# /research/projects/openurl/registry.htm

originally: http://www.oclc.org/research/projects/openurl/registry.htm

# The OpenURL Registry

The OpenURL Registry application was developed to support the Trial Use period of the NISO AX Standard Committee's registry specification (PDF:1.3MB/121pp.). The OpenURL is a protocol for interoperability between an information resource and a service component that offers localized services in an open linking environment. It is in effect an actionable URL that transports metadata or keys to access metadata for the object for which the OpenURL is provided. (http://www.exlibrisgroup.com/sfx_openurl.htm)

The OpenURL Registry application supports the generalization of OpenURL from a fixed framework for linking to web-based scholarly information sources to an abstract (PDF:1.3MB/121pp.) framework for linking to the web in general. The OpenURL Registry contains properties that are fundamental to creating concrete representations of OpenURL ContextObjects and methods to transport them.

Although there is no direct relationship or dependency between the Open Archives Initiative (OAI) and OpenURLs, it was convenient to implement the registry specification using a novel application of OAI.

OAI is generally thought of as a tool for the automated harvesting of metadata, but this registry demonstrates that an OAI repository can be useful on its own, independent of the harvesting function.

This approach involved three innovations:

1. The first innovation is based on observations (PDF:346K/4pp.) made by Herbert Van de Sompel that OAI is capable of disseminating not only the metadata about a registered item, but also the XML content of the registered item itself via an alternative metadata format option. This includes registered XML Schemas and XHTML specification documents.
2. The second innovation is the inclusion of XSLT stylesheet references in OAI responses. These references allow web browsers to render OAI responses into HTML for display to users. Automated processes, including OpenURL mechanisms as well as OAI harvesters, will ignore the XSLT reference and process the XML responses directly. XSLT thus allows both human and automated interaction from the same HTTP response.
   It is particularly interesting to note that the OpenURL registry is useful for human interaction merely by rendering the simple and limited set of OAI responses using XSLT.
3. The third innovation is the use of Persistent URLs (PURLs) to create simple URLs that resolve to OAI GetRecord responses from the registry. Because these GetRecord responses are in XML and include an XSLT stylesheet, they are suitable for both web browser and automated use.
   So, instead of http://alcme.oclc.org/openurl/servlet/OAIHandler?verb=GetRecord&metadataPrefix=mtx&identifier=ori:fmt:kev:mtx:book, users can use a PURL instead (http://www.openurl.info/registry/mtx/ori:fmt:kev:mtx:book).

## Research team

- Thom Hickey (lead researcher)
- Jeff Young

## Related links

- OpenURL Registry
  http://www.openurl.info/registry/
- Open Archives Initiative
  http://www.openarchives.org/
- OCLC Research OpenURL activities overview
  http://www.oclc.org/research/projects/openurl/

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