What path is a mountable engine mounted on

Question

I need to know, from inside of a layout of a mountable engine, what path it\'s currently being mounted on. What would be the way to do it?

E.g. my routes.rb contains the

Answer 1

If the engine is mouted :as => a different name, querying named_routes will not be sufficient. This monkey patch will do:

class Rails::Engine
  def self.mounted_path
    route = Rails.application.routes.routes.detect do |route|
      route.app == self
    end
    route && route.path
  end
end

Now call mounted_path on the engine:

BackendCore::Engine.mounted_path => "/backend"

Note: be careful, in production mode, the classes in your engine are evaluated before the routes of the main app are loaded. Calling this method in class macros might not work!