Network Working Group P. Saint-Andre Internet-Draft Jabber Software Foundation Expires: March 11, 2004 September 11, 2003 XMPP URI Format draft-saintandre-xmpp-uri-00 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 groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on March 11, 2004. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document defines a URI scheme to address entities that can communicate via the Extensible Messaging and Presence Protocol (XMPP). Saint-Andre Expires March 11, 2004 [Page 1] Internet-Draft XMPP URI Format September 2003 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Discussion Venue . . . . . . . . . . . . . . . . . . . . . . . 4 1.3 Intellectual Property Notice . . . . . . . . . . . . . . . . . 4 2. xmpp: URI IANA Registration . . . . . . . . . . . . . . . . . 5 2.1 URI Scheme Name . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 URI Scheme Syntax . . . . . . . . . . . . . . . . . . . . . . 5 2.3 Character Encoding Considerations . . . . . . . . . . . . . . 5 2.4 Intended usage . . . . . . . . . . . . . . . . . . . . . . . . 5 2.5 Security considerations . . . . . . . . . . . . . . . . . . . 5 2.6 Relevant publications . . . . . . . . . . . . . . . . . . . . 6 2.7 Person and email address to contact for further information . 6 2.8 Author/Change controller . . . . . . . . . . . . . . . . . . . 6 2.9 Applications and/or protocols which use this URI scheme name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 4. Security Considerations . . . . . . . . . . . . . . . . . . . 8 Normative References . . . . . . . . . . . . . . . . . . . . . 9 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . . 10 Saint-Andre Expires March 11, 2004 [Page 2] Internet-Draft XMPP URI Format September 2003 1. Introduction The Extensible Messaging and Presence Protocol (XMPP) [1] has been adapted by the XMPP WG from the open protocol originally developed by the Jabber community. Currently there exist tens of thousands of servers on the Jabber network, with millions of end users. The addresses of XMPP entities are not specified as full URIs on the network itself, i.e., within the context of the streaming XML technology that forms the foundation of XMPP. However, many applications external to the existing network would like to address XMPP entities as full URIs in compliance with RFC 2396 [2]. Many types of applications can be built using XMPP. The best-known such application is instant messaging (IM) and presence as defined in XMPP IM [3]. Therefore it might seem appropriate to use the 'im:' and 'pres:' URI schemes defined in Common Profile for Instant Messaging (CPIM) [4] and Common Profile for Presence (CPP) [5], rather than to define an XMPP-specific URI scheme. Unfortunately, these URI schemes are limited to instant messaging (usually understood as exchanging messages with a single other user) and presence. However, fundamentally XMPP is a technology for near-real-time messaging, presence, and request-response services using streaming XML, rather than only an IM or presence technology. XMPP is already in use in applications quite distinct from IM, including 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 fully address any entity that can communicate via XMPP. On the XMPP network itself, entities must be addressed as rather than . However, some interfaces to XMPP services may be provided by non-native applications (e.g., web browsers), and other applications may want to refer to XMPP entities using addresses that are full URIs. The xmpp: URI format is provided for the sake of such interfaces and applications, and MUST NOT be used by native applications for addressing on the XMPP network itself. An xmpp: URI is opaque rather than hierarchical, and thus is similar to a mailto: URI as defined in RFC 2368 [6]. Because an xmpp: URI is opaque, it SHOULD contain only the node identifier (optional) and domain identifier (required) portions of a JID as defined in Section 3 of XMPP Core [1] (including by reference all relevant stringprep profiles). 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 Saint-Andre Expires March 11, 2004 [Page 3] Internet-Draft XMPP URI Format September 2003 in XMPP addresses is the slash character ("/"), which is discouraged by RFC 2396 [2] in opaque URIs. If an xmpp: URI is presented in an interface to an XMPP service (e.g., in 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, sending presence, managing a subscription, sending an information request (IQ get), or updating relevant information (IQ set). This memo conforms to the requirements in Registration Procedures for URL Scheme Names [7]. This memo also follows the recommendations in Guidelines for new URL Schemes [8]. 1.1 Terminology This document inherits terminology defined in XMPP Core [1]. 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 [9]. 1.2 Discussion Venue The author welcomes discussion and comments related to the topics presented in this document. The preferred forum is the mailing list, for which archives and subscription information are available at . 1.3 Intellectual Property Notice This document is in full compliance with all provisions of Section 10 of RFC 2026. Parts of this specification use the term "jabber" for identifying namespaces and other protocol syntax. Jabber[tm] is a registered trademark of Jabber, Inc. Jabber, Inc. grants permission to the IETF for use of the Jabber trademark in association with this specification and its successors, if any. Saint-Andre Expires March 11, 2004 [Page 4] Internet-Draft XMPP URI Format September 2003 2. xmpp: URI IANA Registration This section provides the information required to register the xmpp: URI scheme. 2.1 URI Scheme Name xmpp 2.2 URI Scheme Syntax The syntax for the xmpp: URI is defined below in Augmented Backus-Naur Form as defined by RFC 2234 [10]. XMPP-URI = "xmpp:" jid [ "/" resource] jid = [ node "@" ] host node = *( alphanum / escaped / "-" / "_" / "." / "!" / "~" / "*" / "(" / ")" ) host = hostname / IPv4address / IPv6reference hostname = *( domainlabel "." ) toplabel [ "." ] domainlabel = alphanum / alphanum *( alphanum / "-" ) alphanum toplabel = alpha / alpha *( alphanum / "-" ) alphanum IPv6reference = "[" IPv6address "]" IPv6address = hexpart [ ":" IPv4address ] IPv4address = 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT hexpart = hexseq / hexseq "::" [ hexseq ] / "::" [ hexseq ] hexseq = hex4 *( ":" hex4) hex4 = 1*4HEXDIG resource = *( unreserved / escaped ) reserved = ";" / "/" / "?" / ":" / "@" / "&" / "=" / "+" / "$" / "," / "[" / "]" 2.3 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 [11]. 2.4 Intended usage The xmpp: URI is intended to be used by interfaces to the XMPP network from non-native user agents such as web browsers, as well as by non-XMPP applications in order to address XMPP entities as full URIs. 2.5 Security considerations Saint-Andre Expires March 11, 2004 [Page 5] Internet-Draft XMPP URI Format September 2003 See Security Considerations (Section 4) of this document. 2.6 Relevant publications XMPP Core [1], XMPP IM [3] 2.7 Person and email address to contact for further information Peter Saint-Andre [mailto:stpeter@jabber.org] 2.8 Author/Change controller This scheme is registered under the IETF tree. As such, the IETF maintains change control. 2.9 Applications and/or protocols which use this URI scheme name Applications that provide an interface to XMPP services or that need to address XMPP entities as full URIs. Saint-Andre Expires March 11, 2004 [Page 6] Internet-Draft XMPP URI Format September 2003 3. IANA Considerations This entire document addresses IANA considerations. Saint-Andre Expires March 11, 2004 [Page 7] Internet-Draft XMPP URI Format September 2003 4. Security Considerations Detailed security considerations for XMPP are given in XMPP Core [1]. 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 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. Saint-Andre Expires March 11, 2004 [Page 8] Internet-Draft XMPP URI Format September 2003 Normative References [1] Saint-Andre, P. and J. Miller, "XMPP Core", draft-ietf-xmpp-core-18 (work in progress), September 2003. [2] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998, . [3] Saint-Andre, P. and J. Miller, "XMPP Instant Messaging", draft-ietf-xmpp-im-17 (work in progress), September 2003. [4] Crocker, D. and J. Peterson, "Common Profile for Instant Messaging (CPIM)", draft-ietf-impp-im-03 (work in progress), May 2003. [5] Crocker, D. and J. Peterson, "Common Profile for Presence (CPP)", draft-ietf-impp-pres-03 (work in progress), May 2003. [6] Hoffman, P., Masinter, L. and J. Zawinski, "The mailto URL scheme", RFC 2368, July 1998. [7] Petke, R. and I. King, "Registration Procedures for URL Scheme Names", BCP 35, RFC 2717, November 1999. [8] Masinter, L., Alvestrand, H., Zigmond, D. and R. Petke, "Guidelines for new URL Schemes", RFC 2718, November 1999. [9] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [10] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997. [11] Resnick, P., "Internet Message Format", RFC 2822, April 2001. Author's Address Peter Saint-Andre Jabber Software Foundation EMail: stpeter@jabber.org Saint-Andre Expires March 11, 2004 [Page 9] Internet-Draft XMPP URI Format September 2003 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. 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