如何为 ASP.NET MVC 实现 reCaptcha？

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Answer 1

有一些很好的例子：

• MVC reCaptcha - 使 reCaptcha 更加 MVC 风格。
• ASP.NET MVC 3 中的 ReCaptcha Webhelper
• ASP.NET 的 ReCaptcha 控件来自 Google 代码的 MVC。

之前这个 Stack Overflow 问题也对此进行了介绍。

适用于 MVC 4 和 5 的 NuGet Google reCAPTCHA V2

• NuGet 包
• 演示和文档

Answer 2

我已将 reCaptcha 添加到我当前正在进行的项目中。我需要它来使用 AJAX API，因为 reCaptcha 元素会动态加载到页面中。我找不到任何现有的控件，而且 API 很简单，所以我创建了自己的控件。

我将在这里发布我的代码，以防有人发现它有用。

1：将脚本标记添加到母版页标题

<script type="text/javascript" src="http://www.google.com/recaptcha/api/js/recaptcha_ajax.js"></script>

2：将密钥添加到 web.config

<appSettings>
    <add key="ReCaptcha.PrivateKey" value="[key here]" />
    <add key="ReCaptcha.PublicKey" value="[key here]" />
</appSettings>

3：创建操作属性和 Html Helper 扩展 strong>

namespace [Your chosen namespace].ReCaptcha
{
    public enum Theme { Red, White, BlackGlass, Clean }

    [Serializable]
    public class InvalidKeyException : ApplicationException
    {
        public InvalidKeyException() { }
        public InvalidKeyException(string message) : base(message) { }
        public InvalidKeyException(string message, Exception inner) : base(message, inner) { }
    }

    public class ReCaptchaAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            var userIP = filterContext.RequestContext.HttpContext.Request.UserHostAddress;

            var privateKey = ConfigurationManager.AppSettings.GetString("ReCaptcha.PrivateKey", "");

            if (string.IsNullOrWhiteSpace(privateKey))
                throw new InvalidKeyException("ReCaptcha.PrivateKey missing from appSettings");

            var postData = string.Format("&privatekey={0}&remoteip={1}&challenge={2}&response={3}",
                                         privateKey,
                                         userIP,
                                         filterContext.RequestContext.HttpContext.Request.Form["recaptcha_challenge_field"],
                                         filterContext.RequestContext.HttpContext.Request.Form["recaptcha_response_field"]);

            var postDataAsBytes = Encoding.UTF8.GetBytes(postData);

            // Create web request
            var request = WebRequest.Create("http://www.google.com/recaptcha/api/verify");
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = postDataAsBytes.Length;
            var dataStream = request.GetRequestStream();
            dataStream.Write(postDataAsBytes, 0, postDataAsBytes.Length);
            dataStream.Close();

            // Get the response.
            var response = request.GetResponse();

            using (dataStream = response.GetResponseStream())
            {
                using (var reader = new StreamReader(dataStream))
                {
                    var responseFromServer = reader.ReadToEnd();

                    if (!responseFromServer.StartsWith("true"))
                        ((Controller)filterContext.Controller).ModelState.AddModelError("ReCaptcha", "Captcha words typed incorrectly");
                }
            }
        }
    }

    public static class HtmlHelperExtensions
    {
        public static MvcHtmlString GenerateCaptcha(this HtmlHelper helper, Theme theme, string callBack = null)
        {
            const string htmlInjectString = @"<div id=""recaptcha_div""></div>
<script type=""text/javascript"">
    Recaptcha.create(""{0}"", ""recaptcha_div"", {{ theme: ""{1}"" {2}}});
</script>";

            var publicKey = ConfigurationManager.AppSettings.GetString("ReCaptcha.PublicKey", "");

            if (string.IsNullOrWhiteSpace(publicKey))
                throw new InvalidKeyException("ReCaptcha.PublicKey missing from appSettings");

            if (!string.IsNullOrWhiteSpace(callBack))
                callBack = string.Concat(", callback: ", callBack);

            var html = string.Format(htmlInjectString, publicKey, theme.ToString().ToLower(), callBack);
            return MvcHtmlString.Create(html);
        }
    }
}

4：将验证码添加到您的视图

@using (Html.BeginForm("MyAction", "MyController"))
{
   @Html.TextBox("EmailAddress", Model.EmailAddress)
   @Html.GenerateCaptcha(Theme.White)
   <input type="submit" value="Submit" />
}

5：将属性添加到您的操作

[HttpPost]
[ReCaptcha]
public ActionResult MyAction(MyModel model)
{
   if (!ModelState.IsValid) // Will have a Model Error "ReCaptcha" if the user input is incorrect
      return Json(new { capthcaInvalid = true });

   ... other stuff ...
}

6：请注意，您需要在每次发布后重新加载验证码，即使它是有效的，而表格的另一部分是无效的。使用Recaptcha.reload();

Answer 3

简单而完整的解决方案对我有用。
支持 ASP.NET MVC 4 和 5（支持 ASP.NET 4.0、4.5 和 4.5.1）

第 1 步：通过“Install-Package reCAPTCH.MVC”安装 NuGet 包“

步骤2：在AppSettings部分中将您的公共和私钥添加到Web.config文件中

<appSettings>
    <add key="ReCaptchaPrivateKey" value=" -- PRIVATE_KEY -- " />
    <add key="ReCaptchaPublicKey" value=" -- PUBLIC KEY -- " />
</appSettings>  

。 com/recaptcha/intro/index.html" rel="noreferrer">https://www.google.com/recaptcha/intro/index.html
然后单击页面顶部的“获取 reCAPTCHA”

第 3 步：修改表单以包含 reCaptcha

@using reCAPTCHA.MVC
@using (Html.BeginForm())
{
    @Html.Recaptcha()
    @Html.ValidationMessage("ReCaptcha")
    <input type="submit" value="Register" />
}

第 4 步：实施将处理表单提交和验证码验证的控制器操作

[CaptchaValidator(
PrivateKey = "your private reCaptcha Google Key",
ErrorMessage = "Invalid input captcha.",
RequiredMessage = "The captcha field is required.")]
public ActionResult MyAction(myVM model)
{
    if (ModelState.IsValid) //this will take care of captcha
    {
    }
}

，或者

public ActionResult MyAction(myVM model, bool captchaValid)
{
    if (captchaValid) //manually check for captchaValid 
    {
    }
}

Answer 4

MVC 5 的异步版本（即避免 ActionFilterAttribute，直到 MVC 6 才异步）和 reCAPTCHA 2

ExampleController.cs

public class HomeController : Controller
{
    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> ContactSubmit(
        [Bind(Include = "FromName, FromEmail, FromPhone, Message, ContactId")]
        ContactViewModel model)
    {
        if (!await RecaptchaServices.Validate(Request))
        {
            ModelState.AddModelError(string.Empty, "You have not confirmed that you are not a robot");
        }
        if (ModelState.IsValid)
        {
           ...

ExampleView.cshtml

@model MyMvcApp.Models.ContactViewModel

@*This is assuming the master layout places the styles section within the head tags*@
@section Styles {
    @Styles.Render("~/Content/ContactPage.css")
    <script src='https://www.google.com/recaptcha/api.js'></script>
}

@using (Html.BeginForm("ContactSubmit", "Home",FormMethod.Post, new { id = "contact-form" }))
{
    @Html.AntiForgeryToken()
    ...
    <div class="form-group">
      @Html.LabelFor(m => m.Message) 
      @Html.TextAreaFor(m => m.Message, new { @class = "form-control", @cols = "40", @rows = "3" })
      @Html.ValidationMessageFor(m => m.Message)
    </div>

    <div class="row">
      <div class="g-recaptcha" data-sitekey='@System.Configuration.ConfigurationManager.AppSettings["RecaptchaClientKey"]'></div>
    </div>

    <div class="row">
      <input type="submit" id="submit-button" class="btn btn-default" value="Send Your Message" />
    </div>
}

RecaptchaServices.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using System.Web;
using System.Configuration;
using System.Net.Http;
using System.Net.Http.Headers;
using Newtonsoft.Json;
using System.Runtime.Serialization;

namespace MyMvcApp.Services
{
    public class RecaptchaServices
    {
        //ActionFilterAttribute has no async for MVC 5 therefore not using as an actionfilter attribute - needs revisiting in MVC 6
        internal static async Task<bool> Validate(HttpRequestBase request)
        {
            string recaptchaResponse = request.Form["g-recaptcha-response"];
            if (string.IsNullOrEmpty(recaptchaResponse))
            {
                return false;
            }
            using (var client = new HttpClient { BaseAddress = new Uri("https://www.google.com") })
            {
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                var content = new FormUrlEncodedContent(new[]
                {
                    new KeyValuePair<string, string>("secret", ConfigurationManager.AppSettings["RecaptchaSecret"]),
                    new KeyValuePair<string, string>("response", recaptchaResponse),
                    new KeyValuePair<string, string>("remoteip", request.UserHostAddress)
                });
                var result = await client.PostAsync("/recaptcha/api/siteverify", content);
                result.EnsureSuccessStatusCode();
                string jsonString = await result.Content.ReadAsStringAsync();
                var response = JsonConvert.DeserializeObject<RecaptchaResponse>(jsonString);
                return response.Success;
            }
        }

        [DataContract]
        internal class RecaptchaResponse
        {
            [DataMember(Name = "success")]
            public bool Success { get; set; }
            [DataMember(Name = "challenge_ts")]
            public DateTime ChallengeTimeStamp { get; set; }
            [DataMember(Name = "hostname")]
            public string Hostname { get; set; }
            [DataMember(Name = "error-codes")]
            public IEnumerable<string> ErrorCodes { get; set; }
        }

    }
}

web.config

<configuration>
  <appSettings>
    <!--recaptcha-->
    <add key="RecaptchaSecret" value="***secret key from https://developers.google.com/recaptcha***" />
    <add key="RecaptchaClientKey" value="***client key from https://developers.google.com/recaptcha***" />
  </appSettings>
</configuration>

Answer 5

第 1 步：客户端站点集成

将此代码段粘贴到 HTML 模板上的 结束标记之前：

<script src='https://www.google.com/recaptcha/api.js'></script>

将此代码段粘贴到

的末尾，其中您希望显示 reCAPTCHA 小部件：

<div class="g-recaptcha" data-sitekey="your-site-key"></div>

步骤 2：服务器站点集成

当您的用户提交集成了 reCAPTCHA 的表单时，您将获得一个名为“g-recaptcha-response”的字符串作为负载的一部分。要检查 Google 是否已验证该用户，请发送包含以下参数的 POST 请求：

URL : https: //www.google.com/recaptcha/api/siteverify

秘密：您的密钥

响应：“g-recaptcha-response”的值。

现在您的 MVC 应用程序正在运行：

// return ActionResult if you want
    public string RecaptchaWork()
    {
        // Get recaptcha value
        var r = Request.Params["g-recaptcha-response"];
        // ... validate null or empty value if you want
        // then
        // make a request to recaptcha api
        using (var wc = new WebClient())
        {
            var validateString = string.Format(
                "https://www.google.com/recaptcha/api/siteverify?secret={0}&response={1}",
               "your_secret_key",    // secret recaptcha key
               r); // recaptcha value
             // Get result of recaptcha
            var recaptcha_result = wc.DownloadString(validateString);
            // Just check if request make by user or bot
            if (recaptcha_result.ToLower().Contains("false"))
            {
                 return "recaptcha false";
            }
        }
        // Do your work if request send from human :)
    }

Answer 6

我已经通过以下方式成功实现了 ReCaptcha。
注意：这是用 VB 编写的，但可以轻松转换

1] 首先获取 reCaptcha 库

2] 然后构建自定义 ReCaptcha HTML Helper

    ''# fix SO code coloring issue.
    <Extension()>
    Public Function reCaptcha(ByVal htmlHelper As HtmlHelper) As MvcHtmlString
        Dim captchaControl = New Recaptcha.RecaptchaControl With {.ID = "recaptcha",
                                                                  .Theme = "clean",
                                                                  .PublicKey = "XXXXXX",
                                                                  .PrivateKey = "XXXXXX"}
        Dim htmlWriter = New HtmlTextWriter(New IO.StringWriter)
        captchaControl.RenderControl(htmlWriter)
        Return MvcHtmlString.Create(htmlWriter.InnerWriter.ToString)
    End Function

3] 从这里您需要一个可重复使用的服务器 此行上方的侧面验证器

Public Class ValidateCaptchaAttribute : Inherits ActionFilterAttribute
    Private Const CHALLENGE_FIELD_KEY As String = "recaptcha_challenge_field"
    Private Const RESPONSE_FIELD_KEY As String = "recaptcha_response_field"

    Public Overrides Sub OnActionExecuting(ByVal filterContext As ActionExecutingContext)

        If IsNothing(filterContext.HttpContext.Request.Form(CHALLENGE_FIELD_KEY)) Then
            ''# this will push the result value into a parameter in our Action
            filterContext.ActionParameters("CaptchaIsValid") = True
            Return
        End If

        Dim captchaChallengeValue = filterContext.HttpContext.Request.Form(CHALLENGE_FIELD_KEY)
        Dim captchaResponseValue = filterContext.HttpContext.Request.Form(RESPONSE_FIELD_KEY)

        Dim captchaValidtor = New RecaptchaValidator() With {.PrivateKey = "xxxxx",
                                                                       .RemoteIP = filterContext.HttpContext.Request.UserHostAddress,
                                                                       .Challenge = captchaChallengeValue,
                                                                       .Response = captchaResponseValue}

        Dim recaptchaResponse = captchaValidtor.Validate()

        ''# this will push the result value into a parameter in our Action
        filterContext.ActionParameters("CaptchaIsValid") = recaptchaResponse.IsValid

        MyBase.OnActionExecuting(filterContext)
    End Sub

是可重用的 **一次**

---

此行下方的代码是一遍又一遍地实现 reCaptcha 是多么容易

现在您已经有了可重用的代码...您需要做的就是将验证码添加到你的观点。

<%: Html.reCaptcha %>

当您将表单发布到控制器时......

    ''# Fix SO code coloring issues
    <ValidateCaptcha()>
    <AcceptVerbs(HttpVerbs.Post)>
    Function Add(ByVal CaptchaIsValid As Boolean, ByVal [event] As Domain.Event) As ActionResult


        If Not CaptchaIsValid Then ModelState.AddModelError("recaptcha", "*")


        '#' Validate the ModelState and submit the data.
        If ModelState.IsValid Then
            ''# Post the form
        Else
            ''# Return View([event])
        End If
    End Function

Answer 7

扩展 Magpie 的答案，这里是我在项目中使用的动作过滤器的代码。

它适用于 ASP Core RC2！

public class ReCaptchaAttribute : ActionFilterAttribute
{
    private readonly string CAPTCHA_URL = "https://www.google.com/recaptcha/api/siteverify";
    private readonly string SECRET = "your_secret";

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        try
        {
            // Get recaptcha value
            var captchaResponse = filterContext.HttpContext.Request.Form["g-recaptcha-response"];

            using (var client = new HttpClient())
            {
                var values = new Dictionary<string, string>
                {
                    { "secret", SECRET },
                    { "response", captchaResponse },
                    { "remoteip", filterContext.HttpContext.Request.HttpContext.Connection.RemoteIpAddress.ToString() }
                };


                var content = new FormUrlEncodedContent(values);

                var result = client.PostAsync(CAPTCHA_URL, content).Result;

                if (result.IsSuccessStatusCode)
                {
                    string responseString = result.Content.ReadAsStringAsync().Result;

                    var captchaResult = JsonConvert.DeserializeObject<CaptchaResponseViewModel>(responseString);

                    if (!captchaResult.Success)
                    {
                        ((Controller)filterContext.Controller).ModelState.AddModelError("ReCaptcha", "Captcha not solved");
                    }
                } else
                {
                    ((Controller)filterContext.Controller).ModelState.AddModelError("ReCaptcha", "Captcha error");
                }
            }

        }
        catch (System.Exception)
        {
            ((Controller)filterContext.Controller).ModelState.AddModelError("ReCaptcha", "Unknown error");
        }
    }
}

并在您的代码中使用它，例如

[ReCaptcha]
    public IActionResult Authenticate()
    {

        if (!ModelState.IsValid)
        {
            return View(
                "Login",
                new ReturnUrlViewModel
                {
                    ReturnUrl = Request.Query["returnurl"],
                    IsError = true,
                    Error = "Wrong reCAPTCHA"
                }
            );
        }

Answer 8

对于其他人来说，这里有一组不错的步骤。 http://forums.asp.net/t/1678976.aspx/1

不要忘记像我一样在 OnActionExecuting() 中手动添加密钥。