Multiple ways to devise_for routes for the same rail resource

Question

Multiple ways to devise_for routes for the same rail resource

I am working on an existing web application that uses Rails 3 and Devise. At the moment, my task is to add the JSON API to the application. I created a Mobile :: SessionController (<Devise :: SessionsController) that implements '#create' with a response only to the data.

The problem is routing. Right now, the relevant parts of the .rb routes are as follows:

 # For the web app:
  devise_for :users, :controllers => {:sessions => 'sessions',
                                      :registrations => 'registrations'}
  as :user do
    get "/login" => "devise/sessions#new"
    get "/logout" => "devise/sessions#destroy", :as => :logout
    post '/signup' => 'registrations#signup', :as => :signup
  end
  # And for the API, later on:
  namespace :api do
    namespace :user do
      devise_for :users, :controllers => {:sessions => 'mobile/sessions'},
                 skip: :all
      devise_scope :user do
        post 'login' => 'mobile/sessions#create'
      end
...

The data endpoint is located in / api / user / login. rake routes list the following:

api_user_login POST /api/user/login(.:format) api/user/mobile/sessions#create

My specification has the following:

describe Mobile::SessionsController do
  render_views
  describe '#create' do
    context 'for some condition' do
      let(:params) do
        {
          # basic params
        }
      end
      before do
        post :create, params.merge(format: :json)
      end

      it 'should render a json response' do
        expect(response.headers['Content-Type']).to eq 'application/json; charset=utf-8'
      end
...

When I run spec, it gives the following error:

AbstractController::ActionNotFound: Could not find devise mapping for path "/mobile/sessions/create.json?params=blah.
This may happen for two reasons:

1) You forgot to wrap your route inside the scope block. For example:

  devise_scope :user do
    get "/some/route" => "some_devise_controller"
  end

2) You are testing a Devise controller bypassing the router.
   If so, you can explicitly tell Devise which mapping to use:

   @request.env["devise.mapping"] = Devise.mappings[:user]