private function fetchUserId()
  {
    $pool = Registry::getStash();

    $cache = $pool->getItem('nyaa/user/'.$this->getTorrentId());

    if ($cache->isMiss()) {
      // sadly we have to use the site since nothing provides the user id
      $userId = false;
      $html = file_get_contents($this->siteUrl);

      // lets not depend on the actual domain
      if(preg_match('~\/\?user\=([0-9]+)~i', $html, $match)) {
        $userId = intval($match[1]);
      }

      $cache->set($userId);
    }

    return $cache->get();
  }