微信小程序授权登录--PHP后端接口

public function wxDecode()
    {
        // 接收参数
        $data = request()->param();

        $appid = config(‘site.app_id‘);
        $appsecret = config(‘site.app_secret‘);
        $grant_type = "authorization_code"; //授权（必填）
        $code = $data[‘code‘];        //有效期5分钟 登录会话
        $encryptedData = $data[‘encryptedData‘];
        $iv = $data[‘iv‘];
        $signature = $data[‘signature‘];
        $rawData = $data[‘rawData‘];

        // 拼接url
        $url = "https://api.weixin.qq.com/sns/jscode2session?" . "appid=" . $appid . "&secret=" . $appsecret . "&js_code=" . $code . "&grant_type=" . $grant_type;
        $res = json_decode(curl_get($url), true);
        $sessionKey = $res[‘session_key‘]; //取出json里对应的值
        $signature2 = sha1(htmlspecialchars_decode($rawData) . $sessionKey);
        // 验证签名
        if ($signature2 !== $signature) {
            return json([‘status‘=>201,‘msg‘=>"验签失败"]);
        }

        // 获取解密后的数据
        $pc = new Decrypt($appid, $sessionKey);
        $errCode = $pc->decryptData($encryptedData, $iv, $date);
    }