Relationship between ContainedFiles and AddFile Service is confusing and prevents original_file from being versionable

[flyingzumwalt]

The way Works::GenericFile::ContainedFiles and the Works::AddFileToGenericFile Service are currently implemented is really confusing and makes it unclear how to do things like add thumbnails to a GenericFile. It also prevents us from having a clear way to say "The original_file should be versioned, but the others should not be"

TODO

Read up on contains and directly_contains

• Can we make directly_contains return singular (instead of Array)? (ie. can we use directly_contains to generate setter & getter for thumbnail and have it return one file instead of an array?)
• Can we call directly_contains and have it filter by RDF type?

Read up on Services

• What is the CORRECT way to handle original_file and thumbnail? Should GenericFile have both readers and writers that services simply consume? (currently there are only readers and the Services are the only thing that know how to add thumbs, etc.)

... Fix things as appropriate....

Example: maybe Works::GenericFile::ContainedFiles should look like this (probably requires changes in ActiveFedora to support this)

module Hydra::Works::GenericFile::ContainedFiles
  extend ActiveSupport::Concern

  # allows you to find the specific file from with in the files contained via PCDM::ObjectBehavior#files
  directly_contains_one :original_file, has_member_relation: RDFVocabularies::PCDMTerms.hasFile,
    class_name: "CurationConcerns::VersionableFile", type: ::RDF::URI("http://pcdm.org/OriginalFile")

  directly_contains_one :thumbnail, has_member_relation: RDFVocabularies::PCDMTerms.hasFile,
    class_name: "Hydra::PCDM::File", type: ::RDF::URI("http://pcdm.org/Thumbnail")

  directly_contains_one :extracted_text, has_member_relation: RDFVocabularies::PCDMTerms.hasFile,
    class_name: "Hydra::PCDM::File", type: ::RDF::URI("http://pcdm.org/ExtractedText")
end

Then:

Make original_file versioned. Possibly use pattern from Sufia master, where it sets class_name: “VersionableFile" in the call to contains

[jcoyne]

I think you're on the right track, but I'm not sure that original_file must be versionable in PCDM. I think the default should be Hydra::PCDM::File, but there certainly should be a way to override it.

[flyingzumwalt]

Yeah. We're going to make it versionable in CurationConcerns::GenericFile (previously Sufia::GenericFile), not down in the lower gems. @jcoyne can you offer hints to the answers to the questions about directly_contains, or do you have ideas about the answer to my question about whether Classes should provide getters & setters for things like .thumbnail instead of relying solely on services?

[jcoyne]

I don't think there's any business logic in a relationship getter/setter, so my preference is to add that directly to the model.

[flyingzumwalt]

I agree. :+1:

[flyingzumwalt]

Updated the code sample in the main description to reflect the need for a directly_contains_one method instead of making directly_contains accept an argument of singular: true

[jrgriffiniii]

https://github.com/samvera/hydra-works/commit/10a4c1979d42c62d4536b093537e34e45093b3e0 seems to have addressed this (at least partly). Further feature requests should be proposed for active_fedora.