be no greater than the specified time in seconds (cf. 'max-age' in
HTTP 1.1 [RFC2616]). The document is not willing to use stale content, unless maxstale is also
provided.
maxstale
false
ECMAScript Expression
none
An ECMAScript expression which returns a valid time value for the HTTP 1.1 request
[RFC2616]
The character string returned must be interpreted as a time interval. This indicates that
the document is willing to use content that has exceeded its expiration time (cf. 'max-age' in HTTP 1.1 [RFC2616]). If maxstale is assigned a value, then the document is willing to accept content that has
exceeded its expiration time by no more than the specified number of seconds.
enctype
false
Valid only when the value of the method is "post", otherwise ignored.
ECMAScript Expression
application/x-www-form-urlencoded
valid media encoding type
An ECMAScript expression which returns a character string that indicates the media encoding type of the submitted
document (when the value of the method is "post"). Values defined by the specification are:
application/x-www-form-urlencoded
This indicates that the ccxml variables specified in the namelist must be url encoded.
6.2.10: <exit>
6.2.10.1: Overview
<exit> ends execution of the CCXML session. All pending events are discarded, and there is no way to
restart CCXML execution.
6.2.10.2 <exit> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
expr
false
ECMAScript Expression
undefined
A return ECMAScript expression (e.g. 0 or 'oops!'). If this attribute is omitted, the
return value must be ECMAScript undefined. This value must be stored as a property of the exit event.
namelist
false
Var List
none
List of ECMAScript Variable names
A list of zero or more whitespace separated CCXML unqualified variable names to be
returned. These variable names and their associated values must be set as properties of the exit event.
A CCXML document executing the <exit> will generate a ccxml.exit event to the parent
session. The exiting document will be identified on the exit event by its session ID.
6.2.11: <log>
6.2.11.1: Overview
<log> allows an application to generate a logging or debug message which a developer can use to help in
application development or post-execution analysis of application performance. The manner in which the message is displayed or
logged is platform-dependent. The usage of label is platform-dependent. The use of <log>SHOULD have no other side-effects on interpretation. <log> is an empty element.
6.2.11.2 <log> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
label
false
ECMAScript Expression
none
An ECMAScript expression which returns a character string which must be used, for
example, to indicate the purpose of the log.
expr
true
ECMAScript Expression
none
An ECMAScript expression evaluating to a string to be logged.
6.3: Events
6.3.1: Overview
CCXML allows operations such as document fetching, startup and shutdown to execute independently. CCXML events that describe
these operations are defined below:
6.3.2: fetch.done - Fetch Completion Event
This event is generated when a fetch request completes successfully. It is delivered to the document which issued the
request.
The fields of this event are:
Attribute Name
Required
Type
Details
fetchid
true
string
The internally generated unique fetch identifier
uri
true
string
The URI of the resource that was fetched. If the fetch resulted in one or more HTTP redirects
(e.g. 302), the value of this property is set to the final target URI.
statuscode
true
int
The numeric HTTP status code (eg 200, 202 etc) of the HTTP request.
content
true
string
An ECMAScript representation of the fetched content. If the CCXML browser can not represent the
content in ECMAScript (for example some content that was fetched in processed mode) this may be ECMAScript undefined. In
raw mode it is expected that this attribute will contain a string representation of the fetched content.
contenttype
true
string
The returned content type from the web server.
6.3.3: error.fetch - Fetch Error Event
This event is generated when a fetch request does not successfully complete. It is delivered to the document which issued
the request.
The fields of this event are:
Attribute Name
Required
Type
Details
fetchid
true
string
The internally generated unique fetch identifier
reason
true
string
A string description of the fetch error. Content of this field is platform-specific.
statuscode
true
int
The numeric HTTP status code (eg 404,500 etc) of the failed HTTP request.
uri
true
string
The URI of the resource that was fetched. If the fetch resulted in one or more HTTP redirects
(e.g. 302), the value of this property is set to the final target URI.
content
true
string
An ECMAScript representation of the fetched content. If the CCXML browser can not represent the
content in ECMAScript (for example some content that was fetched in processed mode) this may be ECMAScript undefined. In
raw mode it is expected that this attribute will contain a string representation of the fetched content.
contenttype
true
string
The returned content type from the web server.
6.3.4: ccxml.exit - CCXML Document Exit Event
This event is generated when a CCXML session is terminated for any reason, if the terminated session has a parent session.
This event is sent to the parent session and not the session that was terminated.
The fields of this event are:
Attribute Name
Required
Type
Details
sessionid
true
string
The identifier of the exiting session. This must be the same value that was returned to the
sessionid attribute of the createccxml which created this session.
expr
true
string
The value of the exitexpr attribute. If this attribute is omitted in the
exit, the value must be ECMAScript undefined.
values.*
false
ECMAScript Object
Return values from the ccxml session. This would be the values of each of the objects listed in
the CCXML exit element's namelist.
reason
true
string
Reason that the session ended. Possible values are:
"exit" - Session ended due to a <exit> element
"error" - Session ended due to an unhandled error event
"kill" - Session ended due to ccxml.kill* event
6.3.5: ccxml.loaded - CCXML Document Loaded Event
This event is thrown once the document is parsed and ready for execution (document initialization occurs between the fetched
and loaded events). The CCXML platform MUST generate this event when the CCXML document is first
loaded, both at session startup and after transferring control to a new document with the <goto>. This event
would be processed after the platform had executed the document initialization including executing any elements under the
<ccxml> and before events such as connection.alerting which may have triggered creation of the session.
The fields of this event are:
Attribute Name
Required
Type
Details
sessionid
true
string
The identifier of the session on which this document is executing.
parent
true
string
The identifier of the session which issued the createccxml to start this document. If
this document was started directly by the CCXML platform the value is ECMAScript undefined.
6.3.6: ccxml.kill - CCXML kill Event
The kill event can be used by the platform to terminate a session without an explicit
<exit>. There are two versions of this event: catchable, and non-catchable.
The ccxml.kill event can be caught, typically to perform a clean-up operation at the end of a session. If the
event is caught the session will not be terminated unless an <exit> element is processed. If the event is
not caught the session will be terminated and all active connections, conferences and dialogs that are owned by that session
will be automatically terminated by the platform.
Unlike other events, the ccxml.kill.unconditional event is the only event that cannot be caught by an
application; it will unconditionally terminate the session and all active connections, conferences and dialogs that are owned
by that session will be automatically terminated by the platform.
Note that while the normal cause of a ccxml.kill or ccxml.kill.unconditional event being queued to
a session is that the platform wishes to terminate the session, it is legal for any event I/O processor to generate a
ccxml.kill or ccxml.kill.unconditional event. For instance, it is legal for one CCXML session to
unconditionally kill another session by sending a ccxml.kill.unconditional event using <send>.
Note, however, that platforms may impose rules that prevent one session from arbitrarily killing another (to prevent malicious
applications, for instance).
The fields of this event are:
Attribute Name
Required
Type
Details
sessionid
false
string
The identifier of the session who has sent the event.
reason
true
string
A string describing the reason the platform sent the kill event. Content of this field is
platform-specific, and is only for informative purposes.
This event is generated when a <createccxml> request completes successfully. It is delivered to the
document which issued the request and indicates that the new session has retrieved the specified initial CCXML document, parsed
and has begun execution of it by sending the ccxml.loaded event to the new session.
The fields of this event are:
Attribute Name
Required
Type
Details
sessionid
true
string
The identifier of the newly created CCXML session. This must be the same identifier as was
returned on the sessionid attribute of the createccxml request that created the session.
This event is generated when a <createccxml> request fails to complete. It is delivered to the document
which issued the request and indicates that the new session has not been created.
The fields of this event are:
Attribute Name
Required
Type
Details
sessionid
true
string
The identifier of the failing CCXML session. This is the same identifier as was returned on the
sessionid attribute of the createccxml request that created the session.
reason
true
string
A string description of the error encountered. Content of this field is platform-specific.
This event is generated when an operation that is not supported by the platform is executed.
The fields of this event are:
Attribute Name
Required
Type
Details
reason
true
string
A string description of the error encountered. Content of this field is platform-specific.
7: Dialogs
7.1: Overview
CCXML does not provide any mechanism for interacting with callers but relies on separate dialog environments such as
VoiceXML [VOICEXML]. Whenever interaction with a caller is required, a
CCXML session can create a separate dialog to perform that interaction. After the dialog interaction is complete, an
asynchronous event is sent to the CCXML session which can use any results returned by the dialog environment to decide what
should happen next.
Dialogs initiated by CCXML sessions are not tied to any single dialog language or technology. Any dialog system which
fulfils CCXML's requirements MAY be used for interaction with the caller. Examples of dialog systems
include VoiceXML, SALT, traditional IVR, 3GPP MRF as well as simple media
handling systems for fax, media playback and recording, DTMF detection, answer-machine detectors, etc. A CCXML platform
MAY support interaction with several dialog systems with the selection of the particular technology
being based on the MIME type specified when the dialog is initiated.
All CCXML elements that manipulate dialogs are asynchronous with control returning immediately to the CCXML session after
the operation is initiated. The CCXML session is notified when the dialog operation successfully completes, or fails, by an
asynchronous event. Execution of a <dialogprepare> or <dialogstart> without preparation
creates a Dialog Object immediately, allowing the Dialog Object to be accessed following the
<dialogprepare>/<dialogstart>, within the same transition. However, existence of the Dialog Object
does not guarantee anything about the success of the <dialogprepare>/<dialogstart> request.
A CCXML program initiates a dialog using the <dialogstart> element. Execution of this element connects a
dialog environment to a connection and instructs it to start interacting with the caller. For some dialog environments it may
take some time to initialize the dialog environment and thus the use of the <dialogstart> element alone may
cause the caller to hear silence, or "dead air". To avoid this situation CCXML provides an ability to ready a dialog
environment prior to connecting and starting it, this is done using the <dialogprepare> element. Any dialog
that has been either started with <dialogstart>, or prepared with <dialogprepare> can be
terminated using the <dialogterminate> element. CCXML implementations MUST support
the <dialogprepare>, <dialogstart>, and <dialogterminate> elements
though the exact behavior may vary depending on the dialog environments supported.
The following examples illustrate the valid use patterns for these three elements. Firstly the normal case of preparing a
dialog, starting it, then optionally terminating it before normal completion. This example illustrates the use of
<dialogprepare> to ready a dialog while the call is left in alerting state. When the alerting notification
arrives the script executes a <dialogprepare> to prepare a dialog and associate it with the connection. When
the dialog is prepared the script executes an <accept> to connect the call and then when the connection
transitions to connected state, a <dialogstart> element is used to execute the previously prepared
dialog.
The next example shows a single step dialog invocation without dialog preparation. In this case a connection in alerting
state is accepted and, when the transition to connected state occurs, a <dialogstart> element is used to
start the dialog.
The final example shows the case where a dialog which has been previously prepared is cancelled before a
<dialogstart> has been issued. A dialog may be terminated when it is in the prepared state or while it is
being prepared such as might be the case if the caller hangs up at some arbitrary point. In this case the
<dialogterminate> may be executed before or after the dialog.prepared event is processed.
It is possible for Dialogs to exist that are not joined to a Connection or a Conference. For example, this could be due to a
Connection disconnecting, or due to the application performing an <unjoin/> operation.
7.2: Elements
7.2.1: <dialogprepare>
7.2.1.1: Overview
<dialogprepare> is used to get an appropriate dialog handler ready to process, it is used as the
precursor to a <dialogstart> request. The element includes a URI reference to the initial document for the
dialog. The new dialog is prepared on a separate logical execution thread (this may be a thread, process, or system depending
upon platform implementation) and does not block the processing of further events by the CCXML session. The use of the
<dialogprepare> element is entirely optional, applications may choose to simply use
<dialogstart> without prior preparation.
Optionally the new dialog may be associated with a connection by specifying the connectionid attribute, or with
a conference by specifying the conferenceid attribute.
When preparation of the dialog completes successfully a dialog.prepared event MUST be
posted to the event queue of the CCXML session. If however the dialog cannot be prepared for any reason, an
error.dialog.notprepared event MUST be posted. However should the dialog be terminated
using <dialogterminate> while it is being prepared the platform MUST only post a
dialog.exit event.
CCXML implementations MUST support dialog preparation though the processing carried out as part of
a <dialogprepare> request is dialog manager specific. In the case of a dialog manager that does not support
preparation, the CCXML implementation MUST as a minimum, note the values provided in the
<dialogprepare> attributes, create a Dialog object, and return a new unique value to the location defined by
the dialogid attribute and throw a dialog.prepared event.
The CCXML session selects what it believes to be the appropriate dialog manager based on the MIME type specified by the
type attribute without retrieving the resource specified by the src URI. If, when the dialog manager
retrieves the content, it finds the MIME type, as specified by the HTTP
headers, differs from that specifed by the type attribute, it MUST raise an
error.dialog.notprepared event with a reason indicating the type mismatch. The dialog manager
MUST NOT ignore the type mismatch or render the resource as a different type based on the
HTTP headers or on inspection of the document data. Refer to the W3C
guidelines for client handling of MIME types [MIME-TAG] for further
information.
7.2.1.2: <dialogprepare> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
src
true
ECMAScript Expression
none
a Dialog URI
An ECMAScript expression which returns a character string identifying the URI of the
dialog document that the dialog interpreter must prepare.
type
false
ECMAScript Expression
application/voicexml+xml
a Valid MIME Type
An ECMAScript expression which returns a character string that specifies the MIME type of the document, and as a result
determines which dialog manager environment must actually be used. Values defined by the specification are:
application/voicexml+xml
This MIME type would request a VoiceXML interpreter instance.
audio/x-wav
This MIME type would request a dialog manager that merely plays wave files.
namelist
false
Var List
none
List of ECMAScript Variable names
A list of zero or more whitespace separated CCXML variable names. These variables must be
submitted to the web server, with the same qualification as used in the namelist. When an ECMAScript variable is submitted
to the web server, its value must be first converted into a string before being submitted.
If the variable is an ECMAScript Object, the mechanism by which it is submitted is not currently defined. Instead of
submitting ECMAScript Objects directly, the application developer may explicitly submit the properties of an Object. e.g.
"date.month date.year".
parameters
false
Var List
none
List of ECMAScript Variable names
A list of one or more whitespace separated CCXML variable names. These variables are sent
to the dialog environment as a list of name/value pairs. Names are sent exactly as they are specified; values are formed by
converting the referenced ECMAScript variable to string form (which is undefined for objects). The dialog environment
determines how passed parameters will be handled
dialogid
false
ECMAScript Left Hand Side Expression
none
ECMAScript Variable
An ECMAScript left hand side expression evaluating to a previously defined variable. The
value of the attribute must receive a dialog identifier value for the launched dialog interpreter instance. If the
attribute value is invalid, an error.semantic event MUST be thrown
connectionid
false
Must not be used with conferenceid
ECMAScript Expression
none
Connection IDs
An Optional ECMAScript expression which returns the identifier of a connection. If
specified, the dialog being prepared MUST be joined to the referenced connection as specified by
the mediadirection attribute. Note that if the referenced connection is already bridged to another media
endpoint, those existing bridges may be affected according to the rules specified in section 10.4 even prior to
<dialogstart> being performed If the attribute value is invalid an error.semantic event
must be thrown.
conferenceid
false
Must not be used with connectionid
ECMAScript Expression
none
Conference IDs
An Optional ECMAScript expression which returns the identifier of a conference bridge. If
specified, the dialog being prepared MUST be joined to the referenced conference as specified by
the mediadirection attribute. If the attribute value is invalid an error.semantic event
must be thrown.
mediadirection
false
ECMAScript Expression
both
both dialogtransmit dialogreceive
An ECMAScript expression that defines the direction of the media flow between the Dialog and the Connection or
Conference. The following values must be used:
both
Specifies a full duplex connection where the media flows in both directions.
dialogtransmit
The dialog transmits media to the Connection or Conference but does not receive any media streams.
dialogreceive
The dialog receives media from the Connection or Conference but does not transmit any media streams.
The bridge does not take place until a subsequent <dialogstart> is executed, but this attribute
may be provided as guidance to the dialog environment for preparation. If no value is specified, the dialog environment
must make no assumptions as to the bridging type. For more information about connections and bridges, refer to Section 10 .
maxage
false
ECMAScript Expression
none
A valid time value for the HTTP 1.1 request [RFC2616]
The character string returned must be interpreted as a time interval. This indicates that
the document is willing to use content whose age is no greater than the specified time in seconds (cf. 'max-age' in HTTP
1.1 [RFC2616]). The document is not willing to use stale content, unless maxstale is also
provided.
maxstale
false
ECMAScript Expression
none
A valid time value for the HTTP 1.1 request [RFC2616]
The character string returned must be interpreted as a time interval. This indicates that
the document is willing to use content that has exceeded its expiration time (cf. 'max-stale' in HTTP 1.1 [RFC2616]). If maxstale is assigned a value, then the document is willing to accept content that has
exceeded its expiration time by no more than the specified number of seconds.
enctype
false
Valid only when the value of the method is "post", otherwise ignored.
ECMAScript Expression
application/x-www-form-urlencoded
valid media encoding type
An ECMAScript expression which returns a character string that indicates the media encoding type of the submitted
document (when the value of the method is "post"). Values defined by the specification are:
application/x-www-form-urlencoded
This indicates that the ccxml variables specified in the namelist must be url encoded.
method
false
ECMAScript Expression
get
get post
An ECMAScript expression which returns a character string that indicates the HTTP method to use. Values defined by the
specification are:
get
This indicates that the "GET" method must be used by the dialog manager.
post
This indicates that the "POST" method must be used by the dialog manager.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform for implementing the dialog operation. Note: The meaning of these hints is specific to the
implementing platform and protocol. Platforms that do not support hints MAY ignore this attribute.
See Section 9.5.6 for additional requirements when hints are supported by the implementing
platform.
7.2.2: <dialogstart>
7.2.2.1: Overview
<dialogstart> is used to start a dialog and associate the dialog with a connection or conference. (See
Section 10 for a discussion of connections and bridges). The element MUST include either a URI reference to the initial document for the dialog or the identity of a previously
prepared dialog. The dialog executes on a separate logical execution thread (this may be a thread, process, or system depending
upon platform implementation) and does not block the processing of further events by the CCXML session.
If the dialog cannot be started for any reason, an error.dialog.notstarted event MUST
be posted to the event queue of the CCXML session that processed the <dialogstart> request, otherwise a
dialog.started event MUST be posted to indicate that the dialog has started successfully.
When the dialog completes, a dialog.exit event MUST be posted.
If the connectionid attribute of <dialogstart> is specified, and if the dialog language
allows access to telephony variables such as ANI, DNIS and UUI, values of these variables MUST be
propagated from the specified connection to the dialog application.
If the prepareddialogid attribute is specified and any attribute values conflict with the values specified in
the <dialogprepare> element this MUST result in the throwing of an
error.dialog.notstarted event.
Dialogs MAY only be started on connections while they are in the ALERTING or CONNECTED states. For
connections in the ALERTING state media MAY not be sent or received by the connection making the
bridge effectively full-duplex, half-duplex or silent depending on the underlying telephony environment and the restrictions
imposed by it.
It is not possible to start a dialog that is not joined to a connection or a conference. For dialogs prepared using
<dialogprepare> with neither connectionid nor conferenceid specified and dialogs
being started directly without preparation, if neither connectionid nor conferenceid are specified
then execution of the dialogstartMUST fail, with an error.dialog.notstarted
event generated.
The CCXML session selects the appropriate dialog manager based on the MIME type specified by the type attribute
without retrieving the resource specified by the src URI. If, when the dialog manager retrieves the content, it
finds the MIME type, as specified by the HTTP headers, differs from
that specifed by the type attribute, it MUST raise an
error.dialog.notstarted event with a reason indicating the type mismatch. The dialog manager
MUST NOT ignore the type mismatch or render the resource as a different type based on the
HTTP headers or on inspection of the document data. Refer to the W3C
guidelines for client handling of MIME types [MIME-TAG] for further
information.
7.2.2.2: <dialogstart> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
src
false
This attribute must not be specified in conjunction with the
prepareddialogid attribute.
ECMAScript Expression
none
a valid Dialog URI
An ECMAScript expression which returns a character string identifying the URI of the
dialog document that the dialog interpreter must load and begin execution upon startup.
prepareddialogid
false
This attribute must not be specified in conjunction with the src,
type, parameters, maxage, maxstale, enctype, method or namelist attributes.
ECMAScript Expression
none
a valid dialogid
An ECMAScript expression which returns a dialog identifier of a dialog previously
prepared by the execution of a <dialogprepare> element.
type
false
This attribute must not be specified in conjunction with the
prepareddialogid attribute.
ECMAScript Expression
application/voicexml+xml
a Valid MIME Type
An ECMAScript expression which returns a character string that specifies the MIME type of the document, and as a result
determines which dialog manager environment must actually be used. Values defined by the specification are:
application/voicexml+xml
This MIME type would request a VoiceXML interpreter instance.
audio/x-wav
This MIME type would request a dialog manager that merely plays wave files.
namelist
false
This attribute must not be specified in conjunction with the
prepareddialogid attribute.
Var List
none
List of ECMAScript Variable names
A list of zero or more whitespace separated CCXML variable names. These variables must be
submitted to the web server, with the same qualification as used in the namelist. When an ECMAScript variable
is submitted to the web server, its value must be first converted into a string before being submitted.
If the variable is an ECMAScript Object, the mechanism by which it is submitted is not currently defined. Instead of
submitting ECMAScript Objects directly, the application developer may explicitly submit the properties of an Object. e.g.
"date.month date.year".
parameters
false
This attribute must not be specified in conjunction with the
prepareddialogid attribute.
Var List
none
List of ECMAScript Variable names
A list of one or more whitespace separated CCXML variable names. These variables are sent
to the dialog environment as a list of name/value pairs. Names are sent exactly as they are specified; values are formed by
converting the referenced ECMAScript variable to string form (which is undefined for objects). The dialog environment
determines how passed parameters will be handled
dialogid
false
ECMAScript Left Hand Side Expression
none
ECMAScript Variable
An ECMAScript left hand side expression evaluating to a previously defined variable. The
value of the attribute must receive a dialog identifier value for the launched dialog interpreter instance. This identifier
may be used on future invocations of <dialogterminate>. If the attribute value is invalid, an
error.semantic event MUST be thrown
connectionid
false
Must not be used with conferenceid.
ECMAScript Expression
none
Connection IDs
An Optional ECMAScript expression which returns the identifier of a connection. If
specified, the dialog being started MUST be joined to the referenced connection as specified by the
mediadirection attribute.
If the dialog was previously prepared using a <dialogprepare> element with a connectionid
or conferenceid specified, and this attribute is also specified, execution of the
<dialogstart>MUST fail with an error.dialog.notstarted event.
Note that if the referenced connection is already bridged to another media endpoint, those existing bridges may be affected
according to the rules specified in section 10.4 even prior to <dialogstart> being performed If the
attribute value is invalid an error.semantic event must be thrown.
conferenceid
false
Must not be used with connectionid.
ECMAScript Expression
none
Conference IDs
An Optional ECMAScript expression which returns the identifier of a conference bridge. If
specified, the dialog being started MUST be joined to the referenced conference as specified by the
mediadirection attribute.
If the dialog was previously prepared using a <dialogprepare> element with a connectionid
or conferenceid specified, and this attribute is also specified, execution of the
<dialogstart>MUST fail with an error.dialog.notstarted event. If
the attribute value is invalid an error.semantic event must be thrown.
mediadirection
false
If used in conjunction with prepareddialogid, the bridge type must
match that used on the previous <dialogprepare> element.
ECMAScript Expression
both
both dialogtransmit dialogreceive
An ECMAScript expression that defines the direction of the media flow between the Dialog and the Connection or
Conference. The following values must be used:
both
Specifies a full duplex connection where the media flows in both directions.
dialogtransmit
The dialog transmits media to the Connection or Conference but does not receive any media streams.
dialogreceive
The dialog receives media from the Connection or Conference but does not transmit any media streams.
If both the mediadirection and the prepareddialogid are specified and the bridge type specified
by the mediadirection attribute does not match that used on the previous <dialogprepare>
element, an error.dialog.notstarted event must be raised. If no value for the mediadirection attribute was
specified on the previous <dialogprepare> element, any mediadirection type option may be
specified.
maxage
false
Must not be used with prepareddialogid.
ECMAScript Expression
none
A valid time value for the HTTP 1.1 request [RFC2616]
The character string returned must be interpreted as a time interval. This indicates that
the document is willing to use content whose age is no greater than the specified time in seconds (cf. 'max-age' in HTTP
1.1 [RFC2616]). The document is not willing to use stale content, unless maxstale is also
provided.
maxstale
false
Must not be used with prepareddialogid.
ECMAScript Expression
none
A valid time value for the HTTP 1.1 request [RFC2616]
The character string returned must be interpreted as a time interval. This indicates that
the document is willing to use content that has exceeded its expiration time (cf. 'max-stale' in HTTP 1.1 [RFC2616]). If maxstale is assigned a value, then the document is willing to accept content that has
exceeded its expiration time by no more than the specified number of seconds.
enctype
false
Valid only when the value of the method is "post", otherwise ignored. Must not be used with
prepareddialogid.
ECMAScript Expression
application/x-www-form-urlencoded
valid media encoding type
An ECMAScript expression which returns a character string that indicates the media encoding type of the submitted
document (when the value of the method is "post"). Values defined by the specification are:
application/x-www-form-urlencoded
This indicates that the ccxml variables specified in the namelist must be url encoded.
method
false
Must not be used with prepareddialogid.
ECMAScript Expression
get
get post
An ECMAScript expression which returns a character string that indicates the HTTP method to use. Values defined by the
specification are:
get
This indicates that the "GET" method must be used by the dialog manager.
post
This indicates that the "POST" method must be used by the dialog manager.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform for implementing the dialog operation. Note: The meaning of these hints is specific to the
implementing platform and protocol. Platforms that do not support hints MAY ignore this attribute.
See Section 9.5.6 for additional requirements when hints are supported by the implementing
platform.
7.2.3: <dialogterminate>
7.2.3.1: Overview
A CCXML document may decide that it wants to terminate a currently executing dialog, to throw away a previously prepared
dialog, or to terminate the preparation of a dialog. This is accomplished using the <dialogterminate>
element. When the CCXML interpreter encounters a <dialogterminate> element, it MUST
send a terminate request to the specified dialog.
A dialog terminated due to the processing of a <dialogterminate> element MAY
still return data to the CCXML application using a dialog.exit event if the value of the immediate
attribute is false or unspecified. The details of the data returned are dialog environment specific.
If the immediate attribute is set to true the dialog MUST NOT return data
to the CCXML application and the CCXML interpreter MUST post a dialog.exit event
immediately.
The platform MUST tear down any existing bridges to the dialog and send a
conference.unjoined to the CCXML document once the media paths have been freed.
7.2.3.2: <dialogterminate> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
dialogid
true
ECMAScript Expression
none
valid dialog ID
An ECMAScript expression which returns a character string identifying the dialog. This
dialogid was returned in the variable identified by the dialogid attribute of previous
<dialogstart> or <dialogprepare> request or the value in a dialog.started or
dialog.prepared event. If the attribute value is invalid, an error.semantic event MUST be thrown
immediate
false
ECMAScript Boolean Expression
false
true false
An ECMAScript Boolean expression which returns a character string, that identifies the termination style of the dialog. Valid
values are:
true
This indicates that the dialog must be terminated immediately.
false
This indicates that the dialog must be terminated in a normal fashion.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform for implementing the dialog operation. Note: The meaning of these hints is specific to the
implementing platform and protocol. Platforms that do not support hints MAY ignore this attribute.
See Section 9.5.6 for additional requirements when hints are supported by the implementing
platform.
7.3: Events
7.3.1: Overview
The majority of communication between CCXML interpreter sessions and dialogs is by way of events. Dialog environments post
events to the CCXML interpreter event queue and a CCXML application MAY send an event to a dialog. How this is handled on the
dialog side is dialog manager and CCXML interpreter dependent. On the CCXML side it is done by using <send>
and passing in the dialogid that was received as a result of processing a <dialogstart> or a
<dialogprepare>.
The following are the CCXML events related to dialogs:
7.3.2: dialog.started
The dialog.started event MUST be thrown when a dialog is successfully started. The
fields available in the event are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
true
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
connectionid
false
string
The identifier of the connection to which the dialog connection is bridged (usually the
connectionid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a conference the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog connection is bridged (usually the
conferenceid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a connection the value must be undefined.
7.3.3: dialog.exit
The dialog.exit event MUST be thrown when a dialog terminates either normally or
following a <dialogterminate> request. Termination of a dialog always results in a single
dialog.exit event; if normal dialog termination and a <dialogterminate> occur simultaneously,
the dialog.exit event will reflect the condition that the platform processes first. For example, if a
dialog.exit event is thrown based on normal termination, and the platform subsequently processes a
<dialogterminate> request made by the application, it will discard the <dialogterminate>
and will not generate a second dialog.exit event. The fields available in the event are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
true
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
connectionid
false
string
The identifier of the connection to which the dialog connection is bridged (usually the
connectionid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a conference the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog connection is bridged (usually the
conferenceid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a connection the value must be undefined.
values.*
false
ECMAScript Object
Return values from the dialog. In VoiceXML this would be the values of each of the objects
listed in the exit element's namelist.
7.3.4: dialog.disconnect
The dialog.disconnect event represents a request by a dialog to disconnect the Connection or Conference with
which it is presently associated. The actual handling of this event is determined entirely by the running CCXML application,
which may disconnect the associated Connection, detach the dialog from the Connection/Conference, or elect to ignore the
dialog.disconnect event altogether. The fields available in the event are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
true
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
connectionid
false
string
The identifier of the connection to which the dialog connection is bridged (usually the
connectionid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a conference the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog connection is bridged (usually the
conferenceid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a connection the value must be undefined.
values.*
false
ECMAScript Object
Return values from the dialog. In VoiceXML this would be the values of each of the objects
listed in the dialog element's namelist.
7.3.5: dialog.transfer
The dialog.transfer event represents a request by a dialog to transfer the Connection or Conference with which
it is presently associated to a new destination. The actual handling of this event is determined entirely by the running CCXML
application, which may perform a <redirect> on the associated Connection, use
<createcall> and <join> to establish a bridged transfer, handle the transfer request in
some other way, or elect to ignore the dialog.transfer event altogether. The properties of the
dialog.transfer event reflect the information dialog environments are most likely to supply when requesting a
transfer, but are up to the running CCXML application to interpret. The fields available in the event are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
true
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
connectionid
false
string
The identifier of the connection to which the dialog connection is bridged (usually the
connectionid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a conference the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog connection is bridged (usually the
conferenceid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a connection the value must be undefined.
type
true
string
A string value specifying the transfer type.
uri
true
a valid URI
A URI describing the destination to which this call must be transferred. The format of this
information is protocol and platform specific but might consist of a telephone URI RFC3966 or a
SIP URI RFC3261 .
values.*
false
ECMAScript Object
Properties returned from the dialog processor relating to the dialogs transfer request.
maxtime
true
string
A string in CSS2 format that specifies the maximum amount of time the transfer may stay
connected. If the amount of time is unlimited the value must be 0s.
connecttimeout
true
string
A string in CSS2 format that specifies the maximum amount of time to spend while attempting to
connect the call.
aai
false
string
A string of application-to-application information to be passed to the destination party when
establishing the transfer.
7.3.6: dialog.terminatetransfer
The dialog.terminatetransfer event represents a request by a dialog to terminate an ongoing transfer for
example due to a "hotword" recognition. The actual handling of this event is determined entirely by the running CCXML
application, which may terminate the outgoing call leg and return the media stream of the original call to the dialog using the
<join> element, handle the terminate transfer request in some other way, or elect to ignore the
dialog.terminatetransfer event altogether. The properties of the dialog.terminatetransfer event
reflect the information dialog environments are most likely to supply when terminating a transfer, but are up to the running
CCXML application to interpret. The fields available in the event are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
true
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
connectionid
false
string
The identifier of the connection to which the dialog connection is bridged (usually the
connectionid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a conference the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog connection is bridged (usually the
conferenceid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a connection the value must be undefined.
reason
false
string
A description of the reason the dialog wants the transfer to be terminated. Content of this
field is platform-specific.
7.3.7: error.dialog
The error.dialog event MUST be thrown when there was an unspecified error with the
dialog (for example the dialog server crashed).
The platform MUST implicitly tear down any existing bridges to the dialog and send a
conference.unjoined to the CCXML document once the media paths have been freed. The fields available in the event
are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
true
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
connectionid
false
string
The identifier of the connection to which the dialog was connected to (usually the
connectionid that was specified in the dialogstart or dialogprepare).
If the dialog was being connected to a conference the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog was connected to (usually the
conferenceid that was specified in the dialogstart or dialogprepare).
If the dialog was being connected to a connection the value must be undefined.
reason
true
string
A description of the reason the dialog had an error. Content of this field is
platform-specific.
7.3.8: error.dialog.notstarted
The error.dialog.notstarted event MUST be thrown when the processing of a
<dialogstart> element fails because the dialog cannot be started for some reason. The fields available in
the event are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
true
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
connectionid
false
string
The identifier of the connection to which the dialog connection could not be started (usually
the connectionid that was specified in the dialogstart or dialogprepare).
If the dialog was being connected to a conference the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog connection could not be started (usually
the conferenceid that was specified in the dialogstart or dialogprepare).
If the dialog was being connected to a connection the value must be undefined.
reason
true
string
A description of the reason the dialog could not be started. Content of this field is
platform-specific.
7.3.9: blank
This section is intentionally left blank.
7.3.10: dialog.user.*
The dialog.user.* (where * is the name of the user defined event) MUST be thrown when
a dialog sends a user/application-defined event. The fields available in the event are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
false
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
NOTE that dialog property in this event is optional because there is not a
standard way to raise this event from a dialog system such
as [VOICEXML]
while a basichttp implementation is allowed.
connectionid
false
string
The identifier of the connection to which the dialog connection is bridged (usually the
connectionid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a conference the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog connection is bridged (usually the
conferenceid that was specified in the dialogstart or dialogprepare).
If the dialog is bridged to a connection the value must be undefined.
values.*
false
ECMAScript Object
Return values from the dialog for the user event.
7.3.11: dialog.prepared
The dialog.prepared event MUST be thrown when a dialog has been successfully prepared
following the execution of a <dialogprepare> element. The fields available in the event are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
true
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
connectionid
false
string
The identifier of the connection to which the dialog connection is prepared (usually the
connectionid that was specified in the dialogprepare).
If the dialog was prepared without a connection, the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog connection is prepared (usually the
conferenceid that was specified in the dialogprepare).
If the dialog was prepared without a conference , the value must be undefined.
7.3.12: error.dialog.notprepared
The error.dialog.notprepared event MUST be thrown when the processing of a
<dialogprepare> element fails. The fields available in the event are:
Attribute Name
Required
Type
Details
dialogid
true
string
The ID of the dialog.
dialog
true
ECMAScript Object
An ECMAScript object reference to the dialog object identified by the dialogid property
of this event.
reason
true
string
A description of the reason the dialog could not be prepared. Content of this field is
platform-specific.
connectionid
false
string
The identifier of the connection to which the dialog connection was attempting to be prepared
(usually the connectionid that was specified in the dialogprepare).
If the dialog was prepared without a connection, the value must be undefined.
conferenceid
false
string
The identifier of the conference to which the dialog connection was attempting to be prepared
(usually the conferenceid that was specified in the dialogprepare).
If the dialog was prepared without a conference, the value must be undefined.
7.4: Dialog Object Properties
An instance of the Dialog object is associated with each dialog created by <dialogstart> or
<dialogprepare> and referenced in the session.dialogs associative array.
The Dialog Object is an extension of the Media Endpoint Object as defined in
section 10.4.3.
Dialog Properties
Required
Definitions
dialogid
true
This property is the ECMAScript string value of the Dialog Identifier, which uniquely
identifies each instance of the Dialog class.
type
true
An ECMAScript string value that specifies the MIME type of the document that loaded the
dialog
src
true
An ECMAScript string value identifying the initial URI of the dialog document.
input
true
As defined by the Media Endpoint Object in 10.4.3.
outputs
true
As defined by the Media Endpoint Object in 10.4.3.
objecttype
true
This property states the type of this object which must be 'dialog'.
7.5: Dialog class
All dialog objects MUST be initiated via the Dialog class. The Dialog class currently has no defined properties.
8: Variables and Expressions
8.1: Overview
CCXML expressions are valid ECMAScript [ ECMASCRIPT ] expressions,
assignable to variables with valid ECMAScript names. For further details please see section 3.4.
Many CCXML elements have multiple attributes that are ECMAScript expressions. The CCXML language does not guarantee a
specific order of evaluation of these expressions. Also, some elements such as <transition> may or may not
evaluate all attributes. Hence, attributes containing expressions with side-effects can lead to implementation specific
behavior. It is RECOMMENDED that applications do not use ECMAScript expressions with side-effects in
attributes.
If the implementation is unable to evaluate an ECMAScript expression it MUST throw an
error.semantic event.
8.2: Elements
8.2.1: <assign> and <var>
8.2.1.1: Overview
Variables are declared using the <var> element and are initialized with the results of evaluating the
OPTIONALexpr attribute as an ECMAScript expression. If the expr attribute
is not present in the <var> declaration, the variable is initialized to ECMAScript undefined.
The values of variables MAY be subsequently changed with <assign>.
Variables declared without an explicit initial value MUST be initialized to the ECMAScript value
undefined by the implementation.
It is illegal to make an assignment to a variable that has not been explicitly declared using <var> or a
var statement within a <script>. Attempting to assign to an undeclared variable causes an
error.semantic event to be thrown. Please see Section 9.5 for a detailed
description of error events.
Note that when an ECMAScript object, e.g. "obj", has been properly initialized then its properties, for
instance "obj.prop1", can be assigned without explicit declaration. An attempt to declare ECMAScript object
properties such as "obj.prop1" results in an error.semantic event being thrown.
CCXML uses an ECMAScript scope chain (please see section 3.4 ) to
allow variables to be declared at different levels of hierarchy in an application. For instance, a variable declared at ccxml
(document) scope can be referenced anywhere within that document, whereas a local variable declared in a
<transition> is only available within that element.
The implementation MUST define four scopes - session, application,
ccxml and transition. The relationship between these scopes is shown below.
Variable Scoping
A description of the scopes is provided in the table below.
Scope Name
Details
session
This scope is opened by CCXML implementation before interpretation of
a new session starts and exists until the session exits. Variables within this scope are provided by CCXML implementation
and are read-only. Any attempt to modify the session object or it's properties by the application MUST result in an
error.semantic event to be thrown by the platform.
application
This scope is opened by CCXML implementation before interpretation of
a new session starts and exists until the session exits. Variables within this scope cannot be explicitly declared using
<var> element or var statement within a <script>. They can be created only by assigning a value to a property
of the application object (application.varname = value;). Unlike in the session scope, variables in this scope can be
modified by CCXML programs. They are visible to documents within the CCXML application.
ccxml
This scope is opened by CCXML implementation for each CCXML document
when it is loaded and exists while the document is loaded. Variables within this scope are declared with <var> and
<script> elements that are children of <ccxml>. They are initialized in document order when the document is
loaded. They exist while the document is loaded. They are visible only within that document. Variables in this scope can be
also created without an explicit declaration by assigning a value to a property of the ccxml object (ccxml.varname =
value;).
transition
Each <transition> element has a scope that exists while the
implementation is processing the executable content within that <transition>, and which is visible to the elements of
that <transition>. Variables with transition scope are declared by <var> and <script> child elements of
<transition>. The child <var> and <script> elements of <transition> are initialized in document
order when the executable content is executed. Variables in this scope can be also created without an explicit declaration
by assigning a value to a property of the transition object (transition.varname = value;).
The implementation MUST instantiate a variable within the scope of the closest containing scope
element. The fully-qualified name of a variable is the name of the variable's scope object prepended with a dot to the name of
the variable. The implementation MUST allow reference to variables by their fully qualified names. The
implementation MUST allow reference to variables without requiring use of their fully qualified names.
In the case of like-named variables declared in different scopes, the implementation MUST reference
the variable in the closest containing scope, unless the fully-qualified variable name is used.
The implementation MUST resolve variables by searching the enclosing transition scope
first (if applicable) followed by the ccxml scope, the application scope and then the
session scope, unless the variable reference is qualified with a scope prefix.
If the variable includes a scope prefix, the implementation MUST resolve the variable by searching
the named scope.
If a variable is declared more than once, the implementation MUST evaluate the expr
attribute of each subsequent declaration, and assign the result to the variable declared by the first
<var>.
Variables can be assigned new values using <assign> :
<assign name="currentstate" expr="'cleanup'" />
The implementation MUST evaluate the ECMAScript expression contained in the expr
attribute of <assign>, and assign the results to the variable referenced in the name
attribute.
The variable naming convention is as in ECMAScript, but names beginning with the underscore character ("_") and names ending
with a dollar sign ("$") are reserved for internal use. CCXML variables MUST NOT contain ECMAScript
reserved words. They MUST also follow ECMAScript rules for referential correctness. For example,
variable names must be unique and their declaration MUST NOT include a dot - "var x.y" is
an illegal declaration in ECMAScript. Variable names which violate naming conventions or ECMAScript rules MUST cause an 'error.semantic' event to be thrown.
8.2.1.2: <var> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
name
true
String
none
Valid ECMAScript Variable name
Indicates the name of the variable. It must be a valid ECMAScript variable name.
However, it must not contain a scope prefix. The scope in which the variable is defined must be determined from the
position in the document at which the variable is defined.
expr
false
ECMAScript Expression
undefined
Valid ECMAScript Expression
Indicates the new value of the variable. This will be the initial value. It must
be a valid ECMAScript expression.
8.2.1.3: <assign> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
name
true
ECMAScript Left Hand Side Expression
none
ECMAScript Variable
An ECMAScript left hand side expression evaluating to a previously defined variable. The
value of the attribute must receive the result of the expr attribute.
expr
true
ECMAScript Expression
none
Valid ECMAScript Expression
Indicates the new value of the variable. It must be a valid ECMAScript
expression.
8.2.2: <script>
8.2.2.1: Overview
<script> encloses computations written in the ECMAScript Compact Profile [ECMA327] scripting language. The ECMAScript Compact Profile is a strict subset of the third edition of
ECMA-262 [ECMASCRIPT]. It has been designed to meet the needs of
resource-constrained environments. Special attention has been paid to constraining ECMAScript features that require
proportionately large amounts of system memory, and continuous or proportionately large amounts of processing power. In
particular, it is designed to facilitate prior compilation for execution in a lightweight environment. For specific details on
what ECMAScript functions are not supported please take a look at ECMA-327 specification [ECMA327].
An implementation MUST support the ECMAScript Compact Profile and MAY
support the full ECMA-262 ECMAScript specification.
The example <script> below defines a function that computes the greatest common factor of two
integers:
<script>
<![CDATA[
function gcd(a, b)
{
var t;
if (a < 1 || b < 1)
return -1;
do
{
t = a % b;
a = b;
b = t;
}
while (b > 1);
return (b == 0) ? a : b;
}
]]>
</script>
An implementation MUST support <script> within the <ccxml>
element and in executable content. <transition> and <if> contain executable content. The
implementation MUST evaluate <script> in a <ccxml> immediately
after the document is loaded, along with any <var> and <assign> elements, in document
order. When used as a child of the <ccxml> element, <script> cannot be used to execute
dynamically fetched content obtained using <fetch>. The implementation MUST
evaluate <script> in executable content as it is processed.
The ECMAScript contained within the <script> can declare variables with the ECMAScript var
statement. Variables declared in this manner are declared in the scope of the closest containing scope CCXML element. They are
known from the point of declaration to the end of the containing scope. The implementation MUST allow
reference to these variables from CCXML and from ECMAScript, using either the fully-qualified variable name, or the declared
name.
If the implementation is unable to run the script referenced it MUST throw an
error.semantic event.
INFORMATIVE NOTE: The <script> element's resource loading model is a bit different than the rest of
CCXML for a number of reasons. Because CCXML and ECMAScript applications can be CPU intensive to compile we define
<script>'s src attribute (defining the URI of the document to load) to be a static string instead of a
dynamically valued ECMAScript result. This allows implementations to load ECMAScript content at CCXML document load time and
perform compiling and/or caching of the resulting ECMAScript code. We do however recognize that there are cases where a CCXML
application needs to load a dynamic ECMAScript resource, for this reason applications can use the the
<fetch> element to asynchronously load a resource and then execute it by referencing it's
fetchid in the the <script> element.
8.2.2.2: <script> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
src
false
This attribute must not be specified in conjunction with the fetchid
attribute.
Valid URI
none
a valid URI
A URI which references a resource which is the script content, and which must be resolved
when the CCXML document is compiled.
Note that the value of the src attribute must not be an ECMAScript expression in order to allow it to be resolved at
compile-time. If the ECMAScript script referenced can not be loaded at the CCXML document loading and parsing phase it
should be considered a Fetching & compilation error as defined in section 9.5.1.
fetchid
false
This attribute must not be specified in conjunction with the src
attribute, otherwise ignored.
ECMAScript Expression
none
valid fetch ID
An ECMAScript expression which returns the fetch identifier of a completed fetch request,
acquired either in a fetch with the fetchid attribute, or from the fetchid attribute of a fetch.done event. If the
fetch identifier is invalid, has not completed, or the fetched content is not valid ECMAScript, an error.semantic
event must be thrown.
timeout
false
This attribute is only valid in conjunction with the src attribute, otherwise ignored.
The character string must be interpreted as a time interval. This interval must begin
when the script is requested; If the script has not been fetched at the end of this interval, an error.fetchor error.createccxml
event must be thrown.
maxage
false
This attribute is only valid in conjunction with the src attribute, otherwise ignored.
Character string
none
A valid time value for the HTTP 1.1 request [RFC2616]
The character string must be interpreted as a time interval. This indicates that the
document is willing to use content whose age must be no greater than the specified time in seconds (cf. 'max-age' in HTTP
1.1 [RFC2616]). The document is not willing to use stale content, unless maxstale is also
provided.
maxstale
false
This attribute is only valid in conjunction with the src attribute, otherwise ignored.
Character string
none
A valid time value for the HTTP 1.1 request [RFC2616]
The character string must be interpreted as a time interval. This indicates that the
document is willing to use content that has exceeded its expiration time (cf. 'max-stale' in HTTP 1.1 [RFC2616]). If maxstale is assigned a value, then the document is willing to accept content that has
exceeded its expiration time by no more than the specified number of seconds.
charset
false
Character string
UTF-8
valid character encoding type
A character string that indicates the character encoding type of the script. UTF-8
and UTF-16 encodings of ISO/IEC 10646 must be supported (as in [XML] ) and other
encodings, as defined in the [IANA] , may be supported.
8.3: Session Variables
Every CCXML session has a set of standard ECMAScript variables that are available to the program during execution called
session variables. The session variables are defined by the CCXML implementation when the CCXML session is created and are
read-only to the running script and cannot be modified by the CCXML program. New session variables cannot be declared by CCXML
programs.
Session variable values visible to a CCXML application reflect the state of the executing CCXML session, current as of the
occurrence of the event being processed. For example, when an application processes a Connection event such as
connection.alerting, the value of the state property of the corresponding Connection object will be updated by the
CCXML implementation so that if the CCXML program's event handler evaluates the state variable, it will evaluate to
ALERTING, since connection.alerting always results in a transition to the ALERTING
state. This is true even if the underlying connection is actually DISCONNECTED, in which case a
connection.disconnected event would be queued. It is the responsibility of the CCXML implementation to control and
update the session changes as they occur in the CCXML session. It is assumed that session changes are visible to the CCXML
program as they occur. However, it is permissible for a CCXML implementation to optimize session changes by
"lazy-binding" values as they are accessed or evaluated by a CCXML program, so as to minimize processing time. For example, an
implementation might only update the current Connection states when a CCXML program evaluates the variable during execution
time versus continually updating the Connection states inside ECMAScript scope as state changes. Regardless of when session
variables are updated to reflect changes, the CCXML implementation is REQUIRED to provide the correct
values when accessed by a CCXML program.
Variables defined in the session scope are subject to the parent scope chain delegation model but do not have a parent scope
defined.
The following are the list of standard session variables:
session.startupmode
String that indicates the startup mode that the script was started as:
Value
Details
newcall
Session was started due to a new incoming call.
external
Session was started due to a external session launch request.
createccxml
Session was started due to a <createccxml> request.
session.id
A globally unique string that indicates the session identifier of the executing CCXML session.
session.uri
URI that was used when creating the current CCXML session. If the interpreter fetched multiple documents as a result of
one or more HTTP redirects (e.g. 302), the value of this session variable is set to the URI of the final target.
session.uri includes the query string used when fetching the document, if one is present.
session.parentid
String that indicates the session identifier of the parent of the CCXML session that created this session. In the case
the current session has no parent, the value of the variable will be ECMAScript undefined. Once a new CCXML session is
created, the new session and its parent are completely independent.
session.connections
Associative Array which contains a list of the Connection objects that the session is currently using. The array is
associative and each key in the array is the connection identifier for the Connection. For example,
session.connections["1234"] would return the Connection object for connection ID 1234. The following example
demonstrates the use of the session.connections variable:
<transition state="in_vxml_session" event="connection.disconnected">
<if cond="session.connections['1234'].connectionid==event$.connid">
<-- if the disconnect is on the first connection, do something -->
<else/>
<exit/>
</if>
</transition>
session.conferences
An Associative array which contains a list of the Conference objects for which the session is attached using
<createconference> For example, session.conferences["1234"] would return the Conference
object for conference id 1234.
session.dialogs
Associative Array which contains a list of the Dialog objects that the session is currently using. The array is
associative and each key in the array is the dialog identifier for the Dialog. For example,
session.dialogs["1234"] would return the Dialog object for dialog id 1234.
session.ioprocessors
Associative Array which contains a list of external event I/O access URIs which are available to the current session. The
array is associative and each key in the array is the type of the event I/O processor. For example,
session.ioprocessors["basichttp"] would return the access URI (e.g.
http://www.example.com/ccxml/basichttp) for the "basichttp" type event I/O processor.
session.values
Associative array which contains a list of session parameters passed on session creation. For sessions created using
<createccxml>, session.values contains variables passed using the 'parameters'
attribute of <createccxml>. Other session creation mechanisms, such as the HTTP-based session creation I/O
processor defined in Appendix L, define other mechanisms for populating this variable.
8.4: Application Variables
CCXML provides application variables which, like session variables, persists across the CCXML application. Application variables differ from session variables in that they can be modified by CCXML
programs.
The application object is initialized by the CCXML implementation. Application variables that are properties of the
application object are not explicitly declared.
By default, application variables have the value ECMAScript undefined. Variables in the application scope are subject to the
parent scope chain delegation model and have session as their parent scope. For example:
<assign name="application.userid" expr="'user001'"/>
<assign name="application.obj" expr="new Object()"/>
<assign name="application.obj.prop1" expr="'value of prop1'"/>
<assign name="application.obj.prop2" expr="'value of prop2'"/>
Application variables are visible within documents which form the CCXML
application. For example, a document in a CCXML application could assign an application variable a value using
<assign name="application.userid" expr="'user001'"/>, and a later document in the CCXML application could
reference application.userid to retrieve the value 'user001'.
Application developers should be careful in their use of application variables since they are visible to all CCXML
documents within a CCXML application.
9: Event Handling
This section contains information on <eventprocessor>, <send>,
<cancel>, <transition> and <move>.
9.1: Overview
Event Handling is one of the most powerful features of CCXML. CCXML events can be delivered at any time and from a variety
of sources. This flexible event-handling mechanism is essential for many telephony applications.
Every CCXML session can send and receive events. These might be in response to a previous action by the CCXML session (e.g.,
an outbound-call request, which generates an event to indicate when the call goes off-hook), or on the initiative of some
external source (e.g., an incoming call to be answered). Events can be generated by the telephony system (as in the two
previous examples), other CCXML sessions (which emit events via <send>), Dialogs, or external sources. CCXML
sessions can also send events to themselves.
There is a core set of telephony-related events (derived from the JCC event model for connection objects; see the JAIN Call
Control API (JCC) [JSR021] for more information) that a browser MUST support. Implementers MAY define and support any platform-specific events they
like. In addition, users/programmers may use <send> to send arbitrary events to internal or external
destinations, or may send arbitrary events to CCXML documents from internal or external sources and may specify transition
handlers to handle these events.
The transmission and reception of events both external and internal is controlled by a logical component in the platform
called the "Event I/O Processor". A platform MAY support more than one type of Event I/O Processor and
each of them may support a different format of external events (For example: SOAP, JMS, SIP, Simple HTTP or any other event
transmission approaches). For incoming events the Event I/O Processor is responsible for accepting the incoming event and
transforming it into an ECMAScript event object that can be accessed by CCXML. For outgoing events the Event I/O Processor is
responsible for deciding the serialization and transport formats. The operation and behavior of Event I/O Processors is
platform dependent; however, this specification defines a Basic HTTP Event I/O Processor (Appendix K) that defines event
transmission over HTTP. External Event I/O processors and new events created using <send> will typically
generate application-specific events with different names than those of the standard events in this specification; however, it
is legal for external sources and for events created using <send> to generate standard events. For instance,
it is useful to be able to generate a ccxml.kill event to attempt graceful termination of a session from an
external context, or from another CCXML session. Platforms SHOULD reject any standard events that do
not contain all of the mandatory properties defined in this specification, and SHOULD notify the
sender of the rejection (for instance with an error.send event).
Each running CCXML interpreter has a queue, into which it places incoming events. Events are generally queued on a first-in,
first-out (FIFO) basis; however, certain classes of events are queued differently, as described in the paragraphs below. A
CCXML programmer can only gain access to these queued events by using the <eventprocessor> element with
associated <transition> elements.
An event can be delivered to a CCXML session using a <send> element in which case an optional delay may
be specified. If a delay is specified, the event is not delivered to the target CCXML session until the delay time has elapsed.
When the delay has elapsed, the event is queued as if it had just occurred, using standard queueing rules.
There are three types of events that, when delivered to a CCXML session, are handled differently. All
ccxml.kill and ccxml.kill.* events are placed at the head of the event queue rather than the tail so
that they are processed in preference to all other events. All error.* events are placed at the head of the queue
but behind any error.*, ccxml.kill, or ccxml.kill.* events that are already on the
queue. ccxml.loaded events are always placed at the head of the queue.
An <eventprocessor> is interpreted by an implicit Event Handler Interpretation Algorithm (EHIA). The
EHIA's main loop removes the first event from the CCXML session's event queue, and then selects from the set of
<transition>s contained in the <eventprocessor>. A <transition> always
indicates a set of patterns to match event names, MAY indicate a required current value of the
ECMAScript state variable specified in the <eventprocessor>, and MAY indicate a
further ECMAScript conditional expression to be evaluated. The <transition> that accepts the type for the
just-removed event, is in the specified state, has a satisfied conditional expression, and appears first in the
<eventprocessor> in document order, is the selected <transition>.
Once selected, an object representing the event being processed is created at transition scope, and the elements inside the
<transition> are executed in document order. If an ECMAScript evaluation error occurs during the execution
of an element within a <transition>, error.semanticMUST be raised for
that element, and successive elements within that <transition>MUST NOT be
executed; Note that while an element that references an invalid connection, dialog, or conference identifier also causes the
platform to raise error.semantic, these scenarios MUST NOT terminate execution of the
<transition> in which that element is contained.
At most one <transition> will be chosen. If no <transition> meets all the criteria,
none are selected and the event is simply dropped; the EHIA loop then starts over again, removing the event at the head of the
queue. The only exception to this rule is when ccxml.kill, ccxml.kill.* and error.*
events are received; in this case, the CCXML interpreter will end the session if there are no <transition>s
that match the ccxml.kill, ccxml.kill.* and error.* events explicitly.
Any events that arrive while an event is already being processed are just placed on the queue for later. If the event queue
is empty, and the EHIA wants to process an event, execution pauses until an event arrives.
During the processing of an event by the EHIA, the state of any ECMAScript objects exposed by a platform, such as the
Connection object, must reflect the state of the CCXML session immediately following the occurrence of
the event. For instance, if a 'connection.alerting' event is being processed against a connection with ID 1234,
then session.connections['1234'].state would have a value of Connection.ALERTING. This is true even
if the actual connection has already been terminated, with a 'connection.disconnected' event queued (but not yet
processed) against the session. It is required that the ECMAScript context for the session is updated
prior to the selection of a matching <transition>, since the <transition> might contain
an ECMAScript conditional expression, the value of which depends on the state changes caused by the event.
Elements inside an <transition>SHOULD run "quickly", without blocking
execution. This will allow events to be rapidly processed. CCXML applications should be aware of this and should keep
calculations such as large ECMAScript functions within a transition to a minimum.
The only way for CCXML execution to leave an <eventprocessor> is via an explicit
<goto> or <exit> inside a <transition> or an unhandled error or
ccxml.kill event .
An <eventprocessor>MAY also declare a state variable attribute. An
<eventprocessor>'s state variable must be declared in the ccxml scope using a <var> or a
<script>. The <eventprocessor> can be considered, and programmed as, a
finite-state-automaton, with the state variable indicating the automaton's current state or node, and the
<transition>s, driven by incoming events, moving the machine to a new state and creating side effects along
the way. If a state variable is not defined in the <eventprocessor>'s statevariable attribute a
default variable named "state$" defined at the ccxml scope will be used instead. The initial value will be
ECMAScript 'undefined'.
9.2: Elements
9.2.1: <eventprocessor>
9.2.1.1: Overview
The <eventprocessor> acts as a container for <transition>s. A valid CCXML document
MUST only have a single <eventprocessor>.
9.2.1.2: <eventprocessor> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
statevariable
false
string
state$
ECMAScript Variable name
This is a CCXML variable name, which is the name of the eventprocessor's state
variable. This variable must be defined using the var or the script element in the ccxml scope.
<eventprocessor>MUST contain only <transition> elements.
9.2.2: <transition>
9.2.2.1: Overview
The content of a <transition> specifies the actions to be taken when it is selected. The
<transition> are examined by the EHIA in document order.
In order to be selected, a <transition>MUST satisfy three criteria:
If a state attribute is specified on the <transition> the current value of the associated state
variable (as specified in the parent <eventprocessor>) MUST be equal to one of
the values specified in the state attribute of the <transition>. If no state attribute is
specified on the <transition>, this criteria is met regardless of the value of the
statevariable.
the expression specified by the <transition> 's cond attribute MUST evaluate to true, if that attribute is present
the current event's name property MUST match the pattern specified by the
<transition>'s event attribute, if that attribute is present
A <transition> with none of the attributes, state, cond, or event,
will always be selected when encountered by the EHIA.
The contents of the received event object MUST be available via the transition scoped read-only
event$ ECMAScript variable. This variable is accessible from the <transition>cond
attribute to allow CCXML Applications to conditionally select <transition>'s based on the contents of the
event.
9.2.2.2: <transition> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
state
false
string
none
This indicates the current possible value of the variable associated with the
statevariable attribute of the parent <eventprocessor>. More than one value may be specified, separated
by whitespace.
event
false
string
none
This is a pattern used to match event names as specified in Section 9.2.2.3.
cond
false
ECMAScript Boolean Expression
true
An ECMAScript Boolean expression. If this attribute is present, it must evaluate to true
for the transition to be selected.
9.2.2.3: <transition> Event Matching
The event attribute of a <transition> specifies a pattern used to match event names. Each character in
the pattern specified by event must match the corresponding character in the event name, except for the asterisk
('*') character, which acts as a wildcard that matches any substring of zero or more characters in the event name. Patterns are
dot-separated strings of arbitrary length. Event names are case-insensitive.
Pattern match examples
Pattern
Matches
*
any event name
error.*
error.fetch, error.dialog.notstarted
error.*.*
error.dialog.notstarted
err*
any event name starting with "err"
9.2.3: <send>
9.2.3.1: Overview
<send> is used to send messages containing events or other information directly to another CCXML
Interpreter or other external systems using an Event I/O Processor.
The event target of <send> is specified using the target and targettype
attributes. These attributes control how the platform should dispatch the event to its final destination.
The target attribute specifies the unique identifier of the event target that the Event I/O Processor should
send the event to. This can be the value of a CCXML Session ID or a Dialog ID if you wish to send an event to one of these
respective targets. In the case where you are using some other Event I/O Processor this attribute should be able to describe
how to connect to the event destination (for example a SIP URI for SIP-INFO messages or a HTTP URI for Web Services). If the
value of the target attribute is not supported, invalid or unreachable by the Event I/O Processor the Platform
MUST throw a error.send.targetunavailable event.
The targettype attribute controls what Event I/O Processor the event should be sent to. The default value of
this attribute is 'ccxml'. If the event targettype specified is not supported the platform MUST throw a error.send.targettypeinvalid event.
A platform MUST support the following values for the targettype attribute:
Value
Details
ccxml
CCXML Session Event Processor.
dialog
Dialog Event Processor.
basichttp
Basic HTTP Event I/O engine (See Appendix K).
Platforms MAY support other types of Event I/O Processors, for example: Web-services, SIP or basic
HTTP GET. However, platforms SHOULD name the Event I/O Processor beginning with "x-" to
signify that they are platform dependent.
<send> also specifies the content of the message to be sent. <send>MUST specify message content in one of two ways (the following mechanisms are mutually exclusive):
name attribute with an OPTIONALnamelist
The name attribute specifies an ECMAScript expression that returns the name of the event.
The namelist attribute specifies a space separated list of CCXML ECMAScript variables to be included
with the message.
When inline XML is specified, the content of the <send> is parsed but MUST be
ignored by the sending CCXML Interpreter until the <send> is executed. XML namespace binding within the
<send> element MUST be preserved in the message sent to the
<send> target. This may result in XML namespace declarations being added to the message contents in order to
resolve XML namespace prefixes whose associated namespace declarations were not contained in the message contents in the
original CCXML document. It is the responsibility of the Event I/O Processor responsible for forwarding events to the
<send> target to parse the incoming message and remove the namespace bindings, if required by the
<send> target.
The sending CCXML Interpreter MUST NOT alter the content of the <send> other
than by adding namespace declarations for unresolved namespace bindings. The data contained within a <send>MUST be sent to the destination specified in the target attribute of
<send> using the Event I/O Processor specified by the targettype attribute.
The mechanism by which the content of the message is made available to the target depends on both the
targettype and the way in which the content is specified:
When <send> is used with the name and namelist attributes, and the
targettype is "ccxml", the mapping from namelist variables to event object properties
is well defined. Each variable listed in the namelist attribute is added as a property of the event object.
Qualified variables retain their qualification and are mapped into nested properties of the event object. If a variable is an
ECMAScript Object, then all properties of the variable are mapped into nested properties of the event object.
When <send> is used with inline XML content, and the targettype is "ccxml",
the mapping of that XML content to event object properties is implementation-specific, and outside the scope of this
specification.
When <send> is used with the name and namelist attributes, and the
targettype is "basichttp", each variable in the namelist is sent to the web server as
defined in Appendix K
When <send> is used with either name and namelist attributes or inline XML
content, and the targettype is "dialog" or a platform extension, the mechanism by which
namelist variables or XML content are made available to the event target is implementation-specific, and outside
the scope of this specification.
Although the full set of requirements for the Event I/O Processor is not within the scope of this specification, an event
processor sending an event to a CCXML Interpreter is required to generate an event which can be processed in a CCXML Session.
See Section 9.1 for details regarding the processing of incoming events by an CCXML Interpreter.
When a message is successfully sent to the target, a send.successful event MUST be
thrown. Note that this does not mean that the target processed the message successfully. It is up to the target to generate
events specific to the message. These events are application specific.
If the send request fails, an event signifying the error MUST be returned to the CCXML Session. The
failure events are documented at the end of this section.
Events generated by <send> will have their eventid, eventsource and
eventsourcetype attributes derived from the execution of the <send> element.
eventid will match the value returned via sendid. eventsource will be the ccxml session
id. eventsourcetype will be set to the string 'ccxml'.
9.2.3.2: <send> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
target
true
ECMAScript Expression
none
A valid target URI
An ECMAScript expression returning the target location of the event. The target
attribute specifies the unique identifier of the event target that the Event I/O Processor must send the event to.
targettype
false
ECMAScript Expression
ccxml
ccxml
dialog
basichttp
An ECMAScript expression which returns a character string that specifies the type of the
Event I/O Processor that the event must be dispatched to.
sendid
false
ECMAScript Left Hand Side Expression
none
ECMAScript Variable
An ECMAScript left hand side expression evaluating to a previously defined variable. The
value of the attribute must receive an internally generated unique string identifier to be associated with the event being
sent.
delay
false
ECMAScript Expression
'0s'
An ECMAScript expression which returns a character string in CSS2 [CSS2] format
The character string returned must be interpreted as a time interval. The send
element must return immediately, but the event must not be dispatched until the delay interval elapses. Timers are useful
for a wide variety of programming tasks, and can be implemented using this attribute. Note: The delayed event queue for sending events must be maintained locally. Any events waiting to be sent must be
purged when the session that issued this request terminates.
name
false
This attribute must not be specified in conjunction with inline content
ECMAScript Expression
none
An ECMAScript expression which returns a character string that indicates the event name
being generated. The event name may include alphanumeric characters,
"_" (underscore)
and the "." (dot) character. The first character
MUST NOT be a dot or a digit.
event names are case-insensitive.
namelist
false
This attribute must not be specified in conjunction with inline content
Var List
none
List of ECMAScript Variable names
A list of zero or more whitespace separated CCXML variable names to be included with the
event. Values for these variables are evaluated when the <send> element is processed See section 9.2.3.1
for details on how these variables are made available to the target.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform to configure the Event I/O Processor. The meaning of these hints is specific to the implementing
platform and the Event I/O Processor. Note: The meaning of these hints is specific to the implementing platform and
protocol. Platforms that do not support hints MAY ignore this attribute. See Section 9.5.6 for additional requirements when hints are supported by the implementing platform.
9.2.3.3: <send> Examples
In this example we send the current CCXML session a hello.jack event that contains a single field. We catch the
event, log the field and exit:
In this example we send the current CCXML session an event that contains an ECMAScript Object and a qualified variable. We
catch the event, log some properties resulting in the string "1, 2, 3, 4", and exit:
<move> is used to move an event source (such as a Connection object) to an executing CCXML session. When
an event source is moved to a session, events originating from that source MUST be delivered to that
session's currently executing CCXML document. The event OR the source attribute MUST be specified. If neither attribute is specified or both attributes are specified, an
error.fetch event MUST be thrown.
Support for the <move> element is optional in CCXML platforms. Even if <move> is
supported platforms MAY only support it between a restricted set of CCXML sessions. If
<move> is unsupported the CCXML platform MUST raise an error.move
event.
A <move> attempt MUST fail under any of the following conditions:
The referenced event source does not exist, or does not belong to the session executing the
<move>;
The referenced event source is immovable - the CCXML session itself and various external event I/O processors are
examples of this;
The referenced event source is currently bridged to another object through an implicit or explicit join;
The session to which the event source is being moved does not exist, or cannot accept the event source that is being
moved;
The event attribute is used to identify the event source, but refers to multiple event sources (such as
connection.merge.failed);
A <move> attempt MAY fail for causes other than the above, which may or may not
be platform specific
In the event of a <move> failure, an error.move event MUST be
generated to indicate that the <move> attempt was unsuccessful. Otherwise, a move.successful
event MUST be generated against the session that performed the <move> to indicate
that the request has completed successfully.
Since each CCXML session has an event queue, it is possible that a session executing a <move> will
already have events in its queue from the event source that is being moved. As an example, this situation could easily occur
with connection.alerting and connection.disconnected if the incoming connection is abandoned before a
CCXML platform initiates processing. Any such events MUST be removed from the queue of the session
performing the <move>, and placed into the queue of the session that the event source is being moved to.
Each event moved in this manner MUST be inserted into the queue of the target session as if it was a
new event occurring in the context of that session. The order in which events are queued is the order in which they appear in
the event queue of the session performing the <move>. If the event attribute is specified, then
the referenced event MUST be placed into the queue of the target session before other queued events
from the event source are inserted. Note that queueing rules governing the order in which the inserted events will be processed
continue to apply.
Like all CCXML elements, <move> executes asynchronously. As such, there is a period of time during which
events generated by the event source being moved cannot be processed either by the session performing the
<move>, or by the target session. If the <move> fails, then these events remain in the
queue of the session that attempted the <move>, and MUST be processed normally.
However, while the <move> is being performed, events from event sources other than the one being moved
MUST continue to be processed according to the EHIA. As such, a failed <move>
request may result in events being processed in a different order than if no <move> operation was performed.
Note that the relative ordering of events from the event source being moved is not changed even as a result of such a
failure.
9.2.4.2: <move> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
source
false
This attribute must not be specified in conjunction with the event
attribute.
ECMAScript Expression
none
(valid connection or dialog ID)
An ECMAScript expression which returns a connection ID or dialog ID. The event source
associated with this identifier must be moved to the target session.
event
false
This attribute must not be specified in conjunction with the source
attribute.
ECMAScript Expression
none
An ECMAScript expression which returns an event object.
The event source from which the event object originated, if any, must be moved to the
target session. The event must also be sent to the target session to provide a notification.
sessionid
true
ECMAScript Expression
none
A valid CCXML session id
An ECMAScript expression that identifies the session to which the event source must be
moved.
9.2.5: <cancel>
9.2.5.1: Overview
When a CCXML program uses <send> to send an event and includes a delay attribute, the
<cancel> command will cancel the pending event, if possible.
The cancel operation cancels a pending event by removing it from the delayed event queue of the CCXML session that initiated
the <send>, preventing it from ever being delivered. If the delay has expired and the event has already been
removed from the delayed event queue, the <cancel> request MUST fail and an
error.notallowed event MUST be delivered to the event queue of the CCXML session that
executed the <cancel> with the id property populated with the sendid of the event that the <cancel> was requested for.
Otherwise, a cancel.successful event MUST be
delivered to indicate that the <cancel> was successful, and that the cancelled event was not delivered.
Sessions are only permitted to cancel their own delayed events; they may not cancel the delayed events of other sessions.
9.2.5.2: <cancel> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
sendid
true
ECMAScript Expression
none
A valid event identifier
An ECMAScript expression which returns the value of the event identifier that was
received when the send command was issued.
9.3: Events
9.3.1: error.notallowed
This error event MUST be thrown when the execution of an element causes an invalid operation to be
performed on a session and/or connection. The fields available in this event are:
Attribute Name
Required
Type
Details
sessionid
true
string
The ID of the affected session.
id
false
string
The ID, if specified in the element being executed, of the affected connection, dialog,
session, event, or conference.
reason
true
string
A description of the reason the operation was denied. Content of this field is
platform-specific.
tagname
true
string
This property must be set to the ECMAScript string value of the name of the element that
produced the error (ie accept, reject, etc).
9.3.2: error.semantic
This error event MUST be thrown when there is a semantic error in a CCXML element ( e.g. passing an
incorrect value for an attribute, etc.).
The fields of this event are:
Attribute Name
Required
Type
Details
reason
true
string
This property must be set to the ECMAScript string value of the printable error message
associated with this error. Content of this field is platform-specific.
tagname
true
string
This property must be set to the ECMAScript string value of the name of the element that
produced the error (ie accept, reject, etc).
attributelist.*
false
ECMAScript Object
If available in the interpreter, this property must be an object whose properties are the names
of the attributes of the element in error. The value of each attribute property must be the corresponding string value of
the attribute.
scope
true
string
Identifies the scope and impact of the semantic error; this attribute MUST be set to one of the following string values:
transition - ECMAScript evaluation error, terminating the execution of the transition in which the error occurred.
element - Error at element scope, resulting in the affected element not being executed correctly but not terminating the
execution of other elements within the transition.
9.3.3: error.send.targetunavailable
This error event MUST be thrown when CCXML could not send the event to the target listed in
<send> due to it currently being unavailable. The fields available in this event are:
Attribute Name
Required
Type
Details
sendid
true
string
The ID of the affected event.
reason
true
string
A description of the reason the operation was denied. Content of this field is
platform-specific.
9.3.4: error.send.targettypeinvalid
This error event MUST be thrown when the targettype attribute specified in a
<send> is not valid.
The fields available in this event are:
Attribute Name
Required
Type
Details
sendid
true
string
The ID of the affected event.
reason
true
string
A description of the reason the operation was denied. Content of this field is
platform-specific.
9.3.5: error.send.failed
This error event MUST be thrown when a <send> could not be completed for a
reason not covered by another error.send.* event (for example, due to an invalid event name specified on <send>).
The fields available in this event are:
Attribute Name
Required
Type
Details
sendid
true
string
The ID of the affected event.
reason
true
string
A description of the reason the operation was denied. Content of this field is
platform-specific.
9.3.6: send.successful
This event MUST be thrown when an event is successfully delivered to the specified receiver.
Receipt of the event does not imply the event has been processed by the receiver but simply that it has been sent without
error. The fields available in this event are:
Attribute Name
Required
Type
Details
sendid
true
string
The ID of the send request as returned in the sendid attribute of the send
element.
9.3.7: move.successful
This event MUST be thrown when an event source is successfully moved to a CCXML session. The fields
available in this event are:
Attribute Name
Required
Type
Details
sourceid
true
string
The ID of the event source that has been moved as specified either directly via the
source attribute or indirectly via the event attribute of the move element.
9.3.8: cancel.successful
This event MUST be thrown when the sending of an event has been successfully cancelled. The fields
available in this event are:
Attribute Name
Required
Type
Details
sendid
true
string
The ID of the send event that has been cancelled as specified in the sendid attribute of
the cancel element.
9.3.9: error.move
This event MUST be thrown when a move request performed by a session fails to complete
successfully. The fields available in this event are:
Attribute Name
Required
Type
Details
sourceid
true
string
The ID of the event source referenced either directly via the source attribute or
indirectly via the event attribute of the move element.
sessionid
true
string
The ID of the target session to which it was attempted to move the event source.
reason
true
string
A description of the reason for which the move request failed. Content of this field is
platform-specific.
9.4: Standard Events
9.4.1: Overview
CCXML can generate arbitrarily-named events. While any event name is possible, there is a small set of well-known events
that are generated as a matter of course, and which any telephone application should handle. There are three kinds of these
events: connection events, language events and error events.
The first, and larger set, is present so a CCXML session can keep abreast of events happening with the telephone network.
CCXML is designed to be neutral with respect to the telephony layer, so the event set must be very generic and capable of
describing the behavior of a wide variety of systems (e.g., [Q931], [SS7], VoIP, etc).
9.4.2: Standard Event Attributes
9.4.2.1: Overview
All events received in a CCXML session must have a number of standard fields. It is the responsibility of the Event I/O
Processor that delivered the event to make sure that they are present.
9.4.2.2: Standard Event Attribute Table
Attribute Name
Required
Type
Details
name
true
string
This property MUST be set to the ECMAScript string value of the event
name.
eventid
true
string
The unique identifier for the event. This MUST match the sendid
attribute of send, if the event was generated by a CCXML document.
eventsource
true
string
The unique identifier of the event source. If the event source can receive events, you can use
this identifier in the target of send.
eventsourcetype
true
string
The name of the Event I/O Processor that sent this event. If the event source can receive
events, you can use this in the targettype attribute of send.
9.4.3: Connection Events
9.4.3.1: Overview
CCXML applications are notified of Connection activities by events, which often reflect Connection state changes.
Applications may also take actions which change the state of a Connection and which cause other events to be generated.
Language Events are a general class of responses that occur as a result of the execution of elements within a CCXML
document. These events may be further categorized as follows:
Document Control: These events are detailed in section 6.3
Dialog Control: These events are detailed in section 7.3
Event Handling Control: These events are detailed in section 9.3
Call Control: These events are detailed in section 10
9.4.5: Error Events
9.4.5.1: Overview
CCXML uses its event handling mechanism to notify a CCXML document of errors that occur during execution. An error
notification takes the form of an error event that is added to the event queue of the CCXML document where the error occurred.
All error events are named with the prefix "error." so that a properly defined <transition> can
filter out error events.
Here is an example of a <transition> that can be used to filter out and report error events:
All error events have a set of properties in common, shown in the following table:
Attribute Name
Required
Type
Details
reason
true
string
This property is set to the ECMAScript string value of the printable error message associated
with this error
9.5: Error Handling
Due to the nature of CCXML's event handling mechanism, some error scenarios are treated differently. These scenarios are
described below.
9.5.1: Fetching & compilation errors
Errors that occur in trying to load and compile a CCXML document, such as the inability to fetch the CCXML page or
statically referenced ECMAScript content, XML parsing or validation errors (Including checks for mutually exclusive attributes
or any other constraints as defined in the this specification, it's attribute tables, schema or DTD), compilation errors or
other errors that occur as a result of trying to fetch and run a CCXML page prior to document initialization. The handling of
fetching errors is dependent on the context of the fetch; if the fetch was triggered by a running CCXML document using
<createccxml> or <fetch>, then an error.createccxml or
error.fetch (respectively) MUST be thrown to the initiating session. If an error occurs
fetching the initial CCXML document for a session created to handle an incoming call, the CCXML session created for the
incoming call MUST be terminated; the incoming call SHOULD be rejected. If
the session is created through other means (such as the Session Creation Event I/O Processor), the session MUST be terminated; the creator of the session SHOULD be notified.
9.5.2: Document Initialization Errors
Errors that occur during documentation initialization (elements that occur in the CCXML document before
<eventprocessor>) occur outside of CCXML's event handling mechanism. These errors MUST cause the CCXML thread of execution to terminate and notify the platform of the document error.
9.5.3: Error In <eventprocessor> attributes
An <eventprocessor> contains <transition>s that comprise CCXML's event handling
mechanism. Since errors in <eventprocessor> attribute evaluation could keep the EHIA from correctly
processing an event, these errors MUST cause the CCXML thread of execution to terminate and notify the
platform of the document error.
9.5.4: Error in <transition> attributes
<transition> attributes specify when the elements contained by the <transition> should
be executed. Since errors in <transition> attribute evaluation could keep the
<transition> from correctly handling the error event, these errors MUST cause the
CCXML thread of execution to terminate and notify the platform of the document error.
9.5.5: Errors While Handling Error Events
If an error occurs during the handling of an error event another error event will be raised and posted to the front of the
event queue. In many cases this may be perfectly acceptable and the CCXML application may be able to successfully recover from
the error. In some situations however this can lead to an infinite loop in the CCXML session. Implementations MAY choose to include some form of loop detection and to terminate the CCXML session when a loop is
detected.
9.5.6: Errors in hints attributes
Several elements within this specification define a hints attribute. Platforms that do not support
hints on an element MAY ignore this attribute. If a platform supports the
hints attribute on an element, the attribute is specified, and ECMAScript evaluation of the value of the hint
fails or the ECMAScript expression does not resolve to an ECMAScript object, error.semanticMUST be raised for that element and successive elements within the <transition> containing
that element MUST NOT be executed. Additional processing of hints by the implementing platform is
platform-specific.
10: Telephony Operations and Resources
This section contains information on <accept>, <createcall>,
<createconference>, <destroyconference>, <disconnect>,
<join>, <merge>, <redirect>, <reject>, and
<unjoin>.
10.1: Overview
The primary goal of CCXML is to provide call control throughout the duration of a call. Call control includes handling
incoming calls, placing outgoing calls, bridging (or conferencing) multiple call legs, and ultimately disconnecting calls.
In CCXML call control occurs through three major concepts: Connections, Conferences and Bridges.
A Connection is an object modeling a resource by which two independent unidirectional media streams, and optionally any
associated network signaling traffic, can be controlled by a CCXML session. This corresponds roughly to a "call leg" as the
term is used informally. The picture below illustrates the media streams associated with the Connection c1.
A Bridge occurs when the input and/or output media streams of Connections or Conferences are linked or "joined" together.
The picture below depicts the result of a full duplex <join> between the connections c1 and
c2.
A Conference is an object that controls the mixing of media streams for two or more Connections through Bridges.In the
picture below, the connections c1 and c2 are joined in a full duplex mode to the conference C1.
These concepts are discussed in greater detail in the sections below.
10.1.1 Concepts Background (INFORMATIVE)
The goals of the CCXML call model are to focus on relatively simple types of call control and to be sufficiently abstract so
that the call model can be implemented using all major telephony definitions such as JAIN Call Control(JCC) [JSR021], [CSTA], and [S.100]. The JCC call model meets these requirements by providing an event model for connections which abstracts
away many of the differences between telephone networks (e.g., [Q931], [SS7], VoIP, etc). Additionally, this call model is small and easily-understood so that concrete example
programs can be written.
JCC was designed to be a cross-platform high-level event set to describe as generic a phone model as possible. The JCC call
model consists of Addresses, Calls, Connections, and Providers. In the context of CCXML, it was felt that the Address, Call,
and Provider objects would add more complexity than value, so these were omitted as explicitly visible objects. Instead the
behavior of Connections became the focus.
The CCXML call model therefore is based on the behavior of Connections. A call is received or initiated under control of a
CCXML session through the properties of a Connection.
Note that the JCC model is designed for endpoint devices only.
10.2 Connections
The CCXML call model is based on the behavior of Connections.
Each Connection has one input by which it receives a media stream from another Connection or Conference.
Each Connection has one output media stream that can be directed to the inputs of multiple Connections and/or
Conferences.
If a network call is active on a Connection (in the CONNECTED, PROGRESSING or
ALERTING state), the media stream received from the network is the Connection output, and the Connection input
media stream is transmitted to the network.
Dialogs are also modeled internally as a Connection for the purposes of media interaction. The Dialog object behaves as if
it was a Connection object and can be joined to other resources in the same way as any other Connection. A Dialog will not
however be listed in the session.connections session variable.
For a Connection created by <dialogstart> , the Connection input and output media streams are available
to the Dialog resource.
10.2.1: Connection State
The state of a Connection Object reflects events that are generated, either a result of actions that occur within the
telephony network, or as a result of actions performed by the CCXML application. The following state diagram shows the major
aspects of Connection behavior, but omits some detail in favor of clarity (e.g. the ERROR state).
The list of valid states that a connection can be in is:
ALERTING
PROGRESSING
CONNECTED
FAILED
DISCONNECTED
ERROR
CREATED
Connection Objects are created when a incoming call arrives to the platform via a connection.alerting event or
via the execution of <createcall>.
Connection Objects are automatically destroyed by the platform after they have reached the DISCONNECTED,
FAILED or ERROR states. Platforms are responsible for deciding when to remove unused Connection
Objects, however platforms MUST maintain a Connection Object at least through the <transition> for the
corresponding connection.disconnected, connection.failed, connection.redirected,
connection.merged or error.connection event
The PROGRESSING and ALERTING states have reflexive transitions. This is intended to model
protocols which have additional states at these points, and which may exchange messages such as PROCEEDING,
ALERTING, FACILITY, or NOTIFY. Platforms MAY choose to
implement additional states which may be reflected in the substate property of the Connection object.
10.2.2: Connection Object
An instance of the Connection Object is associated with each telephony event source. Each instance is uniquely identified by
its connection identifier. All Connection instances have a set of properties in common, shown in the following table.
Properties that are not indicated as required only appear on an instance of the Connection object if they have a value. Other
properties will always be present.
The Connection Object is an extension of the Media Endpoint Object as defined in
section 10.4.3.
Connection Properties
Required
Definitions
connectionid
true
This property is the ECMAScript string value of the Connection Identifier, which uniquely
identifies each instance of the Connection object.
state
true
This property identifies the current state of the Connection instance; the value of this
property is one of the constants defined in section 10.2.5.
substate
false
This property is a protocol-dependent property which allows further refinement of the state of
a Connection, if desired.
local
false
This property is a URI which addresses the interpreter platform; for an incoming call, this is
the called URI; for a redirected incoming call, this is also the most recent redirection, and the prior values are
contained in the "redirect" property; for an outgoing call, this is the calling URI.
remote
false
This property is a URI which addresses the remote device; for an incoming call, this is the
calling URI; for a redirected incoming call, this is the requester of the most recent redirection, and prior values are
contained in the "redirect" property; for an outgoing call, this is the called URI.
protocol
false
This property is a reference to an object defining protocol information for the protocol used on this connection; the
referenced object defines information which applies to all connections using this protocol, and it has at least two
properties:
name - the name of the connection protocol; the name MAY also be a property on
the connection instance referencing protocol specific information; if no further protocol specific information is
available, then Connection.protocol[Connection.protocol.name] is undefined; (see Appendix E for a
suggested set of protocol names)
version - the version of the connection protocol
For example, the assignment of protocol-dependent user-to-user information to a variable tmp from a
Connection instance referenced by the variable cx would be: <assign name="tmp" expr="cx.protocol[cx.protocol.name].uui"/>
redirect
false
This property is an array representing the connection redirection paths; the first element,
Connection.redirect[0], is the original number, with each subsequent element representing the target as of
subsequent redirections. Each element of the array MAY define any of the following four
properties:
uri - this element's path
pi - presentation information
si - screening information
reason - this is the reason for the redirect for example, "unknown", "user busy", "no reply", "deflection
during alerting", "deflection immediate response", "mobile subscriber not reachable"
aai
false
This property is the application-to-application information passed during connection
setup.
originator
false
This property is set to either "local" or "remote" and indicates the originator of the
connection; for an incoming call, this property is set to "remote"; for an outgoing call, it is set to "local";
For example, the assignment of the originating URI to a variable uri from a Connection instance referenced by
the variable cx would be: <assign name="uri" expr="cx[cx.originator]"/>
input
true
As defined by the Media Endpoint Object in 10.4.3.
outputs
true
As defined by the Media Endpoint Object in 10.4.3.
objecttype
true
This property states the type of this object which must be 'connection'.
Platforms MAY choose to add properties to Connection instances. By convention, the properties
MUST begin with an underscore, "_", to identify them as platform-dependent.
10.2.3: Connection Events
CCXML applications are notified of Connection activities by events, which often reflect Connection state changes.
Applications may also take actions which change the state of a Connection and which cause other events to be generated.
In addition to the standard event attributes detailed in Section 9.4.2, all Connection
events have a set of properties in common, shown in the following table. Fields that are not indicated as required only appear
on the event object if they have a value. Other fields will always be present.
Attribute Name
Required
Type
Details
connectionid
true
string
The ID of the Connection associated with this event.
protocol
false
string
The platform protocol ID of the Connection protocol.
info
false
ECMAScript Object
An object which provides additional platform or protocol dependent information
connection
true
ECMAScript Object
An ECMAScript object reference to the Connection object identified by the connectionid property
of this event.
Platforms MAY choose to add properties to events. By convention, the properties MUST begin with an underscore, "_", to identify them as platform-dependent.
10.2.4: Connection Operations
CCXML defines a number of elements, specified in detail in section 10.5, that are used to interact with Connection Objects.
Execution of these elements MUST NOT immediately change the state of the Connection Object; Connection
Objects change their state once the event corresponding to the event transition is handed. Elements, such as
<accept> or <disconnect>, do not actually change the state of the connection but instead
issue requests to the platform to process the corresponding command that will in turn raise the events that chance the
connection state. The sole exception to this is <createcall>, which creates a Connection Object immediately,
with its 'state' property set to CREATED, allowing the Connection Object to be accessed following the
<createcall>, within the same transition. However, existence of the Connection Object does not guarantee
anything about the success of the <createcall> request.
When elements are used to request an action against a Connection Object, a corresponding event is always generated to
indicate the result of executing that request. For instance, when the <accept> element is used to answer an
incoming call, a 'connection.connected' event indicates that the call was accepted successfully, whereas a
'connection.failed' indicates that the call could not be accepted. The events that can be generated by elements
that act on connections, and the circumstances under which those events occur, are summarized in the table below. Note that the
<join> and <unjoin> elements are not included, since these apply to both Connections and
Conferences, and are discussed in detail in Section 10.4 on Bridges.
There are two common events that can be generated by any of the connection-affecting elements:
If the element cannot be evaluated, for example if the referenced connectionid contained an invalid
ECMAScript expression, then an 'error.semantic' event is thrown - as is the case for all CCXML elements. The
error.semantic event MUST NOT change the state of the associated Connection
Object(s).
If the element cannot be executed because the current state of the referenced Connection Object (or Objects, in the case
of <merge>) is not valid for the requested action, then an 'error.connection.wrongstate'
event is thrown. Note that an error.connection.wrongstate event is thrown based on the state of the Connection
Object, which in turn reflects the events that have been processed by the CCXML application; it is not based on the actual
real-time state of the underlying connection, which could change at any time.
It is important to note that because CCXML is fully asynchronous, and because events can occur on the underlying
communications network at any time, that connection-related events can occur that are not related to application actions. The
most common of these is connection.disconnected, which can be triggered by a user-initiated hangup, and which can
occur in any state during which the call is active.
Finally, once an event is emitted by a Connection Object that transitions to a final state (such as
DISCONNECTED), further events MUST NOT be generated by that Connection Object. Thus, even
if an application has performed an <accept> and expects to receive one of connection.connected,
'connection.accept.failed', or 'connection.failed', it could receive a
'connection.disconnected' instead. Since this event is associated with a transition to the
DISCONNECTED state, no further events will be generated; thus the application will not receive any event as a
result of having performed an <accept>.
The following table shows the events that reflect the outcome of the connection-oriented elements defined by CCXML, for this
reason the table omits the event generated by the underling network (i.e. connection.alerting and
connection.signal):
Element
Event
Reason
(any)
error.semantic
A semantic error in the application, such as the use of an invalid
ECMAScript expression, preventing the element from being executed. The intended target Connection Object state is
unchanged by this event.
error.connection.wrongstate
An element was used on a Connection Object in a state that is not valid
for that element. For instance, performing an <accept> on a Connection Object in the CONNECTED state
would result in this event. The state of the Connection Object is unchanged by this event.
connection.disconnected
The connection has disconnected; no further events, including events for
any pending requests, will be generated. The Connection Object is now in the DISCONNECTED state. Properties of this event
allow the cause of the disconnection to be determined.
error.connection
A platform operational error has occurred on the connection; no further
events, including events for any pending requests, will be generated. The Connection Object is now in the ERROR
state.
<accept>
connection.connected
A connection in the ALERTING state was successfully accepted by the
platform. This event is associated with a transition to the CONNECTED state.
connection.accept.failed
The <accept> request failed to complete – the
event’s reason property may indicate why the request failed. The state of the Connection Object is unchanged by
this event. Example situations that could result in this event include performing <accept> twice (by
the time the second <accept> is processed, the underlying connection would already have been
accepted), or performing <accept> after performing a <reject>.
connection.failed
The <accept> request failed to complete – the
event’s reason property may indicate why the request failed. This differs from connection.accept.failed in that the
state of the Connection Object changes to FAILED. This event would typically occur if an error occurred during the
process of trying to accept the call.
<redirect>
connection.redirected
The <redirect> request completed successfully; the call was
redirected to the specified destination. This event is associated with a transition to the DISCONNECTED
state.
connection.redirect.failed
The <redirect> request failed to complete – the
event’s reason property may indicate why the request failed. This can happen for any number of common reasons
– redirect target status (busy, no answer, etc), invalid destination number, insufficient resources, and others.
This event does not change the state of the call; a CCXML application might well try to redirect to an alternate number,
or perform some other action.
connection.failed
The <redirect> request failed to complete, but terminated the
connection in the process of attempting the redirection. The Connection Object transitions to the FAILED
state.
<reject>
connection.disconnected
A connection in the ALERTING state was either declined successfully (as
a result of the <reject> request), OR was withdrawn before the rejection was performed. The properties of the
connection.disconnected event must be consulted to determine the actual cause. In either case, the Connection Object
transitions to the DISCONNECTED state.
connection.reject.failed
The <reject> request failed to complete – the event’s
reason property may indicate why the request failed. The state of the Connection Object is unchanged by this request.
Similarly to connection.accept.failed, this event can be caused by performing an <accept> followed by
a <reject>.
connection.failed
The <reject> request failed to complete – the event’s
reason property may indicate why the request failed. Unlike connection.reject.failed, the state of the Connection Object
changes to FAILED.
<createcall>
connection.progressing
An outbound connection is progressing; properties of the event may
provide additional information about the progress of the outbound connection. This event does not imply final success or
failure of an outbound connection, and does not change connection state – the Connection Object remains in the
PROGRESSING state.
connection.connected
The <createcall> request completed successfully,
resulting in the establishment of a connection. The Connection Object transitions to the CONNECTED
state.
connection.failed
The <createcall> request was unsuccessful in
establishing an outgoing connection. This can happen for any number of common reasons – target status (busy, no
answer, etc), invalid destination number, insufficient resources, and others. Properties of the connection.failed event
provide more information as to why the connection attempt failed. The Connection Object transitions to the FAILED
state.
connection.disconnected
The <createcall> request was abandoned at the request
of the application (using <disconnect>). The Connection Object transitions to the DISCONNECTED state. This event is
technically the result of the <disconnect> request, but is listed here because it is a possible outcome of the
<createcall> caused by the application. Note also that a network-triggered connection.disconnected is
not possible when establishing an outbound call, as this would trigger a connection.failed event.
<disconnect>
connection.disconnected
A connection in the PROGRESSING or CONNECTED states was disconnected
successfully at the request of the application, or as a result of network-initiated disconnection occurred. The
properties of the event indicate the actual reason for the disconnection. This event is associated with a transition to
the DISCONNECTED state.
connection.failed
The <disconnect> request failed to complete successfully,
resulting in a transition to the FAILED state. This could reflect an error in the disconnection process (such as the lack
of a disconnect acknowledgement from the network).
<merge>
connection.merged
Two connections were merged successfully as requested by the
application. One connection.merged event is received on each of the two connections that were merged. Both Connection
Objects transition to the DISCONNECTED state when their respective connection.merged events are
processed.
connection.merge.failed
A <merge> request failed to complete successfully – the
event’s reason property may indicate why the request failed. The states of the involved Connection Objects are left
unchanged.
10.2.5: Connection Class
All connection objects MUST be initiated via the Connection class. The Connection class MUST be read-only and provide the properties defined below.
The following table lists the constants that correspond to the possible values of the state property of the
connection object.
Constant
Value
Connection.ALERTING
0
Connection.PROGRESSING
1
Connection.CONNECTED
2
Connection.FAILED
3
Connection.DISCONNECTED
4
Connection.ERROR
5
Connection.CREATED
6
The following table lists the values of each index in the array of Connection states. This array MUST be read-only. Each connection state constant can be used to index into this array to return the
human-readable string corresponding to that constant.
Constant
Value
Connection.states[0]
ALERTING
Connection.states[1]
PROGRESSING
Connection.states[2]
CONNECTED
Connection.states[3]
FAILED
Connection.states[4]
DISCONNECTED
Connection.states[5]
ERROR
Connection.states[6]
CREATED
The following example logs the current state of the connection object:
CCXML applications can use <createconference> to create a new conference, or to attach to an existing
conference. The CCXML application can connect or disconnect existing connections/conferences/dialogs to the new conference
using <join> and <unjoin> (as described in Section
10.4). When a session no longer requires the use of a conference, it uses <destroyconference> to detach
from the conference. Asynchronous events will be sent to the CCXML document upon completion of each of these operations.
Each Conference Object has one logical output and multiple inputs. The actual output streams of a Conference Object are
derived by mixing all its input streams, less any contributed audio of an individual Connection, Conference Object who receives
that output. The output of a Conference Object can be directed to the inputs of multiple Connections and/or Conference Object
(as a result of bridging).
Some telephony call control definitions do not define a separate Conference Object, instead defining a conference simply as
a call with more than two parties. In order to accommodate the widest range of underlying telephony API's, CCXML requires
explicit use of a Conference Object whenever two or more audio streams are mixed.
Unlike connections and dialogs, which are local to a single session (but can be moved between sessions using
<move>), conferences are global across all sessions, and can be bridged with the
connections/conferences/dialogs of any session. Conferences can be named in order to facilitate the use of that conference in
other sessions. Assigning a name using the confname attribute allows other sessions to access the created
conference by performing a <createconference> with the same value for confname. Conferences
continue to exist so long as at least one session exists that has attached to the conference using
<createconference> without a corresponding <destroyconference>. When a session
terminates, it implicitly detaches from any conferences to which it is still attached. Note that it is not necessary for a
session to share a conference by assigning it a name in order for other sessions to make use of that conference. Other sessions
may still establish bridges to a conference using <join> and <unjoin>, regardless of
whether or not they have accessed the conference using <createconference>; only the conference ID is
required for this. Because conferences are global, it is not legal to perform a <move> against a
conference.
NOTE: A simple two-party call does not require the use of a conference object. This is discussed in Section 10.4.
10.3.1: Conference Object Properties
An instance of the Conference class is associated with each Conference Object created by
<createconference> and referenced in the session.conferences associative array.
Conference Properties
Required
Definitions
conferenceid
true
This property is the ECMAScript string value of the Conference Identifier, which uniquely
identifies each instance of the Conference class.
bridges
true
This property is an ECMAScript associative array containing the identifiers of all
connections/dialogs within the session that are currently bridged with the conference. Connections/dialogs owned by other
sessions and joined to the same conference are not visible
conferencename
true
This property is the ECMAScript string value of the conference name that was passed in
<createconference>. If no name was provided the value is ECMAScript undefined.
objecttype
true
This property states the type of this object which must be 'conference'.
10.3.2: Conference class
All conference objects MUST be initiated via the Conference class. The Conference class currently
has no defined properties.
10.4: Bridges
A "bridge" is a relationship between the input and/or output streams of Connection, Dialog, and Conference Objects. The
bridge concept and the details of its behavior are fundamental to CCXML Dialogs and Connections are equivalent with respect to
establishing and terminating bridges; the term "Media Endpoint" is used as a common term to refer both to Connections and
Dialogs from the perspective of bridging operations.
There are two main ways in which CCXML applications can manipulate bridges:
Implicitly, using the <createcall> (with 'joinid') and
<dialogprepare>/<dialogstart> (with 'connectionid'/'conferenceid')
elements;
Explicitly, via the <join> and <unjoin> elements.
Even in the simplest case of a network party interacting with a dialog, two Media Endpoints are REQUIRED, and a bridge is established between them implicitly by the action of <dialogstart>.
More complex situations, such as two-party calls, two-party calls with "hotword" recognition, conference control, and
"coaching" scenarios, all involve the use of multiple Media Endpoint and explicit control of one or more bridges between them
by using <join> and <unjoin>.
The nature of bridges, and the behavior of <join> and <unjoin>, is concerned with the
mapping between the media stream inputs and outputs of Media Endpoints and Conferences:
Each Media Endpoint has one input, and 0 or more outputs. If a network call is active on a Media Endpoint, the media
stream received from the network is the Media Endpoint input, and the Media Endpoint output media stream is transmitted to
the network. For a Media Endpoint created by <dialogstart>, the Media Endpoint input media stream is
available to a recognizer under control of the CCXML session, and the Media Endpoint output media stream can be sourced from
a resource (such as a Text To Speech engine) under control of the CCXML session.
The output of a Media Endpoint or Conference can be directed to the inputs of one or more Media Endpoints and/or
Conferences. This is sometimes called "splitting" media streams. Not all environments/implementations will necessarily
support "splitting" a media stream in this manner. In such environments, a request to establish a bridge that requires the
presence of splitting may fail.
A Media Endpoint input can come from the output of only one Media Endpoint or Conference.
A Conference input can have multiple inputs from the outputs of Media Endpoints or Conferences.
If a new bridge requires a Media Endpoint to "listen", and the Media Endpoint is already listening to a different source,
this existing stream relationship is torn down automatically.
Bridges can be either one-way, in which the media stream flows only from party A to party B (such that B can hear A, but A
cannot hear B), or two-way, in which the media stream flows in both directions between the parties involved.
<join> has a duplex attribute to distinguish between two-way bridges and one-way bridges. For
example, <join>ing Media Endpoint A to Media Endpoint B with duplex=full will direct the A
output to the B input, and the B output to the A input, creating a simple two-party call. If instead the same
<join> is done with duplex=half, it will direct the B output to the A input, and will not have
any effect on the B input. Similarly, <dialogprepare>/<dialogstart> have the
'mediadirection' attribute and <createcall> has the 'joindirection' attribute for
controlling what kind of bridge is established.
For "hotword" recognition on a two-party call, a two-way (full duplex) bridge must be established between two network
Connections, and a one-way (half duplex) bridge must be established from one of the network Connections to a Dialog used to
perform the recognition. There are several ways this arrangement can be achieved, depending on the initial states of the
Connections and Dialogs. For example, if the network party on Connection A is initially interacting with Dialog D (i.e., a full
duplex bridge exists between them), all that is needed then is to do a <join> of Connection A to Connection
B (the other network party) with duplex=full. This example highlights an important and subtle aspect of the
behavior of <join> when one, or both, of the Connections being joined is already in one or more established
bridges.
Note that <join>MUST NOT be used to add a Media Endpoint to an existing
two-party bridge in order to create a 3-way Conference Instead, this functionality can be achieved by first using
<createconference> to create a Conference object and then <join>ing all three Media
Endpoints to this Conference. If a two-way bridge exists between A and B, and A is then <join>ed full duplex
to C, the result will be a two-party bridge between A and C and a one-way bridge from A to B.
CCXML applications MUST only establish bridges on Media Endpoints that are owned by the session
running that application. As such, a session cannot bridge a Media Endpoint that it owns to a Media Endpoint that is owned by
another session, nor can it establish a bridge between two Media Endpoints owned by another session. Since Conferences are
global, however, a session MAY bridge a Media Endpoint that it owns to any Conference
Asynchronous events are used to notify the CCXML application upon the completion of bridging operations performed by that
application. Such events are also used to notify the application of changes to existing bridges that were not requested by the
application - such as a <destroyconference> terminating a conference that a local connection has a bridge
to. However, the execution of bridging operations and completion notification varies depending on how the bridging operation
was performed:
Implicit bridges created using <dialogprepare>/<dialogstart> (by specifing
'connectionid' or 'conferenceid') are established when the dialog is started. No bridging events
are generated; the 'dialog.started' event indicates that the dialog was started and the bridge is in place. If
the specified bridge cannot be established, then the dialog MUST not be started, and an
error.dialog.notstarted event is generated. Note that a session could still receive a
conference.joined event when a dialog is implicitly joined to a conference; this event is generated by the
conference.
Implicit bridges created using <createcall> (with 'joinid') are physically realized as
soon as a platform is capable of doing so; however, the inability to establish the bridge immediately upon execution of a
<createcall> does not constitute an error. Prior to the point in time at which the call enters the
CONNECTED state, it may not be possible to establish the requested bridge, or it may only be possible to
establish the bridge one direction. As a result, when using <createcall> with 'joinid', an
event MUST be generated when the requested bridge operation is completed. This event is independent
of connection-related events such as 'connection.connected', and may occur before or after such events depending
on when the bridge is actually realized. If the bridge is established successfully, the 'conference.joined'
event is generated. If the requested bridge cannot be established even after the connection reaches the
CONNECTED state, or if some other issue prevents the bridge from being established, an
'error.conference.join' event will be generated. Referencing a dialog that has been prepared but not started in
'joinid' always result in an error, and thus an 'error.conference.join' event. Note that the call
itself MUST proceed independently of whether or not the bridge can be established. For instance, it
is possible to receive both an 'error.conference.join' event and a 'connection.connected' event for
a single call initiated using <createcall>.
Explicit bridges creation requests using <join> are performed immediately independently, of the state
of the underlying resource. Requests to terminate existing bridges using <unjoin> are also performed
immediately. CCXML applications can use <join> and <unjoin> at any time, except in the
case of dialogs, where <join> and <unjoin> can only be used on dialogs that have been
started. For instance, a CCXML application can join two connections where one (or even both) of the connections is in the
ALERTING state, providing early media on the ALERTING connection. If the CCXML implementation does
not support a requested <join> due to the current state of an underlying entity, then this will result in
an error.conference.join event with the 'reason' field set appropriately.
10.4.1: <join> Outcomes
As an aid to understanding, the outcomes of all possible <join> operations are shown diagrammatically
below for three different initial conditions:
a single Connection A, that is not currently in a bridge, represented graphically as: (A)
two Connections A and B, with a half duplex bridge (A output to B input), represented graphically as: A -----> B
two Connections A and B, with a full duplex bridge (A output to B input & B output to A input), represented
graphically as: A <====> B
For the initial condition in which a single Connection A is not currently in a bridge, there are four possible
<join> s:
initially
(A)(B)
join A to B half
A <----- B
join A to B full
A <====> B
join B to A half
A -----> B
join B to A full
A <====> B
For the initial condition in which a half duplex bridge exists from Connection A to Connection B (A output to B input), there
are twelve possible <join> s:
initially
A -----> B
join A to B half
A <----- B
join A to B full
A <====> B
join B to A half
A -----> B
join B to A full
A <====> B
join A to C half
A -----> B & A <----- C
join A to C full
A -----> B & A <====> C
join C to A half
A -----> B & A -----> C
join C to A full
A -----> B & A <====> C
join B to C half
(A) & B <----- C
join B to C full
(A) & B <====> C
join C to B half
A -----> B & B -----> C
join C to B full
(A) & B <====> C
For the initial condition in which a full duplex bridge exists between two Connections A and B (A output to B input & B
output to A input), there are twelve possible <join> s:
initially
A <====> B
join A to B half
A <----- B
join A to B full
A <====> B
join B to A half
A -----> B
join B to A full
A <====> B
join A to C half
A -----> B & A <----- C
join A to C full
A -----> B & A <====> C
join C to A half
A <====> B & A -----> C
join C to A full
A -----> B & A <====> C
join B to C half
A <----- B & B <----- C
join B to C full
A <----- B & B <====> C
join C to B half
A <====> B & B -----> C
join C to B full
A <----- B & B <====> C
In summary, <join> behavior always respects three invariants:
The media stream relationship specified in the <join> is established between the two
Connections/Conferences referenced in the <join>. In particular, any existing stream relationship between
these two Connections/Conferences is torn down automatically if it conflicts with the specified relationship.
If the relationship specified in the <join> requires a Connection to "listen" and the Connection is
already listening to a different source, this existing stream relationship is torn down automatically.
Any existing stream relationship that does not present a conflict according to invariant #1 or invariant #2 is
preserved.
10.4.2: Invariant Examples
To illustrate some typical invocations of <join> invariants a few example scenarios are presented below.
In the first scenario, connection c1 is bridged to a conference C1, via a <join> where the
duplex mode is full.
After <join id1="'C1'" id2="'c1'" duplex="'full'">
If c1 then became a participant in a <dialogstart> where d1 represents a connection to a
dialog and the mediadirection is both, the original picture would change as follows:
After <dialogstart connectionid="'c1'" src="'example.vxml'" mediadirection="'both'">
The <dialogstart> required c1 to "listen" to d1, however, c1 was already in an
established bridge listening to C1. Consequently, the full duplex bridge between c1 and C1 is changed to a
half duplex, where c1 is not allowed to "listen" to C1 and a full duplex bridge is established between c1
and d1.
In this second scenario, c1 and c2 have been joined into a conference, C1.
After <join id1="'C1'" id2="'c1'" duplex="'full'">
and: <join id1="'C1'" id2="'c2'" duplex="'full'">
If a <join> is then executed that specifies c2 and C1 as participants and the duplex mode
is half, the bridge between c2 and C1 will be re-established with C1 able to "listen" to c2, but
c2 no longer able to "listen" to C1.
In this third scenario, there are three connections c1, c2 and c3. Connections c1 and c2 are connected with a half duplex
bridge, connection 3 is not bridged at this point.
After <join id1="'c1'" id2="'c2'" duplex="'half'">
Session object properties
Connection and Dialog objects all have a common set of base properties relating to media input/output. The standard set of
media endpoint properties are defined below:
Media Endpoint Properties
Required
Definitions
input
true
The identifier (connectiondid/conferenceid/dialogid) of the single media endpoint (connection,
dialog or conference) providing the input stream to this media endpoint or undefined if there is no input stream. This
property MUST be updated each time a <join>/<unjoin> or any other media
operation changes the media source to this media endpoint.
If the media endpoint does not have a media source the value MUST be ECMAScript undefined.
For example the creation of a half duplex bridge <join id1="con1" id2="con2" duplex="'half'" />
Result
session.connections[con1].input = "con2"
session.connections[con2].input = undefined
outputs
true
An array containing the identifiers of all media endpoints to which the output stream of this
media endpoint is sent. If the media endpoint does not have any media destinations the length of the array MUST be 0.
For example the creation of a half duplex bridge <join id1="con1" id2="con2" duplex="'half'" />
Result
session.connections[con1].outputs.length = 0
session.connections[con2].outputs.length = 1
10.5: Elements
10.5.1: <accept>
10.5.1.1: Overview
The execution of an <accept>MUST cause the underlying platform to signal the
telephony system to connect the specified Connection to the CCXML platform. The CCXML document MAY
then initiate interactive dialog sessions with the incoming caller, or perform other telephony operations (e.g., place outgoing
calls, join calls, etc).
10.5.1.2: <accept> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
connectionid
false
ECMAScript Expression
event$.connectionid if defined, ECMAScript undefined otherwise
Connection IDs
An ECMAScript expression which returns a string that must be the identifier of a
Connection on which the incoming call is signaled. If the connectionid attribute is omitted, the interpreter must
accept using the id indicated in the current event being processed.
If the attribute value is invalid or there is no valid default value, an error.semantic event must be thrown.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform or passed to the network accepting the connection. This information may consist of
protocol-specific parameters.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
10.5.2: <redirect>
10.5.2.1: Overview
When a CCXML document executes a <redirect> within the <transition> block, this
MUST cause the underlying platform to signal the telephony system to send the call to a specified
destination. The use of <redirect> is only valid when a call is in the ALERTING and
CONNECTED states.
If the call is currently joined, it MUST be unjoined before the redirect is performed and a
conference.unjoined event MUST be generated. Note the platform is not required to
generate the conference.unjoined or connection.redirected in any particular order.
10.5.2.2: <redirect> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
connectionid
false
ECMAScript Expression
event$.connectionid if defined, ECMAScript undefined otherwise
Connection IDs
An ECMAScript expression which returns a string that is the identifier of a Connection on
which a call is active or on which an incoming call is being signaled. This call must be redirected. If the
connectionid attribute is omitted, the interpreter must redirect using the id indicated in the current event being
processed.
If the attribute value is invalid or there is no valid default value, an error.semantic event must be thrown.
dest
true
ECMAScript Expression
none
A Valid URI
An ECMAScript expression which returns a string that is the address where the call should
be redirected to. A platform MUST support a telephone URI, as described in [RFC3966] and MAY support other URI schemes such as "sip:" or "h323:".
reason
false
ECMAScript Expression
none
An ECMAScript expression which returns a string that is the reason the call is being
redirected.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform or passed to the network redirecting the connection. This information may consist of
protocol-specific parameters.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
If the platform is unable to redirect the call this MUST result in the generation of an
connection.redirect.failed event.
10.5.3: <reject>
10.5.3.1: Overview
The execution of an <reject>MUST cause the underlying platform to signal the
telephony system to reject the incoming Connection from the platform.
10.5.3.2: <reject> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
connectionid
false
ECMAScript Expression
event$.connectionid if defined, ECMAScript undefined otherwise
Connection IDs
An ECMAScript expression which returns a string that is the identifier of a Connection on
which an incoming call is being signaled. This call must be rejected. If the connectionid attribute is omitted, the
interpreter must reject using the id indicated in the current event being processed.
If the attribute value is invalid or there is no valid default value, an error.semantic event must be thrown.
reason
false
ECMAScript Expression
none
An ECMAScript expression which returns a string that is the reason the call is being
rejected.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform or passed to the network rejecting the connection. This information may consist of
protocol-specific parameters.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
10.5.4: <createcall>
10.5.4.1: Overview
A CCXML document is able to instruct the platform to attempt to place an outgoing call with <createcall>.
This element MUST instruct the platform to allocate a Connection and attempt to place an outgoing call
to a specified address. The CCXML interpreter MUST receive an asynchronous event when the call attempt
is completed. An <eventprocessor> <transition> block can handle this event and perform further call
control, such as conferencing. If the call was successfully placed, the transition block can also initiate a dialog interaction
with the called party.
The execution of <createcall>MUST result in the generation of one or more
connection.progressing events (depending on platform support for call progress) followed by a
connection.connected event on success, or zero or more connection.progressing events followed by a
connection.failed event on failure.
10.5.4.2: <createcall> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
dest
true
ECMAScript Expression
none
A Valid URI
An ECMAScript expression which returns a string that is the target of the outbound
telephone call. A platform MUST support a telephone URI, as described in [RFC3966] and MAY support other URI schemes such as "sip:" or "h323:" or a SIP
URI as described in [RFC3261].
connectionid
false
ECMAScript Left Hand Side Expression
none
ECMAScript Variable
An ECMAScript left hand side expression evaluating to a previously defined variable. The
value of the attribute must receive the identifier of the Connection on which the outgoing call is attempted.
aai
false
ECMAScript Expression
none
An ECMAScript expression which returns a string of application-to-application information
to be passed to the destination endpoint when establishing the connection. Note: Even if an implementation platform accepts the aai data, certain protocols and network elements
may prevent the transmission to the target endpoint. If the platform does not support the transmission of aai
data it must raise a connection.progressing event and indicate that the use of aai is not
supported.
callerid
false
ECMAScript Expression
none
An ECMAScript expression which returns a string defining the caller identity to be used
when making the outbound connection. The format of this information is protocol and platform specific but might consist of
a telephone URI, as described in [RFC3966] or a SIP URI as described in [RFC3261]. Note: An implementation platform is not required to use the specified data and certain protocols and network
elements may prevent its use. If the platform does not support the specification of callerid it must
raise a connection.progressing event and indicate that the use of callerid is not supported.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform when establishing the outbound connection. This information may consist of protocol-specific
parameters, protocol selection guidelines, or routing hints.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
timeout
false
ECMAScript Expression
none
An ECMAScript expression which returns a character string in CSS2 [CSS2] format
The character string returned is interpreted as a time interval. This interval begins
when createcall is executed. The createcall must fail if not completed by the end of this interval. A
completion is defined as the call getting to a CONNECTED state as signaled by a connection.connected event. A failed
createcall must return the connection.failed event.
joinid
false
ECMAScript Expression
none
(valid connection, conference, or dialog ID)
An ECMAScript expression that identifies a connection, conference, or dialog ID that the
new call must be joined to. This is equivalent, from the perspective of the CCXML application, to performing a <join>
immediately following the <createcall>. However, platforms may use knowledge about the connection/conference/dialog
to which the new call will be connected to optimize the call creation process. If the attribute value is invalid an
error.semantic event must be thrown.
joindirection
false
This attribute is only valid in conjunction with the joinid
attribute, otherwise ignored.
ECMAScript Expression
both
both
calltransmit
callreceive
An ECMAScript expression that defines the direction of the media flow between the newly created connection, and the
existing connection/conference/dialog referenced by joinid:
both
Specifes a full duplex connection where the media flows in both directions.
calltransmit
The new connection transmits media to the referenced connection/conference/dialog but does not receive any media
streams.
callreceive
The new connection receives media from the referenced connection/conference/dialog but does not transmit any media
streams.
10.5.4.3: <createcall> examples
The following example illustrates the simplest use of <createcall> .
<createcall dest="'tel:1235551234'"/>
This example illustrates the use of several attributes of <createcall>. A SIP URI is provided as the
originators caller id, a selection of protocol specific parameters are provided (callingDevice and
callCharacteristics) and a string of application specific data is provided to be presented to the remote endpoint.
The connection ID for the new connection is returned in the variable "myConidVar".
A CCXML document can attempt to create or attach to a Conference Object using <createconference>. This
element instructs the implementation to allocate a Conference Object using the specified options. The successful execution of
<createconference>MUST result in the generation of a
conference.created event. If for any reason the implementation is unable to create the Conference Object using the
specified options it MUST fail with a error.conference.create event.
Since conferences are global in scope, it is possible that other sessions will establish or terminate bridges to a
Conference created by an application. Sessions that have created or attached to a Conference using
<createconference> receive notifications of any bridges that are created or destroyed, through the
'conference.joined' and 'conference.unjoined' events. However, if a session establishes or terminates
a bridge between a Connection that it owns and a Conference that it has created/attached to, it will only receive one such
event - not one event each for the Connection and for the Conference.
It is legal for a session to perform a <createconference> multiple times with the same value for the
'confname' parameter. The same conference ID will be returned in each case, allowing this to be used as a
mechanism for looking up conference IDs.
10.5.5.2: <createconference> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
conferenceid
true
ECMAScript Left Hand Side Expression
none
ECMAScript Variable
An ECMAScript left hand side expression evaluating to a previously defined variable. The
value of the attribute must receive the conference identifier. A conference identifier must be globally
unique, so that conferences can be uniquely addressed and possibly connected to.
confname
false
ECMAScript Expression
none
valid conference URI
An ECMAScript expression which returns a string that is the name of the conference. The
conference name corresponds to the conference identifier that will be returned in the variable specified in the
conferenceid attribute.
If the named conference does not exist, the platform must create a conference object as requested and return the
value of the conference identifier to the variable specified in the conferenceid attribute. If a conference already
exists the platform must return the conference identifier of the previously created conference.
reservedtalkers
false
ECMAScript Expression
none
An ECMAScript expression which returns the number of guaranteed speaker slots the
conference mixer must reserve. If the conference already exists, then this attribute must be ignored.
If the conference mixer is unable to reserve this many speaker slots, the createconferencemust fail with a
error.conference.create event.
reservedlisteners
false
ECMAScript Expression
none
An ECMAScript expression which returns the number of guaranteed listener slots the
conference mixer must reserve. If the conference already exists, then this attribute must be ignored.
If the conference mixer is unable to reserve this many listener slots, the createconferencemust fail with a
error.conference.create event.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform when creating the conference.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
10.5.6: <destroyconference>
10.5.6.1: Overview
A CCXML document is able to instruct the platform to attempt to detach from an existing Conference Object using
<destroyconference>. This destroys the conference if no other sessions are attached to it. The target
Conference Object is identified using the conferenceid attribute. The successful execution of
<destroyconference>MUST result in the generation of a
conference.destroyed event. If for any reason the implementation is unable to deallocate the Conference Object it
MUST fail with a error.conference.destroy event.
Since other sessions may have created bridges to a conference using the conference's ID, but without performing a
<createconference>, destroying a conference MAY affect the bridges established by
other sessions. If any bridges are terminated in this fashion, a 'conference.unjoined' event MUST be posted to indicate to the session that its Connection is no longer bridged to the Conference.
The platform MUST implicitly tear down any existing bridges to the dialog and send a
conference.unjoined to the CCXML document once the media paths have been freed.
10.5.6.2: <destroyconference> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
conferenceid
true
ECMAScript Expression
none
Conference IDs
An ECMAScript expression which returns a string that is the identifier of the conference
that must be destroyed.
If the attribute value is invalid an error.semantic event must be thrown.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform when destroying the conference.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
10.5.7: <join>
10.5.7.1: Overview
A CCXML document can attempt to create a bridge between two connections, conferences, or dialogs using
<join>. This element instructs the implementation to bridge the connections, conferences, or dialogs
specified using the id1 and id2 attributes in accordance with media options specified by the other
attributes of <join>. The successful execution of<join>MUST
result in the generation of a conference.joined event. If for any reason the implementation is unable to create
the bridge using the specified options it MUST fail with a error.conference.join
event.
Any Connections or Dialogs referenced by the 'id1' and 'id2' attributes of
<join>MUST be owned by the session performing the <join>. If
id1 or id2 refer to Conferences, then it is not necessary that the session has performed a
<createconference> to create/attach to that conference; it is sufficient that it has a valid conference
ID.
When joining a Connection or Dialog to a Conference, or when joining two Conferences, the 'conference.joined'
event MUST be posted to all sessions that are attached to the affected Conference(s). This MUST NOT result in multiple 'conference.joined' events if the session performing the
<join> is attached to the conference, nor if any session owns both conferences when two conferences are
joined together. If the implementation is unable to join the objects an error.conference.joinMUST only be sent to the session that issued the <join>.
Implementations MAY disallow two dialogs from being joined together. If both id1 and
id2 specify dialogs and the platform does not support joining together two dialogs, then an
error.conference.join event is thrown.
10.5.7.2: <join> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
id1
true
ECMAScript Expression
none
(valid connection, conference, or dialog ID)
An ECMAScript expression which returns a string that is the identifier of a Connection,
Dialog or Conference.
If the attribute value is invalid an error.semantic event must be thrown.
id2
true
ECMAScript Expression
none
(valid connection, conference, or dialog ID)
An ECMAScript expression which returns a string that is the identifier of a Connection,
Dialog or Conference.
If the attribute value is invalid an error.semantic event must be thrown.
duplex
false
ECMAScript Expression
full
full
half
An ECMAScript expression that returns a character string equal to "half" or "full", which defines the direction of the
media flow between id1 resource and id2 resource. Refer to the discussion of bridging in Section
10.4 . The duplex attribute determines whether the join must establish a half-duplex (unidirectional)
or full-duplex (bi-directional) bridge. The following values can be used:
full
Specifies a full duplex bridge where the media flows in both directions.
half
Species a half duplex bridge where the media flows towards id1 resource, but no media flows from id1 resource to
id2 resource.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform or passed to the network when the two specified Connections, Dialogs or Conferences (id1 and id2) are
joined. This information may consist of protocol-specific parameters.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
entertone
false
ECMAScript Expression
'true'
'true'
'false'
URI
An ECMAScript expression that returns a character string that must be used to play a tone or a custom wav file to the
conference participants when this Connection joins. The following values can be used:
'true'
Setting this to 'true' must play the default system beep.
'false'
Setting this to 'false' must result in no alerting sound being played at all.
URI
The developer may also specify a URI value which points to a user-defined wav file to be played instead of the
default system beep.
exittone
false
ECMAScript Expression
'true'
'true'
'false'
URI
An ECMAScript expression that returns a character string that must be used to play a tone or a custom wav file to the
conference participants when this Connection exits
(Note: The exact order of operations in this scenario is to play exittone, then unjoin and finally send conference.unjoined).
The following values can be used:
'true'
Setting this to 'true' will play the default system beep.
'false'
Setting this to 'false' will result in no alerting sound being played at all.
A Valid
The developer may also specify a URI value which points to a user-defined wav file to be played instead of the
default system beep.
autoinputgain
false
ECMAScript Boolean Expression
true
true
false
An ECMAScript Boolean expression that tells the conference mixer if it must use AGC to determine the input gain for this
leg. If a platform does not support AGC, it must ignore this attribute. The following values can be used:
true
AGC must be used to determine input gain for a leg.
false
AGC must not be used.
autooutputgain
false
ECMAScript Boolean Expression
true
true
false
An ECMAScript boolean expression that tells the conference mixer if it must use AGC to determine the output gain for this
leg. If a platform does not support AGC, it must ignore this attribute. The following values can be used:
true
AGC must be used to determine output gain for a leg.
false
AGC must not be used.
dtmfclamp
false
ECMAScript Boolean Expression
true
true
false
An ECMAScript Boolean expression that tells the conference mixer if it must attempt to remove detected DTMF tones If a
platform does not support removal of DTMF tones, it must ignore this attribute. The following values can be used:
true
Conference mixer must attempt to remove detected DTMF tones.
false
Conference mixer must not attempt to remove any detected DTMF tones.
toneclamp
false
ECMAScript Boolean Expression
true
true
false
An ECMAScript Boolean expression that tells the conference mixer if it must attempt to remove loud single-frequency tones
from the audio stream for this leg. If a platform does not support removal of tones, it must ignore this attribute. The
following values can be used:
true
Conference mixer must attempt to remove loud single-frequency tones.
false
Conference mixer must not attempt to remove any loud single-frequency tones.
10.5.8: <unjoin>
10.5.8.1: Overview
A CCXML document is able to instruct the platform to attempt to tear down a bridge between two existing connections,
conferences, or dialogs using <unjoin>. This element instructs the implementation to tear down the bridge
between two connections/conferences/dialogs specified using the id1 and id2 attributes. The
successful execution of <unjoin>MUST result in the generation of a
conference.unjoined event. If for any reason the implementation is unable to terminate the bridge between the
specified connections/conferences/dialogs, or if no such bridge exists, it MUST fail with a
error.conference.unjoin event.
Any Connections or Dialogs referenced by the 'id1' and 'id2' attributes of
<unjoin>MUST be owned by the session performing the
<unjoin>.
When 'id1', 'id2', or both reference to a Conference, the 'conference.unjoined' event
MUST be posted to all session that are attached to the affected Conference(s). This MUST NOT result in multiple 'conference.unjoined' events if the session performing the
<unjoin> is attached to the conference, or if any session owns both conferences when two conferences are
being unjoined. If the implementation is unable to unjoin the objects an error.conference.unjoinMUST only be sent to the session that issued the <unjoin>.
10.5.8.2: <unjoin> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
id1
true
ECMAScript Expression
none
(valid connection, conference, or dialog ID)
An ECMAScript expression which returns a string that is the identifier of a Connection,
Dialog or Conference.
If the attribute value is invalid an error.semantic event must be thrown.
id2
true
ECMAScript Expression
none
(valid connection, conference, or dialog ID)
An ECMAScript expression which returns a string that is the identifier of a Connection,
Dialog or Conference. All media streams between the two specified Connections, Dialogs or Conferences (id1 and id2 ) must
be torn down.
If the attribute value is invalid an error.semantic event must be thrown.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform or passed to the network when the two specified Connections, Dialogs or Conferences (id1 and id2) are
unjoined. This information may consist of protocol-specific parameters.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
10.5.9: <disconnect>
10.5.9.1: Overview
A CCXML document is able to instruct the platform to disconnect a Connection by using <disconnect> . The
underlying platform MUST send the appropriate protocol messages to perform the disconnect, and send an
asynchronous event to the CCXML document when the disconnect operation completes. A CCXML document may use
<disconnect> to abandon an outbound connection created using <createcall> which has not
yet entered the CONNECTED state. If <disconnect> is used to abandon an outbound call, it
results in the generation of a 'connection.disconnected' event.
If the connection had been bridged when the <disconnect> request was made, the platform MUST tear down all bridges to the connection and send a conference.unjoined to the CCXML document
once the media paths have been freed.
Note the platform is not required to generate the connection.disconnected /connection.failed or
conference.unjoined in any particular order, unless an outbound call was abandoned in which case a
connection.disconnected event MUST be generated.
10.5.9.2: <disconnect> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
connectionid
false
ECMAScript Expression
event$.connectionid if defined, ECMAScript undefined otherwise
Connection IDs
An ECMAScript expression which returns a string that is the id of a call leg that
must be disconnected. If the connectionid attribute is omitted, the interpreter must disconnect using the id
indicated in the current event being processed.
If the attribute value is invalid or there is no valid default value, an error.semantic event must be thrown.
reason
false
ECMAScript Expression
none
An ECMAScript expression which returns a string that is the reason the call is being
disconnected.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform or passed to the network disconnecting the connection. This information may consist of
protocol-specific parameters.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
10.5.10: <merge>
10.5.10.1: Background
Many of the network environments in which a CCXML implementation may be expected to operate provide facilities by which two
existing calls can be merged into a single call at the network level. The following diagram illustrates this for the case where
user A has two independent calls with users B and C, and utilizes this functionality to merge the calls together:
Figure 1: Initial Call State
Figure 2: State Following Merge
The diagram illustrates the call control connections, or sessions, that exist between users A, B, C and the network that
connects them; the media streams between users is not shown on the above diagram and may differ from the path for call control
that is shown. The media path between users may or may not be affected as a result of the merge, depending on the properties of
the underlying network; typically any media streams to user A would be terminated since call control sessions between user A
and the network are terminated.
There are many different implementations of the merging capabilities described above, across both PSTN and Voice-over-IP
networks. Known implementations include the following:
Release Link Trunk (RLT) (ISDN [Q.931/DSS1], SS7 ISUP [SS7])
Two B-Channel Transfer (TBCT) (ISDN [Q.931/DSS1], SS7 ISUP
[SS7])
Explicit Call Transfer (ECT) (ISDN [Q.931/DSS1], SS7 ISUP
[SS7]ISUP)
AT&T Transfer Connect (some variants) (ISDN [Q.931/DSS1])
Different implementations may also have different restrictions on when and how merge functionality can be used. Some
implementations might allow calls that are alerting to be merged, whereas others might only operate on calls that are already
in the connected state. In addition, some implementations might only be able to merge calls in which one of the calls is an
outbound call that specifically identifies the associated inbound call when that outbound call is placed (via hints on
<createcall>).
10.5.10.2: Overview
The <merge> element allows two calls being handled by a particular CCXML session to be merged together at
the network level, if supported by the underlying network and CCXML platform.
If successful, the two referenced calls MUST be merged at the network level, and the connections to
the CCXML platform associated with those calls MUST be terminated. A connection.merged
event MUST be generated on each of the two calls affected by a merge. If the merge fails, then a
single connection.merge.failed event MUST be thrown which identifies both of the
connections against which the merge was performed.
The platform MUST implicitly tear down any existing bridges to the connections and send a
conference.unjoined to the CCXML document once the media paths have been freed, except for the media path between
the two connections being merged.
10.5.10.3: <merge> Attribute Details
Name
Required
Attribute Constraints
Type
Default Value
Valid Values
Description
connectionid1
true
ECMAScript Expression
none
Connection IDs
An ECMAScript expression which returns a string that is the identifier of the first
connection that is to be merged. The order (connectionid1 vs. connectionid2) of the Connections does not matter.
If the attribute value is invalid an error.semantic event must be thrown.
connectionid2
true
ECMAScript Expression
none
Connection IDs
An ECMAScript expression which returns a string that is the identifier of the second
connection that is to be merged.
If the attribute value is invalid an error.semantic event must be thrown.
hints
false
ECMAScript Expression
none
An ECMAScript expression that returns an ECMAScript object
The ECMAScript object returned contains information which may be used by the
implementing platform or passed to the network when merging the two connections. This information MAY consist of
protocol-specific parameters.
Note: The meaning of these hints is specific to the implementing platform and protocol. Platforms that do not support hints
MAY ignore this attribute. See Section 9.5.6 for additional requirements
when hints are supported by the implementing platform.
10.6: Events
10.6.1: Overview
This section defines the events related to telephony operations including events related to the call state, success and
failure events for the various telephony operations.
Several of the events defined in this section are associated with the change in state of a Connection Object. For instance,
the 'connection.connected' event causes a transition to the CONNECTED state. Platforms MUST perform updates to Connection Object state when events are dequeued by the EHIA before the
<transition> selection process (and thus before execution of <transition> content). This
is necessary such that conditional expressions on transitions, as well as executable content, can reference Connection Object
state that is consistent with the event being processed
10.6.2: connection.alerting
This event MUST be emitted when the underlying telephony connection transitions to an
ALERTING state or sends notification of call progress while the Connection Object is in the ALERTING
state. This event is a transition to state ALERTING.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
Information provided by the protocol prior to connection is accumulated and stored with the identified Connection object.
This information MAY be available when the connection.alerting event is delivered to the
application. Any further information provided by the protocol prior to connection MAY be provided in
subsequent connection.alerting events, and made available in the updated Connection object.
10.6.3: connection.progressing
This event MUST be emitted when the underlying telephony connection sends a notification of call
progress while the Connection Object is in the PROGRESSING state. This event is a transition to state
PROGRESSING.
Subsequent connection.progressing events MAY be generated to support protocols which
exchange multiple messages during the PROGRESSING state.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
10.6.4: connection.connected
This event must be emitted when an incoming connection is accepted successfully, or as when an
outgoing connection is answered. This event is a transition to state CONNECTED.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
10.6.5: connection.disconnected
This event must be emitted when a connection is disconnected due to an action by the underlying
network (e.g. the user hanging up), the CCXML platform, or the CCXML application. This event is a transition to state
DISCONNECTED.
If this is an off-platform event, the platform MUST implicitly tear down any existing bridges to
the connection and send a conference.unjoined to the CCXML document once the media paths have been freed.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
reason
false
string
A disconnection reason code. Content of this field is platform-specific.
trigger
true
string
Indicates which entity cause the disconnection to occur. Valid values are 'network' for
network-initiated disconnections, 'platform' for disconnections triggered by platform-based rules (such as a maximum
connection duration), or 'application' for disconnections performed as a result of application actions (such as execution
of a <disconnect>).
10.6.6: connection.redirected
This event MUST be emitted to indicate a successful redirection of a connection. This event is a
transition to state DISCONNECTED.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
reason
false
string
A redirect result code. Content of this field is platform-specific.
10.6.7: connection.merged
This event MUST be emitted to indicate that a connection has been successfully merged with another
connection at the network level, and is therefore disconnected from the CCXML application. This event is a transition to state
DISCONNECTED.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
mergeid
true
string
The ID of the Connection with which the Connected referenced by this event was merged.
Note that connectionid1 and connectionid2 of the <merge> element are present in
this event as connectionid property (see section 10.2.3) and mergeid property, respectively
10.6.8: connection.failed
This event MUST be emitted when an incoming or outgoing call fails to complete its connection. This
event is a transition to state FAILED.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
reason
false
string
A failure reason code. Content of this field is platform-specific.
10.6.9: error.connection
This event MUST be emitted if a platform operational error occurs on a connection which renders
that connection unusable. This event is a transition to state ERROR.
If this is an off-platform event, the platform MUST implicitly tear down any existing bridges to
the connection and send a conference.unjoined to the CCXML document once the media paths have been freed.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
reason
true
string
A description of the reason the operation failed. Content of this field is
platform-specific.
10.6.10: connection.signal
This event MAY be emitted by the platform to notify the application of non state changing
Connection related events. This event MUST NOT directly change the state of the connection. Examples
where connection.signal could be generated include:
DTMF received on the media stream after connection, perhaps identifying call setup information such as DNIS;
Messaging received by the protocol after connection, such as that delivered by SIP INFO or ISDN FACILITY messages;
Call analysis results indicating the results of answering machine, FAX, TDD or modem detection attempts.
The Connection Object MAY be updated with new or changed information as the result of a
connection.signal event.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
10.6.11: conference.created
This event MUST be emitted when a conference has been successfully established using
<createconference>. The fields of this event are:
Attribute Name
Required
Type
Details
conferenceid
true
string
The ID of the Conference associated with this event.
conference
true
ECMAScript Object
An ECMAScript object reference to the Conference object identified by the conferenceid
property of this event.
info
false
ECMAScript Object
An object which provides additional platform or protocol dependent information
10.6.12: conference.destroyed
This event MUST be emitted when a session detaches from a conference using
<destroyconference>. Note that this does not imply that the underlying conference has necessarily been
destroyed, since there may be other sessions attached to that conference. The fields of this event are:
Attribute Name
Required
Type
Details
conferenceid
true
string
The ID of the Conference associated with this event.
info
false
ECMAScript Object
An object which provides additional platform or protocol dependent information
10.6.13: conference.joined
This event MUST be emitted when two resources (which are connections or conferences) have been
bridged using <join> or <createcall>. The fields of this event are shown below.
If a session receives a 'conference.joined' event because it is attached to a Conference, either
'id1' or 'id2' may refer to a Connection/Dialog owned by another session. Such identifiers are not
locally meaningful to the session receiving the event (although they can still be used for logging or other purposes).
Join-related events (including conference.joined, conference.unjoined,
error.conference.join, and error.conference.unjoin) use the id1 and id2
attributes to identify the connections, conferences, or dialogs against which the event occurs. The value of id1
and id2 will depend on why the event was generated, and will be set according to the following rules:
For events resulting from a <join> or <unjoin> operation, id1 and
id2 will have the same values supplied via the id1 and id2 attributes in the original
element;
For events resulting from a <createcall> with a joinid attribute, id1 will
reflect Connection ID of the created call, and id2 will have the same value as the joinid
attribute;
For events resulting from a Connection, Conference, or Dialog becoming unavailable, id1 will reflect the ID
of the object that became unavailable, and id2 will reflect the ID of the object it was previously joined to.
Such events may occur for many reasons - asynchronous disconnection, <disconnect>,
<merge>, or <redirect> (on a Connection), <destroyconference>, and
dialog.exit or <dialogterminate> (on a Dialog). Failures may also cause the termination of
bridges. However, due to the asynchronous nature of CCXML, applications should not generally rely on this ordering, since
(for example) a Connection might disconnect at the same time that an application performs a
<dialogterminate>.
The fields of this event are:
Attribute Name
Required
Type
Details
id1
true
string
The ID of the Connection, Conference or Dialog representing a resource associated with this
event.
id2
true
string
The ID of the Connection, Conference or Dialog representing a resource associated with this
event.
object1
true
ECMAScript Object
A Connection, Conference or Dialog object associated with this event.
object2
true
ECMAScript Object
A Connection, Conference or Dialog object associated with this event.
10.6.14: conference.unjoined
This event MUST be emitted when a bridge is torn down between two resources using
<unjoin>.
A conference.unjoinedMUST also be emitted when a bridge needs to be torn down before
an element can be executed or when an event indicates the loss of a one end of a bridge, such as when processing
<disconnect>, <redirect>, <dialogterminate>, <destroyconference> or <merge> elements
or when receiving asynchronous events such as connection.disconnected, error.connection or error.dialog.
If a session receives a 'conference.unjoined' event because it is attached to a Conference, either
'id1' or 'id2' may refer to a Connection/Dialog owned by another session. Such identifiers are not
locally meaningful to the session receiving the event (although they can still be used for logging or other purposes).
The ordering of the id1 and id2 attributes is as specified in 10.6.13:
conference.joined.
The fields of this event are:
Attribute Name
Required
Type
Details
id1
true
string
The ID of the Connection, Conference or Dialog representing a resource associated with this
event.
id2
true
string
The ID of the Connection, Conference or Dialog representing a resource associated with this
event.
object1
true
ECMAScript Object
A Connection, Conference or Dialog object associated with this event.
object2
true
ECMAScript Object
A Connection, Conference or Dialog object associated with this event.
10.6.15: error.conference.create
The processing associated with the <createconference> failed. The fields in this event are:
Attribute Name
Required
Type
Details
conferenceid
true
string
The ID of the affected conference.
reason
true
string
A description of the reason the operation failed. Content of this field is
platform-specific.
10.6.16: error.conference.destroy
The processing associated with the <destroyconference> failed. The fields in this event are:
Attribute Name
Required
Type
Details
conferenceid
true
string
The ID of the affected conference.
reason
true
string
A description of the reason the operation failed. Content of this field is
platform-specific.
10.6.17: error.conference.join
The processing associated with the <join> failed.
The ordering of the id1 and id2 attributes is as specified in 10.6.13:
conference.joined.
The fields in this event are:
Attribute Name
Required
Type
Details
id1
true
string
The ID of the Connection, Conference or Dialog representing a resource associated with this
event.
id2
true
string
The ID of the Connection, Conference or Dialog representing a resource associated with this
event.
reason
true
string
A description of the reason the operation failed. Content of this field is
platform-specific.
10.6.18: error.conference.unjoin
The processing associated with the <unjoin> failed.
The ordering of the id1 and id2 attributes is as specified in 10.6.13:
conference.joined.
The fields in this event are:
Attribute Name
Required
Type
Details
id1
true
string
The ID of the Connection, Conference or Dialog representing a resource associated with this
event.
id2
true
string
The ID of the Connection, Conference or Dialog representing a resource associated with this
event.
reason
true
string
A description of the reason the operation failed. Content of this field is
platform-specific.
10.6.19: connection.merge.failed
This event MUST be emitted when a <merge> attempt fails. This event MUST NOT change the state of either of the Connection Objects involved in the merge operation.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
mergeid
true
string
The ID of the Connection with which the Connected referenced by this event was merged.
reason
true
string
A description of the reason the merge failed. Content of this field is
platform-specific.
Note that connectionid1 and connectionid2 of the <merge> element are present in
this event as connectionid property (see section 10.2.3) and mergeid property, respectively
10.6.20: error.connection.wrongstate
This event MUST be emitted when an application attempts a telephony operation that is not legal for
the current state of the Connection Object. Note that the Connection Object state is current as of the event currently being
processed, but may not reflect events that are currently queued, or other events that occur before the request generated by an
element is processed; therefore, not all failures caused by the state of the actual connection will result in
error.connection.wrongstate. This event indicates that an application performed an action that it should know to
be illegal, and generally reflects an incorrectly written application.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
reason
true
string
A description of the reason the operation failed. Content of this field is
platform-specific.
tagname
true
string
This property must be set to the ECMAScript string value of the name of the element that
produced the error (ie accept, reject, etc).
10.6.21: error.conference
This event MUST be emitted when an error occurs on a conference that a session has created or
attached to, and signals the termination of the referenced conference. It is not necessary for applications to call
<destroyconference> after receiving an error.conference event (in much the same way that it is
not necessary to call <disconnect> upon receiving an error.connection event).
The fields of this event are:
Attribute Name
Required
Type
Details
conferenceid
true
string
The ID of the affected conference.
reason
true
string
A description of the reason the operation failed. Content of this field is
platform-specific.
10.6.22: connection.redirect.failed
This event MUST be emitted when an error occurs when there is an error redirecting a connection
using the <redirect> element.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
reason
true
string
A description of the reason the redirect failed. Content of this field is
platform-specific.
10.6.23: connection.accept.failed
This event MUST be generated when a request to accept an incoming connection cannot be completed.
This event MUST NOT change the state of the Connection Object.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
reason
true
string
A description of the reason the accept failed. Content of this field is
platform-specific.
10.6.24: connection.reject.failed
This event MUST be generated when a request to reject an incoming connection cannot be completed.
This event MUST NOT change the state of the Connection Object.
This event includes the standard event and connection event properties along with the following additional event specific
properties:
Attribute Name
Required
Type
Details
reason
true
string
A description of the reason the reject failed. Content of this field is
platform-specific.
11: Complex Examples
11.1: Calling Card Application
Caller calls an 800 number and after some interaction with an IVR
system places an outbound call to a friend.
<?xml version="1.0" encoding="UTF-8"?>
<vxml xmlns="http://www.w3.org/2001/vxml" version="2.0">
<form>
<block>
Sorry. The Party you are trying to call
is unavailble.
<exit/>
</block>
</form>
</vxml>
<?xml version="1.0" encoding="UTF-8"?>
<vxml xmlns="http://www.w3.org/2001/vxml" version="2.0">
<form id="form2">
<!--.asp consults back-end database before filling this value-->
<assign name="timeleft" expr="600"/>
<block> Time remaining is <value expr="timeleft"/> seconds </block>
<field name="telnum" type="digits" >
<prompt> Please speak the telephone number you want to call including the country code.
for example you would say <say-as interpret-as="characters">14075551234</say-as>
</prompt>
<filled>
<exit namelist="telnum"/>
</filled>
</field>
</form>
</vxml>
11.2: Conferencing application
Different callers call into a conference through an agreed upon telephone number. When each one of them joins the conference
he is told how many people are there in the conference and those already in the conference are informed about a new entrant to
the conference. Similarly when someone hangs up, the fact that a conference participant has exited is announced. A conference
object is created at the beginning of the conference and is destroyed when all the participants have hung up.
<?xml version="1.0" encoding="UTF-8"?>
<vxml xmlns="http://www.w3.org/2001/vxml" version="2.0">
<form>
<block>
Welcome to the W3C conference. There are already
<value expr="'3'" />
participants in the conference.
<!--above value is based on count kept by vconference.asp-->
</block>
</form>
</vxml>
<?xml version="1.0" encoding="UTF-8"?>
<vxml xmlns="http://www.w3.org/2001/vxml" version="2.0">
<form>
<block>
A new participant has entered the conference.
</block>
</form>
</vxml>
This program is a Personal Assistant that operates as an automated answering service.
A subscriber to this service would receive a phone number to the automated service. When a caller wants to talk to the
subscriber, he calls the given number. This automated system asks who the caller is, and records the audio. Then the system
calls the current number of the target person, and asks if the call should be connected.
If so, the calls are bridged. If not, then the original caller is warned and disconnected.
<?xml version="1.0" encoding="UTF-8"?>
<vxml xmlns="http://www.w3.org/2001/vxml" version="2.0">
<form>
<record name="recording">
<prompt>
You have reached the personal assistant for Bill Lumbergh of InnoTech.
If is about the new TPS format please call Dom Portwood to get the new cover sheet.
If this is for any other reason go on and state your name
and I will decide if I want to take your call.
Oh ya, if this is Milt, we're gonna need to go ahead and
move you downstairs into storage B. We have some new people
coming in, and we need all the space we can get. So if you
could go ahead and pack up your stuff and move it down there,
that would be terrific, OK
</prompt>
<filled>
OK, thanks.
<submit next="postRecordingAndExit.vxml" namelist="recording" />
</filled>
</record>
</form>
</vxml>
<?xml version="1.0" encoding="UTF-8"?>
<vxml xmlns="http://www.w3.org/2001/vxml" version="2.0">
<var name="willaccept"/>
<form>
<field id="answer">
<grammar src="yesnogrammar.grxml" />
<prompt>
Hi bill, you have a message from
<audio src="dynamicallyRecordedName.wav" />
Would you like to take it? Say Yes, or No.
</prompt>
<filled>
<if cond="answer=='yes'">
Just a moment, please hold.
<assign name="willaccept" value="true" />
<exit namelist="willaccept" />
<elseif cond="answer==no" />
OK, goodbye.
<assign name="willaccept" value="false" />
<exit namelist="willaccept" />
</if>
</filled>
</field>
</form>
</vxml>
<?xml version="1.0" encoding="UTF-8"?>
<vxml xmlns="http://www.w3.org/2001/vxml" version="2.0">
<form id="Form">
<block>
<prompt bargein="false">
When a man loves a woman
Can't keep his mind on nothin' else
He'd trade the world
For a good thing he's found
If she is bad, he can't see it
She can do no wrong
Turn his back on his best friend
If he puts her down.
</prompt>
<goto next="holdmusic.vxml" />
</block>
</form>
</vxml>
Appendix A - Related Work
CPL
The Call Processing Language [CPL] is an XML based language that can be
used to describe and control Internet telephony services. Its focus is user scripting of call handling behavior for incoming
calls. It is designed to be suitable for running on a server where users may not be allowed to execute arbitrary programs, and
so is not Turing-complete.
CallXML
CallXML [CALLXML] is a markup language created by Voxeo Corporation
that includes both voice and call-control functionality. CallXML is an XML based markup language used to describe the user
interface of a telephone, voice over IP, or multi-media call application to a CallXML browser.
CallXML was designed to make it easy for Web developers to create applications that can interact with and control any number
or type of calls, including:
Telephone or Voice over IP call applications which can control the initiation and routing of a phone call itself,
supporting such features as outbound dialing, conferencing, and multi-call interactions (e.g., conference bridges, Internet
call waiting, follow-me/find-me, etc)
Telephone or Voice over IP call applications which can easily interact and respond to touch-tone based entry and
selection (e.g., voicemail, interactive voice response)
Call Applications which include support for additional media, such as faxes and video (e.g., unified messaging, video
conferencing, etc.)
ECMA-CSTA
The description of CSTA [CSTA] from http://www.ecma-international.org/ is
as follows:
"CSTA specifies an Applications Interface and Protocols for monitoring and controlling calls and devices in a
communications network.
These calls and devices may support various media and can reside in various network environments such as IP, Switched
Circuit Networks and mobile networks. CSTA however, abstracts various details of underlying signalling protocols (e.g.
SIP/H.323) and networks for the applications."
The architecture of CCXML would allow a platform to be based on CSTA for the underlying telephony protocol while still
providing the CCXML execution environment for ease of integration with voice browsers.
TXML
TXML (Telera's Extensible Markup Language) is an XML based language
designed by Genesys (formerly Telera) for remotely controlling the behavior of Point of Presence (POP) servers.
TXML provides the syntax for the XML Pages, which are generated at the customer's application at the premises and used by a
POP server to execute actions on behalf of the customer's application. The XML Pages are simple ASCII text files that are
either stored in a Web server's directory at the premises or generated by scripts at the premises server. The XMLPages are
requested from the premises server via HTTP requests made by a client
on the POP gateway.
The language includes elements for
Media Control
Call Control and Telephony
Call Router Integration
SIP
SIP, the Session Initiation Protocol, [RFC3261] is a signaling protocol
for Internet conferencing, telephony, presence, events notification and instant messaging. As a signaling protocol, SIP sits
"below" the application description level of VoiceXML and CCXML. We expect many CCXML and VoiceXML browsers to support SIP
signaling.
This section describes the details of how CCXML and VoiceXML 2.0 work together to provide dialog functionality in CCXML.
The CCXML application behaviors described below are guidelines and applications are not required to support the full set of
VoiceXML interactions. Platforms however should support the events and methods specified below to allow CCXML applications to
implement the behaviors documented in this Appendix.
Since HTTP is a stateless protocol, application servers typically use cookie-based and/or URI rewriting techniques to enable
stateful interactions with the server. Authors should be aware that application servers employing cookie-based management
techniques will view concurrently executing CCXML and VoiceXML applications as independent (the CCXML and VoiceXML cookie
stores are independent). Authors wishing to correlate CCXML and VoiceXML data at the server can use URI rewriting or
alternatively employ the CCXML sessionid variable together with the connectionid or conferenceid as a common, unique key across
the CCXML and VoiceXML applications.
D.2 Events
CCXML and VoiceXML 2.0 need to be able to exchange events between the browsers. The method of the message passing is up to
the platform but it is assumed that there is some basic capacity in place.
Each running CCXML session has an event queue used to process CCXML events, independently of VoiceXML event processing by
the dialogs created by that CCXML session. The execution of certain CCXML elements, such as
<dialogterminate> and <send>, may cause events to be sent to the VoiceXML browser;
similar, certain VoiceXML elements such as <transfer> will result in the generation of dialog events
delivered to the CCXML session that owns the dialog in question. The sections below define the event relationship between the
CCXML and VoiceXML environments.
VoiceXML 2.0 provides limited capabilities for handling asynchronous or unexpected events. Since CCXML is designed around a
robust event processing mechanism, and since the CCXML session manages connections to the underlying network, processing of
asynchronous events - which may be delivered through externally accessible event I/O processors - typically occurs primarily
within the CCXML application, which can then control the VoiceXML session as appropriate. The VoiceXML dialog can therefore
focus exclusively on interaction with the user.
D.3 VoiceXML Session Variables
When a VoiceXML dialog is bridged to a connection with an associated call leg, the standard VoiceXML session variables
obtain their values from the call leg. Otherwise, these variables are undefined. After the dialog is bridged to a connection,
VoiceXML session variables are not updated again. CCXML defines an additional read-only VoiceXML session variable, also
populated when the dialog is bridged to a connection, called session.connection.ccxml with the following
sub-properties:
session.connection.ccxml.sessionid
This variable evaluates to the CCXML Session ID to which the VoiceXML dialog is currently associated.
session.connection.ccxml.dialogid
This variable evaluates to the CCXML Dialog ID for the current dialog.
session.connection.ccxml.connectionid
This variable evaluates to the CCXML Connection ID to which the VoiceXML dialog is currently bridged. This variable is
undefined if the dialog is not bridged to a connection.
session.connection.ccxml.conferenceid
This variable evaluates to the CCXML Conference ID to which the VoiceXML dialog is currently bridged. This variable is
undefined if the dialog is not bridged to a conference.
session.connection.ccxml.values
This associative array contains the names and values of the parameters attribute supplied in a CCXML
<dialogprepare> or <dialogstart> invocation.
D.4 CCXML <dialogprepare>
When a CCXML application processes a <dialogprepare> element it prepares a VoiceXML application with the
URI that is passed in on the <dialogprepare> element.
Normally it is expected that a VoiceXML dialog environment will use the <dialogprepare> request as an
opportunity to fetch the initial document indicated by the src and namelist attributes along with any
referenced resources such as <audio>, <script>, and <grammar> elements
marked as prefetchable.
Even if a VoiceXML dialog environment is unable to perform any useful preparation the CCXML implementation MUST support the <dialogprepare> element and deliver a dialog.prepared event in
response. The implementation MUST as a minimum, note the values provided via the src,
namelist, and connectionid attributes, create a Dialog object, and return a new unique value to the
location defined by the dialogid attribute.
D.5 CCXML <dialogstart>
When a CCXML application processes a <dialogstart> element it starts up a VoiceXML application on the
connection with the URI that is passed in on the <dialogstart> element or to the dialog that was prepared
using <dialogprepare> and specified using the prepareddialogid attribute.
D.6 CCXML <dialogterminate>
When a CCXML application processes a <dialogterminate> it causes a
"connection.disconnect.hangup" event to be thrown to the VoiceXML application. As far as the VoiceXML application
knows the call was just disconnected. The VoiceXML application still has a chance to return data to the CCXML application by
using <exit> in its <catch> statement.
D.7 VoiceXML <exit>
When a VoiceXML application processes a VoiceXML <exit> it will cause the VoiceXML application to exit
and return the contents of the namelist attribute to the CCXML application in the "dialog.exit" event
in the following form:
<exit namelist="foo bar jar"/>
maps into an event that looks like the following:
dialog.exit
values.foo
values.bar
values.jar
and could be accessed in a CCXML Application like this:
<!-- Process the incoming call -->
<transition state="dialogActive" event="dialog.exit">
<log expr="'Houston, the dialog foo: [' + event$.values.foo + ']'" />
<log expr="'Houston, the dialog bar: [' + event$.values['bar'] + ']'" />
<var name="xxx" expr="'jar'/>
<log expr="'Houston, the dialog jar: [' + event$.values[xxx] + ']'" />
<exit />
</transition>
If the VoiceXML application is returning data using the expr attribute the data will be stored in
"values".
<!-- Process the incoming call -->
<transition state="dialogActive" event="dialog.exit">
<log expr="'Houston, the dialog using expr [' + event$.values + ']'" />
<exit />
</transition>
D.8 VoiceXML <disconnect>
When the VoiceXML application processes a <disconnect> element it causes a
"dialog.disconnect" event to be thrown in the CCXML application. It is then up to the CCXML application to
disconnect the call and sends back a "connection.disconnect.hangup" event by using the
<dialogterminate> element. The following is an example of what would happen:
The VoiceXML application executes a <disconnect>.
As a result, the VoiceXML interpreter sends a disconnect event to CCXML.
CCXML receives a "dialog.disconnect" event from the VoiceXML application. It interprets this as a request
from the VoiceXML application to "please disconnect me".
An eventprocessor in the CCXML document SHOULD have a <transition> element
intended to handle the "dialog.disconnect" event.
The CCXML application would have a <disconnect> element as the child of the transition event. This
would disconnect the call.
An eventprocessor in the CCXML document should have a <transition> element intended to handle the
"connection.disconnected" event.
The <transition> element has a child element which performs a <dialogterminate> on
the dialog.
Here is the example CCXML code that completes the disconnect and returns the "connection.disconnect.hangup"
event back to VoiceXML using <dialogterminate>:
When a VoiceXML application processes a <transfer> element it is handled within CCXML via series of
events between the VoiceXML platform and the CCXML application. The type of transfer is controlled in VoiceXML 2.0 by the
bridge attribute. If the value of bridge is "true" this will come in with a transfer
type of "bridge" and if the value is "false" it will have a type of "blind". Here is an
example of the logic to support the VoiceXML 2.0 transfer types:
The VoiceXML application executes a <transfer> causing a dialog.transfer event to be sent
to the CCXML Session.
The CCXML document should have a <transition> to handle the dialog.transfer event. This
transition should implement the logic in the following steps.
If the type attribute of the dialog.transfer event is "blind" perform the
following:
Execute a <redirect> to move the call to URI specified in the dialog.transfer
event
The CCXML Application sends a connection.disconnect.transfer event to inform the VoiceXML session that
the <transfer> is complete.
If the type attribute of the dialog.transfer event is "bridge" perform the
following:
Invoke a <createcall> to create an outgoing call leg.
If the <createcall> completes with a connection.connected event then do the
following:
Join the two call leg together as full duplex and if needed start a maxtime timer.
If a connection.disconnected event comes in for the original party:
Disconnect the new party
Return a connection.disconnect.hangup using <dialogterminate> to the VoiceXML
session.
If a connection.disconnected event comes in for the new party:
<join> the original connection back to the dialog full dupex
return a dialog.transfer.complete event to the dialog with a reason of
far_end_disconnect.
If a maxtime event comes in:
Disconnect the new party
<join> the original connection back to the dialog full dupex
send a dialog.transfer.complete event to the dialog with a reason of
maxtime_disconnect
If a dialog.terminatetransfer event comes in:
Disconnect the new party
<join> the original connection back to the dialog full dupex
send a dialog.transfer.complete event to the dialog with a reason of
near_end_disconnect
If the <createcall> fails with a connection.failed event then do the following:
Send a dialog.transfer.complete event to the VoiceXML dialog with the failure reason.
If the type attribute of the dialog.transfer event is bridge, and if early media
is desired/permissible, then the above steps should be performed with the following exceptions:
When invoking <createcall> to create the outgoing call leg, the joinid attribute
should be specified and should refer to the connection ID of the inbound leg associated with the dialog performing the
<transfer>;
If the <createcall> completes with a connection.connected event, start a maxtime
timer (if needed), but do not perform a <join> (since the calls are already joined).
dialog.transfer.complete
This event MUST be sent from the CCXML application to the Dialog which uses this to fill transfer
results (i.e. for VoiceXML platforms to fill field item results). The <send> attributes used to send this
event are:
Attribute Name
Required
Type
Details
target
true
ECMAScript Expression
dialogid of the dialog whose transfer is complete
targettype
true
ECMAScript Expression
dialog
sendid
false
ECMAScript Left Hand Side Expression
Optional sendid
delay
false
ECMAScript Expression
Optional delay
name
true
ECMAScript Expression
dialog.transfer.complete
namelist
true
Var List
results
with the value of the transfer field to be filled in
The VoiceXML interpreter is responsible for throwing this event when a "hotword" grammar is matched while performing a
bridged transfer.
D.10 User Disconnect
When a caller hangs up on one of the connections the VoiceXML dialog is not automatically disconnected. The CCXML
application then needs to send a "connection.disconnect.hangup" event to the VoiceXML application by using the
<dialogterminate> element so it can complete any cleanup that is required. The VoiceXML application can then
still return data to the CCXML application by using the VoiceXML <exit> element.
D.11 VoiceXML 2.0 Example
The following example code shows how you would duplicate the standard VoiceXML 2.0 Interpreter Context in a CCXML
Application. This example is not meant to be a complete application and does not handle all error events but is rather meant to
give an overview of what such an application may look like.
<?xml version="1.0" encoding="UTF-8"?>
<ccxml version="1.0" xmlns="http://www.w3.org/2002/09/ccxml">
<!-- Declare the vars we are going to use -->
<var name="in_connectionid" />
<var name="out_connectionid" />
<var name="dialogid" />
<var name="vxml_maxtime"/>
<var name="URI"/>
<var name="maxtime_sendid"/>
<var name="results"/>
<!-- Set an initial state -->
<var name="mystate" expr="'init'"/>
<eventprocessor statevariable="mystate">
<!--
- Deal with an incoming call
-->
<transition state="init" event="connection.alerting">
<!-- Save off the connection ID -->
<assign name="in_connectionid" expr="event$.connectionid" />
<accept connectionid="event$.connectionid"/>
</transition>
<!--
- Call is connected so lets start the dialog
-->
<transition state="init" event="connection.connected">
<dialogstart connectionid="event$.connectionid"
src="http://www.example.com/dialog.vxml"
dialogid="dialogid"/>
<assign name="mystate" expr="'connected'" />
</transition>
<!--
- Dialog is active
-->
<transition state="connected" event="dialog.started">
<assign name="mystate" expr="'dialogActive'" />
</transition>
<!--
- Dialog requests that we disconnect the call
-->
<transition state="dialogActive" event="dialog.disconnect">
<disconnect connectionid="event$.connectionid" />
<assign name="mystate" expr="'disconnecting'" />
</transition>
<!--
- We have disconnected the call. Do a dialog terminate to the dialog.
-->
<transition state="disconnecting" event="connection.disconnected">
<dialogterminate dialogid="dialogid"/>
</transition>
<!--
- Dialog has exited after we disconnected the call.
- We just are going to exit from this CCXML session...
-->
<transition state="disconnecting" event="dialog.exit">
<exit/>
</transition>
<!--
- The caller disconnected. We need to send the event up to
- the Dialog and change our state.
-->
<transition state="dialogActive"
event="connection.disconnected">
<dialogterminate dialogid="dialogid"/>
<assign name="mystate" expr="'userDisconnect'" />
</transition>
<!--
- Dialog has exited after the caller hungup.
- We just are going to exit from this CCXML session...
-->
<transition state="userDisconnect" event="dialog.exit">
<exit/>
</transition>
<!--
-
- Handle a transfer request from a VXML script.
-
-->
<transition state="dialogActive" event="dialog.transfer">
<!-- Branch on transfer type -->
<if cond="event$.type == 'blind'">
<!-- Bridge == false. We are going to just redirect the call -->
<!-- Update our state var -->
<assign name="mystate" expr="'redirecting'" />
<!-- And redirect to the uri specified in the event -->
<redirect connectionid="in_connectionid" dest="event$.uri" />
<!-- Just send the success event to the dialog -->
<send name="'connection.disconnect.transfer'"
target="dialogid"
targettype="'dialog'"/>
<else/>
<!-- Bridge == true. In this case we need to
place a call and bridge the calls -->
<!-- save off maxtime -->
<assign name="vxml_maxtime" expr="event$.maxtime" />
<!-- Update our state var -->
<assign name="mystate" expr="'calling'" />
<!-- Place the call using the values from the transfer request -->
<assign name="URI" expr="event$.uri" />
<createcall dest="event$.uri"
connectionid="out_connectionid"
aai="event$.aai"
timeout="event$.connecttimeout"/>
</if>
</transition>
<!--
- We will get the following events but we do not do anything
- because in VoiceXML 2.0 you just ignore redirect errors.
- We do however process the dialog.exit and shutdown
- the CCXML Session.
-->
<transition state="redirecting"
event="connection.redirected">
</transition>
<transition state="redirecting" event="connection.redirect.failed">
</transition>
<transition state="redirecting" event="dialog.exit">
<exit/>
</transition>
<!--
-
- Handle bridge=true Events
-
- This first event is for if the outbound call failed.
-
-->
<transition state="calling" event="connection.failed">
<!-- Just send the error event to the dialog -->
<assign name="results" expr="event$.reason"/>
<send name="'dialog.transfer.complete'"
target="dialogid"
targettype="'dialog'"
namelist="results" />
<!-- Update our state var back to the original state -->
<assign name="mystate" expr="'dialogActive'" />
</transition>
<!--
- The outbound call has been answered.
-->
<transition state="calling" event="connection.connected">
<!-- Update our state var back to show that we are connected -->
<assign name="mystate" expr="'outgoing_call_active'" />
<!-- Unjoin the calls before it can be connected to other call -->
<join id1=" dialogid" id2=" in_connectionid" duplex="'half'" dtmfclamp="false"/>
</transition>
<!--
- Now connecte the outbound.
-->
<transition state="outgoing_call_active" event="conference.joined">
<!-- Join the two calls together -->
<join id1="in_connectionid" id2="out_connectionid" duplex="'full'" />
</transition>
<!--
- We will get here once the join completes.
-->
<transition state="outgoing_call_active"
event="conference.joined">
<!-- If maxtime has been set then we setup a timer -->
<if cond="vxml_maxtime != null">
<send name="'vxml_maxtime'"
target="session.id"
delay="vxml_maxtime"
sendid="maxtime_sendid"/>
</if>
</transition>
<!--
- Deal with someone disconnecting.
-->
<transition state="outgoing_call_active"
event="connection.disconnected">
<!-- Cancel any maxtime events that are waiting to be fired -->
<if cond="maxtime_sendid != null">
<cancel sendid="maxtime_sendid"/>
<assign name="maxtime_sendid" expr="null"/>
</if>
<!-- Branch off based on what call leg this is for and send
the proper event to the dialog -->
<if cond="event$.connectionid == out_connectionid">
<assign name="results" expr="'far_end_disconnect'" />
<send name="'dialog.transfer.complete'"
target="dialogid"
targettype="'dialog'"
namelist="results" />
<!-- Update our state var back to the original state -->
<assign name="mystate" expr="'dialogActive'" />
<else />
<!-- Set our state to show that the
original caller is disconnected. -->
<assign name="mystate" expr="'userDisconnect'" />
<dialogterminate dialogid="dialogid"/>
</if>
</transition>
<!--
- Deal with a "hotword" type event where the dialog
- requests that we stop the transfer.
-->
<transition state="outgoing_call_active"
event="dialog.terminatetransfer">
<!-- Change our state to show we are dealing with hotword stuff -->
<assign name="mystate" expr="'hotword'" />
<!-- Cancel any maxtime events that are waiting to be fired -->
<if cond="maxtime_sendid != null">
<cancel sendid="maxtime_sendid"/>
<assign name="maxtime_sendid" expr="null"/>
</if>
<!-- unjoin our connections -->
<unjoin id1="in_connectionid" id2="out_connectionid"/>
</transition>
<!--
- Calls have been unjoined.
-->
<transition state="hotword" event="conference.unjoined">
<!-- Rejoin the first connection to the dialog -->
<join id1="in_connectionid" id2="dialogid"/>
<!-- Disconnect the outbound call -->
<disconnect connectionid="out_connectionid"/>
</transition>
<!--
- Send an event to the dialog once we are all back together again.
-->
<transition state="hotword" event="conference.joined">
<!-- Build up our event -->
<assign name="results" expr="'near_end_disconnect'" />
<send name="'dialog.transfer.complete'"
target="dialogid"
targettype="'dialog'"
namelist="results" />
<!-- Update our state var back to the dialogActive state -->
<assign name="mystate" expr="'dialogActive'" />
</transition>
<!--
- Deal with connection.disconnected events in the hotword state.
- We are only going to deal with stuff if the event is
- for the incoming call.
-->
<transition state="hotword" event="connection.disconnected">
<if cond="event$.connectionid == in_connectionid">
<dialogterminate dialogid="dialogid"/>
<!-- Update our state var to the userDisconnect state -->
<assign name="mystate" expr="'userDisconnect'" />
</if>
</transition>
<!--
- Deal with the maxtime event during a call transfer.
- Should this happen we just disconnect the outbound call leg
- and get back to the dialogActive state.
-
- Step one is to disconnect the call...
-->
<transition state="outgoing_call_active"
event="vxml_maxtime">
<assign name="maxtime_sendid" expr="null"/>
<assign name="mystate" expr="'maxtime'" />
<disconnect connectionid="out_connectionid"/>
</transition>
<!--
- Once we have the disconnect event we verify that we
- got it for the outbound call and rejoin the dialog to the
- inbound call. If the inbound call disconnected
- we are going to go on and forward the event along
- and wait for the dialog to exit.
-
-->
<transition state="maxtime" event="connection.disconnected">
<if cond="event$.connectionid == out_connectionid">
<join id1="dialogid" id2="in_connectionid"/>
<else />
<dialogterminate dialogid="dialogid"/>
</if>
</transition>
<!--
-
- We are rejoined. Update our state and send the transfer
- event back to the dialog.
-
-->
<transition state="maxtime" event="conference.joined">
<!-- Update our state var back to the dialogActive state -->
<assign name="mystate" expr="'dialogActive'" />
<assign name="results" expr="'maxtime_disconnect'" />
<send name="'dialog.transfer.complete'"
target="dialogid"
targettype="'dialog'"
namelist="results" />
</transition>
<!--
- Dialog has exited while we were in a hotword state.
- We just are going to exit from this CCXML session...
-->
<transition state="maxtime" event="dialog.exit">
<exit/>
</transition>
<!--
-
- Deal with any extra random events that may come in.
-
-->
<!--
- Make sure that we deal with any extra dialog events
- by ending the session. A real ccxml app would do something
- better here.
-->
<transition event="dialog.*">
<exit/>
</transition>
<!--
- And do the same for any exit events.
-->
<transition event="error.*">
<exit/>
</transition>
<!--
- And last but not least catch any connection.disconnect
- events that made it past us.
-->
<transition event="connection.disconnected">
<exit/>
</transition>
</eventprocessor>
</ccxml>
Appendix E - Telephony Protocol Names
Overview
This section defines a list of recommended telephony protocol names to be used in CCXML platforms
within the connection event objects (See 10.2.3: Connection Events). Platforms MUST use the following list when available. If the protocol is not defined in this list the platform MUST prefix the name with an underscore, "_", to identify them as platform-dependent.
Renamed Changes and Acknowledgments Appendixes (Appendixes G and H)
Changes in Last Call Working Draft
Rewrite of dialog section to prepare for LCWD. This includes language cleanup and references to external specifications.
(Section 7)
Rewrite of variables and expressions section to prepare for LCWD. This includes language cleanup and references to
external specifications. (Section 8)
Better details on variable scope issues. (Section 8)
charset Attribute added to script tag. (Section 8)
New section listing session variables. (Section 8.3)
Rewrite of Event Handling section to prepare for LCWD. This includes language cleanup and references to external
specifications. Some content has been moved to section 10. (Section 9)
Rewrite of Telephony Operations and Resources section to prepare for LCWD. This includes language cleanup and references
to external specifications. (Section 10)
Removed incomplete security section. (Section 11)
Removed inline DTD. (Appendix C)
Removed inline Schema. (Appendix D)
Updated Schema text. (Appendix D)
Updated telephony protocol names to change "SHOULD" to be "MUST". (Appendix F)
Added CAS to list of telephony protocol names. (Appendix F)
Added references section. (Appendix I)
Update of if, elseif, else tags. (Section 6)
New table formats
New example formats
Updated text for section 9. (Section 9)
Updated text for section 10. (Section 10)
Updated text for section 6. (Section 6)
Cleanup of text in full spec. (All)
New session text. (Sections 1, 2, 3 and 6)
CR 122 Text for XMLNS and XML-BASE. (Section 6)
CR 133 Text for meta and metadata. (Section 6)
Cleanup of Schema text. (Appendix D)
Removal of "Section" in section titles. (All)
Update references of <eventhandler> to <eventprocessor>. (All)
Update of Acknowledgments. (Appendix H)
Change elements --> Elements in titles. (All)
Correction of the use of the term "element". (All)
Added ACRONYM tag for IVR. (All)
Added telephony standard references in section 2. (Section 2)
Added URI to defined terms. (Section 3.4.2)
Cleanup of RFC2119 terms. (All)
Added references to Appendix G. (Appendix G)
Reworking of Appendix B (Appendix B)
Update of Acknowledgments. (Appendix H)
Split conid into conferenceid and connectionid for dialog stuff. (Section 7)
CR-136, createccxml/fetch updates. (Section 6)
CR-140, hints attributes on telephony elements. (Section 10.5)
CR-141, move, send, and cancel have no positive confirmation event. (Section 9.3)
Updated Schema (CR-130). (Appendix D)
Updated DTD (CR-130). (Appendix C)
Conference events. (Section 10)
CR-131 src vs srcexpr on script. (Section 8)
Added MIME Type registration info. (Appendix J)
Some of the changes suggested by Paolo. (All)
CR-139 text (Issues with send and cancel) (9.2.5)
CR-52 (Conferencing) text. (10.5.5 and 10.5.7)
CR-144 timeout attribute for createccxml. (6.2.9.2)
Reworked Sections 1 and 2 from F2F meeting (Sections 1-2)
error.unsupported to be thrown on any unsupported action
Added tagname to error.connection.wrongstate
Added tagname to error.notallowed
(8.1) Reporting ECMAScript errors
(10.6) Connection state changes from Rachel
(7) Minor changes editorial changes from Paolo
(createccxml) Server type clarification
(dialogprepare) Server type clarification
(dialogstart) Server type clarification
(fetch) Server type clarification
(send) changed tag to element
(ccxml.exit) values.* clarification
(dialog.exit) values.* clarification
(dialog.user.*) values.* clarification
Removed cookies from I/O processor sections
Fixed outdated text in I/O processor sections
Clarification on transition selection criteria
evt.uri of fetch.done and error.fetch after 302
connection.state constants
<send> data --> name
Connection model changes from Mark Scott (133003)
Minor connection event table text changes from Paolo (133003)
section k multiple value parameters (123991)
should fail to compile when transition has state but eventprocessor has no statevariable (123997)
CCXML spec comments/questions for section 10 (132989)
ccxml.loaded put at front of event queue (132985)
Comments on CCXML WD dated 23 March 2006 (132988)
inconsistency in 10.4 (185805)
ccxml errata (185808)
Minutes for 2006-01-19 CCXML call (133002)
Comments on CCXML WD dated 9 March 2006 (132991)
Section 10.4 Bridges (132995)
Section 10.2 Assertion Review (132996)
Section 10.5 Assertion Review (132998)
LCWD publication comments from Paolo (187115)
Namelist changes on session creation, dialogstart and createccxml (133005)
CCXML spec change --- Connection states class (185572)
Publication Prep
Changes in Last Call Working Draft 4
There are no changes in this version.
Changes in Candidate Recommendation
ISSUE-182 - Section 7.2 - MISSING CHANGES in LCWD 2007_01_19
ISSUE-183 - Section 7.3 - MISSING CHANGES in LCWD 2007_01_19
ISSUE-184 - [ccxml] Questions about Appendix D
ISSUE-182 - removed extra "include" in 7.2.2.1.
ISSUE-182 - added error.semantic text to dialogid attributes of dialogprepare and dialogterminate
ISSUE-193 - removed reference to old "name" attribute on transition element.
ISSUE-194 - cleaned up basichttp text in send element and moved some definitions to appendix K
ISSUE-196 - added text for <send> around eventid, eventsource and eventsourcetype
ISSUE-197 - renamed connectionid to id and added dialogs to the list for the error.notallowed event properties.
ISSUE-114 - white space fixes from editorial change list
ISSUE-117 - fixed references and updated acknowledgments section
ISSUE-198/ISSUE-199 - Removed standard attributes.
ISSUE-241 - Section 9.1 review.
ISSUE-242 - Section 9.2 review.
ISSUE-243 - Section 9.3 review.
ISSUE-242 - Section 9.2 review. - Item 10. Removed error text from the 9.2.4.2 event table as it's covered in the element description.
ISSUE-230 - PUBLIC - LCWD - Nezic-1 - Comments on CCXML Working Draft 19 January 2007 - Reworked fetch error handing event.
ISSUE-231 - PUBLIC - LCWD - Nezic-2 - Comments on CCXML Working Draft 19 January 2007 - Removed unneeded error.fetch references from the specification. The behavior of parse time / schema validation errors are defined in section 9.5.1.
ISSUE-222 - PUBLIC - LCWD - Fixed createccxml element table.
ISSUE-224 - PUBLIC - LCWD - Fixed createcall-joindirection attribute constraints.
ISSUE-112 - Updating VoiceXML session variables.
ISSUE-116 - error.semantic/hints.
ISSUE-234 - PUBLIC - LCWD - murulidhara-2 - query.
ISSUE-115, ISSUE-122 - XML 1.1 and IRI support.
ISSUE-228 - Removed connection.rejected from connection state diagram.
ISSUE-251 - clarified move behavior.
ISSUE-231 - Cleaned up 9.5.1 to be more specific.
ISSUE-231 - Fixed script error handing text.
ISSUE-231 - Added informative note explaining reasons for script src being a static string.
ISSUE-290 - Section 10.5.1.1 - extra MUST
ISSUE-292 - Review of Section 9.2.1 assertions - closed, but something strange in spec
ISSUE-293 - Review on Section 9.2.2 assertions
ISSUE-294 - Comments on Section 9.2.3 assertions
ISSUE-295 - Comments on Section 9.2.4 assertions
ISSUE-297 - Review on Section 9.3 assertions
ISSUE-298 - Section 9.4 & 9.5 assertions
ISSUE-291 - Section 9.1 - Assertion review
ISSUE-244 - Section 10.2 Assertions
ISSUE-244 - Section 10.2.1 - Removed connection.disconnected transition from PROGRESSING state
ISSUE-244 - Section 10.2 - Added PROGRESSING to the list of active states
ISSUE-244 - Section 10.6.5 - Reworded text to bring in line with "This event MUST be emitted..." text used elsewhere in the document
ISSUE-252 - Status Section - Created features at risk section and listed move+dialogs
ISSUE-293 - Section 9.2.2.1 - Removed reference to error.fetch
ISSUE-297 - Section 9.3.4 - Reworded text about when this error was raised per assertion review
ISSUE-303 - Appendix K - IR review/rewording
ISSUE-296 - Section 9.2.5 - IR review/rewording - "will" to "MUST"
ISSUE-305 - Appendix L IR Review - updated ignored payload parameters
ISSUE-303 - Appendix K IR Review - fixed reference to session --> sessionid
ISSUE-313 - Appendix K.4 - 2XX response codes are considered success.
ISSUE-314 - Section 10.2 - IR comments and changes.
ISSUE-314 - Fixed leftover event details in 10.6.2: connection.alerting
ISSUE-304 - <join> and <unjoin> error.semantic text.
ISSUE-316 - 10.5.5.2 - Removed requirement that conference IDs MUST be in URI format.
ISSUE-308 - Connection.signal rewording
ISSUE-319 - error.semantic and control flow
ISSUE-320 - connectionid and conferenceid attributes for <dialogprepare>/<dialogstart>
ISSUE-238 - PUBLIC - LCWD - Sajeesh-2 [CCXML]Regarding namelist attribute
ISSUE-120 - Fixed sub issue 51. Corrected 10.4 text around multiple inputs to conferences.
ISSUE-121 - Ordering of id1 and id2 attributes to be clear.
ISSUE-233 - Added section 9.5.6 to define error handling for invalid default attribute values.
ISSUE-236 - PUBLIC - LCWD - Kuba-1 - CCXML: Dialog and Connection objects.
ISSUE-237 - PUBLIC - LCWD - Kuba-2 - CCXML: Dialog and Connection objects.
ISSUE-321 - <createccxml> and creation time of associated Connection Object.
ISSUE-324 - maxage & maxstale attributes of <dialogprepare>, <dialogstart> should NOT be CSS2 times.
ISSUE-336 - replace "audio/wav" with "audio/x-wav"
ISSUE-482 - connection.disconnect used in appendix D
ISSUE-483 - Appendix D should use dialog terminate instead of send with connection.disconnect.hangup
ISSUE-325 - PUBLIC - CCXML state variable
ISSUE-488 - Small typo in Appendix D.9
ISSUE-499 - Editorial review of Section 10.6 - s10.6.13, s10.6.21
ISSUE-500 - Changes in current draft and wrong reference - s9.4.3
ISSUE-501 - TYPO on CCXML Spec - 10.2.5
ISSUE-498 - Issues with fetch and non CCXML/ECMAScript data
ISSUE-519 - 10.4 Connection/Dialog -> Media endpoint
ISSUE-527 - type of statuscode on fetch.done
ISSUE-524 - <disconnect/> on outbound call
ISSUE-117 - Twicks before publishing
ISSUE-115 - LCWD - Comments from i18n core WG on CCXML - Removed seeAlso from meta tag
ISSUE-553 - Incorrect example in the CCXML spec
ISSUE-554 - ISSUE about connection.merge.failed event properties
ISSUE-555 - ISSUE about VoiceXMLIntegration example
ISSUE-225 - PUBLIC - LCWD - Nagesh S-4 - Query in CCXML 1.0 Specification
ISSUE-227 - PUBLIC - LCWD - Nagesh S-6 - Query in CCXML 1.0 Specification
ISSUE-556 - Major and minor spec changes
ISSUE-225, ISSUE-227 - required DTD, Schema and example updates:
ISSUE-225, ISSUE-227 - Further updates to schema
ISSUE-555 - Fixed duplex of join
ISSUE-556 - Major and minor spec changes
ISSUE-566 - <dialogstart>/<dialogprepare> attribute constraints can not be enforced using DTD/Schema. The fix to this was to relax the schema and DTD and the text in the attribute tables remain the normative text and expected behavior.
ISSUE-567 - Make Error Handling within a <transition> Consistent
ISSUE-569 - PUBLIC - posting ccxml.exit to parent upon child getting a ccxml.kill event
ISSUE-572 - Attribute table missing for <redirect>
ISSUE-567 - Make Error Handling within a <transition> Consistent
ISSUE-580 - TYPO about 'half' and 'full' , values for duplex attribute
ISSUE-581 - ISSUE about BRIDGE call transfer management on Appendix D, paragraph D.11
ISSUE-603 - <move event=event$> in transition for "connection.merge.failed"
ISSUE-570 - Limiting amount of connection inputs and other comments
ISSUE-612 - dialog.transfer event$.uri
ISSUE-613 - default value for dtmfclamp attribute
ISSUE-616 - connection.redirect failed instead of connection.failed event on Appendix D
ISSUE-622 - Add session to the list of allowed values to session.notallowed (9.3.1)
ISSUE-633 - PUBLIC - using Object in the application scope - example error (8.4)
ISSUE-637 - PUBLIC - Comments on CCXML specification - Attribute 'info' in the conference.created and conference.destroyed events (10.6.11, 10.6.12)
Changes in Proposed Recommendation
ISSUE-668 - PUBLIC - CR - April 2010 CCXML's DTD is broken (Appendix B)
ISSUE-669 - PUBLIC - CR - attribute type error in 1 April 2010 CCXML (Sections 10.6.13 and 10.6.14) .
ISSUE-670 - PUBLIC - CR - CCXML Implementation Report: asserts 714 and 715 (Section 6.3.6).
Added clarification around what session the attribute referred to and addressed cases for external events where session id does not exist.
ISSUE-671 - PUBLIC - CR - Recommended addition to the April 2010 CCXML DTD (Appendix B)
ISSUE-674 - PUBLIC - CR - CCXML specification: Application variables (Section 8.4).
Clarified and removed legacy text from prior drafts of the spec.
ISSUE-677 - PUBLIC - CR - April CCXML: test case conflicts with ECMA rules (Section 3.3.1).
Added an implementation note around Line by line vs Batch ECMAScript execution based on IR testing.
Based on years of implementation experience the CCXML working group believes that CCXML application code
that would be affected by these scenarios is very rare. Any such code likely relies on unusual ordering
of variable declarations and assignment statements or the use of confusing variable names and scopes;
such code is discouraged due to its potential for producing unintended results.
ISSUE-681 - PUBLIC - CR - April CCXML: "Class" definition (Section 3.4).
Removed extra definition text that was unneeded as what we really were trying to do is just follow ECMAScript.
ISSUE-682 - PUBLIC - CR - April CCXML: Dialog properties inconsistency (Section 7.2.1.1).
Removed old text left over from prior language.
ISSUE-697 - PUBLIC - CR - April CCXML: 3 bugs in 7_1.txml - Item 2 (Section 7.2.3.2).
Clarified that the attribute was a boolean.
ISSUE-699 - Another typo on CCXML Spec (Section 7.1)
ISSUE-702 - PUBLIC - CR - April CCXML: 3 problems with manual tests 10_5_7_A_*.txml (Section 10.5.7.2).
Clarified the order of operations when using the exittone attribute based on IR testing.
ISSUE-707 - PUBLIC - CR - April CCXML: attribute 'id' of the error.notallowed event (Sections 9.2.5.1 and 9.3.1).
Clarified the contents of the id attribute incase of error.
ISSUE-710 - PUBLIC - CR - April CCXML, 7_1: attribute enctype used with the value of the method "post" in <dialogprepare> (Sections 6.2.7.2, 6.2.9.2, 7.2.1.2 and 7.2.2.2)
ISSUE-714 - PUBLIC - CR - April CCXML: format of the name attribute in <send> (Section 9.2.3.2).
Clarified that _ is allowed in event names based on IR testing and original intent.
ISSUE-717 - PUBLIC - CR - April CCXML 7_3: required property reason in dialog.terminatetransfer (Section 7.3.6).
Clarified requirement level of reason attribute based on results of IR testing.
ISSUE-719 - PUBLIC - CR - April CCXML 9_2_3_B: handling of invalid event name in <send> (Section 9.3.5)
ISSUE-724 - PUBLIC - CR - April CCXML, 7_2: combination of attributes in <dialogstart> (Sections 8.2.2.2 and 10.5.4.2).
Clarified error handling on attribute combinations based on IR testing.
ISSUE-732 - PUBLIC - CR - July CCXML Implementation Report: 8_2_3: how to handle error in loading static <script> (Section 8.2.2.2).
Clarified correct event to throw in some cases based on IR testing.
ISSUE-734 - PUBLIC - CR - July CCXML Implementation Report: 9_2_3_B: improper error event used in <send> (Section 9.3.5)
ISSUE-743 - PUBLIC - CR - CCXML: VoiceXML dialog.transfer.complete's result type incorrect (Appendix D.9)
ISSUE-744 - PUBLIC - CR - CCXML: dialog.transfer example incorrect (Appendix D.11)
ISSUE-754 - PUBLIC - CR - Fix test of dialog.user.* (Section 7.3.10).
Relaxed requirement level of dialog object based on IR test results and need to inject event via HTTP IO Processor.
Appendix G - Acknowledgments
This version of CCXML was written with the participation of members of the W3C Voice Browser Working Group, and a special
thanks is in order for the following contributors:
Kazuyuki Ashimura, W3C
David Attwater, BTexact Technologies
RJ Auburn, Voxeo Corporation
Paolo Baggia, Loquendo
Patrizio Bergallo, Loquendo
Eric Burger, Snowshore
David Burke, VoxPilot
Emily Candell, Comverse
Ken Davies, Hey Anita
Rajiv Dharmadhikari, Genesys
Dave Donnelly, BTexact Technologies
Daniel Evans
Mike Galpin, Syntellect
Rob Green, Voxeo Corporation
Markus Hahn
Jeff Haynie, Vocalocity
David W Heileman, Unisys
Gadi Inon
Jim Larson
Rob Marchand, Genesys
Scott McGlashan, Hewlett-Packard
Rachel Muller, Aspect
Brad Porter, Tellme Networks
Kenneth Rehor, Cisco
Dave Renshaw, IBM
Laura Ricotti, Loquendo
Mark Scott, Genesys
Saravanan Shanmugham, Cisco
Scott Slote, Nortel Networks
Govardhan Srikant, Nortel Networks
Jim Trethewey, Intel
Wai-Yip Tung, Cisco
Matt Womer, W3C
This W3C specification is based upon a former CCXML specification, contributed to the Voice Browser Working Group in April
2001. The CCXML authors were:
XML Schema Part 2: Datatypes Second Edition,
P.V. Biron and A. Malhotra, Editors. World Wide Web Consortium, October 2004. This version of the XML Schema Part 2
Recommendation is http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/. The latest version of XML Schema 2 is available at http://www.w3.org/TR/xmlschema-2/.
A document is a Conforming CCXML Document if it meets all of the following conditions:
it is a well-formed XML 1.0 or 1.1 document [XML] conforming to namespaces in XML
[XMLNS]
it has a <ccxml> root element which includes a version attribute of "1.0"
the <ccxml> element designates the CCXML namespace. This can be achieved by declaring an
xmlns attribute or an attribute with an xmlns prefix [XMLNS].
The namespace for CCXML is defined to be "http://www.w3.org/2002/09/ccxml"
it adheres to the specification described in this document (Voice Browser Call Control: CCXML Version 1.0) including the
constraints expressed in the schema (see Appendix C)
It is recommended that the <ccxml> element indicate the location of the CCXML schema (see Appendix C) via
the xsi:schemaLocation attribute from [SCHEMA2]:
There may be a DOCTYPE declaration in the document prior to the root element. If present, the public identifier included in the
DOCTYPE declaration must reference the CCXML DTD (Appendix B) using its Formal Public Identifier:
<!DOCTYPE ccxml PUBLIC "-//W3C//DTD CCXML 1.0//EN" "http://www.w3.org/TR/ccxml/ccxml.dtd">
The system identifier may be modified appropriately. The DTD subset must not be used to override any parameter entities in
the DTD.
Here is an example of a Conforming CCXML Document:
Note that in this example, the recommended xmlns:xsi and xsi:schemaLocation attributes are
included. Note also, the inclusion of an XML declaration. An XML declaration like the one above is not required in all XML
documents. CCXML document authors are strongly encouraged to use XML declarations in all their documents. Such a declaration is
required when the character encoding of the document is other than the default UTF-8 or UTF-16 and no encoding was determined
by a higher-level protocol.
The CCXML language or these conformance criteria provide no designated size limits on any aspect of CCXML documents. There
are no maximum values on the number of elements, the amount of character data, or the number of characters in attribute
values.
J.2 - Using CCXML with other namespaces
The CCXML namespace may be used with other XML namespaces as per [XMLNS], although
such documents are not strictly conforming CCXML documents as defined above. Future work by W3C will address ways to specify
conformance for documents involving multiple namespaces.
J.3 - Conforming CCXML Processors
A CCXML Processor is a program that can parse and process Conforming CCXML Documents. In a CCXML Processor, the XML parser
must be able to parse and process all XML constructs defined by XML 1.0 [XML10], XML 1.1
[XML] and Namespaces in XML [XMLNS]. This XML parser
is not required to perform validation of a CCXML document as per its schema or DTD; this implies that during processing of a
CCXML document it is optional to apply or expand external entity references defined in an external DTD.
A Conforming CCXML Processor must correctly understand and apply the semantics of each markup element as described by this
document.
When a Conforming CCXML Processor encounters elements or attributes, other than xml:lang and
xml:base, in a non-CCXML namespace it may:
ignore the non-standard elements and/or attributes, or
process the non-standard elements and/or attributes, or
reject the document containing those elements and/or attributes
There is, however, no conformance requirement with respect to performance characteristics of the CCXML Processor.
J.4 - IRI vs URI
In all places that URIs [URI] are referenced as being valid in a CCXML document a CCXML
processor MUST accept IRIs [IRI].
Appendix K - Basic HTTP Event I/O Processor
This section is Normative.
K.1 Overview
This appendix describes a "basichttp" event I/O event processor which uses HTTP ([RFC2616]) to transport events between a CCXML implementation and external components.
A CCXML implementation receives events from an external component via the "basichttp" processor. If the event
is destined for an active CCXML session, the event and its parameters are injected into the session. Using the
"basichttp" processor, events can be sent from a CCXML session with the <send> element to an
external component.
The "basichttp" processor is intended as a minimal interoperable mechanism for sending and receiving
events between external components and CCXML 1.0 implementations. Other event I/O processors may be more appropriate for
advanced application scenarios. HTTP Basic Access Authentication ([RFC2617]) should be
supported at a minimum. HTTP Digest Access Authentication ([RFC2617]), HTTPS, or other
security techniques should be considered.
A CCXML 1.0 implementation must support the "basichttp" processor. Implementations may support other event
injection processors so long as they do not have the type "basichttp" which is reserved for the processor
described in this section.
K.2 Access URI
The access URI for the "basichttp" event I/O processor is the URI to which an external component can send an
event for injection into an active session.
The access URI is available in a CCXML session via session.ioprocessors using the key "basichttp".
For example, session.ioprocessors["basichttp"] returns the access URI (e.g.
http://www.example.com/ccxml/basichttp) for the "basichttp1" processor.
The access URI for the "basichttp" event processor may be sent to external components by, for example, its
inclusion in the namelist attribute of the <send> element.
The access URI may also be specified in an implementation-specific manner (for example, product documentation).
K.3 Receiving Events
Input from external components MUST be received by the CCXML implementation at the
"basichttp" access URI as HTTP POST requests. The request is analyzed by the "basichttp" event
processor, resulting in
an event being injected into an active CCXML session, or
no action being taken (an error occurred, operation not permitted, etc)
The "basichttp" processor MUST indicate the result to the external component via the
response code contained in the HTTP response.
Parameter values MUST be passed into the "basichttp" processor using an encoded
application/x-www-form-urlencoded body.
To inject an event into an existing CCXML session, the HTTP request must specify the id of the session and the name of the
event. The session id MUST be specified as an HTTP parameter named "sessionid"
The name of the event must be specified using the HTTP parameter "name".
The following HTTP parameters are reserved:
sessionid
The value specifies the id of session into which the event is to be injected.
name
The value specifies the name of the event. The value is composed of alphanumeric and "." (dot) characters only. The first
character must not be a dot or digit. The parameter is required.
eventsource
The value specifies a URI to which events may be sent (i.e. it may be used as the value of the target
attribute in a <send> element). The parameter is optional.
Any non-reserved HTTP request parameters (in other words, all HTTP request parameters that are not listed in the table
above) define the properties of the injected CCXML event. For instance, if the HTTP request contained a parameter named
"foo" with value "bar", then the corresponding CCXML event object would have a property named
"foo" (accessible as event$.foo), the value of which would be the string value
"bar".
Request parameters names may contain one or more periods, in order to allow the injection of events with properties that are
objects. For example, a parameter named
"a.b"
with a value of "1" represents an object named "a", which
has a property "b" with a value of "1". A subsequent parameter "a.c" with a value of
"2" would add a property named "c" with a value of "2" to that event. This scheme
applies recursively; using "a.d.x" = "3" and "a.d.y" = "4" would result in
a multi-level object. Request parameter names must be valid ECMAScript variable names, or must be composed of period-separated
ECMAScript variable names. Request parameter values, both reserved and non-reserved, are treated as strings. The omission of a
request parameter value will be treated as an empty string. Parameter names may not be repeated within a request. A request
with repeated parameter names is considered to be invalid, and should be rejected by the "basichttp" event I/O
processor.
The following subset of HTTP response codes are defined:
Response Code
Description
204 (No Content)
Injection successful: session id matches an active CCXML session id, event name
and payload parameters are valid
400 (Bad Request)
Injection failed: one or more parameters have an invalid name or value
401 (Unauthorized)
Used in conjunction with HTTP Authentication ([RFC2617]): The request requires user authentication
403 (Forbidden)
Injection failed: other reason (e.g. session id does not match an existing CCXML
session id)
404 (Not Found)
Injection failed: access URI invalid.
500 (Internal Server Error)
Injection failed: internal server error.
Events injected into an active CCXML session by the "basichttp" processor provide the standard event attributes
as described in Section 9.4.2. The name has the value of the
"name" parameter. The eventsource has the value of the "eventsource" parameter if
provided; otherwise eventsource is undefined. The eventid is a unique string identifier
of the event generated by the "basichttp" processor. The eventsourcetype has the value
"basichttp".
The payload parameters and their values are exposed as top level properties of the event object (complex parameter names
require appropriate initialization of sub-objects). To avoid conflict with standard event attributes, payload parameters with
the name "eventid" or "eventsourcetype" are ignored.
For example, if the access URI for the "basichttp" processor is set to
"http://www.example.com/ccxml/basichttp", an external component can send an HTTP request as follows:
If the session id matches an active CCXML session (i.e. its session.id is "ccxmlsession1") and the
parameter names and values are valid, the processor injects the event into the session and sends an HTTP 204 response code. The
event may then be handled by a transition such as:
where event$.name would have the value "basichttp.myevent", event$.eventsourcetype
the value "basichttp", event$.eventsource the value "http://www.example.org/ccxmlext",
event$.agent the value "agent12", event$.site.location the value "orlando"
and event$.site.code the value "RE445".
K.4 Sending Events
Events may be sent from the CCXML implementation to an external component with the
"basichttp" processor using the <send> element (Section 9.2.3)
with the targettype attribute set to "basichttp". The target attribute MUST be set to the access URI of the external component.
The HTTP method MUST be "POST" and parameter values MUST be
encoded in an application/x-www-form-urlencoded body (POST method).
The id of the CCXML session id MUST be sent as a HTTP parameter named "sessionid".
The name attribute MUST be specified as an HTTP parameter named "name".
If the namelist attribute is defined, its variable names and values MUST be mapped to
HTTP parameters. Inline content is not supported. The parameter name is the variable name, with the same
qualification as used in the namelist. The parameter value is the variable value after being converted into a
string. If a variable in the namelist is an ECMAScript Object, the mechanism by which it must be submitted is not
currently defined. Instead of submitting ECMAScript Objects directly, the application developer may explicitly submit the
properties of an Object (e.g. "date.month date.year").
The basic HTTP event I/O processor generates events in response to <send> as described in Section 9.3. An HTTP success 2XX response code returned by the external component (or a successful
challenge-response resulting from a 401 Unauthorized response) MUST be mapped to the CCXML event
send.successful; all other non-successful (non 2xx) HTTP response codes MUST be mapped to
error.send.failed.
Appendix L - Session Creation Event I/O Processor
This section is Normative.
L.1 Overview
This appendix describes a "createsession" event processor which can receive HTTP ([RFC2616]) requests from an external component to create new CCXML sessions.
The "createsession" processor is intended as a minimal interoperable mechanism to allow external
components to create new sessions in CCXML 1.0 implementations. Other event I/O processors may be more appropriate for advanced
application scenarios. Security issues may need to be addressed by the implementation. If security is not addressed as part of
the deployment network configuration, then HTTP Authentication ([RFC2617]) , HTTPS, or
other security techniques should be considered. Implementations may use additional HTTP parameters specifically to address
security.
A CCXML 1.0 implementation may support a "createsession" event processor. Implementations may support
alternative session creation event processors so long as they do not have the type "createsession" which is
reserved for the processor described in this section.
L.2 Access URI
The access URI for the "createsession" event I/O processor is the URI to which an external component can send a
session creation event.
If the implementation supports the "createsession" event processor, then its access URI is available in a CCXML
session via session.ioprocessors using the key "createsession". For example,
session.ioprocessors["createsession"] returns the access URI (e.g.
http://www.example.com/ccxml/createsession) for the "createsession" type event I/O processor.
The access URI may also be specified in an implementation-specific manner (for example, product documentation).
L.3 Receiving Session Creation Events
A new CCXML session can be created by an external component when the "createsession" processor receives at its
access URI an HTTP POST request with a "uri" parameter whose value is the CCXML document to load.
The following HTTP parameters are reserved:
uri
The value specifies the URI of the CCXML document for the session. The parameter is required.
eventsource
The value specifies a URI to which events may be sent from the created session using, for example, the
"basichttp" event processor. The parameter is optional.
method
Equivalent to <createccxml>'s 'method' attribute; used to set the HTTP method applied in
the fetch of the specified CCXML document. Allowed values are "get" or "post" (case-insensitive).
If omitted, the default value is "get".
timeout
Equivalent to <createccxml>'s 'timeout' attribute; used to set the maximum time allowed
when fetching a CCXML document before abandoning the fetch attempt and returning an error. If omitted, the CCXML platform
will use a default value
maxage
Equivalent to <createccxml>'s 'maxage' attribute; used to set the max-age
value of the Cache-Control header when fetching CCXML documents. If omitted, the CCXML platform will use a
default value.
maxstale
Equivalent to <createccxml>'s 'maxstale' attribute; used to set the
max-stale value of the Cache-Control header when fetching CCXML documents. If omitted, the CCXML
platform will use a default value.
postbody
Used to set the application/x-www-form-urlencoded encoded HTTP body for "post" requests. This
parameter is ignored if 'method' is set to "get". The value of this parameter is the prepared
application/x-www-form-urlencoded content that has been URL-encoded.
fetchparam
Equivalent to <createccxml>'s 'fetchparam' attribute; used to pass information about the
newly created session to the application server. If omitted, the default value is "none".
Other parameters provided in the HTTP request are treated as the event payload and made available in the created session.
Single parameter values must be supported; multiple value parameters may be supported.
Payload parameter names must be valid ECMAScript variable names. Valid complex variable names are permitted; for example,
"agent.role". Reserved and payload parameter values must be valid ECMAScript expressions.
The following HTTP response codes are defined:
Response Code
Description
200
CCXML session created successful
400
Session not created: one or more parameters have an invalid name or value
401
Session not created: request lacks proper authorization
403
Session not created: other reason (e.g. CCXML document not found)
408
Session not created: timeout fetching CCXML document
If the CCXML session was created successfully, the HTTP 200 response MUST contain an
'application/x-www-form-urlencoded' body. The 'session.id' property of the newly created session
MUST be returned in this body; other information MAY also be returned by the
platform.
In the created session, session.startupmode is set to "external", the session.uri is
to set to the value of the uri parameter and a session.values object is defined with the property
type set to the value "createsession" and the property eventsource set to the value of
the "eventsource" parameter. Other payload parameters are exposed as properties of session.values
(complex parameter names require appropriate initialization of sub-objects). To avoid conflict with type and
eventsource defined above, payload parameters with the name "type" and eventsource are ignored.
For example, an external component sends the following HTTP request to the "createsession" access URI :
If the "createsession" processor is supported by the CCXML implementation, the request parameter names and
values are valid, and the ccxml document is successfully fetched and processed, then a new CCXML session is created with the
following session variables:
The "createsession" processor then responds to the originating HTTP request by generating an HTTP 200 response
code. The session id of the newly created CCXML session MUST be returned in the body of the
response.
Appendix M - MIME Type and File Suffix
This section is normative.
The media type associated to the Call Control eXtensible Markup Language Specification documents is "application/ccxml+xml" and the
filename suffix is ".ccxml" as defined in [RFC4267].
Figure 1: Initial Call State
Figure 2: State Following Merge