Includes url_for into the host class. The class has to provide a RouteSet by implementing the _routes method. Otherwise, an exception will be raised.

In addition to AbstractController::UrlFor, this module accesses the HTTP layer to define url options like the host. In order to do so, this module requires the host class to implement env and request, which need to be a Rack-compatible.

class RootUrl
  include ActionController::UrlFor
  include Rails.application.routes.url_helpers

  delegate :env, :request, to: :controller

  def initialize(controller)
    @controller = controller
    @url        = root_path # named route from the application.
  end
end