Understanding Named Routes in Rails

This post is part of my handbook on the Rails Router.

So far, we've learned how the Rails router matches the incoming URL to a route defined in the routes.rb file and dispatches that request to the corresponding action method on a controller class.

However, the Rails router also works in the other way. That is, given the controller and action, it can generate the URL for that route. You can also name a route and use it to generate the matching URL.

How to Name a Route in Rails?

You can name a route by passing the :as option. Naming a route creates two methods in your Rails application. The method names follow the convention of {name}_path and {name}_url, where name is the name of the route.

For example, consider the following route.

get "/account", to: "pages#account", as: "user_account"

Rails will automatically generate the methods user_account_path and user_account_url.

What's the difference between _path and _url?

• Calling user_account_path method generates only the path component of the URL: /account
• Calling user_account_url method generates the entire URL, including host and protocol: http://www.example.com/account.

You can use these helper methods in any place where you need a URL or a path, for example, the helpers such as link_to or button_to:

link_to user_account_path

How to Access URL Helper Methods in Rails?

You can use the helper methods directly in the views as well as the integration tests.

button_to user_account_path

However, if you want to access them in the controller, you've to use the helpers method, which returns an instance of the view.

class PagesController < ApplicationController
  def profile
    helpers.user_account_url
    # ...
  end
end

Additionally, you can access the helper methods in the Rails console using the app object available in the console.

>> app.root_path
"/"

If the route expects any dynamic segments, you have to pass them via a hash to the named methods. Consider the following route:

get "/portal/:product", to: "pages#portal", as: "portal"

To generate the URL corresponding to this route, you'll pass the product value as follows:

portal_url(product: "ipad")    # "http://www.example.com/portal/ipad", 
portal_path(product: "iphone") # "/portal/iphone",