C#编写的一个反向代理工具，可以缓存网页到本地
proxy.ashx 主文件

<%@ WebHandler Language="C#" Class="proxy" %>     using System;  using System.Web;  using System.Net;  using System.Text;  using System.IO;  using System.Collections.Generic;  using System.Configuration;           /// <summary>  /// 把http headers 和 http 响应的内容 分别存储在 /proxy/header/ 和 /proxy/body/ 中  /// 分层次创建目录  /// </summary>  public class proxy : IHttpHandler  {         HttpResponse Response;      HttpRequest Request;      HttpApplicationState Application;      HttpServerUtility Server;         static string proxyCacheFolder = ConfigurationManager.AppSettings["proxyCacheFolder"];      static string proxyDomain = ConfigurationManager.AppSettings["proxyDomain"];      static string proxyReferer = ConfigurationManager.AppSettings["proxyReferer"];      bool proxyCacheDirectAccess = ConfigurationManager.AppSettings["proxyCacheDirectAccess"] == "true";      int proxyCacheSeconds = int.Parse(ConfigurationManager.AppSettings["proxyCacheSeconds"]);               public void ProcessRequest(HttpContext context)      {          Response = context.Response;          Request = context.Request;          Application = context.Application;          Server = context.Server;             string path = context.Request.RawUrl;          bool delCache = path.IndexOf("?del") > 0;          if (delCache)          {              path = path.Replace("?del", string.Empty);              DeleteCacheFile(path);              return;          }                bool allowCache = Request.QueryString["cache"] == "true";          string seconds = Request.QueryString["seconds"] ?? string.Empty;          if (!int.TryParse(seconds, out proxyCacheSeconds))          {              proxyCacheSeconds = 3600;          }             if (allowCache)          {                 EchoData(path);          }          else          {                 WebClient wc = new WebClient();              wc.Headers.Set("Referer", proxyReferer);              byte[] buffer = wc.DownloadData(proxyDomain + path);              Response.ContentType = wc.ResponseHeaders["Content-Type"];              foreach (string key in wc.ResponseHeaders.AllKeys)              {                     Response.Headers.Set(key, wc.ResponseHeaders[key]);              }              wc.Dispose();              Response.OutputStream.Write(buffer, 0, buffer.Length);          }               }            /// <summary>      /// 清理失效的缓存      /// </summary>      /// <param name="d"></param>      void ClearTimeoutCache(DirectoryInfo d)      {          if (d.Exists)          {              FileInfo[] files = d.GetFiles();              foreach (FileInfo file in files)              {                  TimeSpan timeSpan = DateTime.Now - file.LastAccessTime;                  if (timeSpan.TotalSeconds > proxyCacheSeconds)                  {                      file.Delete();                  }              }          }      }         string GetCacheFolderPath(string hash)      {          string s = string.Empty;          for (int i = 0; i <= 2; i++)          {              s += hash[i] + "/";          }             return s;      }         /// <summary>      /// 读取缓存的header 并输出      /// </summary>      /// <param name="cacheHeaderPath"></param>      void EchoCacheHeader(string cacheHeaderPath)      {          string[] headers = File.ReadAllLines(cacheHeaderPath);          for (int i = 0; i < headers.Length; i++)          {              string[] headerKeyValue = headers[i].Split(':');              if (headerKeyValue.Length == 2)              {                  if (headerKeyValue[0] == "Content-Type")                  {                      Response.ContentType = headerKeyValue[1];                  }                  Response.Headers.Set(headerKeyValue[0], headerKeyValue[1]);              }             }         }               void DeleteCacheFile(string path)      {          string absFolder = Server.MapPath(proxyCacheFolder);          string hash = GetHashString(path);             string folder = GetCacheFolderPath(hash);             string cacheBodyPath = absFolder + "/body/" + folder + hash;          string cacheHeaderPath = absFolder + "/header/" + folder + hash;             FileInfo cacheBody = new FileInfo(cacheBodyPath);          FileInfo cacheHeader = new FileInfo(cacheHeaderPath);             if (cacheBody.Exists)          {              cacheBody.Delete();          }             if (cacheHeader.Exists)          {              cacheHeader.Delete();          }             Response.Write("delete cache file Success!\r\n" + path);      }         /// <summary>      /// 输出缓存      /// </summary>      /// <param name="cacheHeaderPath">缓存header 的文件路径</param>      /// <param name="cacheBodyPath">缓存 body 的文件路径</param>      /// <param name="ifTimeout">是否进行判断文件过期</param>      /// <returns>是否输出成功</returns>      bool EchoCacheFile(string cacheHeaderPath, string cacheBodyPath, bool ifTimeout)      {          FileInfo cacheBody = new FileInfo(cacheBodyPath);          FileInfo cacheHeader = new FileInfo(cacheHeaderPath);             ClearTimeoutCache(cacheBody.Directory);          ClearTimeoutCache(cacheHeader.Directory);             if (cacheBody.Exists && cacheHeader.Exists)          {                 if (ifTimeout)              {                  TimeSpan timeSpan = DateTime.Now - cacheBody.LastWriteTime;                  if (timeSpan.TotalSeconds < proxyCacheSeconds)                  {                      EchoCacheHeader(cacheHeaderPath);                         Response.TransmitFile(cacheBodyPath);                      return true;                  }              }              else              {                  EchoCacheHeader(cacheHeaderPath);                     Response.TransmitFile(cacheBodyPath);                  return true;              }             }             return false;      }         void EchoData(string path)      {             string absFolder = Server.MapPath(proxyCacheFolder);          string hash = GetHashString(path);             string folder = GetCacheFolderPath(hash);             string cacheBodyPath = absFolder + "/body/" + folder + hash;          string cacheHeaderPath = absFolder + "/header/" + folder + hash;             bool success;          if (proxyCacheDirectAccess)          {              success = EchoCacheFile(cacheHeaderPath, cacheBodyPath, false);              if (!success)              {                  Response.Write("直接从缓存读取失败!");              }              return;          }             success = EchoCacheFile(cacheHeaderPath, cacheBodyPath, true);             if (success)          {              return;          }                      //更新Cache File          string ApplicationKey = "CacheList";          List<string> List = null;                if (Application[ApplicationKey] == null)          {                         Application.Lock();              Application[ApplicationKey] = List = new List<string>(1000);              Application.UnLock();          }          else          {                 List = (List<string>)Application[ApplicationKey];             }                //判断是否已有另一个进程正在更新Cache File          if (List.Contains(hash))          {              success = EchoCacheFile(cacheHeaderPath, cacheBodyPath, false);              if (success)              {                  return;              }              else              {                     WebClient wc = new WebClient();                  wc.Headers.Set("Referer", proxyReferer);                  //主体内容                  byte[] data = wc.DownloadData(proxyDomain + path);                     //处理header                  Response.ContentType = wc.ResponseHeaders["Content-Type"];                  foreach (string key in wc.ResponseHeaders.AllKeys)                  {                      Response.Headers.Set(key, wc.ResponseHeaders[key]);                  }                  wc.Dispose();                  Response.BinaryWrite(data);                                 }          }          else          {                                     WebClient wc = new WebClient();              wc.Headers.Set("Referer", proxyReferer);              StringBuilder headersb = new StringBuilder();                 List.Add(hash);              //主体内容              byte[] data = wc.DownloadData(proxyDomain + path);                             //处理header                 Response.ContentType = wc.ResponseHeaders["Content-Type"];              foreach (string key in wc.ResponseHeaders.AllKeys)              {                  headersb.Append(key);                  headersb.Append(":");                  headersb.Append(wc.ResponseHeaders[key]);                  headersb.Append("\r\n");                  Response.Headers.Set(key, wc.ResponseHeaders[key]);              }              wc.Dispose();                 string headers = headersb.ToString().Trim();              if (!Directory.Exists(absFolder + "/header/" + folder))              {                  Directory.CreateDirectory(absFolder + "/header/" + folder);              }                 StreamWriter sw = File.CreateText(absFolder + "/header/" + folder + hash);              sw.Write(headers);              sw.Close();              sw.Dispose();                    //处理缓存内容              if (!Directory.Exists(absFolder + "/body/" + folder))              {                  Directory.CreateDirectory(absFolder + "/body/" + folder);              }                 FileStream fs = File.Create(absFolder + "/body/" + folder + hash);              fs.Write(data, 0, data.Length);              fs.Close();              fs.Dispose();                 List.Remove(hash);                                             Response.BinaryWrite(data);          }      }                  string GetHashString(string path)      {          string md5 = GetMd5Str(path);          return md5;      }            static string GetMd5Str(string ConvertString)      {          System.Security.Cryptography.MD5CryptoServiceProvider md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();          string t2 = BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(ConvertString)), 4, 8);          t2 = t2.Replace("-", "");             return t2;      }            public bool IsReusable      {          get          {              return false;          }      }     }   

<?xml version="1.0"?>  <configuration>    <configSections>      <section name="RewriterConfig" type="URLRewriter.Config.RewriterConfigSerializerSectionHandler, URLRewriter"/>       </configSections>    <RewriterConfig>      <Rules>                       <RewriterRule>          <LookFor>~/.*$</LookFor>          <SendTo>          <!--cache=true 设置此路径进行缓存-->            <![CDATA[~/proxy.ashx?cache=true&seconds=30]]>          </SendTo>        </RewriterRule>           <RewriterRule>          <LookFor>~/ajax/.*$</LookFor>          <SendTo>          <!--cache=false 设置此路径不允许缓存-->            <![CDATA[~/proxy.ashx?cache=false]]>          </SendTo>        </RewriterRule>               </Rules>    </RewriterConfig>       <appSettings>             <!--#反向代理设置 start-->         <!--设置站点-->      <add key="proxyDomain" value="http://127.0.0.1:12123/"/>         <!--缓存文件夹-->      <add key="proxyCacheFolder" value="/proxyCache/"/>         <!--缓存时长-->      <add key="proxyCacheSeconds" value="3600"/>         <!--设置不再判断缓存文件是否超时，直接从缓存读取-->      <add key="proxyCacheDirectAccess" value="false"/>         <!--设置反向代理Referer-->      <add key="proxyReferer" value="http://www.www.com/"/>      <!--#反向代理设置 end-->                  </appSettings>         <system.webServer>      <modules runAllManagedModulesForAllRequests="true">        <add type="URLRewriter.ModuleRewriter, URLRewriter" name="ModuleRewriter"/>      </modules>    </system.webServer>       <system.web>      <compilation debug="true"/>    </system.web>       </configuration>