XEP-xxxx: JSON Content Type support

Abstract:This specification defines JavaScript Object Notation (JSON) use in XMPP service.
Author:Mika Helander
Copyright:© 1999 - 2011 XMPP Standards Foundation. SEE LEGAL NOTICES.
Status:ProtoXEP
Type:Standards Track
Version:0.0.1
Last Updated:2010-05-07

WARNING: This document has not yet been accepted for consideration or approved in any official manner by the XMPP Standards Foundation, and this document is not yet an XMPP Extension Protocol (XEP). If this document is accepted as a XEP by the XMPP Council, it will be published at <http://xmpp.org/extensions/> and announced on the <standards@xmpp.org> mailing list.


Table of Contents


1. Introduction
2. Requirements
3. Use Cases
    3.1. BOSH
    3.2. C2S
4. Implementation Notes
    4.1. HTTP Header
    4.2. Initial BOSH request/response in JSON
5. Security Considerations
6. IANA Considerations
7. XMPP Registrar Considerations
8. XML Schema

Appendices
    A: Document Information
    B: Author Information
    C: Legal Notices
    D: Relation to XMPP
    E: Discussion Venue
    F: Requirements Conformance
    G: Notes
    H: Revision History


1. Introduction

This spesification defines how JSON data type is used to exchange information between client and XMPP-service. Intended use is in JavaScript-based clients running in web browser, widget runtime etc.

This JSON handling in service is targetet both for C2S and BOSH connections.

2. Requirements

The following design requirements reflect the need to offer performance as close as possible to standard XMPP-based stanza handling.

  1. JSON default character set must be UTF-8
  2. JSON stanza must contain (or retain) all XMPP stanza content and hierarchy
  3. Server must support both XML and JSON content-types.

3. Use Cases

Intent for following use-cases is to support JavaScript-based clients which typically start XMPP-session from HTTP-dialog, and then depending on network environment and run-time support end using BOSH or C2S through Web Sockets.

3.1 BOSH

Initial BOSH request from browser or equivalent uses in http header content-type "application/jsonrequest". This initial request payload is in JSON format, and server responds with same content-type and JSON playload.

If server doesn't support JSON it responds with http status 400 "Bad Request". In that case client either switches to content-type "text/xml; charset=utf-8" and XML-payload.

3.2 C2S

In Client to Service connection initialization client proposes stream feature "json" TBD...

4. Implementation Notes

Client (and server) implementation needs to take care of using such JSON object format which retains all structure of all XMPP XML stanzas.

4.1 HTTP Header

Following http-header is used to communicate with server using JSON playload:

4.1.1 Request

POST /http-bind HTTP/1.1
Host: httpcm.jabber.org
Accept-Encoding: gzip, deflate
Content-Type: application/jsonrequest
Content-Length: 230
    

4.1.2 Response

HTTP/1.1 200 OK
Content-Type: application/jsonrequest
Content-Length: 513

4.2 Initial BOSH request/response in JSON

In following example server name is modified so content length is not accurate. Also JSON payload is modified for better clarity of its structure.

4.2.1 Client request

POST /http-bind HTTP/1.1
Host: httpcm.jabber.org
Accept-Encoding: gzip, deflate
Content-Type: application/jsonrequest
Content-Length: 230

{ "body" : {
  "hold" : 1,
  "ver" : "1.6",
  "wait" : 285,
  "requests" : 2,
  "rid" : 2669000493,
  "to" : "server.com",
  "lang" : { "$$" : "xml", "$" : "en" },
  "version" : { "$$" : "xmpp", " : "1.0" },
  "xmlns" : {
    "$", "http://jabber.org/protocol/httpbind",
    "@xmpp" : "urn:xmpp:xbosh" }
  }
}

4.2.2 Server response

HTTP/1.1 200 OK
Content-Type: application/jsonrequest
Content-Length: 513

{ "body" : {
  "sid" : "b1165122e8856a087c0be4c53c229713a95d8ce6",
  "wait" : "285",
  "requests" : "2",
  "inactivity" : "30",
  "maxpause" : "120",
  "polling" : "2",
  "ver" : "1.6",
  "from" : "server.com",
  "secure" : "true",
  "authid" : "1402940319",
  "xmlns" : {
    "$" : "http://jabber.org/protocol/httpbind",
    "@xmpp" : "urn:xmpp:xbosh",
    "@stream" : "http://etherx.jabber.org/streams"
  },
  "version" : { "$$" : "xmpp", "$" : "1.0" },
  "$" : {
    "features" : {
      "$$" : "stream",
      "$" : {
        "mechanisms" : {
          "xmlns" : "urn:ietf:params:xml:ns:xmpp-sasl",
          "$" : { "mechanism" : "PLAIN" }
        }
      }
    }
  }
}

4.2.3 JSON syntax explained

5. Security Considerations

Same security issues apply as XML-payload. When using JSON class of later html5-supported browsers no need to use eval to convert JSON-string into variable value.

6. IANA Considerations

REQUIRED.

7. XMPP Registrar Considerations

The XMPP Registrar [??] includes 'xx:xx:xx' in its registry of protocol namespaces.

8. XML Schema

Makes me wonder how to use XML Schema for playing with JSON payload ?


Appendices


Appendix A: Document Information

Series: XEP
Number: xxxx
Publisher: XMPP Standards Foundation
Status: ProtoXEP
Type: Standards Track
Version: 0.0.1
Last Updated: 2010-05-07
Approving Body: XMPP Council
Dependencies: XMPP Core, XEP-xxxx, Etc.
Supersedes: None
Superseded By: None
Short Name: NOT_YET_ASSIGNED
This document in other formats: XML  PDF


Appendix B: Author Information

Mika Helander

Organization: Nokia Corporation
Email: mika.helander@nokia.com
JabberID: mikah@ovi.com


Appendix C: Legal Notices

Copyright

This XMPP Extension Protocol is copyright (c) 1999 - 2009 by the XMPP Standards Foundation (XSF).

Permissions

Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the "Specification"), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specification, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or substantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or publisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation.

Disclaimer of Warranty

## NOTE WELL: This Specification is provided on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. In no event shall the XMPP Standards Foundation or the authors of this Specification be liable for any claim, damages, or other liability, whether in an action of contract, tort, or otherwise, arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification. ##

Limitation of Liability

In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall the XMPP Standards Foundation or any author of this Specification be liable for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising out of the use or inability to use the Specification (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if the XMPP Standards Foundation or such author has been advised of the possibility of such damages.

IPR Conformance

This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which may be found at <http://www.xmpp.org/extensions/ipr-policy.shtml> or obtained by writing to XSF, P.O. Box 1641, Denver, CO 80201 USA).

Appendix D: Relation to XMPP

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 3920) and XMPP IM (RFC 3921) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.


Appendix E: Discussion Venue

The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.

Discussion on other xmpp.org discussion lists might also be appropriate; see <http://xmpp.org/about/discuss.shtml> for a complete list.

Errata can be sent to <editor@xmpp.org>.


Appendix F: Requirements Conformance

The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".


Appendix G: Notes


Appendix H: Revision History

Note: Older versions of this specification might be available at http://xmpp.org/extensions/attic/

Version 0.0.1 (2010-05-07)

First draft.

(MiH)

END