CODEWITHSUNDEEP
ruby-on-rails-3jsonrestactivemodel
odigity
odigity

Reputation: 8176

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

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

But when serving a single resource, you want to include all the attributes:

/people/1

I don't see how to do that using ActiveModel::Serializers, since the examples all use the pattern of defining one serializer per model (with a standard naming convention) and having AMS automatically use the right one in the controller when you do:

render json: @people

or:

render json: @person

Upvotes: 47

Views: 29124

Answers (5)

heratyian
heratyian

Reputation: 414

IMO it's best to have a specific serializer for each controller action. I built this concern to handle it. (which I add to base controller)

module Serializable
  extend ActiveSupport::Concern

   alias each_serializer serializer

   def serializer
     "#{params[:controller].classify}s::#{params[:action].classify}Serializer".constantize
   end
end

That way you can just call

render json: @person, serializer:

in your controller and it will find the correct serializer.

Upvotes: 0

Mars
Mars

Reputation: 1528

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.

Upvotes: 4

tehprofessor
tehprofessor

Reputation: 3013

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

Upvotes: 2

Alexey Pismenskiy
Alexey Pismenskiy

Reputation: 151

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

or

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

Upvotes: 11

phaedryx
phaedryx

Reputation: 2054

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

Upvotes: 130

Related Questions