Oai pmh events

[eilmiv]

Summary of changes

• Add Dublin Core serialization for events
• Merge events and materials in OAI-PMH results
• Expose OAI-PMH sets for just materials or events

Motivation and context

Closes #1351

Screenshots

Events can be found alongside materials in the OAI-PMH results:

Checklist

• I have read and followed the CONTRIBUTING guide.
• I confirm that I have the authority necessary to make this contribution on behalf of its copyright owner and agree to license it to the TeSS codebase under the BSD license.

[Copilot]

Pull request overview

This PR extends the OAI-PMH endpoint to expose Event records alongside Material records, including Dublin Core and RDF serializations and set filtering to allow clients to harvest only events or only materials.

Changes:

• Add Event#to_oai_dc and Event#to_rdf serialization methods and corresponding model tests.
• Replace the single-model OAI provider wrapper with a new MultiModel provider model to merge Materials + Events and expose OAI sets.
• Expand OAI controller integration tests to cover event records, sets, and resumption token paging behavior.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
test/models/event_test.rb	Adds unit tests validating Event OAI-DC + RDF serialization.
test/controllers/oai_controller_test.rb	Adds integration tests for events in OAI responses, ListSets, and paging/resumption tokens.
config/initializers/oai_provider.rb	Introduces MultiModel to merge multiple AR scopes into one OAI-PMH model and expose sets.
app/models/event.rb	Implements to_oai_dc and to_rdf serialization for events.
app/controllers/oai_controller.rb	Switches OAI endpoint to use MultiModel over both visible Materials and Events.

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Suppressed comments (1)

test/controllers/oai_controller_test.rb:146

• The pagination setup counts all visible Events/Materials across every space, but the OAI endpoint only serves in_current_space. If fixtures include visible records in non-current spaces, base_count will be too high, records_needed too low, and this test can fail to generate enough records to trigger a resumption token.

    base_count = Event.where(visible: true).count + Material.where(visible: true).count
    records_needed = [0, 105 - base_count].max

[fbacall]

One comment, plus a potential performance improvement...

When I tried this locally and visited the /oai-pmh endpoint to list records, it performed ~500 queries and took ~600ms to respond.

I added this after line 43 of the OAI provider:

    scopes = scopes.map do |s|
      fields = [:contributors, :operation_links, :scientific_topic_links, :content_provider]
      fields << :instructors if s.model == Event
      fields << :materials if s.model == Event
      fields << :authors if s.model == Material
      s.includes(*fields)
    end

to eager load various associations that are used in the to_oai_dc methods, which cut it down to 19 queries and ~122ms.

Potentially worth investigating (and finding a less hacky way of doing) this. Maybe the OAI library allows you to eager load associations like sunspot does

[fbacall]

Can we get the description from i18n somehow instead of hard-coding it here?