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Versions: 00 01 02 03 04 05 06 07 08                                    
Network Working Group                                     P. Saint-Andre
Internet-Draft                                Jabber Software Foundation
Expires: October 10, 2004                                 April 11, 2004


                            XMPP URI Format
                      draft-saintandre-xmpp-uri-03

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that other
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   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on October 10, 2004.

Copyright Notice

   Copyright (C) The Internet Society (2004). All Rights Reserved.

Abstract

   This document defines a URI scheme for use in addressing entities
   that can communicate via the Extensible Messaging and Presence
   Protocol (XMPP).













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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   1.1 Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   1.2 Discussion Venue . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Narrative  . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.1 Rationale  . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.2 Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.3 Query Component  . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  xmpp: URI IANA Registration  . . . . . . . . . . . . . . . . .  6
   3.1 URI scheme name  . . . . . . . . . . . . . . . . . . . . . . .  6
   3.2 URI scheme syntax  . . . . . . . . . . . . . . . . . . . . . .  6
   3.3 Character encoding considerations  . . . . . . . . . . . . . .  6
   3.4 Intended usage . . . . . . . . . . . . . . . . . . . . . . . .  6
   3.5 Security considerations  . . . . . . . . . . . . . . . . . . .  6
   3.6 Relevant publications  . . . . . . . . . . . . . . . . . . . .  6
   3.7 Person and email address to contact for further information  .  6
   3.8 Author/change controller . . . . . . . . . . . . . . . . . . .  7
   3.9 Applications and/or protocols which use this URI scheme
       name . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  7
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  7
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  7
       Normative References . . . . . . . . . . . . . . . . . . . . .  7
       Informative References . . . . . . . . . . . . . . . . . . . .  8
       Author's Address . . . . . . . . . . . . . . . . . . . . . . .  8
   A.  Revision History . . . . . . . . . . . . . . . . . . . . . . .  8
   A.1 Changes from draft-saintandre-xmpp-uri-02  . . . . . . . . . .  8
   A.2 Changes from draft-saintandre-xmpp-uri-01  . . . . . . . . . .  9
   A.3 Changes from draft-saintandre-xmpp-uri-00  . . . . . . . . . .  9
       Intellectual Property and Copyright Statements . . . . . . . . 10





















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1. Introduction

   The Extensible Messaging and Presence Protocol (XMPP) [XMPP-CORE]
   specifies that within the context of the streaming XML technology
   that forms the foundation of XMPP, the addresses of XMPP entities are
   not to be prepended with a URI scheme (as defined in RFC 2396 [URI]).
   However, many applications external to the existing network would
   like to address XMPP entities as full URIs; examples are databases
   that need to store XMPP addresses as URIs and non-native user agents
   (such as web browsers) that provide an interface to XMPP services.
   This memo defines an xmpp: URI scheme for use by such applications,
   and conforms to both the requirements in Registration Procedures for
   URL Scheme Names [URL-REG] and the recommendations in Guidelines for
   new URL Schemes [URL-GUIDE].

1.1 Terminology

   This document inherits terminology described in [XMPP-CORE].

   The capitalized key words "MUST", "MUST NOT", "REQUIRED", "SHALL",
   "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in RFC
   2119 [TERMS].

1.2 Discussion Venue

   The author welcomes discussion and comments related to the topics
   presented in this document.  The preferred forum is the
   <xmppwg@jabber.org> mailing list, for which archives and subscription
   information are available at <http://www.jabber.org/cgi-bin/mailman/
   listinfo/xmppwg/>.

2. Narrative

2.1 Rationale

   Many types of application can be built using XMPP.  The best-known
   such application is instant messaging (IM) and presence (as described
   in [IMP-MODEL] and [IMP-REQS] and defined for XMPP in [XMPP-IM]).
   Therefore it might seem appropriate to use the im: and pres: URI
   schemes specified by Common Profile for Instant Messaging (CPIM)
   [CPIM] and Common Profile for Presence (CPP) [CPP], rather than to
   define an XMPP-specific URI scheme.  However, while the im: and pres:
   URI schemes are appropriate for instant messaging and presence
   applications and are therefore mentioned normatively in [XMPP-IM],
   they are not necessarily appropriate for all XMPP applications.
   Because XMPP is fundamentally an XML streaming technology rather than
   an instant messaging and presence technology per se, XMPP



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   applications may conform to [XMPP-CORE] but not [XMPP-IM] and thus
   not implement instant messaging and presence semantics.  Indeed, XMPP
   is already used in applications such as network management, workflow
   applications, generic publish-subscribe, remote procedure calls,
   content syndication, gaming, and middleware.  These applications
   require an addressing scheme that is not tied to the particular
   semantics of the im: and pres: URI schemes.  Therefore, this document
   defines a generic URI scheme that will enable applications to address
   as a URI any entity that can communicate via XMPP.

   Note well that on an XMPP network, entities are to be addressed as
   <[node@]domain[/resource]> (i.e., without a URI scheme) rather than
   as <xmpp:[node@]domain[/resource]>.  The xmpp: URI format is provided
   for the sake of non-native interfaces and applications only; native
   applications are strongly encouraged not to prepend XMPP addresses
   with the xmpp: URI scheme when addressing XML stanzas sent over an
   XMPP network.

2.2 Form

   The syntax for an xmpp: URI is as follows (where the jid rule is
   defined in [XMPP-CORE]).

         "xmpp:" jid [ "?" query ]

   An xmpp: URI is opaque rather than hierarchical, and thus is similar
   to a mailto: URI as specified in RFC 2368 [MAILTO].  Because an xmpp:
   URI is opaque, the JID contained therein SHOULD include only a node
   identifier (OPTIONAL) and domain identifier (REQUIRED) as defined in
   [XMPP-CORE].  An xmpp: URI MAY include the resource identifier
   portion of a JID if the XMPP entity must be addressed as such, but
   this is not recommended since the delimiter used before a resource
   identifier in XMPP addresses is the slash character ("/"), which is
   discouraged by [URI] in opaque URIs.

2.3 Query Component

   If an xmpp: URI is presented in an end-user application that provides
   a non-native interface to an XMPP service (e.g., a web browser),
   interacting with such a URI SHOULD trigger the application to present
   a user with an appropriate interface to complete an action such as
   sending a message or sending presence.  In order to specify the
   possible actions, two "header" values of the query component are
   defined: "presence" and "message". Usage is described below.

2.3.1 Messages

   In order to invoke an interface for sending a message, the URI SHOULD



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   be of the form <xmpp:user@host?message>.

   The query component MAY include parameters that further specify the
   message to be sent to the intended recipient.  The following
   parameters are OPTIONAL for messages, corresponding to the <body/>,
   <subject/>, and <thread/> children of the XML <message/> stanza as
   defined in [XMPP-IM]:

   o  body (the natural-language contents of the message)

   o  subject (the topic of the message)

   o  thread (for grouping of multiple messages into a common thread)

   The following example illustrates the use of these parameters:

   Sending a message

      xmpp:user@host?message&subject=hi&body=Hello%20World&thread=abc123


2.3.2 Presence

   In order to invoke an interface for sending presence information, the
   URI SHOULD be of the form <xmpp:user@host?presence>.  The intended
   scope is the sending of presence notifications about the availability
   of the sender, not the management of presence subscriptions (for the
   semantic and syntactic differences between presence notifications and
   presence subscriptions, see [XMPP-IM]).

   The query component MAY include parameters that further specify the
   presence information to be sent to the intended recipient.  The
   following parameters are OPTIONAL for presence, corresponding to the
   'type' attribute and the <show/>, <status/>, and <priority/> children
   of the <presence/> stanza as defined in [XMPP-IM]:

   o  type (the only allowable value for presence notifications is
      "unavailable"; if the type is not specified, the sender is defined
      to be available)

   o  show (one of "away", "xa", "dnd", or "chat")

   o  status (a user-defined status message)

   o  priority (an integer specifying the rough likelihood of receiving
      messages at this resource)

   The following example illustrates the use of these parameters:



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   Sending Presence Information

      xmpp:user@host?presence&show=dnd&status=taking%20a%20nap


3. xmpp: URI IANA Registration

   This section provides the information required to register the xmpp:
   URI scheme.

3.1 URI scheme name

   xmpp

3.2 URI scheme syntax

   The syntax for an xmpp: URI is defined below using Augmented
   Backus-Naur Form as specified by [ABNF].  The jid rule is defined in
   [XMPP-CORE].

   XMPP-URI = "xmpp:" jid [ "?" query ]


3.3 Character encoding considerations

   Representation of non-ASCII character sets in local-part strings is
   limited to the standard methods provided as extensions to RFC 2822
   [IMF].  Specifically, for each byte, if the byte is not in the set
   A-Za-z0-9!$*.?_~+= then transform the byte to %hexhex as described in
   Section 2.2.5 of [URL-GUIDE].

3.4 Intended usage

   The xmpp: URI is intended to be used by interfaces to an XMPP network
   from non-native user agents such as web browsers, as well as by
   non-native applications that need to address XMPP entities as full
   URIs.

3.5 Security considerations

   See Security Considerations (Section 5) of this document.

3.6 Relevant publications

   [XMPP-CORE]

3.7 Person and email address to contact for further information




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   Peter Saint-Andre [mailto:stpeter@jabber.org]

3.8 Author/change controller

   This scheme is registered under the IETF tree.  As such, the IETF
   maintains change control.

3.9 Applications and/or protocols which use this URI scheme name

   Applications (other than native native XMPP applications) that
   provide an interface to XMPP services or that need to address XMPP
   entities as full URIs.

4. IANA Considerations

   This entire document addresses IANA considerations.

5. Security Considerations

   Detailed security considerations for XMPP are given in [XMPP-CORE].
   Providing an interface to XMPP services from non-native applications
   introduces new security concerns.  For example, the ability to
   interact with XMPP entities via a web browser may expose sensitive
   information to attacks that are not possible or that are unlikely on
   a native XMPP network.  Due care must be taken in deciding what
   information is appropriate for representing in xmpp: URIs; in
   particular, passwords MUST NOT be represented.

Normative References

   [ABNF]     Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 2234, November 1997.

   [IMF]      Resnick, P., "Internet Message Format", RFC 2822, April
              2001.

   [TERMS]    Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [URI]      Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
              Resource Identifiers (URI): Generic Syntax", RFC 2396,
              August 1998, <http://www.ietf.org/rfc/rfc2396.txt>.

   [URL-GUIDE]
              Masinter, L., Alvestrand, H., Zigmond, D. and R. Petke,
              "Guidelines for new URL Schemes", RFC 2718, November 1999.

   [URL-REG]  Petke, R. and I. King, "Registration Procedures for URL



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              Scheme Names", BCP 35, RFC 2717, November 1999.

   [XMPP-CORE]
              Saint-Andre, P., "Extensible Messaging and Presence
              Protocol (XMPP): Core", draft-ietf-xmpp-core-22 (work in
              progress), January 2004.

   [XMPP-IM]  Saint-Andre, P., "Extensible Messaging and Presence
              Protocol (XMPP): Instant Messaging and Presence",
              draft-ietf-xmpp-im-21 (work in progress), January 2004.

Informative References

   [CPIM]     Peterson, J., "Common Profile for Instant Messaging
              (CPIM)", draft-ietf-impp-im-04 (work in progress), August
              2003.

   [CPP]      Peterson, J., "Common Profile for Presence (CPP)",
              draft-ietf-impp-pres-04 (work in progress), August 2003.

   [IMP-MODEL]
              Day, M., Rosenberg, J. and H. Sugano, "A Model for
              Presence and Instant Messaging", RFC 2778, February 2000.

   [IMP-REQS]
              Day, M., Aggarwal, S. and J. Vincent, "Instant Messaging /
              Presence Protocol Requirements", RFC 2779, February 2000.

   [MAILTO]   Hoffman, P., Masinter, L. and J. Zawinski, "The mailto URL
              scheme", RFC 2368, July 1998.


Author's Address

   Peter Saint-Andre
   Jabber Software Foundation

   EMail: stpeter@jabber.org

Appendix A. Revision History

   Note to RFC Editor: please remove this entire appendix, and the
   corresponding entries in the table of contents, prior to publication.

A.1 Changes from draft-saintandre-xmpp-uri-02

   o  Corrected several small textual errors.




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   o  Clarified the scope of allowable presence information.


A.2 Changes from draft-saintandre-xmpp-uri-01

   o  Clarified guidelines for escaping of UTF-8 characters.

   o  Specified usage of query component.


A.3 Changes from draft-saintandre-xmpp-uri-00

   o  Modified ABNF to track changes to XMPP Core.

   o  Clarified a few matters in the text.




































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Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
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   The IETF invites any interested party to bring to its attention any
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   this standard. Please address the information to the IETF Executive
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Full Copyright Statement

   Copyright (C) The Internet Society (2004). All Rights Reserved.

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   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION



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   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.











































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