Some thoughts on OpenURL version 1.0

1. Some thoughts on OpenURL version 1.0 NISO AX meeting, Getty Museum, May 30-31 2002 Herbert Van de Sompel Los Alamos National Laboratory – Research Library

2. Topics • The EBNF • Extensibility • Registries

3. 1. The EBNF • human readable, construction-oriented: • insignificance of order not encoded • relation private zones and Referrer zone not encoded • optional administrative zone • by-reference mechanism for all entities • vendorId:dbaseId type problem • what is covered by URI scheme • what exactly is network-location

4. 2. OpenURL extensibility • registration: • by-value formats (referent) • by-reference formats (referent, requester, ?, ?, ?) • namespace identifiers (referent, requester, referrer, referring-entity, service-type) • local prefix – referrer id required • namespace-identifiers (referent, requester, referrer, referring-entity, service-type) • by-value format identifiers (referent) • by-reference format identifiers (referent, requester, ?, ?, ?) • private zones – referrer id required • (referent, requester, referrer, referring-entity, service-type)

5. 3. OpenURL Registries • Inventory of required registries • OpenURL Format Registry • Registry for by-value and by-reference formats • Architecture for Format Registry • Policy issues • Identifier Registry • de-facto (URI scheme) • OpenURL identifier registration • Deployment strategy

6. Inventory of required registries

7. Inventory of required registries

8. OpenURL Registries - formats • local formats – no registry • single OpenURL Format Registry • same type can occur as different entities • (think article as referent and referring-entity) • indicate by-value and/or by-reference nature • mandatory definition of registered formats by means of XML Schema • in sync with trend in our focus community • simplifies handling by-ref: the doc that is pointed at is always XML instance doc that can be validated • local formats can be whatever • see examples journal.xsd , jissue.xsd , jarticle.xsd

9. OpenURL Registries - formats • using XML Schema to define by-value formats: • the Schema: • flat structure required: root and single level down • format-identifier == name of root-element of Schema • metadata-tags == names of direct childs of root-element • can be used as by-reference • could provide template to support creation • the Registry: • XML Schema validation • guarantee uniqueness of root-element name • reject Schema with underscores in child element names • reject id, pid, sid, submit as element names

10. OpenURL Registries - formats • using XML Schema to define by-reference formats: • the Schema: • no limitations on Schema structure • format-identifier: • name of root-element of Schema • schemaLocation (uri flavor) • XML Namespace URI • can not necessarily be used as by-value • the Registry: • XML Schema validation • guarantee uniqueness of root-element name (probably not feasible)

11. XML Schema XML Schema XML Schema URL1 URL2 URLn linking servers central repository registrars O A I - P M H r e g i s . P o l l registry model registration user service polling OAI-PMH harvesting

12. XML Schema XML Schema XML Schema URL1 URL2 URLn registrars • Goal: • inform linking servers re Schema • ease of admin for all parties involved • limit human overhead

13. XML Schema XML Schema XML Schema URL1 URL2 URLn central repository registrars r e g i s . • Registry: • schemaLocation • registration date • mirror of Schema registration

14. XML Schema XML Schema XML Schema URL1 URL2 URLn central repository registrars r e g i s . P o l l • Poll: • fetch schema at schemaLocation • log failure/success • compare fetched Schema with mirror • changed => replace mirror • removed => deregistered registration polling

15. XML Schema XML Schema XML Schema URL1 URL2 URLn central repository registrars O A I - P M H r e g i s . P o l l • OAI repo: • record-ids = schemaLocation • oai_dc record : • registration info • (de)registration datestamp • xsi record : • mirror schema • schema update datestamp • poll record : • process info • recent poll datestamp registration polling

16. XML Schema XML Schema XML Schema URL1 URL2 URLn linking servers central repository registrars O A I - P M H r e g i s . P o l l registration user service polling OAI-PMH harvesting

17. OpenURL Registries – formats – policy issues • peer-reviewed or open approach to registration • if peer-reviewed • what are the criteria • who does the review (for which formats) • if open • how to avoid (unnecessary) proliferation of Schema • what constitutes a deregistration • what to do with mirror-schema in case of deregistration • which kind of party should operate the registry

18. OpenURL Registries – namespace identifiers • local identifiers – no registry • URI-scheme identifiers – what does it cover? • require RFC • require IANA registration • based on informal W3C registry • compile list based on the above • OpenURL-defined identifiers • registration criteria • technique for namespace description • relationship to formats

19. OpenURL Registries – deployment • need something for formats and namespace-identifiers starting with test-phase • proposal: restrict • registered formats: • 6 by-value formats • select some by-ref formats: oai_dc, marc21, … • registered namespace identifiers: • cf OpenURL 0.1: doi, oai, pmid, bibcode, dns • URIidentifiers: • select a few: http, doi, dns, … • allow no further registration • provide helpdesk • host at library site, where OpenURL experience is available

20. OpenURL Registries – deployment • in parallel with test-phase, define: • registry requirements: technical, functional, policy • implementation plan