code: public function checkQuery($name)
      {
          $parts = explode('&', $this->_urlParts['query']);
  
          foreach ($parts as $p) {
              $paramData = explode('=', $p);
              if ($paramData[0] === $name) {
                  return true;
              }
          }
  
          return false;
      }
docs: Check if parameter is present in query
  
  @param string $name Parameter name
  @return bool