public function getServer() {
        $server = 'mongodb://';

        if ($servers = $this->getConfig('servers')) {
            $server .= implode(',', $servers);

        } else {
            if ($socket = $this->getSocket()) {
                $server .= $socket;
            } else {
                $server .= $this->getHost() . ':' . $this->getPort();
            }
        }

        return $server;
    }