public function getTorrentId()
  {
    if ($this->torrentId === null) {
      $this->torrentId = false;

      if (preg_match('~tid=([0-9]+)~', $this->torrentUrl, $match)) {
        $this->torrentId = intval($match[1]);
      }
    }

    return $this->torrentId;
  }