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Web Services for Digital Library Construction. T. Hickey Indo-US Workshop June 2003. What are Web Services?. Machine-to-machine communication Run over standard Web protocols XML syntax, HTTP packaging Several approaches REST Representational State Transfer SOAP
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Web Services forDigital Library Construction T. Hickey Indo-US Workshop June 2003
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
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
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.wsdl • WSDL • UDDI
A set of Web services for the digital library • Register • Search • Resolve • Navigate • Decompose • Enhance • Transform Skip to examples
Registration Services • Metadata about metadata • Dublin Core extensions • Digital format descriptions • Metadata about objects • Books • Web resources • Metadata about agents • People • Institutions
Search Services • Go from data to links • Name to preferred form • Search terms to record list
Resolution Services • From links to data • Record numbers to records • Controlled names to name metadata • Class number to textual description
Navigation Services • Movement within hierarchies • Classification, e.g. DDC • FRBR (work, expression, manifestation, item) • General network movement • Link selection and following
Decomposition Services • DDC Numbers • Names within a list • Citations within a paper • Structure of a document • Letters within an image
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
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?
Examples of Web Services • XISBN service • Maps ISBNs to ISBNs • OpenURL Registry • Provides names and definitions for OpenURL services • GSAFD Thesaurus
The XISBN Web Service Amazon FRBRized ISBN Server User Library
OpenURL Registry • OAI-PMH Registry • http://purl.org/openurl/ • OAI implies XML delivered • But, stylesheets can produce • HTML display • Web browser user interface
GSAFD as a test case • Enhanced subject authority records for genre terms are now available via the OAICat framework. This development is a result of the combined efforts of the OAICat project and the Terminology Services project. The enhanced authority file is a version of the MARC 21 authority records for GSAFD genre terms. The enhanced version of the file has the following features: • The content of the file is MARC XML • Established terms in the file are accessible via a URL • Established terms in the file are mapped to equivalent Library of Congress Subject Headings (lcsh) and Library of Congress subject headings: Annotated Card Program (lcshac) (i.e., LC Children’s heading) • Authority records can be displayed in MARC or in a thesaurus-style display • The file is also accessible via SRW/SRU under the Zthes protocol