CODEWITHSUNDEEP
ruby-on-railsserialization
user857461
user857461

Reputation: 41

Active model JSON Serialization of a rails inherited model

I have 3 models Persona, Assertion and class P2c is inherited from class Assertion

class Persona < ActiveRecord::Base
  # create_table "personas", :force => true do |t|
  #  t.text     "name",        :null => false
  #  t.text     "description"
  #  t.datetime "last_change", :null => false
  # end
    has_many :p2cs
end

class Assertion < ActiveRecord::Base
# create table "assertions", :primary_key => "id", :force => true do |t|
#    t.text "rationale",
# end
end

class P2c < Assertion
#create_table "p2cs", :primary_key => "assertion_ptr_id", :force => true do |t|
#  t.integer "persona_id",         :null => false
# end
    belongs_to :persona, :class_name => "Persona", :foreign_key => "persona_id"
end

I need help to write the serialization classes using gem active_model_serializers

Upvotes: 0

Views: 2230

Answers (2)

Diego d&#39;Ursel
Diego d&#39;Ursel

Reputation: 91

I don't understand your question. But I guess you had issue with your STI. STI and polymorphism are not explained in the RailsCast 409, but they talk about it in the documentation.

The key is that you have to specify the serializer. Lets say I have a 

class Parent < ActiveRecord::Base 
class Child < Parent

I would have the following show/index actions:

def index
  render json: children, each_serializer: ParentSerializer
end

def show
  render json: child, serializer: ParentSerializer
end

Upvotes: 1

m_x
m_x

Reputation: 12554

Your question is not clear, but i assume you want to include p2cs in your personnae. as_json is the preferred way to implement default JSON serialization in rails

class Personna < ActiveRecord::Base
  def as_json( options={} )
    super( {include: [:p2cs]}.merge options )
  end
end

If your problem is to implement different behavior for P2c and Assertion, just implement as_json as needed in each of the classes.

note you may find that blog post about json serialization interesting, because it clarifies the difference between as_json and to_json : http://jonathanjulian.com/2010/04/rails-to_json-or-as_json/

the idea is that we need to split json serialization into two steps : build a ruby hash of attributes (as_json), and then serialize it (to_json). This way inheritance and overloading are easier, because we can just process a ruby hash.

Upvotes: 0

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