Network Working Group P. Stickler Internet-Draft Nokia Research Center Expires: July 17, 2002 January 16, 2002 The 'qname:' URI Scheme for XML Namespace Qualified Names draft-pstickler-qname-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 July 17, 2002. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract This document describes the 'qname:' Uniform Resource Identifier (URI) scheme for the representation of XML Namespace qualified names. Stickler Expires July 17, 2002 [Page 1] Internet-Draft The 'qname:' URI Scheme January 2002 Table of Contents 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. BNF for the 'qname:' URI Scheme . . . . . . . . . . . . . . . . 4 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 Full Copyright Statement . . . . . . . . . . . . . . . . . . . . 6 Stickler Expires July 17, 2002 [Page 2] Internet-Draft The 'qname:' URI Scheme January 2002 1. Overview The 'qname:' URI scheme is intended to provide a simple but consistent means by which XML Namespace qualified names [2] may be represented for the sake of communication between web applications. The 'qname:' URI scheme provides for the distinction between elements, global attributes, and per-element attributes to be made fully explicit; thus preserving contextual information about the occurrence of the name within a given XML instance which may be significant to its interpretation. The 'qname:' URI scheme belongs to the class of URIs known as Uniform Resource Values (URV) which are themselves a subclass of Uniform Resource Primitives (URP), a class of URI which constitutes a "WYSIWYG" URI, one which is not dereferencible to and does not denote another web resource, but constitutes a self-contained resource where the full realization of that resource is expressed in the URI itself. For a full discussion of the properties of URPs and URVs, please see [1]. Familiarity with the concepts defined therein will facilitate the full understanding of this document. Because a URP is not dereferencible, and hence does not permit the suffixation of a fragment identifier (there is no such thing as a URP Reference), it is not necessary to escape any hash marks '#' occurring in the namespace URI Reference part of a 'qname:' URI. Examples: qname:title:voc://nokia.com/MARS-2.2/ qname:title:http://www.w3.org/1999/xhtml# qname:title:http://purl.org/dc/elements/1.1/ qname:label:http://www.w3.org/2000/01/rdf-schema# qname:date:http://www.w3.org/2001/XMLSchema# qname:widget:mailto:jane.doe@booga.com qname:e28b11f:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 qname:author@name:urn:com:books-r-us qname:A@HREF:http://www.w3.org/TR/REC-html40 qname:@CLASS:http://www.w3.org/TR/REC-html40 These examples are provided for illustrative purposes only and do not necessarily constitute actual URIs. See the BNF definition below for an explicit definition of 'qname:' URI syntax. Note that, although it is common practice to represent an XML Namespace qualified name in a form where the namespace preceeds the name, such as "{namespace}name"; in this URI scheme, the name preceeds the namespace in order to achieve a representation which Stickler Expires July 17, 2002 [Page 3] Internet-Draft The 'qname:' URI Scheme January 2002 facilitates easier parsing by applications, as the URI can be partitioned into its name and namespace components simply by scanning for the colon ':' after the name portion without any further need to parse the namespace URI itself. It also positions the most mnemmonic part of the qualified name first, which can enhance readability. 2. BNF for the 'qname:' URI Scheme This is a BNF-like description of the 'qname:' Uniform Resource Identifier syntax, using the conventions of RFC 822[3], except that "|" is used to designate alternatives, and brackets [] are used around optional or repeated elements. Briefly, literals are quoted with "", optional elements are enclosed in [brackets], and elements may be preceded with * to designate n or more repetitions of the following element; n defaults to 0. This BNF description adopts sub-definitions defined in RFC 2396 "Uniform Resource Identifiers (URI): Generic Syntax" [4] and the W3C Recommendation REC-xml-names "Namespaces in XML" [2] which are not repeated here. qname-URI = "qname:" name ":" namespace name = element | globalAttr | perElementAttr namespace = absoluteURI [ "#" fragment ] element = NCName attribute = NCName globalAttr = "@" attribute perElementAttr = element "@" attribute NCName = absoluteURI = fragment = Note that the URI scheme prefix "qname:" is considered to be a valid URI denoting this URI scheme, though it is not itself a valid URI according to this URI scheme. 3. Security Considerations This document raises no known security issues. 4. Acknowledgements Thanks to Sean Palmer (sean@mysterylights.com) for his insightful comments and suggestions regarding earlier formulations of this URI scheme and for suggesting the preservation of contextual information Stickler Expires July 17, 2002 [Page 4] Internet-Draft The 'qname:' URI Scheme January 2002 differentiating elements, global attributes, and per-element attributes. References [1] Stickler, P., "An Extended Class Taxonomy of Uniform Resource Identifier Schemes", January 2002, . [2] World Wide Web Consortium, "REC-xml-names: Namespaces in XML", January 1999, . [3] Crocker, D., "STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES", RFC 822, August 1982. [4] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. Author's Address Patrick Stickler Nokia Research Center Visiokatu 1 Tampere 33720 FI EMail: patrick.stickler@nokia.com Stickler Expires July 17, 2002 [Page 5] Internet-Draft The 'qname:' URI Scheme January 2002 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Stickler Expires July 17, 2002 [Page 6]