使用C#的HttpWebRequest模拟登陆网站

很久没有写新的东西了，今天在工作中遇到的一个问题，感觉很有用，有种想记下来的冲动。

这篇文章是有关模拟登录网站方面的。

实现步骤；

1. 启用一个web会话
2. 发送模拟数据请求（POST或者GET）
3. 获取会话的CooKie 并根据该CooKie继续访问登录后的页面，获取后续访问的页面数据。

我们以登录人人网为例，首先需要分析人人网登录时POST的数据格式，这个可以通过IE9中只带的F12快捷键，调出开发人员工具。如下图：

通过开始捕获得到POST的地址和POST的数据

POST数据：

email=aaa@163.com&password=111&icode=&origURL=http%3A%2F%2Fwww.renren.com%2Fhome&domain=renren.com&key_id=1&_rtk=90484476

POST地址：

http://www.renren.com/PLogin.do

下面就是代码示例来得到登录后页面（http://guide.renren.com/guide）的数据

HTMLHelper类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;
using System.Threading;

namespace Test
{
   public class HTMLHelper
    {
       /// <summary>
        /// 获取CooKie
       /// </summary>
       /// <param name="loginUrl"></param>
       /// <param name="postdata"></param>
       /// <param name="header"></param>
       /// <returns></returns>
       public static CookieContainer GetCooKie(string loginUrl, string postdata, HttpHeader header)
       {
           HttpWebRequest request = null;
           HttpWebResponse response = null;
           try
           {
               CookieContainer cc = new CookieContainer();
               request = (HttpWebRequest)WebRequest.Create(loginUrl);
               request.Method = header.method;
               request.ContentType = header.contentType;
               byte[] postdatabyte = Encoding.UTF8.GetBytes(postdata);
               request.ContentLength = postdatabyte.Length;
               request.AllowAutoRedirect = false;
               request.CookieContainer = cc;
               request.KeepAlive = true;

               //提交请求
               Stream stream;
               stream = request.GetRequestStream();
               stream.Write(postdatabyte, 0, postdatabyte.Length);
               stream.Close();

               //接收响应
               response = (HttpWebResponse)request.GetResponse();
               response.Cookies = request.CookieContainer.GetCookies(request.RequestUri);

               CookieCollection cook = response.Cookies;
               //Cookie字符串格式
               string strcrook = request.CookieContainer.GetCookieHeader(request.RequestUri);

               return cc;
           }
           catch (Exception ex)
           {

               throw ex;
           }
       }

       /// <summary>
       /// 获取html
       /// </summary>
       /// <param name="getUrl"></param>
       /// <param name="cookieContainer"></param>
       /// <param name="header"></param>
       /// <returns></returns>
       public static string GetHtml(string getUrl, CookieContainer cookieContainer,HttpHeader header)
       {
           Thread.Sleep(1000);
           HttpWebRequest httpWebRequest = null;
           HttpWebResponse httpWebResponse = null;
           try
           {
               httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(getUrl);
               httpWebRequest.CookieContainer = cookieContainer;
               httpWebRequest.ContentType = header.contentType;
               httpWebRequest.ServicePoint.ConnectionLimit = header.maxTry;
               httpWebRequest.Referer = getUrl;
               httpWebRequest.Accept = header.accept;
               httpWebRequest.UserAgent = header.userAgent;
               httpWebRequest.Method = "GET";
               httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
               Stream responseStream = httpWebResponse.GetResponseStream();
               StreamReader streamReader = new StreamReader(responseStream, Encoding.UTF8);
               string html = streamReader.ReadToEnd();
               streamReader.Close();
               responseStream.Close();
               httpWebRequest.Abort();
               httpWebResponse.Close();
               return html;
           }
           catch (Exception e)
           {
               if (httpWebRequest != null) httpWebRequest.Abort();
               if (httpWebResponse != null) httpWebResponse.Close();
               return string.Empty;
           }
       }
    }

   public class HttpHeader
   {
       public string contentType { get; set; }

       public string accept { get; set; }

       public string userAgent { get; set; }

       public string method{get;set;}

       public int maxTry { get; set; }
   }
}

测试用例：

  HttpHeader header = new HttpHeader();
                header.accept = "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/x-silverlight, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-ms-application, application/x-ms-xbap, application/vnd.ms-xpsdocument, application/xaml+xml, application/x-silverlight-2-b1, */*";
                header.contentType = "application/x-www-form-urlencoded";
                header.method = "POST";
                header.userAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022)";
                header.maxTry = 300;

                string html = HTMLHelper.GetHtml("http://guide.renren.com/guide", HTMLHelper.GetCooKie("http://www.renren.com/PLogin.do",
                    "email=aaa@163.com&password=111&icode=&origURL=http%3A%2F%2Fwww.renren.com%2Fhome&domain=renren.com&key_id=1&_rtk=90484476", header), header);

                Console.WriteLine(html);

               Console.ReadLine();