DEF System Architecture XML Web Services

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DEF System ArchitectureXML Web Services

• Fedora and the Zebra Search Engine
• in an OAI Eprints Application

by Gert Schmeltz Pedersen, DTV gsp_at_dtv.dk - 45
4525 7244
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Contents

1. XML Web Services and the 3-tier Architecture
2. The DEF Eprints Service
3. DEF-XWS Eprints
4. Generic Search Service
5. Repository Federation

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DEF-XWS project suite

• "XML Web Services and the 3-tier architecture"
• a project suite within the programme area System
  Architecture at Denmark's Electronic Research
  Library (DEFF) (http//defxws.cvt.dk)
• a collaboration with The Royal Library, The State
  and University Library, Aarhus Business School
  Library a.o.
• Get web services hands-on and experience.
• Get Fedora hands-on and experience.
• Use Fedora to implement a web service version of
• DEF Eprints - International eprints metadata
  harvested from Open Archives, a DEF project
  carried out at DTV.
• Add full text indexing and retrieval.

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DEff 3-tier Service Oriented Architecture
Central Portal
Local Portal
Common service
Common service
Common service
Local service
Local service
Common service
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The DEF Eprints ServiceArchitecture of the DEF
Eprints Service Provider
Protocol
for Metadata Harvesting
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DEF-XWS Eprints
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DEF-XWS Eprints
ZebraForFedora, a module for Fedora
(http//www.indexdata.dk/zebra) Purpose to
obtain powerful text index and search
functionality and performance. The original text
index and search functionality in Fedora is
simple SQL on a table, where DC element texts are
stored in fields. ZebraForFedora is a set of
Java classes that deploys over existing Fedora
and Zebra installations by the running of an Ant
target. In the Fedora configuration file
ltmodule role"fedora.server.search.FieldSearch"
class"dk.defxws.eprints.fedora.server.search.Fiel
dSearchZebraModule"gt ltcommentgtInstead of
fedora.server.search.FieldSearchSQLModulelt/comment
gt ltdatastore id"zebra"gt
ltcommentgtZebra serverlt/commentgt ltparam
name"host" value"defxws.cvt.dk"/gt
ltparam name"port" value"9395"/gt
lt/datastoregt
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DEF-XWS Eprints
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DEF-XWS Eprints

• Purpose achieved
• Fedora hands-on and experience
• web services hands-on and experience
• DEF-XWS Eprints available from web services
• http//defxws.cvt.dk8082/fedora/access/soap?wsdl
• http//defxws.cvt.dk8082/fedora/accessDEF-XWS/soa
  p?wsdl
• ready for 3-layered system architecture
• applications combining many web services
• Lesson
• Do not override field search,
• provide generic search service instead ...

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Generic Search Service
Generic
Zebra
...
Lucene

• Core Fedora Repository Service
• new services are deployed as web applications
  (.war files), with a configuration file.
• The Generic Search Service shall be a webapp,
  configurable to use an existing Fedora repository
  and an existing installation of an indexing and
  searching engine, like Zebra, Lucene, and others.
  
• Functionality to be decided by a working group of
  Fedora users and developers.

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Generic Search Service

• preliminary analysis of what has been done by
  others already,
• approaches and issues people have taken in the
  following areas
• a.  what kinds of search engines?
• b.  how is indexing done and how is it kept up to
  date?
• c.  configuration options?  How can you specify
  what datastreams/disseminations to index?
• d.  what interfaces for doing searches?
• e.  how do you deal with security in terms of the
  service interacting with Fedora?
• f.   what are problems with current approaches?
• g.  what would be desirable in a generic search
  service that would be delivered with Fedora?
• gathering of requirements and issues for moving
  towards a reference implementation
• - ZebraForFedora may serve as a reference
  implementation
• from a broader perspective, how to deal with
  search for federations of repositories
• - P2P search in EU project Alvis may be relevant

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Repository Federation
Idea under elaboration Fedora as Superpeer in
an ALVIS peer-to-peer system
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DEF-XWS
Thank you!
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DEF-XWS Eprints
Web Services Description Language
DEF-XWS Pilot
DEF-XWS Pilot
http//host/fedora/ws/soap?wsdl
Simple Object Access Protocol or
REST Representational State Transfer
Java Test UI
Java Eprint WS
php Test UI
DEF-XWS Pilot Web Service-Oriented
Architecture Graphics from Web Services A
Manager's Guide, by Anne Thomas Manes,
Addison-Wesley, 2003