Getting nested JSON output from Rails

Question

Suppose I have a Rails app with two models Post and Comment. A post has_many comments and a comment belongs_to a post.
How can I override the respond_to function in the show action in order to get a JSON response containing both the Post properties and an array of Comment objects that it has?

Currently it is the vanilla Rails default:

# posts_controller.rb
def show
  @post = current_user.posts.find(params[:id])

  respond_to do |format|
    format.html # show.html.erb
    format.json { render json: @post }
  end
 end

score 4 · Answer 1 · answered Apr 17 '12 at 05:45

4

You can do that using Active Record serialization method.

to_json

Below code should work.

 format.json { render json: @post.to_json(:include => :comments) }

answered Apr 17 '12 at 05:45

Soundar Rathinasamy

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score 2 · Answer 2 · answered Apr 17 '12 at 04:28

Try using active_model_serializers for json serialization. It is easy to include associated objects and also separates things by having a different file for serialization.

Example:

class PostSerializer < ApplicationSerializer
    attributes :id, :title, :body
    has_many :comments
end

score 2 · Answer 3 · edited Feb 03 '13 at 00:41

2

You can override to_json in model or you can use Jbuilder or rabl.

edited Feb 03 '13 at 00:41

JJD

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answered Apr 17 '12 at 04:31

Amar

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score 1 · Answer 4 · answered Apr 17 '12 at 06:05

Rails has provide the best way to respond :

Define respond_to on the top of your controller . like :

class YourController < ApplicationController
  respond_to :xml, :json

  def show
    @post = current_user.posts.find(params[:id])
    respond_with (@post)
  end
end

For more info take a look on : http://davidwparker.com/2010/03/09/api-in-rails-respond-to-and-respond-with/

Getting nested JSON output from Rails

4 Answers4