XEP-0317: Hats

Abstract:This specification defines a more extensible model for roles and affiliations in Multi-User Chat rooms.
Author:Peter Saint-Andre
Copyright:© 1999 - 2014 XMPP Standards Foundation. SEE LEGAL NOTICES.
Status:Experimental
Type:Standards Track
Version:0.1
Last Updated:2013-01-03

WARNING: This Standards-Track document is Experimental. Publication as an XMPP Extension Protocol does not imply approval of this proposal by the XMPP Standards Foundation. Implementation of the protocol described herein is encouraged in exploratory implementations, but production systems are advised to carefully consider whether it is appropriate to deploy implementations of this protocol before it advances to a status of Draft.


Table of Contents


1. Introduction
2. Discovery
3. Protocol
    3.1. Including a Hat in Presence
    3.2. Adding a Hat
    3.3. Removing a Hat
4. Security Considerations
5. IANA Considerations
6. XMPP Registrar Considerations
    6.1. Protocol Namespaces
7. XML Schema
8. Acknowledgements

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

Multi-User Chat (XEP-0045) [1] defines a widely-implemented XMPP extension for chatrooms, including basic roles and affiliations such as owner, administrator, and moderator. However, in many scenarios it is desirable to define different roles that are appropriate for the relevant application. Examples might include a "presenter" or a "scribe" in an online meeting system, a "representative" or a "manager" in a customer service application, a "comms officer" in a military chat system, an "incident manager" in a first responder system, a "teacher" or a "teacher's assistant" in an online classroom, specialized roles in online games, etc. To prevent confusion with standard MUC roles, these extended roles are call "hats", since a participant can "wear many hats" in a room.

2. Discovery

A MUC service that supports hats MUST advertise a Service Discovery (XEP-0030) [2] feature of "urn:xmpp:hats:0".

3. Protocol

3.1 Including a Hat in Presence

MUC already includes a way for the room to signal the roles and affiliations of room occupants. Hats are signalled in a similar way. For example, the following presence notification would be sent by the room for an occupant who is a MUC room moderator but who also has a hat of "teacher's assistant" in an online classroom.

Example 1. Presence With Hat

<presence
    from='physicsforpoets@courses.example.edu/Terry'
    id='DE5C66DE-EC7D-4ECB-844A-B717A67CCE3D'
    to='steve@example.edu/tablet'>
  <x xmlns='http://jabber.org/protocol/muc#user'>
    <item affiliation='owner' role='moderator'/>
  </x>
  <hats xmlns='urn:xmpp:hats:0'>
    <TeacherAssistant xmlns='http://tech.example.edu/hats' displayname='Teacher&apos; Assistant' xml:lang='en-us'/>
  </hats>
</presence>
    

Note: The format is open for debate. Possibilities include:

  1. XML element in the hats namespace with name as a URI:

    <hat xmlns='urn:xmpp:hats:0' name='http://tech.example.edu/hats#TeacherAssistant' display='Teacher&apos;s Assistant' xml:lang='en-us'/>

    Pro: Clients that don't understand the 'http://tech.example.edu/hats#TeacherAssistant' semantics can at least display a human-readable name. Names can be registered with the XMPP Registrar. Also appropriate as a field name in Ad-Hoc Commands.

    Con: Not a very Jabberish way of structuring information.

  2. XML element in the hats namespace with name scoped using Clark Notation:

    <hat xmlns='urn:xmpp:hats:0' name='{http://tech.example.edu/hats}TeacherAssistant' display='Teacher&apos;s Assistant' xml:lang='en-us'/>

    Pro: Clients that don't understand the 'http://tech.example.edu/hats#TeacherAssistant' semantics can at least display a human-readable name. Names can be registered with the XMPP Registrar. Also integrates well with Ad-Hoc Commands.

    Con: Not a very Jabberish way of structuring information.

  3. XML element qualified by custom namespace:

    <TeacherAssistant xmlns='http://tech.example.edu/hats' displayname='Teacher&apos;s Assistant' xml:lang='en-us'/>

    Pro: A more Jabberish way to structure information.

    Con: Clients won't show anything if they don't understand the custom namespace.

As noted, a participant can wear many hats. The following example shows a participant who is a MUC room owner and both a "host" and a "presenter" in an online meeting system.

Example 2. Presence With Multiple Hats

<presence
    from='meeting123@meetings.example.com/Harry'
    id='D568A74F-E062-407C-83E9-531E91526516'
    to='someone@example.com/foo'>
  <x xmlns='http://jabber.org/protocol/muc#user'>
    <item affiliation='owner' role='moderator'/>
  </x>
  <hats xmlns='urn:xmpp:hats:0'>
    <hat displayName='Host' name='http://schemas.example.com/hats#host' xml:lang='en-us'/>
    <hat displayName='Presenter' name='http://schemas.example.com/hats#presenter' xml:lang='en-us'/>
  </hats>
</presence>
    

3.2 Adding a Hat

Hats are added and removed using Ad-Hoc Commands (XEP-0050) [3].

The following flow shows how to add a hat.

Example 3. Admin Requests to Add a Hat

<iq from='professor@example.edu/office'
    id='fdi3n2b6'
    to='physicsforpoets@courses.example.edu'
    type='set'
    xml:lang='en'>
  <command xmlns='http://jabber.org/protocol/commands' 
           action='execute'
           node='urn:xmpp:hats:commands:don'/>
</iq>
    

Unless an error occurs, the service returns the appropriate form.

Example 4. Service Returns Form to Admin

<iq from='physicsforpoets@courses.example.edu'
    id='fdi3n2b6'
    to='professor@example.edu/office'
    type='result'
    xml:lang='en'>
  <command xmlns='http://jabber.org/protocol/commands' 
           node='urn:xmpp:hats:commands:don'
           sessionid='A971D19A-2226-4DAD-B261-8D0886B9A026'
           status='executing'>
    <x xmlns='jabber:x:data' type='form'>
      <title>Assigning a Hat</title>
      <instructions>Fill out this form to assign a hat.</instructions>
      <field type='hidden' var='FORM_TYPE'>
        <value>urn:xmpp:hats:commands</value>
      </field>
      <field label='User Address'
             type='jid-single'
             var='accountjid'>
        <required/>
      </field>
      <field label='The role'
             type='list-single'
             var='hat'>
        <option label='Teacher'><value>http://tech.example.edu/hats#Teacher</value></option>
        <option label='Teacher&apos;s Assistant'><value>http://tech.example.edu/hats#TeacherAssistant</value></option>
        <option label='Test Proctor'><value>http://tech.example.edu/hats#Proctor</value></option>
      </field>
    </x>
  </command>
</iq>
    

Example 5. Admin Submits Form

<iq from='professor@example.edu/office'
    id='9fens61z'
    to='physicsforpoets@courses.example.edu'
    type='set'
    xml:lang='en'>
  <command xmlns='http://jabber.org/protocol/commands' 
           node='urn:xmpp:hats:commands:don'
           sessionid='A971D19A-2226-4DAD-B261-8D0886B9A026'>
    <x xmlns='jabber:x:data' type='submit'>
      <field type='hidden' var='FORM_TYPE'>
        <value>urn:xmpp:hats:commands</value>
      </field>
      <field var='accountjid'>
        <value>terry.anderson@example.edu</value>
      </field>
      <field var='hat'>
        <value>http://tech.example.edu/hats#TeacherAssistant</value>
      </field>
    </x>
  </command>
</iq>
    

Example 6. Service Informs Admin of Completion

<iq from='physicsforpoets@courses.example.edu'
    id='9fens61z'
    to='professor@example.edu/office'
    type='result'
    xml:lang='en'>
  <command xmlns='http://jabber.org/protocol/commands' 
           node='urn:xmpp:hats:commands:don'
           sessionid='A971D19A-2226-4DAD-B261-8D0886B9A026'
           status='completed'/>
</iq>
    

Note: only one hat is added at a time, and the form uses a field of type "list-single" to enforce that logic.

3.3 Removing a Hat

The following flow shows how to remove a hat.

Example 7. Admin Requests to Remove a Hat

<iq from='professor@example.edu/office'
    id='fdi3n2b6'
    to='physicsforpoets@courses.example.edu'
    type='set'
    xml:lang='en'>
  <command xmlns='http://jabber.org/protocol/commands' 
           action='execute'
           node='urn:xmpp:hats:commands:doff'>
    <x xmlns='jabber:x:data' type='submit'>
      <field type='hidden' var='FORM_TYPE'>
        <value>urn:xmpp:hats:commands</value>
      </field>
      <field var='accountjid'>
        <value>terry.anderson@example.edu</value>
      </field>
      <field var='hat'>
        <option label='Teacher&apos;s Assistant'><value>http://tech.example.edu/hats#TeacherAssistant</value></option>
      </field>
    </x>
  </command>
</iq>
    

Example 8. Service Informs Admin of Completion

<iq from='physicsforpoets@courses.example.edu'
    id='9fens61z'
    to='professor@example.edu/office'
    type='result'
    xml:lang='en'>
  <command xmlns='http://jabber.org/protocol/commands' 
           node='urn:xmpp:hats:commands:doff'
           sessionid='A971D19A-2226-4DAD-B261-8D0886B9A026'
           status='completed'/>
</iq>
    

4. Security Considerations

To follow.

5. IANA Considerations

This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [4].

6. XMPP Registrar Considerations

6.1 Protocol Namespaces

The XMPP Registrar shall add "urn:xmpp:hats:0" to its registry of protocol namespaces.

7. XML Schema

To follow.

8. Acknowledgements

The concepts underlying this specification were first discussed several years ago at an XMPP Summit in Brussels, Belgium. Special thanks to Joe Hildebrand and Ralph Meijer for their contributions to those discussions. Thanks also to Matt Miller, Kevin Smith, and Matthew Wild for their feedback on the written specification.


Appendices


Appendix A: Document Information

Series: XEP
Number: 0317
Publisher: XMPP Standards Foundation
Status: Experimental
Type: Standards Track
Version: 0.1
Last Updated: 2013-01-03
Approving Body: XMPP Council
Dependencies: XMPP Core, XEP-0045, XEP-0050
Supersedes: None
Superseded By: None
Short Name: NOT_YET_ASSIGNED
Source Control: HTML
This document in other formats: XML  PDF


Appendix B: Author Information

Peter Saint-Andre

Email: stpeter@jabber.org
JabberID: stpeter@jabber.org
URI: https://stpeter.im/


Appendix C: Legal Notices

Copyright

This XMPP Extension Protocol is copyright © 1999 - 2014 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. ##

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 from, out of, or in connection with the Specification or the implementation, deployment, or other use of 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 can be found at <http://xmpp.org/about-xmpp/xsf/xsf-ipr-policy/> or obtained by writing to XMPP Standards Foundation, 1899 Wynkoop Street, Suite 600, Denver, CO 80202 USA).

Appendix D: Relation to XMPP

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) 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

1. XEP-0045: Multi-User Chat <http://xmpp.org/extensions/xep-0045.html>.

2. XEP-0030: Service Discovery <http://xmpp.org/extensions/xep-0030.html>.

3. XEP-0050: Ad-Hoc Commands <http://xmpp.org/extensions/xep-0050.html>.

4. The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>.


Appendix H: Revision History

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

Version 0.1 (2013-01-03)

Initial published version approved for publication by the XMPP Council; clarified ad-hoc commands logic and syntax.

(psa)

Version 0.0.2 (2012-12-09)

Described use of ad-hoc commands for adding and removing hats.

(psa)

Version 0.0.1 (2012-12-06)

First draft.

(psa)

END