Include an association with Active Model Serializer

Question

In a Rails 5 application, I'm using Active Model Serializer 0.10.0.rc4 . I want to include a relation in a json hash.

I have this serializer :

class GroupSerializer < ActiveModel::Serializer
  attributes :id, :name, :subscription_ids, :nb_places, :description,
    :schedule, :course_id
end

And I'm using it like this :

resource = Group.all
ActiveModel::Serializer.serializer_for(resource).new(resource, include: :subscriptions).as_json

And I have this :

{"group"=>{:id=>1, :name=>"12", :subscription_ids=>[1, 2, 3], :nb_places=>12, :description=>nil, :schedule=>"12", :course_id=>1}}

I don't understand why subscriptions are not included. I don't want to use has_many in the serializer because it cause infinite loop when the there is multiple rules.

I want something like this :

{"group"=>{:id=>1, :name=>"12", :subscription_ids=>[1], :nb_places=>12, :description=>nil, :schedule=>"12", :course_id=>1, :subscriptions=>[{:id=>1,:name=>'something'}]}

What can I do?

Answer 1

You can create a subscriptions method like this:

attributes :subscriptions

def subscriptions
  object.subscriptions.as_json(only: [:id, :name])
end