Using ActiveModel::Serializer How Can I Add a table attribute to each model

Question

I want the JSON returned for each model to include a table attribute indicating the database table the object comes from (with STI this isn't the same as the model class) and to look up the appropriate factory function to instantiate objects.

I suppose I could manually override a table attribute for each serializer but that seems really ugly. Is there any way to do this generally?

Answer 1

This works.

Have all my serializers inherit from the following:

class ApplicationSerializer < ActiveModel::Serializer

  attributes :table_name

  def table_name
      object.class.table_name
  end
end

Answer 2

A good solution will be extending ActiveRecord::Base , overriding the attributes method and then using inheritance.

Extending ActiveRecord::Base and the override.

class ActiveRecordExtension < ActiveRecord::Base
    self.abstract_class = true

    def attributes
        res = super
        res["class_name"] = class_name
        res 
    end

    def class_name
        self.class.name
    end
end

Inheritance

class User < ActiveRecordExtension
end

You can also create a monkey patch but inheritance is neater. The only thing that is useful in a monkey patch is that you will not change inheritance from ActiveRecord::Base to another class.

I did not use ActiveModel::Serializer but if you insist on using it you can learn more about it in this cast although I guess each model would need a serializer in contrast to my solution.