reCAPTCHA v3

 

reCAPTCHA 已經進化到第三版了，個人覺得其驗證流程應該算更精簡了吧？

reCAPTCHA v3 部份內容是從 reCAPTCHA v2 繼承過來的，

在後端驗證還需要參考 reCAPTCHA v2 文件。

reCAPTCHA v3 主要特色是多了評分功能，

範圍從 1.0(看起來是真人) ~ 0.0(看起來像是機器人) 分，

後端程式可以去取得該評分，可以根據自身需求，

評分在多少分以上才被視為真人能通過程式。

 

範例如下

Model 為

ReCAPTCHA_V2_Response.cs

using Newtonsoft.Json;
using System;

namespace WebApplication1.Models
{
    public class ReCAPTCHA_V2_Response
    {
        public bool success { set; get; }
        public DateTime challenge_ts { set; get; }
        public string hostname { set; get; }
        [JsonProperty("error-codes")]
        public string[] errorCodes { get; set; }

        public string ErrorCodesToString()
        {
            string result = "";

            foreach (string item in errorCodes)
            {
                result = result + " " + item;
            }
            return result;
        }
    }
}

 

ReCAPTCHA_V3_Response.cs

namespace WebApplication1.Models
{
    public class ReCAPTCHA_V3_Response :ReCAPTCHA_V2_Response
    {
        public float score { set; get; }
        public string action { set; get; }
    }
}

 

Controller 為

HomeController.cs

using Newtonsoft.Json;
using System;
using System.IO;
using System.Net;
using System.Web.Mvc;
using WebApplication1.Models;

namespace WebApplication1.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            return View();
        }

        public ActionResult About()
        {
            ViewBag.Message = "Your application description page.";

            return View();
        }

        public ActionResult Contact()
        {
            ViewBag.Message = "Your contact page.";

            return View();
        }

        [HttpPost]
        public ActionResult VerifyBot(string token)
        {
            try
            {
                string secret = "your_secret_key";
                string g_recaptcha_response = token;
                WebRequest WebRequest = WebRequest.Create("https://www.google.com/recaptcha/api/siteverify?secret=" + secret + "&response=" + g_recaptcha_response);
                WebResponse WebResponse = WebRequest.GetResponse();
                StreamReader sr = new StreamReader(WebResponse.GetResponseStream());
                String apiResponse = sr.ReadToEnd();
                sr.Close();
                ReCAPTCHA_V3_Response ReCAPTCHA_V3_Response = JsonConvert.DeserializeObject<ReCAPTCHA_V3_Response>(apiResponse);

                if (ReCAPTCHA_V3_Response.success == true  && ReCAPTCHA_V3_Response.score >= 0.5)
                {
                    return Content(apiResponse);
                }
                else
                {
                    return Content(ReCAPTCHA_V3_Response.ErrorCodesToString());
                }
            }
            catch (Exception ex)
            {
                //ViewBag.Success = ex.ToString();
                return View();
            }
        }

    }
}

 

View 為

Index.cshtml

@{
    ViewBag.Title = "Home Page";
}

<form id="myform" action="@Url.Action("")" method="post">
    <input id="submit" type="submit" name="name" value="submit" />
</form>

<script src='https://www.google.com/recaptcha/api.js?render=reCAPTCHA_site_key'></script>
<script>
    grecaptcha.ready(function () {
        grecaptcha.execute('reCAPTCHA_site_key', { action: 'homepage' })
            .then(function (token) {
                // Verify the token on the server.
                document.getElementById("myform").addEventListener("submit", function () {
                    $.ajax({
                        type: 'POST',
                        url: '@Url.Action("VerifyBot", "Home")',
                        data: { token: token },
                        success: (res) => {
                            console.log('result => ', res);
                        }
                    });
                    event.preventDefault();
                });
            });
    });
</script>

 

參考資料：

reCAPTCHA admin console

reCAPTCHA v3