use the Hyrax::FileSetFileService to determine "primary file"

[no-reply]

Hyrax::FileSetFileService was introduced to un-hard code the assumption that the :original_file PCDM Use is the "primary" file for a given file set. use it throughout the code base to avoid requiring that assumption in downstream apps.

this should allow downstream apps to wire in a new service and resolve the "primary file" for each object according to local requirements. e.g. it may be desirable for apps to treat "preservation file" or "service file" as "primary"

Changes proposed in this pull request:

• adds support for overriding the "primary" file resolution behavior

@samvera/hyrax-code-reviewers

[marrus-sh]

The fallback in #primary_file (at least) does

fallback_id = file_set.file_ids.first

This should probably use a query service too instead, yeah? (Maybe we need a “first file metadata in file set” query?)

I’d also very much like to get rid of the dependence on file_set.original_file_id in that method (which I think suffers from the same modelling issues that file_ids does), but I couldn’t figure out a way how when I wrote that method originally. Is there a query we could use for that instead?

(The difference between the service and any original file query is, and should remain, that the service has fallback behaviour if there is no original file, whereas the query would return nil.)

[no-reply]

i think you're probably right, on both points.

i remember the #primary_file setup being pretty fussy though (between Wings and PG), and i think for our purposes it's moot anyway, since we want to override this whole service in comet. getting this much through unblocks that, and next steps can be explored from there.

[no-reply]

re: original_file_id, i think custom_queries.find_original_file(file_set: file_set) is the preferred approach, and is executed in the other branch. but i presume there's a reason for original_file_id getting used preferentially.