Polymorphic association on JSON API

[joaomdmoura]

When using JSON-API with polymorphic associations there is a strange behavior, instead of using the name of the resource it chooses to use the name assigned to the polymorphic relation.

This is not wrong ©️, but if you think about the most of JS clients frameworks around, it makes more sense to use the resource's name.

Here is as example to illustrate:

model/address.rb

class Address < ActiveRecord::Base
  belongs_to :addressable, polymorphic: true
end

model/user.rb

class Address < ActiveRecord::Base
  has_one :home_address, as: :addressable, class_name: 'Address', dependent: :destroy
end

The serialized JSON output for address will be:

'data': {
  'id': 1,
  'type': 'addresses',
  'attributes': {
    ...
  },
  'relationships':  {
    'addressable': {
      'data': {
        'id': 1,
        'type': 'users'
      }
    }
  }
}

My point is related to this part:

  'relationships':  {
    'addressable': {
      'data': {
        'id': 1,
        'type': 'users'
      }
    }
  }
}

Despite of being a user the root name of this node is addressable, and IMO it should be user.

[beauby]

I agree. We might need a polymorphic relationship option as described in #1420.

[beauby]

cf #1453

[joaomdmoura]

Checked both! Nice!

[beauby]

What happens when the addressable association is nil? What name should we give it?
What happens with heterogeneous has_many polymorphic associations?

[cgmckeever]

Realize this is closed, but I am fighting a similar issue around the naming of polymorphic associations. No offense @joaomdmoura, but I feel the way the json-api is set up is correct. There may be multiple of those polymorphs, so nesting them under 'addressable' and then defining what type it is gives the flexibility needed.

It appears that this behavior stopped happening for the JSON adapter circa rc3
#1420 (comment)

And, again, I feel this is limited ... I also have a issue open around this demonstrating more #1717