Web API 2 c# 中的 Google reCaptcha

Question

我有一个 ASP.NET Web API 2 项目。我正在尝试从表单中读取 Google Captcha。 我试过这个代码：

    public string Post(FoundingRequest model)
    {
        var response = Request["g-recaptcha-response"];
        string secretKey = "my key";
        var client = new WebClient();
        var result = client.DownloadString(
        $"https://www.google.com/recaptcha/api/siteverify?secret={secretKey}&response={response}");
        var obj = JObject.Parse(result);
        model.Captcha = (bool)obj.SelectToken("success");
        ....
    }

但我在第一行收到一个错误：

无法将 [] 索引应用于类型表达式 'HttpRequestMessage'

为什么？以及如何解决？谢谢

Answer 1

该方法的主体对我来说效果很好：

 const string secretKey = "YOUR KEY";
            string responseFromServer = "";

            HttpWebRequest req = (HttpWebRequest)WebRequest.Create("https://www.google.com/recaptcha/api/siteverify?secret=" + secretKey + "&response=" + response);

            using (WebResponse resp = req.GetResponse())
            using (Stream dataStream = resp.GetResponseStream())
            {
                if (dataStream != null)
                {
                    using (StreamReader reader = new StreamReader(dataStream))
                    {
                        // Read the content.
                        responseFromServer = reader.ReadToEnd();
                    }
                }
            }

            dynamic jsonResponse = new JavaScriptSerializer().DeserializeObject(responseFromServer);

            return jsonResponse == null || bool.Parse(jsonResponse["success"].ToString());

更新

关于评论，可以在客户端查看

var response = window.grecaptcha.getResponse()

然后将这个变量传递给Web API

这是我的客户端脚本的一部分：

      if (typeof window.grecaptcha != 'undefined') {
        var capResponse = window.grecaptcha.getResponse();

        if (!capResponse || capResponse.length === 0) {
            user.isCaptchaPassed = false;
            //alert("Captcha not Passed");
            return false;
        }

        user.gReCaptcha = capResponse;
    }

“user”是之前创建的JS对象，通过JS传递给服务器。 （AJAX 调用）

Answer 2

这就是我的做法。我不使用挑战，所以我没有打扰 试图弄清楚为什么它没有正确转换为 DateTime 。 也许其他人已经解决了这个问题。

   public class ReCaptchaResponse
        {
            public bool Success;
            public string ChallengeTs;
            public string Hostname;
            public object[] ErrorCodes;
        }

        [HttpPost]
        [Route("captcha")]
        public bool Captcha([FromBody] string token)
        {
            bool isHuman = true;

            try
            {
                string secretKey = ConfigurationManager.AppSettings["reCaptchaPrivateKey"];
                Uri uri = new Uri("https://www.google.com/recaptcha/api/siteverify" +
                                  $"?secret={secretKey}&response={token}");
                HttpWebRequest request = WebRequest.CreateHttp(uri);
                request.Method = "POST";
                request.ContentType = "application/x-www-form-urlencoded";
                request.ContentLength = 0;
                HttpWebResponse response = (HttpWebResponse) request.GetResponse();
                Stream responseStream = response.GetResponseStream();
                StreamReader streamReader = new StreamReader(responseStream);
                string result = streamReader.ReadToEnd();
                ReCaptchaResponse reCaptchaResponse = JsonConvert.DeserializeObject<ReCaptchaResponse>(result);
                isHuman = reCaptchaResponse.Success;
            }
            catch (Exception ex)
            {
                Trace.WriteLine("reCaptcha error: " + ex);
            }

            return isHuman;
        }

Answer 3

我找到了答案，我创建了一个具有特定名称的隐藏输入，并在 Captcha 回调中更新了它的值。代码：

   <input type="hidden" value="" id="recaptcha" name="recaptcha" />
   <div class="g-recaptcha" data-callback="imNotARobot" data-sitekey="key"></div>

而 Javascript 是：

<script type="text/javascript">
    var imNotARobot = function () {
       $("#recaptcha").val(grecaptcha.getResponse());
    };
</script>

服务器端：

public string Recaptcha { get; set; }

模型绑定器完成所有工作。

Answer 4

我假设这个请求来自一个表单，更改这个：

var response = Request["g-recaptcha-response"];

至此：

var response = Request.Form["g-Recaptcha-Response"];

也改变这个：

var result = client.DownloadString($"https://www.google.com/recaptcha/api/siteverify?secret={secretKey}&response={response}");

至此：

var result = client.DownloadString(string.Format("https://www.google.com/recaptcha/api/siteverify?secret={0}&response={1}", secretKey, response));