1. Web Services Overview Thomas Hickey

2. 2 What are Web Services? Machine-to-machine communication Run over standard Web protocols –XML syntax, HTTP packaging Several approaches –REST Representational State Transfer –SOAP Simple Object Access Protocol

3. 3 REST REST is simplest –Send an HTTP request –Get back a response (XML, HTML) –Examples Web browser OpenURL Z39.50 as a Web service: SRU http://sfx.bath.ac.uk/sfxmenu?genre=book&isbn=1234-5678 http://www.kb.nl/ cgi-zoek/srw.pl?query=test&maxRec=10&recSchema=dc_record

4. 4 REST: OAI-PMH Now in version 2.0 Allows synchronization of databases Other services can be layered –ODL: Open Digital Libraries –XTCat name authority service

5. 5 SOAP is more complex Simple Object Access Protocol Z39.50 as a SOAP service: SRW –http://www.loc.gov/z3950/agency/zing/srwu /wsdl/zing_srw_binding.wsdlhttp://www.loc.gov/z3950/agency/zing/srwu /wsdl/zing_srw_binding.wsdl WSDL UDDI

6. 6 Classes of Services Register Search Resolve Navigate Decompose Enhance Transform

7. 7 Registration Services Metadata about metadata –Dublin Core extensions –Digital format descriptions Metadata about objects –Books –Web resources Metadata about agents –People –Institutions

8. 8 Search Services Go from data to links –Name to preferred form –Search terms to record list

9. 9 Resolution Services From links to data –Record numbers to records –Controlled names to name metadata –Class number to textual description

10. 10 Navigation Services Movement within hierarchies –Classification, e.g. DDC –FRBR (work, expression, manifestation, item) General network movement –Link selection and following

11. 11 Decomposition Services DDC Numbers Names within a list Citations within a paper Structure of a document Letters within an image

12. 12 Enhancement Services Normalization –Linkage to registered forms Addition of DDC numbers Authority control on agents Content augmentation –Add information to a brief record from a matching longer record

13. 13 Transformation Services Syntax translation –MARC21 to MARC XML Semantic translation –Qualified Dublin Core to MARC21 –Library of Congress SH to FAST Content translation –English to French?

14. 14 An Example: ePrints UK Records harvested from archives Web services to enhance metadata

15. 15 Institutional e-print archives Non-institutional e-print archives Personal e-print archives Subject Classification Service Name Authority Service Citation Analysis Service RDN Gateway/portal Service RDN Gateway/portal Service RDN Gateway/portal Service OAI-PMH SOAP HTTP Z39.50 e-Prints UK

16. 16 Web Services for ePrints UK Personal name authorities Subject classification Citation analysis

17. 17 Example: XTCat Union catalog of thesis and dissertation metadata Records extracted from WorldCat Available via OAI-PMH –Separate ‘set’ for electronic theses We harvest from other repositories Integrate with existing records Allow re-harvesting (e.g. by VTLS)

18. 18 Issues Syntax Semantics Content

19. No one promised us tomorrow Hawaiian proverb