/**
  * Add the port to the domain if necessary.
  *
  * @param  string  $domain
  * @return string
  */
 protected function addPortToDomain($domain)
 {
     if (in_array($this->request->getPort(), array('80', '443'))) {
         return $domain;
     }
     return $domain . ':' . $this->request->getPort();
 }