Rails 5 Routes: Scope vs Namespace

You may be wondering about the difference between scope and namespace for the routes in your Rails application. It's important to know the difference, because they affect the path of your resources and the controllers.

`namespace`

This is the simple option. When you use namespace, it will prefix the URL path for the specified resources, and try to locate the controller under a module named in the same manner as the namespace.

With the following code in the routes.rb file,

namespace :admin do
  resources :users
end

You will end up with the following routes:

Prefix Verb   URI Pattern                Controller#Action
admin_users GET    /admin/users(.:format)     admin/users#index
            POST   /admin/users(.:format)     admin/users#create
admin_user  GET    /admin/users/:id(.:format) admin/users#show
            PATCH  /admin/users/:id(.:format) admin/users#update
            PUT    /admin/users/:id(.:format) admin/users#update
            DELETE /admin/users/:id(.:format) admin/users#destroy

As you can see, admin was added as a prefix in the URI path (/admin/users) and as a module containing the controller (admin/users#index). With this code, Rails will expect Admin::UsersController to be located at app/controllers/admin/users_controller.rb.

`scope`

scope is a bit more complex - but the advantage is that it gives you more options to fine-tune exactly what you want to do.

No Options

When using scope without any options and only a scope name, it will just change the resources path.

# routes.rb
scope :admin do
  resources :users
end

Here are the generated routes:

Prefix Verb   URI Pattern                Controller#Action
 users GET    /admin/users(.:format)     users#index
       POST   /admin/users(.:format)     users#create
  user GET    /admin/users/:id(.:format) users#show
       PATCH  /admin/users/:id(.:format) users#update
       PUT    /admin/users/:id(.:format) users#update
       DELETE /admin/users/:id(.:format) users#destroy

As you can see, /admin was added as a prefix before /users, but the users controller doesn't have to be inside any module.

With Options

scope supports three options: module, path and as.

`module`

module lets us define in which module the controller for the embedded resources will live.

scope module: 'admin' do
  resources :users
end

Prefix Verb   URI Pattern          Controller#Action
 users GET    /users(.:format)     admin/users#index
       POST   /users(.:format)     admin/users#create
  user GET    /users/:id(.:format) admin/users#show
       PATCH  /users/:id(.:format) admin/users#update
       PUT    /users/:id(.:format) admin/users#update
       DELETE /users/:id(.:format) admin/users#destroy

`path`

path allows us to set the prefix that will appear in the URI, before the resource name.

scope module: 'admin', path: 'fu' do
  resources :users
end

Prefix Verb   URI Pattern             Controller#Action
 users GET    /fu/users(.:format)     admin/users#index
       POST   /fu/users(.:format)     admin/users#create
  user GET    /fu/users/:id(.:format) admin/users#show
       PATCH  /fu/users/:id(.:format) admin/users#update
       PUT    /fu/users/:id(.:format) admin/users#update
       DELETE /fu/users/:id(.:format) admin/users#destroy

`as`

Finally, as can be used to change the name of the path method used to identify the resources.

scope module: 'admin', path: 'fu', as: 'cool' do
  resources :users
end

In this case, we now have cool as a prefix for the path names cool_users and cool_user.

Prefix Verb   URI Pattern             Controller#Action
cool_users GET    /fu/users(.:format)     admin/users#index
           POST   /fu/users(.:format)     admin/users#create
cool_user  GET    /fu/users/:id(.:format) admin/users#show
           PATCH  /fu/users/:id(.:format) admin/users#update
           PUT    /fu/users/:id(.:format) admin/users#update
           DELETE /fu/users/:id(.:format) admin/users#destroy