Getting Rails 5 app to return JSON API format

Question

I'm trying to get my app to return in lowercase camelcase for eventual JSON API formatting.

I've installed gem 'active_model_serializers' and created a new initializer with the following code in it:

ActiveModelSerializers.config.adapter = :json_api
ActiveModelSerializers.config.key_transform = :camel_lower

Then I have a small API that returns json, as all of the best internet applications do:

class Api::V1::UsersController < API::V1::BaseController
  def sky
      @user = User.find_by_id(params[:user_id])

      if @user
          obj =  {
              sky: {
                  sectors: @user.sectors,
                  slots: @user.slots
              }
          }

          render json: obj
      else
          raise "Unable to get Sky"
      end
  end

More on the API controller inheritance pattern: class API::V1::BaseController < ActionController::Base

The Problem

In my API response, things are still snake cased and I see this error in the console [active_model_serializers] Rendered ActiveModel::Serializer::Null but my research has led me to a dead end as to what to do.

Any suggestions would be very welcome. Thanks!

This is a rails app, not a rails-api app, fwiw

Zack Shapiro
– Zack Shapiro

2017-06-16 21:42:07 +00:00
Commented Jun 16, 2017 at 21:42 — Zack Shapiro
– Zack Shapiro, Commented Jun 16, 2017 at 21:42

George · Accepted Answer · 2017-06-28 22:56:56Z

3

The problem is you're not calling an active record serializer in your controller, so those config settings aren't being picked up.

Solution: Create a UserSerializer in "app/serializers/user_serializer.rb" that should look something like this:

class UserSerializer < ActiveModel::Serializer
  attributes :id

  has_many :sectors
  has_many :slots
end

as well as similarly structured SectorSerializer and a SlotSerializer with all of the attributes you want from each (Here are the getting started docs and the general syntax docs for active record serializers)

Then in your controller:

class Api::V1::UsersController < API::V1::BaseController
  def sky
    @user = User.includes(:sectors, :slots).find_by_id(params[:user_id])

    if @user
      render json: @user
    else
      raise "Unable to get Sky"
    end
  end
end

Which will eager load :slots and :sectors with includes then calls your UserSerializer using your camel_case config options.

edited Jun 28, 2017 at 22:56

answered Jun 22, 2017 at 14:25

George

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14 Comments

Zack Shapiro Over a year ago

No. It's still camel cased

Zack Shapiro Over a year ago

snake cased, rather

George Over a year ago

@zack which version of active model serializers are you using?

George Over a year ago

run bundle show | grep active_model_serializers to get the version

Zack Shapiro Over a year ago

active_model_serializers (0.10.6)

|

alehn96 · Accepted Answer · 2017-06-24 06:50:10Z

3

+25

In your controller put respond_to :json

class Api::V1::UsersController < API::V1::BaseController

  respond_to :json

and in the action put same that you have

def sky
   ...      
   render json: obj
   ...       
end

and define in base controller

protect_from_forgery with: :null_session, if: Proc.new { |c| c.request.format == 'application/json' }

answered Jun 24, 2017 at 6:50

alehn96

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1 Comment

Zack Shapiro Over a year ago

Still snake cased

bratsche · Accepted Answer · 2017-06-19 00:06:28Z

2

From this pull request (*) it looks like you should be able to configure key_format = :lower_camel in your ActiveModel::Serializers config.

(*) https://github.com/rails-api/active_model_serializers/pull/534

answered Jun 19, 2017 at 0:06

bratsche

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Comments

Alexey · Accepted Answer · 2017-06-24 23:32:48Z

2

i think it helps you. in my case i use gem 'active_model_serializers', '~> 0.10.5' which depends on case_transform (>= 0.2)

and in rails console i can do

CaseTransform.camel_lower(initially_serialized_output)                                                       
=> {:name=>"My Company", :jsonThings=>{:rating=>8, :aKey=>{:aSubkey=>{:anotherKey=>"value"}}}}

my research was by steps: https://github.com/rails-api/active_model_serializers/pull/1993 => https://github.com/NullVoxPopuli/case_transform-rust-extensions

did you find this?

answered Jun 24, 2017 at 23:32

Alexey

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1 Comment

Alexey Over a year ago

initially_serialized_output = { "name": "My Company", "json_things": { "rating": 8, "a_key": { "a_subkey": { "another_key": "value" } } } }

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