[FEATURE REQUEST] Add Support for Resource Level Meta

[andrew-waters]

Is your feature request related to a problem? Please describe.

The spec defines the ability for an API to implement meta on the resource level:

In addition, a resource object MAY contain any of these top-level members:

 - attributes: an attributes object representing some of the resource’s data.
 - relationships: a relationships object describing relationships between the resource and other JSON:API resources.
 - links: a links object containing links related to the resource.
 - meta: a meta object containing non-standard meta-information about a resource that can not be represented as an attribute or relationship.

It appears that the library currently only has support for top level meta using the CompoundDocument pattern.

This request is to add meta support to the resources, for example this abbreviated resource:

{
  "data": [{
    "type": "articles",
    "id": "1",
    "attributes": {
      "title": "JSON:API paints my bikeshed!"
    },
    "meta": {
      "views": 2
    }
  }]
}

Describe the solution you'd like

There may be a more elegant solution, but it feels like the interface should be something similar to either:

@ResourceWrapper(type: "people")
struct Person: Equatable {
  var id: String

  @ResourceAttribute var firstName: String
  @ResourceAttribute var lastName: String
  @ResourceAttribute var twitter: String?

  @ResourceMeta var meta: PersonMeta
}

Or by extending the ResourceWrapper:

@ResourceWrapper(type: "people", meta: PersonMeta)
struct Person: Equatable {
  var id: String

  @ResourceAttribute var firstName: String
  @ResourceAttribute var lastName: String
  @ResourceAttribute var twitter: String?
}

It feels like the second option is the cleanest, but that may come with the caveat that an opinionated decision needs to be made by the library about the visibility of the property - when using this library in an SDK, properties need to be public for them to be useful. Therefore, the first solution may be the desired one, albeit a bit more verbose. It is also more in line with the @ResourceRelationship.

In either case, the user would simply define their meta struct:

struct PersonMeta: Equatable {
  var views: Int
}

Describe alternatives you've considered

n/a

Additional context

n/a

Acceptance Criteria

Describe the criteria for considering this feature request complete and satisfactory.

• Resource level meta is decoded alongside other data for one and many requests
• The visibility of the new meta property can be controlled by the package user

Resources

• https://jsonapi.org/format/#document-resource-objects

Stakeholders

n/a

Related Issues

n/a

[andrew-waters]

Hey @gonzalezreal - just following up on this one. This is an increasingly large concern for us. I just wanted to check in with you to see what your appetite was for this functionality in the lib and whether this is something you had planned or would prefer an external contribution to.

[gonzalezreal]

Hi @andrew-waters,

Thanks for putting this together! Personally, I prefer the @ResourceMeta approach rather than extending the @ResourceWrapper macro with a meta parameter.

We don't have any plans to work on this in the near feature. So, we would happily consider any external contribution that follows the project code conventions and adds sufficient test coverage.