public function getMediaSource($mediaId, $expiredInSeconds, $options = array())
    {
        list($config) = $this->parseOptions($options, 'config');

        if (empty($mediaId)) {
            throw new BceClientException("The parameter mediaId should NOT be null or empty string");
        }
        if (empty($expiredInSeconds)) {
            $expiredInSeconds = -1;
        }

        $params = array(
            'sourcedownload' => null,
            'expiredInSeconds' => $expiredInSeconds,
        );
        return $this->sendRequest(
            HttpMethod::GET,
            array(
                'config' => $config,
                'params' => $params,
            ),
            "/media/$mediaId"
        );
    }