Rails Router

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The Rails Router has two purposes: 1) to recognize URLs and dispatch them to a controller's action, and 2) to generate paths and URLs so you don't need to hardcode them into your programs.

URL Mapping:

Explicit Form

The mapping can be explicit:

	match "/contact", to: "static_pages#contact"

This routes all incoming requests for http://localhost:3000/contact (and eventually yourdomain.com/contact) to the contact action in the static_pages controller like a telephone dispatcher.

Implicit Form

If the URL to match and controller/action combination are the same, you can simply write:

	get "/static_pages/contact"

Which will map http://localhost:3000/static_pages/contact to the contact action in the static_pages controller.

URLs are matched in the order they are declared. The router will direct the request to the first controller the request matches.

The Root Route

To match the root ("/", "http://localhost:3000/," or "yoursite.com"), use:

	root to: "static_pages#index"

Which maps the root to the index action in the static_pages controller.

Resourceful Routes

HTTP Verb	CRUD	Path	Action	Used To
GET	Retrieve	/users	index	Display a list of all users
GET	Retrieve	/users/new	new	Return an HTML form for creating a user
POST	Create	/users	create	Create a user
GET	Retrieve	/users/:id	show	Display a specific user
GET	Retrieve	/users/:id/edit	edit	Render an HTML form for editing a user
PUT	Update	/users/:id	update	Update a specific user
DELETE	Destroy	/users/:id	destroy	Delete a specific user

Path and URL Generation

Named Routes

Route declarations automatically create "named routes:" variables that you can refer to in the rest of your Rails program. For instance:

	match "/about", to: "static_pages#about"

Automatically creates the named route "about_path."

match "/about" 						=> about_path
match "/about_us" 					=> about_us_path
match "/about_us_were_very_cool" 	=> about_us_were_very_cool_path

Even though named paths are automatically created, they should usually be explicitly defined.

	match "/about_us", to: "static_pages#about", as: "about"

The as: option defines the named route. Although the dev in this example has allowed "about_us" to be matched to the about action, the named route will stay the same.

Defining the as option explicitly makes your code less brittle: if you use the named route defined via an as option throughout your tests, you won't break anything by changing the URL to that maps to the controller.