XEP-0483: HTTP Online Meetings

1. Introduction¶

XMPP protocol extensions already defines a method for initiating peer-to-peer media sessions such as Jingle (XEP-0166) [1] however due to its very nature of being peer-to-peer it presents a few challenges in scenarios with online meetings that depend on a central Selective Forwarding Unit (SFU) or a Multipoint Control Unit (MCU) to host the meeting..

Using a web browser to manually request a meeting URL from an HTTP server and sharing the link has been a workaround for this for a long time now. While users have a variety of services to choose from, the downside of this manual approach is that an XMPP client can not automate this process on behalf of the user since these services don’t share a common API.

This XEP defines an approach to request initiation of an online meeting via an HTTP server and receive a URL can be used to join and invite others to the meeting. It has two main features:

1. An IQ-based protocol to request a meeting link from a server.
2. An element that can be added to a message stanza for sending the received meeting link to another party

The second feature is achieved by using Call Invites (XEP-0482) [2], which describes call invites using Jingle and external URIs. The XEP mentions how a web URLs can be used as external URI to join a call. For completeness, an example is repeated here to explicitly show how meeting invitations should be sent to invitees.

Call Invites (XEP-0482) [2] has other call mangement features, like announcing call join and leave on the XMPP side. These are relevant for online meetings when the website behind the URL is opened in a frame or similar inside the XMPP client. The meeting host xmpp client can track meeting participants and know when users leave the meeting without having to depend on APIs provided by the meeting service provider which may present cross-domain challenges. For completeness, examples are also repeated in this XEP to explicity show their application for online meeting invitations.

2. Requirements¶

• Be as easy to implement as possible. This is grounded on the idea that most programming languages already have HTTP libraries available.
• Usable with Meeting service providers that have no XMPP integration.
• Anyone who knows the URL SHOULD be able to access it.

3. Discovering Support¶

<iq from='romeo@montague.tld/garden'
    to='montague.tld'
    id='disco_01'
    type='get'>
  <query xmlns='http://jabber.org/protocol/disco#info'/>
</iq>

<iq from='montague.tld'
    to='romeo@montague.tld/garden'
    id='disco_01'
    type='result'>
  <query xmlns='http://jabber.org/protocol/disco#info'>
    <identity
        category='server'
        type='im'
        name='Openfire Server'/>
    <feature var='urn:xmpp:http:online-meetings:initiate:0'/>
    <feature var='urn:xmpp:http:online-meetings#jitsi'/>
    <feature var='urn:xmpp:http:online-meetings#galene'/>
  </query>
</iq>

<iq from='romeo@montague.tld/garden'
    to='juliet@capulet.example/balcony'
    id='disco_02'
    type='get'>
  <query xmlns='http://jabber.org/protocol/disco#info'/>
</iq>

<iq from='juliet@capulet.example/balcony'
    to='romeo@montague.tld/garden'
    id='disco_02'
    type='result'>
  <query xmlns='http://jabber.org/protocol/disco#info'>
    <identity
        category='client'
        type='im'
        name='Spark'/>
    <feature var='urn:xmpp:http:online-meetings:invite:0'/>
    <feature var='urn:xmpp:http:online-meetings#jitsi'/>
  </query>
</iq>

4. Requesting a Meeting¶

A client requests an online new meeting to be initiated by sending an IQ-get to the server containing a <query> child element qualified by the 'urn:xmpp:http:online-meetings:invite:0' namespace.

This 'query' MUST include the type attribute specifying the Meeting Service type, which SHOULD be registered as described in the Meeting Service Type Registry section of this document.

<iq from='romeo@montague.tld/garden'
    to='montague.tld'
    id='initiate_01'
    type='get'>
  <query xmlns='urn:xmpp:http:online-meetings:0'
         type='jitsi'/>
</iq>

If the requesting entity desires to (re)initiate a meeting with a specific identifier, the optional 'id' attribute can be used to specify the identity of the online meeting requested. When the provided value cannot be used, for example when it does not match the format used by a meeting provider, or a meeting with that particular value is already in use, the server SHOULD return an error.

<iq from='romeo@montague.tld/garden'
    to='montague.tld'
    id='initiate_02'
    type='get'>
  <query xmlns='urn:xmpp:http:online-meetings:0'
         type='jitsi'
         id='my_meeting'/>
</iq>

An optional 'desc' child element can be used to assign a human-readable description to the meeting. The server MAY use this value when configuring the online meeting with the service provider, and SHOULD use this value in its response, but otherwise treat this as an opaque value.

<iq from='romeo@montague.tld/garden'
    to='montague.tld'
    id='initiate_03'
    type='get'>
  <query xmlns='urn:xmpp:http:online-meetings:0'
         type='jitsi'>
    <desc>Meeting room for Open Standards discussion</desc>
  </query>	
</iq>

The XMPP server responds with one or two child elements: a 'initiate' element that contains a URL to be used to create and configure the meeting, and an 'invite' element as specified by Call Invites (XEP-0482) [2] to invite others into the meeting.

In the URLs that it returns, the server MAY specify a web-based protocol handler if available and registered by the user. Otherwise, standard HTTPS protocol will be specified. In any case, the fully resolved URL provided by the host MUST provide Transport Layer Security (RFC 5246 [5]). The HTTPS URL MUST adhere to RFC 3986 [6]. Non ASCII characters MUST be percent-encoded.

<iq from='montague.tld'
    to='romeo@montague.tld/garden'
    id='initiate_03'
    type='result'>
  <query xmlns='urn:xmpp:http:online-meetings:0'>
    <initiate type='jitsi'>
      <url>web+jitsi:OpenStandardsMuchGreatness</url>
      <desc>Meeting room for Open Standards discussion</desc>
    </initiate>
    <invite xmlns='urn:xmpp:call-invites:0'>
	  <external uri='web+jitsi:OpenStandardsMuchGreatness' />
	  <meeting xmlns='urn:xmpp:http:online-meetings:0' 
               type='jitsi' 
               desc='Meeting room for Open Standards discussion' />
    </invite>  	
  </query>
</iq>

<iq from='montague.tld'
    to='romeo@montague.tld/garden'
    id='initiate_03'
    type='result'>
  <query xmlns='urn:xmpp:http:online-meetings:0'>
    <initiate type='jitsi'>
      <url>https://meet.jit.si/OpenStandardsMuchGreatness</url>
      <desc>Meeting room for Open Standards discussion</desc>
    </initiate>
    <invite xmlns='urn:xmpp:call-invites:0'>
	  <external uri='https://meet.jit.si/OpenStandardsMuchGreatness' />
	  <meeting xmlns='urn:xmpp:http:online-meetings:0' 
               type='jitsi' 
               desc='Meeting room for Open Standards discussion' />
    </invite>  
  </query>
</iq>

The XMPP server MAY be tightly integrated with the Meeting Provider and facilitate registration, configuration and association of a web-based protocol handler, but the protocol to implement such integration is out of scope of this document.

If the XMPP server is tightly integrated with the Meeting Provider, and no other data is needed for a meeting to be initiated, the XMPP server MAY initiate a meeting on behalf of the requester and leave out the 'initiate' element from the response. Note that a server SHOULD include a 'initiate' URL in its response if it cannot initiate a meeting on behalf of the requesting entity, even if it knows that no additional data is needed for a meeting to be automatically initiated upon joining the meeting URL. Inclusion of the 'initiate' element signals that the requesting entity may need join the meeting as the first participant, in order to be assigned 'creator' or 'moderator' privileges.

5. Error conditions¶

Instead of providing the client with a URL the server MAY respond with an error if the request fails. In addition, the HTTP entity MAY inform the requester about the reason for the failure.

<iq from='montague.tld'
    to='romeo@montague.tld/garden'
    id='initiate_01'
    type='error'>
  <query xmlns='urn:xmpp:http:online-meetings:0'
         type='jitsi'/>
  <error type='cancel'>
    <service-unavailable xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
    <text xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'>The 'jitsi' meeting service provider type is not supported.</text>
  </error>
</iq>

<iq from='montague.tld'
    to='romeo@montague.tld/garden'
    id='initiate_02'
    type='error'>
  <query xmlns='urn:xmpp:http:online-meetings:0'
         type='jitsi'
         id='my-meeting'/>
  <error type='modify'>
    <not-acceptable xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
    <text xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'>Meeting is in use</text>
  </error>
</iq>

For any other type of error the service SHOULD respond with appropriate error types to indicate temporary or permanent errors.

For temporary errors such as exceeding a personal quota the service MAY include a <retry/> element qualified by the 'urn:xmpp:http:online-meetings:0' namespace as a child of the <error/> element. The retry element MUST include an attribute 'stamp' which indicates the time at which the requesting entity may try again. The format of the timestamp MUST adhere to the date-time format specified in XMPP Date and Time Profiles (XEP-0082) [7] and MUST be expressed in UTC.

<iq from='montague.tld'
    to='romeo@montague.tld/garden'
    id='initiate_01'
    type='error'>
  <query xmlns='urn:xmpp:http:online-meetings:0'
         type='jitsi'/>
  <error type='wait'>
    <resource-constraint xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
    <text xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'>Quota reached. You can only request 5 meetings a day</text>
    <retry xmlns='urn:xmpp:http:online-meetings:0' stamp='2017-12-03T23:42:05Z'/>
  </error>
</iq>

<iq from='montague.tld'
    to='romeo@montague.tld/garden'
    id='initiate_01'
    type='error'>
  <query xmlns='urn:xmpp:http:online-meetings:0'
         type='jitsi'/>
  <error type='auth'>
    <forbidden xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
    <text xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'>Only premium members are allowed to initiate meetings</text>
  </error>
</iq>

6. Meeting Invitation¶

After the requesting entity has successfully initiated a meeting, it MAY invite other entities to join the meeting using the 'invite' element it received to propose the meeting

To allow users of clients that do not support Call Invites (XEP-0482) [2] to receive the invitation, a Out-of-Band Data (XEP-0066) [8] element and/or a 'body' element containing the meeting details MAY be included.

There is no further XMPP communication required between the server and the requesting entity for participants to join the meeting. The actual online meeting engagement with the provided URL is out of scope of this document.

<message
    id='invite_01'
    from='romeo@montague.tld/garden'
    to='juliet@capulet.example/balcony'>
  <invite xmlns='urn:xmpp:call-invites:0'>
    <external uri='https://meet.jit.si/OpenStandardsMuchGreatness' />
    <meeting xmlns='urn:xmpp:http:online-meetings:0' 
             type='jitsi' 
             desc='Meeting room for Open Standards discussion' />
  </invite>  
  <x xmlns='jabber:x:oob'>
    <url>https://meet.jit.si/OpenStandardsMuchGreatness</url>
    <desc>Meeting room for Open Standards discussion</desc>
  </x>
  <body>You are invited to join 'Meeting room for Open Standards discussion' at https://meet.jit.si/OpenStandardsMuchGreatness</body>
</message>

<message to='juliet@capulet.example/balcony'>
  <retract id='invite_01' xmlns='urn:xmpp:call-invites:0' />
</message>

<message to='romeo@montague.tld/garden'>
  <accept id='invite_01' xmlns='urn:xmpp:call-invites:0'>
    <external uri='https://meet.jit.si/OpenStandardsMuchGreatness' />
    <meeting type='jitsi' desc='Meeting room for Open Standards discussion' />
  </accept>
</message>

<message to='romeo@montague.tld/garden'>
  <reject id='invite_01' xmlns='urn:xmpp:call-invites:0' />
</message>

<message to='romeo@montague.tld/garden'>
  <left id='invite_01' xmlns='urn:xmpp:call-invites:0' />
</message>

7. Implementation Notes¶

The server SHOULD choose an appropriate timeout for the validity of the URL. Since there is no reason for a client to wait between requesting the URL and joining the meeting via the URL before dispatching invitations, relatively low timeout values of around 300s are RECOMMENDED.

8. Security Considerations¶

9. IANA Considerations¶

This document requires no interaction with the the Internet Assigned Numbers Authority (IANA) [9]

10. XMPP Registrar Considerations¶

11. XML Schema¶

<xml version="1.0" encoding="utf8">
<!-- TBD -->

Appendices

Appendix A: Document Information¶

Series

XEP

Number

0483

Publisher

XMPP Standards Foundation

Status

Experimental

Type

Standards Track

Version

0.2.0

Last Updated

2023-12-12

Approving Body

XMPP Council

Dependencies

None

Supersedes

None

Superseded By

None

Short Name

http_online-meetings

Source Control

HTML

This document in other formats: XML  PDF

Appendix B: Author Information¶

Dele Olajide

Email

dele@olajide.net

JabberID

dele.olajide@igniterealtime.org

Guus der Kinderen

Email

guus.der.kinderen@gmail.com

JabberID

guus.der.kinderen@igniterealtime.org

Appendix C: Legal Notices¶

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 <https://xmpp.org/community/> 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 https://xmpp.org/extensions/attic/

1. Version 0.2.0 (2023-12-12)¶
   • Use XEP-0482 to send the meeting link to another party
   do
2. Version 0.1.0 (2023-12-11)¶
   • Promoted to Experimental.
   XEP Editor: kis
3. Version 0.0.3 (2023-09-12)¶
   • Modified wording of abstract.
   • Specified distribution of URL / add meeting invitation
   • Differentiate between Meeting service providers that are integrated with XMPP server, and those that are not.
   • Differentiate between URL to create and join meeting
   • Replaced textual references with XML entities
   • Introduced distinct namespaces for create and invite, retaining type-specific namespaces for feature discovery
   • Introduced Meeting Service type registry
   • Removed CORS-related implementation note
   • Meeting ID in request now optional
   • Add optional 'desc' in the meeting request.
   • Moved IQ child elements into a wrapper, renamed 'create' element to 'initiate'
   • Add fall-back body element to invite message stanza.
   • Removed dependency on XEP-0066.
   gdk
4. Version 0.0.2 (2023-08-22)¶
   • Remove base URL attribute.
   • Add support for a web-based protocol handler in OOB data result.
   do
5. Version 0.0.1 (2023-08-21)¶
   • Initial version.
   do

Appendix I: Bib(La)TeX Entry

@report{olajide2023http_online-meetings,
  title = {HTTP Online Meetings},
  author = {Olajide, Dele and der Kinderen, Guus},
  type = {XEP},
  number = {0483},
  version = {0.2.0},
  institution = {XMPP Standards Foundation},
  url = {https://xmpp.org/extensions/xep-0483.html},
  date = {2023-08-21/2023-12-12},
}

END