How to implement multiple different serializers for same model using ActiveModel::Serializers?

Question

Let\'s say you\'re implementing a REST API in Rails. When serving a collection, you might want to only include a few attributes:

/people

B

Answer 1

You can have multiple serializers for the same model, e.g.

class SimplePersonSerializer < ActiveModel::Serializer
  attributes :id, :name
end

and

class CompletePersonSerializer < ActiveModel::Serializer
  attributes :id, :name, :phone, :email
end

simple info for people in one controller:

render json: @people, each_serializer: SimplePersonSerializer

complete info for people in another:

render json: @people, each_serializer: CompletePersonSerializer

simple info for a single person:

render json: @person, serializer: SimplePersonSerializer

complete info for a single person:

render json: @person, serializer: CompletePersonSerializer

Answer 2

Adding to what @phaedryx said, what I do for this is call a method that returns the correct serializer... for your question, I'd use:

class MyController < ApplicationController

  def index
    render json: @people, each_serializer: serializer_method
  end

  private

  def serializer_method
    defined?(@people) ? PeopleSerializer : PersonSerializer
  end

end

Answer 3

To avoid mixing view concerns into your models (via serialized variations), use the view to render your JSON for each action, much like we do for HTML.

jbuilder & rabl both fill this data templating need quite nicely.

Update 2013-12-16: The ActiveModelSerializers library does support defining multiple serializers for one model, as @phaedryx answered later, by using custom serializers.

Answer 4

class CompletePersonSerializer < ActiveModel::Serializer
  root :person
  attributes :id, :name, :phone, :email
end

or

render json: @people, each_serializer: CompletePersonSerializer, root: :person