如何为ASP.NET MVC实现reCaptcha？[关闭]

Answers:

82

有几个很好的例子：

在此堆栈溢出问题中也已对此进行了介绍。

适用于MVC 4和5的NuGet Google reCAPTCHA V2

— 乔治·斯托克
source
感谢您的快速回复。我有一个问题，谁创造的Recaptcha.dll？Google小组？
— xport 2011年
4
我相信ReCaptcha由卡内基梅隆大学的教授创建。
— 乔治·斯托克
1
第三个（dotnetcurry.com/ShowArticle.aspx?ID=611）对我来说很棒。
— 2012年
我正在使用Dirik Whittaker的代码。引用了Microsoft.Web.Helpers，但是我在此行上得到了一个命名空间名称“ Recaptcha”，未发现错误：var captchaValidtor = new Recaptcha.RecaptchaValidator
— M3NTA7 2014年
@ M3NTA7您可能想提出一个比此评论更深入的问题。
— 乔治·斯托克2014年
32

我已将reCaptcha添加到我目前正在从事的项目中。我需要它来使用AJAX API，因为reCaptcha元素已动态加载到页面中。我找不到任何现有控件，并且该API很简单，所以我创建了自己的控件。

如果有人觉得有用，我将在此处发布我的代码。

1：将脚本标签添加到母版页眉

<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：创建动作属性和HTML Helper扩展

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中

[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，即使帖子有效且表单的另一部分无效，您也需要在每次发布后重新加载验证码。使用Recaptcha.reload();

— 鹊
source
5次登录失败后，是否可以使用此代码仅注释ReCaptcha？
— 罗布2014年
2
如果您要实施此解决方案，请考虑到新的API网址为：google.com/recaptcha/api/siteverify（源）
— Axel Prieto
13

简单而完整的解决方案为我工作。支持ASP.NET MVC 4和5（支持ASP.NET 4.0、4.5和4.5.1）

步骤1：通过“ Install-Package reCAPTCH.MVC ”安装NuGet软件包

步骤2：将您的公钥和私钥添加到appsettings部分中的web.config文件中

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

您可以在https://www.google.com/recaptcha/intro/index.html 上为您的网站创建一个API密钥对，然后单击页面顶部的Get reCAPTCHA。

步骤3：修改您的表单以包括reCaptcha

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

步骤4：实施Controller Action，以处理表单提交和验证码验证

[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
    {
    }
}

要么

public ActionResult MyAction(myVM model, bool captchaValid)
{
    if (captchaValid) //manually check for captchaValid 
    {
    }
}
— 门司
source
遗憾的是，由于，无法在同一页面中以两种不同的形式使用它Uncaught Error: ReCAPTCHA placeholder element must be empty。
— Alisson
1
由于reCaptcha使用web.config作为密钥，因此不需要提供PrivateKey = "your private reCaptcha Google Key"。这是当你有不同的环境不同的键更加容易
— 红
13

MVC 5的异步版本（即避免使用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>
— 布伦特
source
这对我有用！... MVC v5，recaptcha
— v2〜
8

步骤1：客户网站整合

将此代码段粘贴到</head>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<form>到要显示reCAPTCHA小部件的末尾：

<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reCAPTCHA的表单时，您将获得一个名为“ g-recaptcha-response”的字符串作为有效载荷的一部分。为了检查Google是否已验证该用户，请发送带有以下参数的POST请求：

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

秘密：您的秘密密钥

response：“ g-验证码-响应”的值。

现在可以在您的MVC应用中使用：

// 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 :)
    }
— Thinh Vu
source
6

我已经通过以下方式成功实现了ReCaptcha。
注意：这在VB中，但是可以轻松转换

1]首先获取reCaptcha库的副本

2]然后建立一个自定义的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]从这里需要一个可重复使用的服务器端验证器

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

此行上方是可重复使用的**一次**代码

在此行之下，一遍又一遍地实施reCaptcha是多么容易

现在您已经拥有了可重用的代码...您要做的就是将验证码添加到您的视图中。

<%: Html.reCaptcha %>

当您将表单发布到您的控制器时...

    ''# 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
— 大通弗洛雷尔
source
注意：这是在VB中，但可以轻松转换为C＃
— Chase Florell 2011年
1
非常感谢您阐述解决方案。这是非常详细的答案。我喜欢它。
— xport 2011年
1
根据Joel的最新博客，StackOverflow的创建者希望这是一个Wiki Repository，而不仅仅是将用户重定向到其他站点。现在，将您发送到网站可能会回答您的问题，但是当明年该外部页面出现故障时，无法解决其他人的问题。在此处发布正确答案也将对将来的求职者有所帮助。我相信这是回答问题的正确方法。
— Chase Florell 2011年
看起来几乎类似于devlicio.us/blogs/derik_whittaker/archive/2008/12/02/...除了语言方面的区别..
— 的Gmail用户
2

扩展Magpie的答案，这是我在项目中使用的动作过滤器的代码。

它可以与ASP Core RC2一起使用！

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

[ReCaptcha]
    public IActionResult Authenticate()
    {

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