The value of a URI scheme (see RFC 3986 ) for Jabber/XMPP communications has long been recognized within the Jabber community, and such a scheme has been formally defined in RFC 5122  as a way of identifying entities that adhere to XMPP Core  or its antecedents. Unfortunately, URI schemes are slow to be accepted on the Internet, such that it might be years (if ever) before widely deployed software such as web browsers will support addresses of the form <xmpp:user@domain>.
Thankfully, it is not necessary for the large existing base of deployed software to support the xmpp: URI scheme in order to integrate Jabber/XMPP support. A well-accepted alternative approach  is to define a MIME type (in accordance with RFC 2045 ) and then reconfigure the relevant server and client software to correctly handle the new MIME type.
Therefore, this document defines a MIME type of "application/jabber+xml" (in particular, an XML media type in accordance with RFC 3023 ). Files of this MIME type would commonly be accessed with a web browser via HTTP, although other access methods are possible (e.g., attachment of the MIME type to an email message). On opening a file of this type, a browser would (by configuration) invoke an appropriate "helper" application (i.e., an external Jabber client, plugin, or internal module) that would enable the user to interact with a Jabber/XMPP server. If the user is not currently connected to a server, the invoked program would be responsible for connecting the user with appropriate prompting for authentication credentials. The file passed to the helper application would define parameters needed to complete a certain use case, such as sending a message to another user.
Note: The "application/jabber+xml" MIME type defined herein is not to be confused with the "application/xmpp+xml" MIME type defined in RFC 3923 ; the two MIME types address different requirements and do not overlap or conflict.
The solution MUST enable a user to complete the following use cases, support for which is REQUIRED:
In addition, the solution SHOULD enable a user to complete the following use cases, support for which is RECOMMENDED:
These use cases are defined below.
In order to send a message to a contact, the user opens an XMPP file of the following form:
The browser passes this file to the helper application, which shall instantiate an appropriate interface for sending a single message to the JID defined in the file. If the user completes the interface, the helper application shall then send a message stanza of type='normal' as specified in XMPP IM , first authenticating with the user's Jabber/XMPP server if necessary.
The browser passes this file to the helper application, which shall instantiate an appropriate interface for chatting with the JID defined in the file. If the user completes the interface, the helper application shall then send a message stanza of type='chat' as specified in XMPP IM, first authenticating with the user's Jabber/XMPP server if necessary.
The browser passes this file to the helper application, which shall instantiate an appropriate interface for sending a presence subscription request to the JID defined in the file (e.g., specifying a name and/or group for the contact). If the user completes the interface, the helper application shall then send a presence stanza of type='subscribe' as specified in XMPP IM, first authenticating with the user's Jabber/XMPP server if necessary. The helper application SHOULD perform a "roster set" before sending the presence subscription request, as described in XMPP IM.
The browser passes this file to the helper application, which shall instantiate an appropriate interface for joining the conference room associated with the JID defined in the file. If the user completes the interface, the helper application shall then send a directed presence stanza to the JID (appending a room nickname to the JID as the resource identifier) as described in Multi-User Chat (XEP-0045) , first authenticating with the user's Jabber/XMPP server if necessary.
The browser passes this file to the helper application, which shall send an IQ stanza of type='get' to the service associated with the JID defined in the file in order to determine the registration requirements (first authenticating with the user's Jabber/XMPP server if necessary), as described in In-Band Registration (XEP-0077) . The helper application shall then instantiate an appropriate interface for registering with the service. If the user completes the interface, the helper application shall then send an IQ stanza of type='set' to the JID as described in XEP-0077.
Detailed security considerations for instant messaging and presence protocols are given in RFC 2779  (Sections 5.1 through 5.4), and for XMPP in particular are given in RFC 3920 (Sections 12.1 through 12.6). In addition, all of the security considerations specified in RFC 3023 apply to the "application/jabber+xml" media type.
When a helper application has finished processing a file of type "application/jabber+xml", it SHOULD discard the file; this helps to prevent security-related problems that may result from HTTP caching.
This document requires registration of the "application/jabber+xml" content type with the Internet Assigned Numbers Authority (IANA) . The registration is as follows:
The XMPP Registrar shall interact with the IANA in order to register the media type defined herein.
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This XMPP Extension Protocol is copyright © 1999 – 2018 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 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 <email@example.com> discussion list.
Discussion on other xmpp.org discussion lists might also be appropriate; see <http://xmpp.org/about/discuss.shtml> for a complete list.
Given that this XMPP Extension Protocol normatively references IETF technologies, discussion on the <firstname.lastname@example.org> list might also be appropriate.
Errata can be sent to <email@example.com>.
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".
4. See, for instance, <http://www.mozilla.org/docs/web-developer/mimetypes.html> for information about MIME support in the Mozilla family of web browsers.
12. 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/>.
13. The XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <https://xmpp.org/registrar/>.
Note: Older versions of this specification might be available at http://xmpp.org/extensions/attic/