Question

I am getting this error:

Routing Error
uninitialized constant RegistrationsController

This is my log:

Started GET "/registrants/1/registrations/new" for 127.0.0.1 at 2012-07-03 00:55:44 -0500

ActionController::RoutingError (uninitialized constant RegistrationsController):

Rendered /.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.1.3/lib/action_dispatch/middleware/templates/rescues/routing_error.erb within rescues/layout (8.5ms)

This is the part of my routes.rb that is appropriate:

registrant_registrations GET    /registrants/:registrant_id/registrations(.:format)          {:action=>"index", :controller=>"registrations"}
                                   POST   /registrants/:registrant_id/registrations(.:format)          {:action=>"create", :controller=>"registrations"}
       new_registrant_registration GET    /registrants/:registrant_id/registrations/new(.:format)      {:action=>"new", :controller=>"registrations"}
      edit_registrant_registration GET    /registrants/:registrant_id/registrations/:id/edit(.:format) {:action=>"edit", :controller=>"registrations"}
           registrant_registration GET    /registrants/:registrant_id/registrations/:id(.:format)      {:action=>"show", :controller=>"registrations"}
                                   PUT    /registrants/:registrant_id/registrations/:id(.:format)      {:action=>"update", :controller=>"registrations"}

This is my Registrations Controller, which is at /app/controllers/portal/registrations_controller.rb:

class Portal::RegistrationsController < ApplicationController
  def create
        @registrant = current_member.registrants.find(params[:registrant])
        @registration = @registrant.registrations.build

        respond_to do |format|
          if @registration.save
            format.html {   redirect_to root_path, :notice => "Registration successfully created!" }
            format.json { head :ok }
          else
           format.html { redirect_to root_path, :notice => "There was a problem with the registration." }
          end
        end     
  end

end

I get this error when I call new_registrant_registration_path(registrant) from a view in Portal#index.

Edit:

For completeness, here is my routes.rb file in its entirety before the solution was found. Radar mentioned the gist I posted, but I figured I would put the code here in case that gist is deleted.

MyApp::Application.routes.draw do

  match 'admin' => 'admin/dashboard#index', :as => :admin_root
  match 'portal' => 'portal#index', :as => :member_root

  namespace 'admin' do
    match 'profile' => 'profile#show', :as => :profile

    resources :members
    resources :admins
        resources :packages
        resources :products
        resources :levels
        resources :lessons
        resources :registrations
        resources :registrants, :controller => 'customers/registrants'
        resources :locations
        resources :schools
        resources :terms
        resources :customers
        resources :invoices
        resources :payments
  end

  namespace 'member' do
    resources :registrations
  end

  match 'register' => 'member/registrations#new', :as => :signup  
  match 'login' => 'member_sessions#new', :as => :login
  match 'logout' => 'member_sessions#destroy', :as => :logout  
  match 'admin/login' => 'admin_sessions#new', :as => :admin_login
  match 'admin/logout' => 'admin_sessions#destroy', :as => :admin_logout

  match 'member/activate/:activation_code' => 'member/activations#create', :as => :member_activation
  match 'member/:id/activate/resend' => 'member/activations#resend', :as => :resend_member_activation
  match 'member/:id/activate' => 'member/activations#new', :as => :new_member_activation

  match 'member/password/reset/begin' => 'member/password_resets#new', :as => :new_member_password_reset, :via => :get
  match 'member/password/reset' => 'member/password_resets#create', :as => :member_password_resets, :via => :post
  match 'member/password/:token/finish' => 'member/password_resets#edit', :as => :edit_member_password_reset, :via => :get
  match 'member/password/reset' => 'member/password_resets#update', :as => :member_password_reset, :via => :put

  match 'admin/packages/new/:partial' => 'admin/packages#new'

  resources :admins

  resources :registrants, :controller => 'portal/registrants' do
    resources :registrations
  end

  resource :admin_session
  resource :member_session

  root :to => 'portal#index'

end

Answer 1

To make things clear: marcamillion came into #rubyonrails and Freenode and shared his config/routes.rb. That’s where I figured out the error that he was making and then figured out the answer.

---

Two things.

First: Admin root route

Rather than defining the root route for your admin namespace like this:

match 'admin' => 'admin/dashboard#index', :as => :admin_root

Define it inside the namespace :admin call like this:

namespace 'admin' do
  root :to => "dashboard#index"
end

This will automatically define it as admin_root_path and admin_root_url, so you won’t need to do that, and it will automatically prefix the controller with the admin/ prefix, so you won’t need to do that either.

Second: Referencing RegistrantsController

You have this currently in your config/routes.rb:

resources :registrants, :controller => 'portal/registrants' do
  resources :registrations
end

What this will do is define resources routes for registrants correctly using the Portal::RegistrantsController, but won’t define the nested routes underneath this using Portal::RegistrationsController. What it will do is attempt to use RegistrationsController, which is why you’re getting that error.

To fix this, I’d recommend you use the scope method, like this:

scope :module => Portal do
 resources :registrants do
  resources :registrations
 end
end

The scope method, when used in this way, will tell Rails that the controllers for the routes inside the block are under the Portal namespace. This means that it will know that resources :registrants is for Portal::Registrants and that resources :registrations is for Portal::Registrations, thereby fixing the error that you’re seeing.