WebXDC [1] is a specification for sharing interactive embeddable widgets built with web-like technologies (HTML, JavaScript) via a chat platform, and sharing state between participants in the chat without allowing external network connections for the sandboxed web content. In order to provide support for WebXDC [1] widgets, the host protocol (XMPP in our case) must define a way to transmit these widgets and the associated state updates.
This specification uses some terminology defined below:
A widget may be attached to a message using any file-transfer mechanism supported by the client, such as Out-of-Band Data (XEP-0066) [3] or Stateless Inline Media Sharing (XEP-0385) [4]. The message MUST contain a <thread/> element with a new, unique id. Note: including multiple file-transfer mechanisms in the same message may be beneficial for broader compatibility.
<message to='romeo@montague.lit' type='chat'>
<thread>018fe972-ea89-7f4b-90f8-729b85b7f32d</thread>
<media-sharing xmlns='urn:xmpp:sims:1'>
<file xmlns='urn:xmpp:jingle:apps:file-transfer:5'>
<media-type>application/webxdc+zip</media-type>
<name>Calendar</name>
<size>3032449</size>
<hash xmlns='urn:xmpp:hashes:2' algo='sha3-256'>2XarmwTlNxDAMkvymloX3S5+VbylNrJt/l5QyPa+YoU=</hash>
<thumbnail xmlns='urn:xmpp:thumbs:1' uri='cid:sha1+ffd7c8d28e9c5e82afea41f97108c6b4@bob.xmpp.org' media-type='image/png' width='96' height='96'/>
</file>
<sources>
<reference xmlns='urn:xmpp:reference:0' type='data' uri='https://download.montague.lit/4a771ac1-f0b2-4a4a-9700-f2a26fa2bb67/calendar.xdc />
</sources>
</media-sharing>
<x xmlns='jabber:x:oob'>
<url>https://download.montague.lit/4a771ac1-f0b2-4a4a-9700-f2a26fa2bb67/calendar.xdc</url>
</x>
</message>When a widget needs to communicate an update to peers in a chat, this update may contain one or more of the following items as defined in WebXDC [5].
| Item | Description |
|---|---|
| info | Human readable message to send to the chat |
| summary | Text which may be shown next to the widget launcher |
| document | Title which may be shown next to the widget launcher |
| payload | Arbitrary JSON serializable value |
These items are delivered in a message which MUST have the same <thread> as the message which originally delivered the widget itself. The stanza SHOULD contain a x child having the urn:xmpp:webxdc:0 namespace, with these items (except for info) as children, as defined below.
The info item is human-readable and is not needed by the widget itself, thus it is appropriate to transmit it anywhere that it might be visible to all participants, such as in a message body. If this is the only item present, an empty <x> element SHOULD still be included in the message to signal this update came from the widget.
<message to='romeo@montague.lit' type='chat'> <thread>018fe972-ea89-7f4b-90f8-729b85b7f32d</thread> <x xmlns='urn:xmpp:webxdc:0' /> <body>Juliet has added an event.</body> </message>
These items are delivered as children of the <x> item, and in the same namespace. The document item using a <document> child and the summary item using a <summary> child.
<message to='romeo@montague.lit' type='chat'>
<thread>018fe972-ea89-7f4b-90f8-729b85b7f32d</thread>
<x xmlns='urn:xmpp:webxdc:0'>
<document>Our Calendar</document>
<summary>12 events</summary>
</x>
</message>The payload item is delivered using JSON Containers (XEP-0335) [6] as a child of the <x> element
<message to='romeo@montague.lit' type='chat'>
<thread>018fe972-ea89-7f4b-90f8-729b85b7f32d</thread>
<x xmlns='urn:xmpp:webxdc:0'>
<json xmlns='urn:xmpp:json:0'>{}</json>
</x>
</message>WebXDC [7] widgets get various data injected into them by the host application. One of these worth mentioning is the selfAddr property.
xmpp:juliet@capulet.litoccupant-id.The selfName property defined by WebXDC [7] is human readable and may be set to anything useful per that specification. It MAY be set to the local Multi-User Chat (XEP-0045) [2] nickname or User Nickname (XEP-0172) [9] where relevant.
None
It is assumed that an implementation of this XEP will be paired with an implementation of WebXDC [1]. Please see WebXDC [1] for sandboxing and security considerations for your WebXDC implementation.
This XEP does not introduce any specific security considerations besides those present in any WebXDC [1] implementation.
It should be clear to users that their actions inside an embedded widget may be transmitted to other participants.
This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [10].
This specification defines the following XML namespace: urn:xmpp:webxdc:0
If the protocol defined in this specification undergoes a revision that is not fully backwards-compatible with an older version, the XMPP Registrar shall increment the protocol version number found at the end of the XML namespaces defined herein, as described in Section 4 of XEP-0053.
<?xml version='1.0' encoding='UTF-8'?>
<xs:schema
xmlns:xs='http://www.w3.org/2001/XMLSchema'
targetNamespace='urn:xmpp:webxdc:0'
xmlns='urn:xmpp:webxdc:0'
xmlns:json='urn:xmpp:json:0'
elementFormDefault='qualified'>
<xs:annotation>
<xs:documentation>
The protocol documented by this schema is defined in
XEP-0491: http://www.xmpp.org/extensions/xep-0491.html
</xs:documentation>
</xs:annotation>
<xs:import namespace='urn:xmpp:json:0' schemaLocation='https://xmpp.org/schemas/json.xsd' />
<xs:element name='x'>
<xs:complexType>
<xs:sequence>
<xs:element name='summary' type='xsd:string' minOccurs='0' maxOccurs='1'/>
<xs:element name='document' type='xsd:string' minOccurs='0' maxOccurs='1'/>
<xs:element name='json' type='json:json' minOccurs='0' maxOccurs='1'/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
Thanks to NLNet foundation for funding the work on this specification.
This document in other formats: XML PDF
This XMPP Extension Protocol is copyright © 1999 – 2024 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. ##
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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. WebXDC docs: https://webxdc.org/docs/
2. XEP-0045: Multi-User Chat <https://xmpp.org/extensions/xep-0045.html>.
3. XEP-0066: Out of Band Data <https://xmpp.org/extensions/xep-0066.html>.
4. XEP-0385: Stateless Inline Media Sharing (SIMS) <https://xmpp.org/extensions/xep-0385.html>.
5. WebXDC sendUpdate: https://webxdc.org/docs/spec/sendUpdate.html
6. XEP-0335: JSON Containers <https://xmpp.org/extensions/xep-0335.html>.
7. WebXDC selfAddr and selfName: https://webxdc.org/docs/spec/selfAddr_and_selfName.html
8. XEP-0421: Anonymous unique occupant identifiers for MUCs <https://xmpp.org/extensions/xep-0421.html>.
9. XEP-0172: User Nickname <https://xmpp.org/extensions/xep-0172.html>.
10. 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/
Initial version.
@report{weber2024webxdc,
title = {WebXDC},
author = {Weber, Stephen Paul},
type = {XEP},
number = {0491},
version = {0.1.3},
institution = {XMPP Standards Foundation},
url = {https://xmpp.org/extensions/xep-0491.html},
date = {2024-06-05/2024-10-17},
}END