Include associated model when rendering JSON in Rails

Question

Right now I have this line:

 render json: @programs, :except => [:created_at, :updated_at]

However, since a Program belongs_to a Company I would like to show the Company name instead of the Company Id.

How can I include the company name when rendering Programs?

possible duplicate: http://stackoverflow.com/questions/7506089/how-to-get-full-belongs-to-object-in-json-render — , Jul 18 '13 at 17:41

score 91 · Accepted Answer · answered Jul 18 '13 at 17:42

91

Something like this should work:

render :json => @programs, :include => {:insurer => {:only => :name}}, :except => [:created_at, :updated_at]

answered Jul 18 '13 at 17:42

Nobita

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5

I still don't understand... any documentation on how to do this? – Meekohi Mar 30 '17 at 01:00
1

@Meekohi http://api.rubyonrails.org/classes/ActiveModel/Serializers/JSON.html#method-i-as_json – 3limin4t0r May 08 '18 at 17:53

score 20 · Answer 2 · answered Sep 03 '15 at 15:10

20

i was getting the same "can't clone Symbol file" error while rendering json with includes from a controller method. avoided it like so:

render :json => @list.to_json( :include => [:tasks] )

answered Sep 03 '15 at 15:10

Sean M

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score 13 · Answer 3 · answered Feb 18 '15 at 03:52

You can also do this at the model level.

program.rb

  def as_json(options={})
    super(:except => [:created_at, :updated_at]
          :include => {
            :company => {:only => [:name]}
          }
    )
  end
end

Now in your controller:

render json: @programs

score 9 · Answer 4 · edited Oct 11 '16 at 07:54

9

Consider using jbuilder to include nested models in a maintainable way:

# /views/shops/index.json.jbuilder
json.shops @shops do |shop|

  # shop attributes to json
  json.id shop.id
  json.address shop.address

  # Nested products
  json.products shop.products do |product|
    json.name product.name
    json.price product.price
  end

end

edited Oct 11 '16 at 07:54

Adrien Lamothe

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answered Sep 04 '14 at 13:09

Arenzel

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score 4 · Answer 5 · answered Jun 16 '15 at 22:51

Try this. Ref

#`includes` caches all the companies for each program (eager loading)
programs = Program.includes(:company)

#`.as_json` creates a hash containing all programs
#`include` adds a key `company` to each program
#and sets the value as an array of the program's companies
#Note: you can exclude certain fields with `only` or `except`
render json: programs.as_json(include: :company, only: [:name])

Also, no need to make @programs an instance variable, as I'm assuming we are not passing it to a view.

user3716986 · Answer 6 · 2017-11-13T08:28:42.010

0

#includes is used to avoid n+1 query.
# http://guides.rubyonrails.org/active_record_querying.html#eager-loading-associations
Here is an example for the above example.Lets say you have posts and each post has many comments to it.

  @posts = Post.where('id IN [1,2,3,4]').includes(:comments)
  respond_to do |format|
     format.json {render json: @posts.to_json(:include => [:comments]) }
  end

  #output data
  [
    {id:1,name:"post1",comments:{user_id:1,message:"nice"}}
    {id:2,name:"post2",comments:{user_id:2,message:"okok"}}
     {id:3,name:"post1",comments:{user_id:12,message:"great"}}
    {id:4,name:"post1",comments:{user_id:45,message:"good enough"}}
  ]

edited Nov 13 '17 at 08:28

answered Jun 23 '17 at 12:26

user3716986

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I think you meant to use a comma: `@posts, include: :comments`. I believe you will get an error if you try to execute posts as a function with parameters ie `@posts(` – Marklar Oct 24 '17 at 03:36
I can see you edited the code to include `to_json` so I assume that's why it now works and the old code of `@posts(:include => [:comments])` didn't work? – Marklar Nov 13 '17 at 22:55

Include associated model when rendering JSON in Rails

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