通用輔助類
下面是我編寫的一個輔助類,在這個類中採用了HttpWebRequest中發送GET/HTTP/HTTPS請求,因爲有的時候需要獲取認證信息(如Cookie),所以返回的是HttpWebResponse對象,有了返回的HttpWebResponse實例,可以獲取登錄過程中返回的會話信息,也可以獲取響應流。
代碼如下:
<span style="font-family:SimSun;font-size:14px;">using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.DirectoryServices.Protocols;
using System.ServiceModel.Security;
using System.Net;
using System.IO;
using System.IO.Compression;
using System.Text.RegularExpressions;
/*
* 作者:周公(zhoufoxcn)
* 日期:2011-05-08
* 原文出處:http://blog.csdn.net/zhoufoxcn 或http://zhoufoxcn.blog.51cto.com
* 版權說明:本文可以在保留原文出處的情況下使用於非商業用途,周公對此不作任何擔保或承諾。
* */
namespace BaiduCang
{
/// <summary>
/// 有關HTTP請求的輔助類
/// </summary>
public class HttpWebResponseUtility
{
private static readonly string DefaultUserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
/// <summary>
/// 創建GET方式的HTTP請求
/// </summary>
/// <param name="url">請求的URL</param>
/// <param name="timeout">請求的超時時間</param>
/// <param name="userAgent">請求的客戶端瀏覽器信息,可以爲空</param>
/// <param name="cookies">隨同HTTP請求發送的Cookie信息,如果不需要身份驗證可以爲空</param>
/// <returns></returns>
public static HttpWebResponse CreateGetHttpResponse(string url,int? timeout, string userAgent,CookieCollection cookies)
{
if (string.IsNullOrEmpty(url))
{
throw new ArgumentNullException("url");
}
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
request.Method = "GET";
request.UserAgent = DefaultUserAgent;
if (!string.IsNullOrEmpty(userAgent))
{
request.UserAgent = userAgent;
}
if (timeout.HasValue)
{
request.Timeout = timeout.Value;
}
if (cookies != null)
{
request.CookieContainer = new CookieContainer();
request.CookieContainer.Add(cookies);
}
return request.GetResponse() as HttpWebResponse;
}
/// <summary>
/// 創建POST方式的HTTP請求
/// </summary>
/// <param name="url">請求的URL</param>
/// <param name="parameters">隨同請求POST的參數名稱及參數值字典</param>
/// <param name="timeout">請求的超時時間</param>
/// <param name="userAgent">請求的客戶端瀏覽器信息,可以爲空</param>
/// <param name="requestEncoding">發送HTTP請求時所用的編碼</param>
/// <param name="cookies">隨同HTTP請求發送的Cookie信息,如果不需要身份驗證可以爲空</param>
/// <returns></returns>
public static HttpWebResponse CreatePostHttpResponse(string url,IDictionary<string,string> parameters,int? timeout, string userAgent,Encoding requestEncoding,CookieCollection cookies)
{
if (string.IsNullOrEmpty(url))
{
throw new ArgumentNullException("url");
}
if(requestEncoding==null)
{
throw new ArgumentNullException("requestEncoding");
}
HttpWebRequest request=null;
//如果是發送HTTPS請求
if(url.StartsWith("https",StringComparison.OrdinalIgnoreCase))
{
ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
request = WebRequest.Create(url) as HttpWebRequest;
request.ProtocolVersion=HttpVersion.Version10;
}
else
{
request = WebRequest.Create(url) as HttpWebRequest;
}
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
if (!string.IsNullOrEmpty(userAgent))
{
request.UserAgent = userAgent;
}
else
{
request.UserAgent = DefaultUserAgent;
}
if (timeout.HasValue)
{
request.Timeout = timeout.Value;
}
if (cookies != null)
{
request.CookieContainer = new CookieContainer();
request.CookieContainer.Add(cookies);
}
//如果需要POST數據
if(!(parameters==null||parameters.Count==0))
{
StringBuilder buffer = new StringBuilder();
int i = 0;
foreach (string key in parameters.Keys)
{
if (i > 0)
{
buffer.AppendFormat("&{0}={1}", key, parameters[key]);
}
else
{
buffer.AppendFormat("{0}={1}", key, parameters[key]);
}
i++;
}
byte[] data = requestEncoding.GetBytes(buffer.ToString());
using (Stream stream = request.GetRequestStream())
{
stream.Write(data, 0, data.Length);
}
}
return request.GetResponse() as HttpWebResponse;
}
private static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
{
return true; //總是接受
}
}
}
從上面的代碼中可以看出POST數據到HTTP和HTTPS站點不同,POST數據到HTTPS站點的時候需要設置ServicePointManager類的ServerCertificateValidationCallback屬性,並且在POST到https://passport.baidu.com/?login時還需要將HttpWebResquest實例的ProtocolVersion屬性設置爲HttpVersion.Version10(這個未驗證是否所有的HTTPS站點都需要設置),否則在調用GetResponse()方法時會拋出“基礎連接已經關閉: 連接被意外關閉。”的異常。
用法舉例
這個類用起來也很簡單:
(1)POST數據到HTTPS站點,用它來登錄百度:
string loginUrl = "https://passport.baidu.com/?login";
string userName = "userName";
string password = "password";
string tagUrl = "http://cang.baidu.com/"+userName+"/tags";
Encoding encoding = Encoding.GetEncoding("gb2312");
IDictionary<string, string> parameters = new Dictionary<string, string>();
parameters.Add("tpl", "fa");
parameters.Add("tpl_reg", "fa");
parameters.Add("u", tagUrl);
parameters.Add("psp_tt", "0");
parameters.Add("username", userName);
parameters.Add("password", password);
parameters.Add("mem_pass", "1");
HttpWebResponse response = HttpWebResponseUtility.CreatePostHttpResponse(loginUrl, parameters, null, null, encoding, null);
string cookieString = response.Headers["Set-Cookie"]; </span>
(2)發送GET請求到HTTP站點
在cookieString中包含了服務器端返回的會話信息數據,從中提取了之後可以設置Cookie下次登錄時帶上這個Cookie就可以以認證用戶的信息,假設我們已經登錄成功並且獲取了Cookie,那麼發送GET請求的代碼如下:
<span style="font-family:SimSun;font-size:14px;">string userName = "userName";
string tagUrl = "http://cang.baidu.com/"+userName+"/tags";
CookieCollection cookies = new CookieCollection();//如何從response.Headers["Set-Cookie"];中獲取並設置CookieCollection的代碼略
response = HttpWebResponseUtility.CreateGetHttpResponse(tagUrl, null, null, cookies); </span>
(3)發送POST請求到HTTP站點以登錄51CTO爲例:
<span style="font-family:SimSun;font-size:14px;">string loginUrl = "http://home.51cto.com/index.php?s=/Index/doLogin";
string userName = "userName";
string password = "password";
IDictionary<string, string> parameters = new Dictionary<string, string>();
parameters.Add("email", userName);
parameters.Add("passwd", password);
HttpWebResponse response = HttpWebResponseUtility.CreatePostHttpResponse(loginUrl, parameters, null, null, Encoding.UTF8, null); </span>