浮雲雅築: [研究] [ASP.NET WebForm C#] Google reCAPTCHA 試用

2016年5月25日星期三

[研究] [ASP.NET WebForm C#] Google reCAPTCHA 試用

[研究] [ASP.NET WebForm C#] Google reCAPTCHA 試用

2016-05-25

Google reCAPTCHA
https://www.google.com/recaptcha/intro/index.html

替你的網址 (例如 : forum.shaurong.idv.tw ) 註冊一個 reCAPTCHA 使用
https://www.google.com/recaptcha/admin#list

為了在本機測試，我用 localhost 去申請，沒想到過了 (其實並不合適)

在 .aspx 檔案中 (ex : :Login.aspx )

在 <head> 和 </head> 之間，</head> 之前插入

繁體中文用戶，可考慮改用

在 <form> 和 </form> 之間，</form> 之前插入

這邊有些官方資訊可以參考
https://developers.google.com/recaptcha/docs/display#auto_render
https://developers.google.com/recaptcha/docs/verify#api-request

但是 Server端的驗證，官方的資訊看的有點頭大，所以另外找參考資料

How to Validate Recaptcha V2 Server side
http://www.codeproject.com/Tips/851004/How-to-Validate-Recaptcha-V-Server-side

在 Visual Studio 2015 測試成功
Default.aspx 內容如下

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebApplication2.Default" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title></title>
<script type="text/javascript" src='https://www.google.com/recaptcha/api.js'></script>
</head>
<body>
<form id="form1" runat="server">
<div>
<div class="g-recaptcha" data-sitekey="換上你的 Site Key "></div>
</div>
<asp:Button ID="btnLogin" runat="server" Text="Check Recaptcha" OnClick="btnLogin_Click" TabIndex ="4"/>
</form>
<asp:Label ID="lblmsg" runat="server" Text="Label"></asp:Label>
</body>
</html>

在 <form> 和 </form> 之間，</form> 之前插入

using System;
using System.IO;
using System.Net;
using System.Web.Script.Serialization;

namespace WebApplication2
{
public class MyObject
{
public string success { get; set; }
}
public partial class Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}

protected void btnLogin_Click(object sender, EventArgs e)
{
if (Validate())
{
lblmsg.Text = "Valid Recaptcha";
lblmsg.ForeColor = System.Drawing.Color.Green;
}

else
{
lblmsg.Text = "Not Valid Recaptcha";
lblmsg.ForeColor = System.Drawing.Color.Red;
}
}
public bool Validate()
{
string Response = Request["g-recaptcha-response"];//Getting Response String Append to Post Method
bool Valid = false;
//Request to Google Server
HttpWebRequest req = (HttpWebRequest)WebRequest.Create
(" https://www.google.com/recaptcha/api/siteverify?secret=換上你的 Secret Key&response=" + Response);
try
{
//Google recaptcha Response
using (WebResponse wResponse = req.GetResponse())
{

using (StreamReader readStream = new StreamReader(wResponse.GetResponseStream()))
{
string jsonResponse = readStream.ReadToEnd();

JavaScriptSerializer js = new JavaScriptSerializer();
MyObject data = js.Deserialize<MyObject>(jsonResponse);// Deserialize Json

Valid = Convert.ToBoolean(data.success);
}
}

return Valid;
}
catch (WebException ex)
{
throw ex;
}
}
}
}

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