- From: Hammond, Tony (ELSLON) <T.Hammond@elsevier.com>
- Date: Wed, 27 Aug 2003 12:34:05 +0100
- To: www-tag@w3.org
- Cc: uri@w3.org
- Message-ID: <54A600C436EA694581B93E4BD4D4788A07E2F2D0@elslonexc004.eslo.co.uk>
Apropos the recent Draft TAG Finding 'The Use of Metadata in URIs' of July 8, 2003 [1], we would like to draw attention to the ANSI/NISO Draft Standard on 'The OpenURL Framework for Context-Sensitive Services'. This Draft Standard defines two things: 1) a data structure termed the ContextObject, and 2) a Registry mechanism for information components to build the ContextObject. This ContextObject can be serialized into multiple formats. Specifically of interest here a Key/Encoded-Value format is defined for serializing the ContextObject onto an 'http' URI querystring - the so-called OpenURL. The OpenURL querystring provides a unique signature token for the parameter key 'ver_id' - the ANSI/NISO standard number 'Z39.88-2003' (although the actual year signifier may result as '2004' instead of '2003'). The Key/Encoded-Value format is defined in the Draft Standard and is a registered information component. This means that the payload of an 'http' URI querystring can be deconstructed and validated as being a conformant ContextObject within the OpenURL Framework. The combination of a unique signature token and a defined public data structure means that OpenURLs are distinguished URIs and can be both recognized and validated as such. OpenURLs challenge the notion of authority-specific URI structures by providing public vehicles for the exchange of metadata. Note that this is in direct opposition to the caveat raised by the TAG Finding: "However, observers are cautioned that assignment policies are not generally subjected to standardization and may be changed by the relevant authority at any time." The OpenURL by contrast will be subject to such standardization and software programmed on the basis of the OpenURL Framework specification will be robust. The ContextObject data structure is a simple Entity/Descriptor matrix. Six Entities are defined in the ContextObject: * the Referent - the subject of the ContextObject * the ReferringEntity - a resource that references the subject * the Requester - the agent requesting services about the subject * the ServiceType - the type of service to be provided * the Resolver - the network service component that delivers services * the Referrer - the host platform which generated the ContextObject The Referent is the only mandatory Entity. To describe these Entities four types of Descriptor are defined: * an Identifier type * a Metadata (By-Value) type * a Metadata (By-Reference) type * a Private Data type Descriptors are not exclusive but may be used together, i.e. an Entity may be described by a combination of mulitple identifiers and multiple metadata terms. Some simple examples of OpenURLs can be found in a recent submission to rss-dev of the 'mod_context' module, which defines a serialization of the ContextObject as an RSS 1.0 module, see [2]. In these examples, an OpenURL is used as a public query API to network service components which return context-sensitive RSS 1.0 feeds. For further information on the OpenURL Framework see the Draft Standard documents Part 1 [3] and Part 2 [4] on the ANIS/NISO AX website [5]. We hope that the use of OpenURL as a public data structure for the exchange of metadata will be of interest to the URI community in general and invite feedback [6]. Regards, Tony [1] http://www.w3.org/2001/tag/doc/metaDataInURI-31.html <http://www.w3.org/2001/tag/doc/metaDataInURI-31.html> [2] http://www2.elsevier.co.uk/~tony/spec/rss/mod_context.html <http://www2.elsevier.co.uk/~tony/spec/rss/mod_context.html> [3] http://library.caltech.edu/openurl/PubComDocs/StdDocs/Part1-PC-20030513.pdf <http://library.caltech.edu/openurl/PubComDocs/StdDocs/Part1-PC-20030513.pdf > [4] http://library.caltech.edu/openurl/PubComDocs/StdDocs/Part2-PC-20030513.pdf <http://library.caltech.edu/openurl/PubComDocs/StdDocs/Part2-PC-20030513.pdf > [5] http://library.caltech.edu/openurl/Public_Comments.htm <http://library.caltech.edu/openurl/Public_Comments.htm> [6] mailto:openurl.comment@library.caltech.edu Tony Hammond Advanced Technology Group, Elsevier 32 Jamestown Road, London NW1 7BY, UK <mailto:t.hammond@elsevier.com <mailto:t.hammond@elsevier.com> > <tel:+44-20-7424-4445>
Received on Wednesday, 27 August 2003 07:47:06 UTC