Relationships not respecting jsonapi standard outside controller. ( It's actually a serializer lookup problem )

[fazelmk]

Tried debugging but didn't get anywhere. Maybe a problem caused by namespace.

Using

   active_model_serializers 
   ruby 2.2.5p319 (2016-04-26 revision 54774) [x86_64-linux]
   Rails 5.0.2
   Ubuntu 14.04 64bits

Serializers

class V1::Admin::CharacteristicSerializer < V1::ApiSerializer
  attributes :id, :name, :characteristic_type, :min, :max, :active

  has_many :admin_characteristic_values, each_serializer: ::V1::Admin::CharacteristicValueSerializer
end

class V1::Admin::CharacteristicValueSerializer < V1::ApiSerializer
  attributes :id, :value, :active

  belongs_to :admin_characteristic, serializer: ::V1::Admin::CharacteristicSerializer
end

Expected behavior vs actual behavior

Behavior outside controller

object = ::Admin::Characteristic.includes(:admin_characteristic_values)
ActiveModelSerializers::SerializableResource.new(object, each_serializer: V1::Admin::CharacteristicSerializer).as_json

:relationships=>
      :admin_characteristic_values=>
       {:data=>
         [{"id"=>21, "value"=>"Value 0", "active"=>true, "admin_characteristic_id"=>5, "created_at"=>Sun, 02 Apr 2017 09:25:18 BRT -03:00, "updated_at"=>Sun, 02 Apr 2017 09:25:18 BRT -03:00},
          {"id"=>23, "value"=>"Value 2", "active"=>true, "admin_characteristic_id"=>5, "created_at"=>Sun, 02 Apr 2017 09:25:18 BRT -03:00, "updated_at"=>Sun, 02 Apr 2017 09:25:18 BRT -03:00},
          {"id"=>25, "value"=>"Value 4", "active"=>true, "admin_characteristic_id"=>5, "created_at"=>Sun, 02 Apr 2017 09:25:18 BRT -03:00, "updated_at"=>Sun, 02 Apr 2017 09:25:18 BRT -03:00}]}

Behavior inside controller

"relationships"=>
   "admin_characteristic_values"=>
     {"data"=>
       [{"id"=>"1", "type"=>"admin-characteristic_value"},
        {"id"=>"3", "type"=>"admin-characteristic_value"},
        {"id"=>"5", "type"=>"admin-characteristic_value"}]}

[fazelmk]

I did some debugging. And this is as far as got til now.

active_model_serializers/adapter/json_api.rb

437: def relationships_for(serializer, requested_associations, include_slice)
438:   include_directive = JSONAPI::IncludeDirective.new(
439:     requested_associations,
440:     allow_wildcard: true
441:   )
442:   serializer.associations(include_directive, include_slice).each_with_object({}) do |association, hash|
443:     hash[association.key] = Relationship.new(serializer, instance_options, association).as_json
444:     binding.pry
445:   end
446: end

From controller using render json: @records, each_serializer: V1::Admin::CharacteristicSerializer

hash[assotiation.key] has

{:data=>[{:id=>"1", :type=>"admin-characteristic_value"}, {:id=>"3", :type=>"admin-characteristic_value"}]}

and assotiation variable has

#<struct ActiveModel::Serializer::Association
name=:admin_characteristic_values,
options=
 {:each_serializer=>V1::Admin::CharacteristicValueSerializer,
  :namespace=>V1::Admin,
  :include_data=>true,
  :links=>{},
  :meta=>nil,
  :serializer=>
   #<ActiveModel::Serializer::CollectionSerializer:0x007efe28731298
    @object=
     [#<Admin::CharacteristicValue:0x007efe28ec9938
       id: 1,
       value: "Value 0",
       active: true,
       admin_characteristic_id: 1,
       created_at: Mon, 03 Apr 2017 19:05:52 BRT -03:00,
       updated_at: Mon, 03 Apr 2017 19:05:52 BRT -03:00>,
      #<Admin::CharacteristicValue:0x007efe28ec95f0
       id: 3,
       value: "Value 2",
       active: true,
       admin_characteristic_id: 1,
       created_at: Mon, 03 Apr 2017 19:05:52 BRT -03:00,
       updated_at: Mon, 03 Apr 2017 19:05:52 BRT -03:00>],
    @options=
     {:namespace=>V1::Admin,
      :scope=>#<User id: 1, email: "teste@teste.teste", created_at: "2017-04-03 22:05:52", updated_at: "2017-04-03 22:05:52">,
      :scope_name=>:current_user,
      :serializer_context_class=>V1::Admin::CharacteristicSerializer},
    @root=nil,
    @serializers=
     [#<V1::Admin::CharacteristicValueSerializer:0x007efe26f0f318
       @instance_options=
        {:namespace=>V1::Admin,
         :scope=>#<User id: 1, email: "teste@teste.teste", created_at: "2017-04-03 22:05:52", updated_at: "2017-04-03 22:05:52">,
         :scope_name=>:current_user,
         :serializer_context_class=>V1::Admin::CharacteristicSerializer},
       @object=
        #<Admin::CharacteristicValue:0x007efe28ec9938
         id: 1,
         value: "Value 0",
         active: true,
         admin_characteristic_id: 1,
         created_at: Mon, 03 Apr 2017 19:05:52 BRT -03:00,
         updated_at: Mon, 03 Apr 2017 19:05:52 BRT -03:00>,
       @root=nil,
       @scope=#<User id: 1, email: "teste@teste.teste", created_at: "2017-04-03 22:05:52", updated_at: "2017-04-03 22:05:52">>,
      #<V1::Admin::CharacteristicValueSerializer:0x007efe26f0bce0
       @instance_options=
        {:namespace=>V1::Admin,
         :scope=>#<User id: 1, email: "teste@teste.teste", created_at: "2017-04-03 22:05:52", updated_at: "2017-04-03 22:05:52">,
         :scope_name=>:current_user,
         :serializer_context_class=>V1::Admin::CharacteristicSerializer},
       @object=
        #<Admin::CharacteristicValue:0x007efe28ec95f0
         id: 3,
         value: "Value 2",
         active: true,
         admin_characteristic_id: 1,
         created_at: Mon, 03 Apr 2017 19:05:52 BRT -03:00,
         updated_at: Mon, 03 Apr 2017 19:05:52 BRT -03:00>,
       @root=nil,
       @scope=#<User id: 1, email: "teste@teste.teste", created_at: "2017-04-03 22:05:52", updated_at: "2017-04-03 22:05:52">>]>},
block=nil>

From rspec using ActiveModelSerializers::SerializableResource.new( @records, each_serializer: V1::Admin::CharacteristicSerializer )

hash[assotiation.key] has

{:data=>
  [{"id"=>1, "value"=>"Value 0", "active"=>true, "admin_characteristic_id"=>1, "created_at"=>Mon, 03 Apr 2017 19:05:52 BRT -03:00, "updated_at"=>Mon, 03 Apr 2017 19:05:52 BRT -03:00},
   {"id"=>3, "value"=>"Value 2", "active"=>true, "admin_characteristic_id"=>1, "created_at"=>Mon, 03 Apr 2017 19:05:52 BRT -03:00, "updated_at"=>Mon, 03 Apr 2017 19:05:52 BRT -03:00}]}

and assotiation variable has

#<struct ActiveModel::Serializer::Association
 name=:admin_characteristic_values,
 options=
  {:each_serializer=>V1::Admin::CharacteristicValueSerializer,
   :namespace=>nil,
   :include_data=>true,
   :links=>{},
   :meta=>nil,
   :virtual_value=>
    [{"id"=>1, "value"=>"Value 0", "active"=>true, "admin_characteristic_id"=>1, "created_at"=>Mon, 03 Apr 2017 19:05:52 BRT -03:00, "updated_at"=>Mon, 03 Apr 2017 19:05:52 BRT -03:00},
     {"id"=>3, "value"=>"Value 2", "active"=>true, "admin_characteristic_id"=>1, "created_at"=>Mon, 03 Apr 2017 19:05:52 BRT -03:00, "updated_at"=>Mon, 03 Apr 2017 19:05:52 BRT -03:00}]},
 block=nil>

someone has any clue why the difference?

[fazelmk]

Ok the serializer lookup is causing the problem due to namespacing.

ActiveModelSerializers::SerializableResource.new( @records, { each_serializer: V1::Admin::CharacteristicSerializer namespace: "V1::Admin" }) solved the issue.

I think it would be better to look first in the serializer to see if the serializer was defined (I did define it), then look in the same namespace and finally look in the root namespace.

[bf4]

@fazelmk Thanks so much for this!

I'm sorry you had to read through that json api relationships code. It's a beast!

What do you think we should do to help future us?

[fazelmk]

@bf4 this is what I would do.

If the serializer for the relationship was defined (as the code bellow shows) it should use it.

class V1::Admin::CharacteristicSerializer < V1::ApiSerializer
  attributes :id, :name, :characteristic_type, :min, :max, :active

  has_many :admin_characteristic_values, each_serializer: ::V1::Admin::CharacteristicValueSerializer
end

Basic lookup (leave some common use cases not treated)
first with same namespace of the serializer containing the association
if did'n find use root namespace

Accurate lookup
It may be wise to do a lookup in every namespace going from the namespace of the serializer to the root namespace.

As the example I got namespace V1::Admin, if I didn't declare the serializer it could be V1::Admin or just V1 if it's a serializer outside the admin namespace. This would cover almost all the use cases.

Leaving cross-version (which I think shouldn't be treated) and models in sub-domains of the serilizer domain (which we wouldn't have at hand to do lookup).

This exceptions can be treated by declare the serializer for the relationship in the current serializer, so it won't be a problem for the user.

I didn't dig up enough to find the lookup code. If you point me in the right direction I can make a PR for this.

[bf4]

@fazelmk I just want to acknowledge I've read this. I'm spread pretty thinly and haven't yet read it carefully enough to make a suggestion.

[ysyyork]

Jesus, this saved me a day lol. Thanks @fazelmk