You are in right place if you want to get root url along with port number in rails.

Code that works

This can be achieved by either root_url or request.env[HTTP_HOST].

Use Case

In applications you may need to generate url that will link back to your application while sending email.

Problems it has solved:

Previously, we used to have environment variable like HOST: localhost:3000 saved in application.yml which would be later called by ENV['HOST'].