PHP Quake Live ZMQ implementation

function qlServerExecute($command, $server, $password, $timeout = 1.5, $filter = true) {
  $identity = "WebControlPanel";
  $client = new ZMQSocket(new ZMQContext(), ZMQ::SOCKET_DEALER);

  $client->setSockOpt(ZMQ::SOCKOPT_PLAIN_USERNAME, "rcon");
  $client->setSockOpt(ZMQ::SOCKOPT_PLAIN_PASSWORD, $password);
  $client->setSockOpt(ZMQ::SOCKOPT_IDENTITY, $identity);
  $client->setSockOpt(ZMQ::SOCKOPT_ZAP_DOMAIN, "rcon");

  $client->connect("tcp://" . $server);

  $client->send("register");
  $client->send($command, ZMQ::MODE_NOBLOCK);
  sleep($timeout); // otherwise the server crashes...
  $response = $client->recv(ZMQ::MODE_NOBLOCK);

  $client->disconnect("tcp://" . $server);

  if ($filter) {
    return substr($response, (24 + strlen($identity)));
  } else {
    return $response;
  }
}

var_dump(qlServerExecute("map campgrounds", "ip:28960", "password"));