Network Working Group A. Coates
Request for Comments: 3085 Reuters
Category: Informational D. Allen
IPTC
D. Rivers-Moore
Rivcom
March 2001
URN Namespace for NewsML Resources
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
This document describes a URN (Uniform Resource Name) namespace for
identifying NewsML NewsItems. A NewsItem is an information resource
that is expressible as a NewsML element within a NewsML document
conforming to the NewsML Document Type Declaration (DTD) as defined
by the International Press Telecommunications Council (IPTC).
1. Introduction
NewsML is an XML format for packaging multimedia news resources. It
has been created under the auspices of the International Press
Telecommunications Council (IPTC), and version 1.0 was approved by
the IPTC on 6 October 2000.
The same logical NewsItem may exist in multiple physical locations.
The NewsML specification allows NewsItems to have multiple URLs, but
only a single URN. It is the latter which then uniquely names the
resource.
This namespace specification is for a formal namespace.
2. Specification Template
Namespace ID:
"newsml" requested.
Coates, et al. Informational [Page 1]
RFC 3085 URN Namespace for NewsML Resources March 2001 Registration Information: Registration Version Number: 1 Registration Date: 2000-11-07 Declared registrant of the namespace: David Allen ho73@dial.pipex.com IPTC Royal Albert House Sheet Street Windsor SL4 1BE Declaration of structure: The identifier has the following ABNF[6] specification: NSS = ProviderId ":" DateId ":" NewsItemId ":" RevisionId Update ProviderId = string DateId = date NewsItemId = string RevisionId = posint Update = 0*1( "A" / "U" ) date = century year month day century = ( "0" posdig ) / ( posdig DIGIT ) year = 1*2DIGIT month = ( 0 posdig ) / ( "1" ( "0" "1" "2" ) ) day = ( 0 posdig ) / ( ( "1" / "2" ) DIGIT ) / "30" / "31" string = 1*char char = ALPHA / DIGIT / symbol / escape symbol = "(" / ")" / "+" / "," / "-" / "." / "=" / "@" / ";" / "$" / "_" / "!" / "*" / "'" escape = "%" HEXDIG HEXDIG posint = posdig *DIGIT posdig = "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9" The ProviderId must be an Internet domain name, and must be owned by the organisation creating the NewsML resource and allocating the URN to it, at the date identified by the DateId. DateId is a date in ISO 8601 Basic Format (CCYYMMDD), and must correspond to a date at which the organisation allocating the URN owned the domain name specified in the ProviderId. The NewsItemId must be unique among all NewsItems emanating from the same provider and having the same DateId. Coates, et al. Informational [Page 2]
RFC 3085 URN Namespace for NewsML Resources March 2001 RevisionId is a positive integer indicating which revision of a given NewsItem this is. Any positive integer may be used, but it must always be the case that of two instances of a NewsItem that have the same ProviderId, DateId and NewsItemId, the one whose RevisionId has the larger value must be the more recent revision. A RevisionId of 0 is not permitted. If the NewsItem contains an "Update" element or elements, then Update must be set to "U". If the NewsItem consists only of a replacement set of NewsManagement data, then Update must be set to "A". If neither of these is the case, then Update must be suppressed. Relevant ancillary documentation: None Identifier uniqueness considerations: The combination of ProviderId and DateId serves to uniquely identify the organisation that is allocating the URN. That organisation is responsible for ensuring the uniqueness of the DateId/NewsItemId/RevisionId combination. Identifier persistence considerations: A NewsML URN may only be allocated by an organisation that owns an Internet domain name. The URN identifies a date on which the organisation owned that domain name. The combination of date and domain name will serve to uniquely identify that organisation for all time. Process of identifier assignment: The organisation identified by the ProviderId/DateId combination is responsible for allocating a NewsItemId that is unique among all those that it allocates with that DateId. Process of identifier resolution: NewsML providers are responsible for the provision of a URN resolution service, if any, for NewsML URNs they have assigned with a valid ProviderId/DateId combination. Rules for Lexical Equivalence: URNs are lexically equivalent if the ProviderId, DateId, NewsItemId, and RevisionId are all identical (case-insensitive comparison). Coates, et al. Informational [Page 3]
RFC 3085 URN Namespace for NewsML Resources March 2001 Conformance with URN Syntax: No special considerations beyond the syntax herein described. Validation mechanism: Organisations that allocate NewsML URNs are responsible for the provision of a URN validation service, if any, for URNs they have assigned with a valid ProviderId/DateId combination. Scope: Global 3. Examples The following examples are representative of NewsML URNs, but may not refer to actual resources. urn:newsml:iptc.org:20001006:NewsMLv1.0:1 urn:newsml:reuters.com:20000206: IIMFFH05643_2000-02-06_17-54-01_L06156584:1U 4. Security Considerations There are no additional security considerations other than those normally associated with the use and resolution of URNs in general. References [1] Rivers-Moore, D., "NewsML Version 1.0 Functional Specification", November 2000, <http://www.iptc.org/NewsML/specification/NewsMLv1.0.pdf>. [2] Rivers-Moore, D., "NewsML Version 1.0 DTD", November 2000, <http://www.iptc.org/NewsML/DTD/NewsMLv1.0.dtd>. [3] W3C, XML WG, "Extensible Markup Language (XML) 1.0", February 1998, <http://www.w3.org/TR/REC-xml>. [4] Moats, R., "URN Syntax", RFC 2141, May 1997. [5] Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom, "URN Namespace Definition Mechanisms", RFC 2611, June 1999. [6] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997. Coates, et al. Informational [Page 4]
RFC 3085 URN Namespace for NewsML Resources March 2001 Authors' Addresses Anthony B. Coates Reuters 85 Fleet St London EC4P 4AJ United Kingdom Phone: +44 20 75 42 21 65 EMail: tony.coates@reuters.com David Allen IPTC Royal Albert House Sheet Street Windsor SL4 1BE United Kingdom Phone: +44 17 53 70 50 51 EMail: ho73@dial.pipex.com Daniel Rivers-Moore Rivcom Lotmead Business Village Swindon SN4 0UY United Kingdom Phone: +44 17 93 79 20 00 EMail: daniel.rivers-moore@rivcom.com Coates, et al. Informational [Page 5]
RFC 3085 URN Namespace for NewsML Resources March 2001
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