OAI-PMH

'Open Archives Initiative Protocol for Metadata Harvesting'

Description

• Leightweight:
  • A low barrier interoperability specification
  • RESTful: HTTP based, GET / POST requests, XML responses
• Clear concepts:
  • Based around metadata harvesting model
  • Metadata about resources, mandates unqualified Dublin Core as default
  • Not a search protocol! That could be for example enhanced or merged versions of OpenSearch/GeoRSS and SRU/SRW besides WFS.
• Extendable: Has extension mechanism for more domain specific metadata models
• Stable: OAI has committed to making subsequent revisions of the protocol backwards compatible.
• Established: Implemented - among others - by Google, CiteSeer and MSN as well as by dozens of open source tools, like OAICat (Java) or mod_oai (C, installed at 500 sites); see more tools in the Weblinks section below.

There are following alternatives (Remarks: all considered either inappropriate or not established or at least 'painfull' compared to OAI-PMH):

• Z39.50 and SRW - the more leightweight and 'modern' successor of Z39.50
• UDDI - the SOAP thing
• WFS - the OGC thing

Architecture

Specifications

• OAI-PMH 2.0 Spec. - Specification for Open Archives Initiative Protocol for Metadata Harvesting 2.0
  • OAI-PMH Implementation Guidelines
• OAI-PMH Static Repository 2.0 Spec. - Specification for an OAI Static Repository and an OAI Static Repository Gateway 2.0
  • Specification for an OAI Static Repository and an OAI Static Repository Gateway

For Tools and Demos see Weblinks section below.

Weblinks

• Open Archives Initiative (OAI) Home)
• OAI forum and OAI general mailing list

• Tutorials and short explanations:
  • Concise technical description of the protocol
  • OAI for beginners, OAI and OAI-PMH for absolute beginners by Philip Hunter, 2005.
• Papers:
  • Haixia Mao (2005), OAI-PMH Based Interoperation For Spatial Metadata. In: ISPRS Workshop on Service and Application of Spatial Data Infrastructure, XXXVI(4/W6), Oct.14-16 2005, Hangzhou, China.
  • Use of OAI to disclose metadata as an output from the portal From: Go-Geo! Geo-Data Portal Project
  • 'Open Content and Access for Digital Scholarship' by Gerry McKiernan, 2004 (describes use of map resources)
• Software and Tools:
  • OAI-PMH Data Provider Components (open source):
    • OAI tools list
    • Java: OAICat
    • PHP: hu-berlin.de, ...
  • OAI-PMH Static Repository Gateways (open source):
    • srepod - OAI-PMH Static Repository Gateway (C)
  • Digital Repository System Software (open source):
    • DSpace (Java)
• Demos and examples:
  • Demo of OAICat - The OAICat Open Source project is a Java Servlet web application providing an OAI-PMH v2.0 repository framework.
  • OAIster - Most often mentioned collection of freely available, previously difficult-to-access, academically-oriented digital resources that are easily searchable by anyone.
  • PKP Open Archives Harvester - Free metadata indexing system developed by the Public Knowledge Project through its federally funded efforts to expand and improve access to research.
  • OJAX Demo - Federated Metasearch Service using Ajax/Lucene