OAuth::refreshToken PHP Method

    public static function refreshToken()
    {
        $params = array('client_id' => self::$client_id, 'client_secret' => self::$client_secret, 'grant_type' => 'refresh_token', 'refresh_token' => $_SESSION['t_refresh_token']);
        $url = self::$accessTokenURL . '?' . http_build_query($params);
        $r = TencentHttp::request($url);
        parse_str($r, $out);
        if ($out['access_token']) {
            //获取成功
            $_SESSION['t_access_token'] = $out['access_token'];
            $_SESSION['t_refresh_token'] = $out['refresh_token'];
            $_SESSION['t_expire_in'] = $out['expires_in'];
            return $out;
        } else {
            return $r;
        }
    }