optional_port

Returns a number port suffix like 8080 if the port number of this request is not the default HTTP port 80 or HTTPS port 443.

req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:80'
req.optional_port # => nil

req = ActionDispatch::Request.new 'HTTP_HOST' => 'example.com:8080'
req.optional_port # => 8080