string $ip:
string $url:
string $method:
array
private function buildQuery($ip, $url, $method) {
  $query = array();
  if (!empty($ip)) {
    $query['ip'] = $ip;
  }
  if (!empty($url)) {
    $query['url'] = $url;
  }
  if (!empty($method)) {
    $query['method'] = $method;
  }
  return $query;
}