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.
A MUC service that supports hats MUST advertise a Service Discovery (XEP-0030) [2] feature of "urn:xmpp:hats:0".
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.
<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'>
<hat uri='http://tech.example.edu/hats#TeacherAssistant' title='Teacher's Assistant' xml:lang='en-us'/>
</hats>
</presence>
Every hat is uniquely identified by its URI. Hats also carry a human-readable title for display purposes. Within XMPP, a hat is contained within a <hat/> element in the 'urn:xmpp:hats:0' namespace. This element MUST possess a 'uri' attribute (containing the hat's URI), a 'title' attribute containing the name of the hat for display purposes, and MAY contain an 'xml:lang' attribute that identifies the language used in the 'title' attribute. The <hat/> element MAY contain additional custom payloads defined by other XEPs, or payloads specific to an implementation or deployment.
Entities may have multiple hats. The <hats/> element is defined as a container of zero or more <hat/> elements.
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. This system also demonstrates how hats can be annotated with custom information (here, the example <badge/> element).
<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 title='Host' uri='http://schemas.example.com/hats#host' xml:lang='en-us'>
<badge xmlns="urn:example:badges" fgcolor="#000000" bgcolor="#58C5BA"/>
</hat>
<hat title='Presenter' uri='http://schemas.example.com/hats#presenter' xml:lang='en-us'>
<badge xmlns="urn:example:badges" fgcolor="#000000" bgcolor="#EC0524"/>
</hat>
</hats>
</presence>
Hats are added and removed using Ad-Hoc Commands (XEP-0050) [3].
The following flow shows how 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.
<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'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>
<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>
<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.
The following flow shows how 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's Assistant'><value>http://tech.example.edu/hats#TeacherAssistant</value></option>
</field>
</x>
</command>
</iq>
<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>
To follow.
This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [4].
The XMPP Registrar shall add "urn:xmpp:hats:0" to its registry of protocol namespaces.
To follow.
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.
This document in other formats: XML PDF
This XMPP Extension Protocol is copyright © 1999 – 2020 by the XMPP Standards Foundation (XSF).
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.
## 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 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.
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 <https://xmpp.org/about/xsf/ipr-policy> or obtained by writing to XMPP Standards Foundation, P.O. Box 787, Parker, CO 80134 USA).
The HTML representation (you are looking at) is maintained by the XSF. It is based on the YAML CSS Framework, which is licensed under the terms of the CC-BY-SA 2.0 license.
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.
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 <https://xmpp.org/community/> for a complete list.
Errata can be sent to <editor@xmpp.org>.
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".
1. XEP-0045: Multi-User Chat <https://xmpp.org/extensions/xep-0045.html>.
2. XEP-0030: Service Discovery <https://xmpp.org/extensions/xep-0030.html>.
3. XEP-0050: Ad-Hoc Commands <https://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/>.
Note: Older versions of this specification might be available at https://xmpp.org/extensions/attic/
Select a syntax for hats.
Initial published version approved for publication by the XMPP Council; clarified ad-hoc commands logic and syntax.
Described use of ad-hoc commands for adding and removing hats.
First draft.
@report{saint-andre2012xep0317,
title = {Hats},
author = {Saint-Andre, Peter and Wild, Matthew},
type = {XEP},
number = {0317},
version = {0.2.0},
institution = {XMPP Standards Foundation},
url = {https://xmpp.org/extensions/xep-0317.html},
date = {2012-12-06/2023-06-28},
}END