Routing

The router maps screen paths like /users/42 to a controller action. You declare routes once with a small DSL (usually in config/routes.rb), and the runtime resolves every navigation through them — there is no other way to reach a screen. For the broader picture of how routes, controllers, and views fit together, see Routing.

Defining routes

Routes are usually defined in config/routes.rb:

MyApp::Application.routes do
  root "home#show"
  screen "/users/:id", to: "users#show", title: "User"
end

DSL methods:

• root "controller#action", title: "Home" maps /.
• screen "/path", to: "controller#action", title: nil maps a screen path.
• Omitting #action in to: defaults the action to #show.

Resolution rules

• Exact routes win over dynamic routes.
• Dynamic segments use :name and match one segment.
• Params are symbol-keyed, for example params[:id].
• Params are URL-decoded.
• Missing routes raise KeyError.

So navigating to /users/42 with the routes above dispatches UsersController#show with params[:id] == "42".

Route objects

Route objects expose:

• path
• controller_class
• action
• title
• params