Unlike for XMPP connections via TCP as specified in RFC 6120 [1], there exists no specificiation of implicit connection endpoints for XMPP over WebSocket (RFC 7395 [2]). As a result, XMPP services which whish to provide WebSocket connectivity need to announce their WebSocket endpoints, so that clients are able to discover them (RFC 7395 § 4). This XEP fills this gap. It eventually enables, under certain conditions, XMPP services to provide WebSocket connectivty, without resorting to Discovering Alternative XMPP Connection Methods (XEP-0156) [3] nor requiring manual configuration by the user.
The following implicit XMPP WebSocket endpoints are specified:
TODO: Use implicit endpoints only if no other endpoints were discovered?
Implementations should note that due this XEP, the collection of potential endpoints may contain duplicates. This is because the implicit WebSocket connection endpoints defined herein may match the ones that where discovered (RFC 7395 § 4, XEP-0156). Implementations may want to ensure that no such duplicates exist.
Furthermore, implementations attempting to connect to the discovered endpoints serially, as opposed to concurrently, may use the implicit endpoints only as last resort.
Since the implicit WebSocket connection endpoints are defined to include the XMPP service name, the verification required when using the secured variant of the WebSocket transport provides the necessary security.
This document requires no interaction with the Internet Assigned Numbers Authority (IANA) [4].
This document requires no interaction with the XMPP registrar.
No XML schema specification is required, as this XEP does not specify any XML data.
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This XMPP Extension Protocol is copyright © 1999 – 2020 by the XMPP Standards Foundation (XSF).
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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 <http://xmpp.org/about/discuss.shtml> 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. RFC 6120: Extensible Messaging and Presence Protocol (XMPP): Core <http://tools.ietf.org/html/rfc6120>.
2. RFC 7395: An Extensible Messaging and Presence Protocol (XMPP) Subprotocol for WebSocket <http://tools.ietf.org/html/rfc7395>.
3. XEP-0156: Discovering Alternative XMPP Connection Methods <https://xmpp.org/extensions/xep-0156.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 http://xmpp.org/extensions/attic/
First draft.
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