The Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) provides an application-independent interoperability framework based on metadata harvesting.
See also the PMH section at the Open Archives Initiative website.
With this plugin a REST resource on behalf of OAI-PMH can be implemented in your site.
Documentation is available at bloomreach-forge.github.io/oai-pmh-provider
The documentation is generated by this command:
mvn clean site:site
The output is in the docs directory; push it and GitHub Pages will serve the site automatically.