Lightweight wrapper around fast-xml-parser that converts between JSON and DUIS formats. This tool has been developed to provide an easy to use client side parser for DCC Boxed. XML schema validation and digital signatures are out of scope of this tool, and it is intended to be used in conjunction with SmartDCCInnovation/dccboxed-signing-tool which provides these features.

Developed and tested against node 16. Install from npm:

npm i @smartdcc/duis-parser

import { parseDuis } from '@smartdcc/duis-parser'
import { readFile } from 'node:fs/promises'

const duis = parseDuis('simplified', await readFile('/path/to/duis/file.xml'))

For example, a parsed Read Instantaneous Import Registers (SRV 4.1.1) could yield the following:

{
  header: {
    type: 'request',
    requestId: {
      originatorId: '90-b3-d5-1f-30-01-00-00',
      targetId: '00-db-12-34-56-78-90-a0',
      counter: 1000n
    },
    commandVariant: {
      number: 1,
      description: 'Non Critical Service Request for Command to be sent to a Device via the SM WAN',
      input: 'Service Request',
      output: 'Command',
      webService: 'Send Command Service',
      critical: 'No'
    },
    serviceReference: '4.1',
    serviceReferenceVariant: {
      'Service Request Name': 'Read Instantaneous Import Registers',
      'Service Reference': '4.1',
      'Service Reference Variant': '4.1.1',
      Critical: 'No',
      'On Demand': 'Yes',
      'Future Dated Response Pattern': 'DSP',
      'DCC Scheduled': 'No',
      'Non-Device Request': 'No',
      'Eligible User Roles': [ 'IS', 'GS', 'ED', 'GT' ]
    }
  },
  body: { ReadInstantaneousImportRegisters: '' }
}

As a convenience, the commandVariant and serviceReferenceVariant items are automatically converted from simple types (i.e. number and string, respectively) into meta-data objects with human readable meanings. These items are extracted from the DUIS Word document, the interested reader should view the DUIS Word document (available for download from the Smart Energy Code website) for their meanings.

To aid with interrogating a DUIS response to determine what type of response is provided a number of utility functions are provided:

• isSimplifiedDuisInput
• isSimplifiedDuisInputRequest
• isSimplifiedDuisOutput
• isSimplifiedDuisOutputRequest
• isSimplifiedDuisOutputResponse
• isSimplifiedDuisResponseBody_ResponseMessage_X
• isSimplifiedDuisResponseBody_ResponseMessage
• isSimplifiedDuisResponseBody_DeviceAlertMessage
• isSimplifiedDuisResponseBody_DCCAlertMessage
• isXMLData

These can be used from TypeScript as type predicates. E.g.

const duis = parseDuis('simplified', await readFile('/path/to/duis/file.xml'))
if (
  isSimplifiedDuisOutputResponse(duis) &&
  isSimplifiedDuisResponseBody_ResponseMessage_X('GBCSPayload', duis.body)
) {
  /* duis.body.ResponseMessage.GBCSPayload is valid */
}

Then to reconstruct the result back into a DUIS file:

import { constructDuis } from '@smartdcc/duis-parser'

const xml: string = constructDuis('simplified', duis)

When reconstructing, it is not required to give the full meta-data objects for commandVariant and serviceReferenceVariant. Instead, their simple types can be provided, thus the following will produce and equivalent XML as the example above (notice).

{
  header: {
    type: 'request',
    requestId: {
      originatorId: '90-b3-d5-1f-30-01-00-00',
      targetId: '00-db-12-34-56-78-90-a0',
      counter: 1000n
    },
    commandVariant: 1,
    serviceReference: '4.1',
    serviceReferenceVariant: '4.1.1'
  },
  body: { ReadInstantaneousImportRegisters: '' }
}

As another example. It is often not convenient (or necessary) to enter the counter as a BigInt as in the above example, the counter can be provided as a normal integer. This means the input can be JSON:

{
    "header": {
        "type": "request",
        "requestId": {
            "originatorId": "90-b3-d5-1f-30-01-00-00",
            "targetId": "00-db-12-34-56-78-90-a0",
            "counter": 0
        },
        "commandVariant": 1,
        "serviceReference": "6.24",
        "serviceReferenceVariant": "6.24.1"
    },
    "body": {
        "RetrieveDeviceSecurityCredentialsKRP": {
            "RemotePartyRole": [{"#text": "Root"}, {"#text": "Supplier"}, {"#text": "TransCoS"}]
        }
    }
}

In the above example, the usage of #text is required to build multiple RemotePartyRole entities. This is documented within the fast-xml-parser manual. But as an example, if only one RemotePartyRole is needed, then this can be simplified to:

{
    "header": {
        "type": "request",
        "requestId": {
            "originatorId": "90-b3-d5-1f-30-01-00-00",
            "targetId": "00-db-12-34-56-78-90-a0",
            "counter": 0
        },
        "commandVariant": 1,
        "serviceReference": "6.24",
        "serviceReferenceVariant": "6.24.1"
    },
    "body": {
        "RetrieveDeviceSecurityCredentialsKRP": {
            "RemotePartyRole": "Supplier"
        }
    }
}

To sign the resulting payload from constructDuis for use with DCC Boxed, please see the SmartDCCInnovation/dccboxed-signing-tool tool.

In both examples above, simplified was used. This is recommended as it strips out the XML digital signature (if present), enriches the header with meta-data and removes the namespaces so it intuitive to use.

Alternatively, a normal mode is provided that is close to the unprocessed output from fast-xml-parser and has a direct correspondence with the original XML. For example:

console.log(parseDuis('normal', await readFile('/path/to/duis/file.xml')))

Could output the following. While initially it looks more complex, this is because the digital signature and XML namespaces are present.

{
  '?xml': { '@_version': '1.0', '@_encoding': 'UTF-8' },
  'sr:Request': {
    'sr:Header': {
      'sr:RequestID': '90-B3-D5-1F-30-01-00-00:00-DB-12-34-56-78-90-A0:1000',
      'sr:CommandVariant': '1',
      'sr:ServiceReference': '4.1',
      'sr:ServiceReferenceVariant': '4.1.1'
    },
    'sr:Body': { 'sr:ReadInstantaneousImportRegisters': '' },
    'ds:Signature': {
      'ds:SignedInfo': {
        'ds:CanonicalizationMethod': { '@_Algorithm': 'http://www.w3.org/2001/10/xml-exc-c14n#' },
        'ds:SignatureMethod': {
          '@_Algorithm': 'http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha256'
        },
        'ds:Reference': {
          'ds:Transforms': {
            'ds:Transform': {
              '@_Algorithm': 'http://www.w3.org/2000/09/xmldsig#enveloped-signature'
            }
          },
          'ds:DigestMethod': { '@_Algorithm': 'http://www.w3.org/2001/04/xmlenc#sha256' },
          'ds:DigestValue': 'ZGVmYXVsdA==',
          '@_URI': ''
        }
      },
      'ds:SignatureValue': 'ZGVmYXVsdA==',
      'ds:KeyInfo': {
        'ds:X509Data': {
          'ds:X509IssuerSerial': {
            'ds:X509IssuerName': 'CN=U1, OU=07',
            'ds:X509SerialNumber': '1234567890'
          }
        }
      },
      '@_xmlns': 'http://www.w3.org/2000/09/xmldsig#'
    },
    '@_xmlns:ds': 'http://www.w3.org/2000/09/xmldsig#',
    '@_xmlns:sr': 'http://www.dccinterface.co.uk/ServiceUserGateway',
    '@_xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
    '@_schemaVersion': '5.1'
  }
}

Contributions are welcome!

When submitting a pull request, please ensure:

1. Each PR is concise and provides only one feature/bug fix.
2. Unit test are provided to cover feature. The project uses jest. To test, run npm run test:cov to view code coverage metrics.
3. Bugfixes are reference the GitHub issue.
4. If appropriate, update documentation.
5. Before committing, run npm run lint and npm run prettier-check.

If you are planning a new non-trivial feature, please first raise a GitHub issue to discuss it to before investing your time to avoid disappointment.

Any contributions will be expected to be licensable under GPLv3.

Copyright 2022, Smart DCC Limited, All rights reserved. Project is licensed under GPLv3.