/**
  * Get the base URL for the request.
  *
  * @param  string  $scheme
  * @param  string  $root
  * @return string
  */
 protected function getRootUrl($scheme, $root = null)
 {
     if (is_null($root)) {
         $root = $this->forcedRoot ?: $this->request->root();
     }
     $start = starts_with($root, 'http://') ? 'http://' : 'https://';
     return preg_replace('~' . $start . '~', $scheme, $root, 1);
 }