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；

启用一个web会话

发送模拟数据请求（POST或者GET）

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();