static function send_text($content, $openid)
    {
        if (!Cache::has('mini_access_token'))
            WechatController::get_access_token();

        $access_token = Cache::get('mini_access_token');

        $argv = [
            "touser" => $openid,
            "msgtype" => "text",
            "text" => [
                "content" => $content,
            ],
        ];

        $payload = json_encode($argv, JSON_UNESCAPED_UNICODE);

        $uri = "https://api.weixin.qq.com/cgi-bin/message/custom/send?access_token=$access_token";

        $ch = curl_init($uri);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLINFO_HEADER_OUT, true);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $payload);
         
        curl_exec($ch);
        
        curl_close($ch);
    }