Rails route namespacing (in different flavors)

TL;DR There are three dimensions you can control when scoping routes:

Copyscope module: 'module', path: 'url_prefix', as: 'path_helper_name' do
  resources :examples, only: :index
end

as → prefixes path helpers: path_helper_name_examples_path and path_helper_name_examples_url
path → prefixes URL segments: /url_prefix/examples
module → nests the controller: controller Module::ExamplesController, found at app/controllers/module/examples_controller.rb with views in app/views/module/examples/.

These options work with resources as well, e.g. resources :examples, path: 'demonstration'

Two macros for namespacing routes

Rails offers two macros for namespacing routes. As its name suggests, namespace is the tool for fully namespacing a group of routes. scope on the other hand is fit for modifications of select properties for a group of route definitions. See the examples below.

• scope is a "plumbing method" that will only set the dimensions that you pass as arguments (module, path, as).
• namespace is a shorthand that sets its argument on all three dimensions. You can override dimensions by setting them as additionally.

Examples

Note that all of these examples could be implemented with either scope or namespace.

Changing URLs only

When you want to inject a "subdirectory" in URLs, but leave the corresponding controllers and url helpers unaffected, use the scope method like this:

Copyscope path: 'sub' do
  resources :examples
end

• URL: /sub/examples
• Route helper: examples_path
• Controller class: ExamplesController

A typical use case is the customer asking you to change some URLs.

Namespacing controllers and path helpers without changing URLs

When you want to namespace your controller classes (group some controllers into a folder) but leave the corresponding routes unaffected, use the namespace method like this:

Copynamespace 'module', path: '/' do
  resources :examples
end

• URL: /examples
• Route helper: module_examples_path
• Controller class: Module::ExamplesController

Namespacing without changing path helpers

When you want to namespace some resources of your application, but keep plain route helpers, use the scope method like this:

Copyscope module: 'module', path: 'module' do
  resources :examples
end

• URL: /module/examples
• Route helper: examples_path
• Controller class: Module::ExamplesController