Network Working Group C. Daboo
Request for Comments: 5689 Apple Inc.
Updates: 4791, 4918 September 2009
Category: Standards Track
Extended MKCOL for Web Distributed Authoring and Versioning (WebDAV)
Abstract
This specification extends the Web Distributed Authoring and
Versioning (WebDAV) MKCOL (Make Collection) method to allow
collections of arbitrary resourcetype to be created and to allow
properties to be set at the same time.
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
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Daboo Standards Track [Page 1]
RFC 5689 Extended MKCOL for WebDAV September 2009
not be created outside the IETF Standards Process, except to format
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. WebDAV Extended MKCOL . . . . . . . . . . . . . . . . . . . . 4
3.1. Extended MKCOL Support . . . . . . . . . . . . . . . . . . 5
3.1.1. Example: Using OPTIONS for the Discovery of
Support for Extended MKCOL . . . . . . . . . . . . . . 5
3.2. Status Codes . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Additional Precondition for Extended MKCOL . . . . . . . . 5
3.4. Example: Successful Extended MKCOL Request . . . . . . . . 6
3.5. Example: Unsuccessful Extended MKCOL Request . . . . . . . 6
4. Using Extended MKCOL as an Alternative for MKxxx Methods . . . 8
4.1. MKCALENDAR Alternative . . . . . . . . . . . . . . . . . . 8
4.1.1. Example: Using MKCOL Instead of MKCALENDAR . . . . . . 8
5. XML Element Definitions . . . . . . . . . . . . . . . . . . . 10
5.1. mkcol XML Element . . . . . . . . . . . . . . . . . . . . 10
5.2. mkcol-response XML Element . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
8. Normative References . . . . . . . . . . . . . . . . . . . . . 11
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RFC 5689 Extended MKCOL for WebDAV September 2009
1. Introduction
WebDAV [RFC4918] defines the HTTP [RFC2616] method MKCOL. This
method is used to create WebDAV collections on the server. However,
several WebDAV-based specifications (e.g., CalDAV [RFC4791]) define
"special" collections -- ones that are identified by additional
values in the DAV:resourcetype property assigned to the collection
resource or by other means. These "special" collections are created
by new methods (e.g., MKCALENDAR). The addition of a new MKxxx
method for each new "special" collection adds to server complexity
and is detrimental to overall reliability due to the need to make
sure intermediaries are aware of these methods.
This specification defines an extension to the WebDAV MKCOL method
that adds a request body allowing a client to specify WebDAV
properties to be set on the newly created collection or resource. In
particular, the DAV:resourcetype property can be used to create a
"special" collection; alternatively, other properties can be used to
create a "special" resource. This avoids the need to invent new
MKxxx methods.
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
This document uses XML DTD fragments (Section 3.2 of
[W3C.REC-xml-20081126]) as a purely notational convention. WebDAV
request and response bodies cannot be validated by a DTD due to the
specific extensibility rules defined in Section 17 of [RFC4918] and
due to the fact that all XML elements defined by this specification
use the XML namespace name "DAV:". In particular:
1. Element names use the "DAV:" namespace.
2. Element ordering is irrelevant unless explicitly stated.
3. Extension elements (elements not already defined as valid child
elements) may be added anywhere, except when explicitly stated
otherwise.
4. Extension attributes (attributes not already defined as valid for
this element) may be added anywhere, except when explicitly
stated otherwise.
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RFC 5689 Extended MKCOL for WebDAV September 2009
When an XML element type in the "DAV:" namespace is referenced in
this document outside of the context of an XML fragment, the string
"DAV:" will be prefixed to the element type.
This document inherits, and sometimes extends, DTD productions from
Section 14 of [RFC4918].
3. WebDAV Extended MKCOL
The WebDAV MKCOL request is extended to allow the inclusion of a
request body. The request body is an XML document containing a
single DAV:mkcol XML element as the root element. The Content-Type
request header MUST be set appropriately for an XML body (e.g., set
to "text/xml" or "application/xml"). XML-typed bodies for an MKCOL
request that do not have DAV:mkcol as the root element are reserved
for future usage.
One or more DAV:set XML elements may be included in the DAV:mkcol XML
element to allow setting properties on the collection as it is
created. In particular, to create a collection of a particular type,
the DAV:resourcetype XML element MUST be included in a DAV:set XML
element and MUST specify the expected resource type elements for the
new resource, which MUST include the DAV:collection element that
needs to be present for any WebDAV collection.
As per the PROPPATCH method (Section 9.2 of [RFC4918]), servers MUST
process any DAV:set instructions in document order (an exception to
the normal rule that ordering is irrelevant). If any one instruction
fails to execute successfully, all instructions MUST fail (i.e.,
either all succeed or all fail). Thus, if any error occurs during
processing, all executed instructions MUST be undone and a proper
error result returned. Failure to set a property value on the
collection MUST result in a failure of the overall MKCOL request --
i.e., the collection is not created.
The response to an extended MKCOL request MUST be an XML document
containing a single DAV:mkcol-response XML element, which MUST
contain DAV:propstat XML elements with the status of each property
when the request fails due to a failure to set one or more of the
properties specified in the request body. The server MAY return a
response body in the case where the request is successful, indicating
success for setting each property specified in the request body.
When an empty response body is returned with a success request status
code, the client can assume that all properties were set.
In all other respects, the behavior of the extended MKCOL request
follows that of the standard MKCOL request.
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RFC 5689 Extended MKCOL for WebDAV September 2009
3.1. Extended MKCOL Support
A server supporting the features described in this document MUST
include "extended-mkcol" as a field in the DAV response header from
an OPTIONS request on any URI that supports use of the extended MKCOL
method.
3.1.1. Example: Using OPTIONS for the Discovery of Support for Extended
MKCOL
>> Request <<
OPTIONS /addressbooks/users/ HTTP/1.1
Host: addressbook.example.com
>> Response <<
HTTP/1.1 200 OK
Allow: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, COPY, MOVE
Allow: MKCOL, PROPFIND, PROPPATCH, LOCK, UNLOCK, REPORT, ACL
DAV: 1, 2, 3, access-control, extended-mkcol
Date: Sat, 11 Nov 2006 09:32:12 GMT
Content-Length: 0
3.2. Status Codes
As per Section 9.3.1 of [RFC4918].
3.3. Additional Precondition for Extended MKCOL
WebDAV ([RFC4918], Section 16) defines preconditions and
postconditions for request behavior. This specification adds the
following precondition for the extended MKCOL request.
Name: valid-resourcetype
Namespace: DAV:
Use with: Typically 403 (Forbidden)
Purpose: (precondition) -- The server MUST support the specified
resourcetype value for the specified collection.
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RFC 5689 Extended MKCOL for WebDAV September 2009
3.4. Example: Successful Extended MKCOL Request
This example shows how the extended MKCOL request is used to create a
collection of a fictitious type "special-resource". The response
body is empty as the request completed successfully.
>> Request <<
MKCOL /home/special/ HTTP/1.1
Host: special.example.com
Content-Type: application/xml; charset="utf-8"
Content-Length: xxxx