OAI-PMH Repository

This plugin is available for accounts with Silver, Gold, or Platinum plans.

The OAI-PMH Repository plugin exposes metadata for Omeka items using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). This is the reverse of the functionality provided by the OaiPmhHarvester plugin.

Metadata Formats

The repository plugin ships with support for four standard metadata formats:

  • Dublin Core (oai_dc): This is required by the OAI-PMH specification for all repositories. Omeka metadata fields are mapped one-to-one with fields for this output format, and it is the preferred format to use with the plugin.
  • CDWA Lite (cdwalite): The mapping between Omeka’s metadata and CDWA Lite metadata is more complicated, and certain fields may not be populated correctly. The chief advantage of using CDWA Lite output is that file URLs can be output in a controlled format, unlike Dublin Core. Harvesters may therefore be able to harvest or link to files in addition to metadata.
  • MODS (mods): This output crosswalks the Dublin Core metadata to MODS using the mapping recommended by the Library of Congress.
  • METS: The Metadata Encoding and Transmission Standard exposes files to harvesters.


The plugin has three user-configurable values. You will be prompted to set these at installation time, or you can change them at any time from the Configure link on the Plugin management page.

Repository name

  • Name for this OAI-PMH repository. This value is sent as part of the response to an Identify request, and it is how the repository will be identified by well-behaved harvesters.
  • Default: The name of the Omeka.net installation.

Namespace identifier

  • The oai-identifier specification requires repositories to specify a namespace identifier. This will be used to form globally unique IDs for the exposed metadata items. This value is required to be a domain name you have registered. Using other values will generate invalid identifiers.
  • Default: yoursite.omeka.net. This should suffice for most instances.

Expose files

  • Whether the repository should expose direct URLs to all the files associated with an item as part of its returned metadata. This gives harvesters the ability to directly access the files described by the metadata.
  • Default: true

The base URL of the repository can be found by appending /oai-pmh-repository/request to the base URL of your Omeka site.

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