//通用辅助类
//下面是我编写的一个辅助类,在这个类中采用了HttpWebRequest中发送GET/HTTP/HTTPS请求,因为有的时候需要获取认证信息(如Cookie),所以返回的是HttpWebResponse对象,有了返回的HttpWebResponse实例,可以获取登录过程中返回的会话信息,也可以获取响应流
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
* 原文出处:http://blog.csdn.net/zhoufoxcn 或http://zhoufoxcn.blog.51cto.com
* 版权说明:本文可以在保留原文出处的情况下使用于非商业用途,周公对此不作任何担保或承诺。
* */
namespace BaiduCang
{
/// <summary>
/// 有关HTTP请求的辅助类
/// </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>
/// 创建GET方式的HTTP请求
/// </summary>
/// <param name="url">请求的URL</param>
/// <param name="timeout">请求的超时时间</param>
/// <param name="userAgent">请求的客户端浏览器信息,可以为空</param>
/// <param name="cookies">随同HTTP请求发送的Cookie信息,如果不需要身份验证可以为空</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>
/// 创建POST方式的HTTP请求
/// </summary>
/// <param name="url">请求的URL</param>
/// <param name="parameters">随同请求POST的参数名称及参数值字典</param>
/// <param name="timeout">请求的超时时间</param>
/// <param name="userAgent">请求的客户端浏览器信息,可以为空</param>
/// <param name="requestEncoding">发送HTTP请求时所用的编码</param>
/// <param name="cookies">随同HTTP请求发送的Cookie信息,如果不需要身份验证可以为空</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;
//如果是发送HTTPS请求
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数据
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;
//总是接受
}
}
}
//从上面的代码中可以看出POST数据到HTTP和HTTPS站点不同,POST数据到HTTPS站点的时候需要设置ServicePointManager类的ServerCertificateValidationCallback属性,并且在POST到https://passport.baidu.com/?login时还需要将HttpWebResquest实例的ProtocolVersion属性设置为HttpVersion.Version10(这个未验证是否所有的HTTPS站点都需要设置),否则在调用GetResponse()方法时会抛出“基础连接已经关闭: 连接被意外关闭。”的异常。
//用法举例
// 这个类用起来也很简单:
// (1)POST数据到HTTPS站点,用它来登录百度:
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"];
//(2)发送GET请求到HTTP站点
//在cookieString中包含了服务器端返回的会话信息数据,从中提取了之后可以设置Cookie下次登录时带上这个Cookie就可以以认证用户的信息,假设我们已经登录成功并且获取了Cookie,那么发送GET请求的代码如下:
string userName =
"userName";
string tagUrl =
"http://cang.baidu.com/"+userName+
"/tags";
CookieCollection cookies =
new CookieCollection();
//如何从response.Headers["Set-Cookie"];中获取并设置CookieCollection的代码略
response = HttpWebResponseUtility.CreateGetHttpResponse(tagUrl,
null,
null, cookies);
//(3)发送POST请求到HTTP站点
//以登录51CTO为例
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);
//总结
//在本文只是讲解了在C#中发送请求到HTTP和HTTPS的用法,分GET/POST两种方式,为减少一些繁琐和机械的编码,周公将其封装为一个类,发送数据之后返回HttpWebResponse对象实例,利用这个实例我们可以获取服务器端返回的Cookie以便用认证用户的身份继续发送请求,或者读取服务器端响应的内容,不过在读取响应内容时要注意响应格式和编码,本来在这个类中还有读取HTML和WML内容的方法(包括服务器使用压缩方式传输的数据),但限于篇幅和其它方面的原因,此处省略掉了。如有机会,在以后的文章中会继续讲述这方面的内容。
转载于:https://www.cnblogs.com/LiMin/archive/2013/04/06/3001950.html