Custom mime types ignored in `produces`

The default content types can be overridden using the DSL content_type, which adds to a :content_types Hash in the settings, which takes precedence over the default CONTENT_TYPES.

However, when generating documentation Grape::Endpoint#produces_object employs GrapeSwagger::DocMethods::ProducesConsumes to lookup mime types by symbol, and that goes directly to CONTENT_TYPES, bypassing any customisation.

class MyApi < Grape::API
  content_type :jsonapi, 'application/vnd.api+json'

  resource :foo do
    desc '/fooey', { produces: [:jsonapi] }

    get do
      {
        # My JSON API response...
      }
    end
  end
end

The generated Swagger will say

...
"paths": {
  "/fooey": {
    "get": {
      "produces": ["jsonapi"]
    }
  }
}
...

rather than the expected "produces": ["application/vnd.api+json"]. You have to explicitly specify the mime type rather than the symbol to workaround.

I assume that consumes is similarly affected.

... Or is this as intended?

Start in grape-swagger/endpoint.rb at Grape::Endpoint#produces_object and follow the lookup into doc_methods/produces_consumes.rb. Compare that lookup with the custom :content_types settings described in the issue, then check the corresponding consumes path. Done means custom symbols produce their configured MIME values in the generated Swagger output for both produces and consumes.