Network Working Group A. B. Coates
Internet-Draft Reuters
Expires: May 8, 2001 D. Allen
IPTC
D. Rivers-Moore
RivCom
November 7, 2000
URN Namespace for NewsML Resources
draft-iptc-newsml-urn-00.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
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Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
This document describes a URN 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 DTD as defined by the IPTC.
1. Introduction
NewsML is an XML format for packaging multimedia news resources. It
has been created under the auspices of the International Press
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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.
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
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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.
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
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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).
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>.
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[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.
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
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