Improved Problem Response Content-Type headers

[rvesse]

Iterates on a change made in the 0.25.0 release where we stopped setting the Content-Type header at all to allow the JAX-RS server to do content negotiation properly. However, turns out that in some corner cases this results in a Problem response being defaulted to
application/octet-stream responses which is rarely useful/helpful.

Therefore this improves the behaviour to make a best effort to add a recognised Content-Type header, when it is compatible with the acceptable content types indicated by the clients Accept header. A new toResponse(HttpHeaders) overload is added to facilitate this, and existing callers of toResponse() updated to call the new method instead.

Also greatly expands the test coverage in this area to validate various scenarios around different combinations of Accept header, resource @Produces headers and the resulting Content-Type header.

Related Issues and PRs

• Discovered while reviewing Dependabot PRs for the 0.25.0 upgrade e.g. https://github.com/Telicent-io/user-preferences-service/actions/runs/12345464738/job/34449662984 was failing with the following:

  TestUserPreferencesServerBlocking>AbstractUserPreferencesServerTests.givenAuthenticatedUser_whenSavingQueryWithInvalidId_thenBadRequest:503->AbstractUserPreferencesServerTests.verifyInvalidId:480->AbstractUserPreferencesServerTests.verify:172 » MessageBodyProviderNotFound MessageBodyReader not found for media type=application/octet-stream, type=class io.telicent.smart.cache.server.jaxrs.model.Problem, genericType=class io.telicent.smart.cache.server.jaxrs.model.Problem.

  • Using a SNAPSHOT build from this branch those errors no longer occur