/*************************************
   * 一个基础的代理服务器类
   *************************************
   */
  import java.net.*;
  import java.io.*;

  public class httpproxy extends thread {
    static public int connect_retries=5;
    static public int connect_pause=5;
    static public int timeout=50;
    static public int bufsiz=1024;
    static public boolean logging = false;
    static public outputstream log=null;
    // 传入数据用的socket
    protected socket socket;
    // 上级代理服务器，可选
    static private string parent=null;
    static private int parentport=-1;
    static public void setparentproxy(string name, int pport) {
   parent=name;
   parentport=pport;
    }

    // 在给定socket上创建一个代理线程。
    public httpproxy(socket s) { socket=s; start(); }

    public void writelog(int c, boolean browser) throws ioexception {
   log.write(c);
    }

    public void writelog(byte[] bytes,int offset, int len, boolean browser) throws ioexception {
   for (int i=0;i<len;i++) writelog((int)bytes[offset+i],browser);
    }

    // 默认情况下，日志信息输出到
    // 标准输出设备
    // 派生类可以覆盖它
    public string processhostname(string url, string host, int port, socket sock) {
  java.text.dateformat cal=java.text.dateformat.getdatetimeinstance();
  system.out.println(cal.format(new java.util.date()) + " - " + url + " "
              + sock.getinetaddress()+"/n");
   return host;
    }

    // 执行操作的线程

    public void run() {
  string line;
  string host;
  int port=80;
        socket outbound=null;
   try {
     socket.setsotimeout(timeout);
     inputstream is=socket.getinputstream();
     outputstream os=null;
     try {
                // 获取请求行的内容
    line="";
    host="";
    int state=0;
    boolean space;
    while (true) {
      int c=is.read();
      if (c==-1) break;
      if (logging) writelog(c,true);
      space=character.iswhitespace((char)c);
      switch (state) {
      case 0:
     if (space) continue;
          state=1;
      case 1:
     if (space) {
       state=2;
       continue;
     }
     line=line+(char)c;
     break;
      case 2:
     if (space) continue; // 跳过多个空白字符
            state=3;
      case 3:
     if (space) {
       state=4;
                            // 只取出主机名称部分
       string host0=host;
       int n;
       n=host.indexof("//");
       if (n!=-1) host=host.substring(n+2);
       n=host.indexof('/');
       if (n!=-1) host=host.substring(0,n);
                            // 分析可能存在的端口号
       n=host.indexof(":");
       if (n!=-1) {
    port=integer.parseint(host.substring(n+1));
    host=host.substring(0,n);
       }
       host=processhostname(host0,host,port,socket);
       if (parent!=null) {
    host=parent;
    port=parentport;
       }
       int retry=connect_retries;
       while (retry--!=0) {
    try {
        outbound=new socket(host,port);
        break;
    } catch (exception e) { }
                                // 等待
    thread.sleep(connect_pause);
       }
       if (outbound==null) break;
       outbound.setsotimeout(timeout);
       os=outbound.getoutputstream();
       os.write(line.getbytes());
       os.write(' ');
       os.write(host0.getbytes());
       os.write(' ');
       pipe(is,outbound.getinputstream(),os,socket.getoutputstream());
       break;
   }
   host=host+(char)c;
   break;
      }
    }
     }
     catch (ioexception e) { }

    } catch (exception e) { }
    finally {
      try { socket.close();} catch (exception e1) {}
      try { outbound.close();} catch (exception e2) {}
       }
    }

    void pipe(inputstream is0, inputstream is1,
         outputstream os0,  outputstream os1) throws ioexception {
   try {
     int ir;
     byte bytes[]=new byte[bufsiz];

     while (true) {
    try {
      if ((ir=is0.read(bytes))>0) {
   os0.write(bytes,0,ir);
   if (logging) writelog(bytes,0,ir,true);
      }
      else if (ir<0)
   break;
    } catch (interruptedioexception e) { }
    try {
      if ((ir=is1.read(bytes))>0) {
   os1.write(bytes,0,ir);
   if (logging) writelog(bytes,0,ir,false);
      }
      else if (ir<0)
   break;
    } catch (interruptedioexception e) { }
     }
   } catch (exception e0) {
       system.out.println("pipe异常: " + e0);
   }
      }

    static public void startproxy(int port,class clobj) {
   serversocket ssock;
   socket sock;
        try {
     ssock=new serversocket(port);
     while (true) {
    class [] sarg = new class[1];
    object [] arg= new object[1];
    sarg[0]=socket.class;
    try {
      java.lang.reflect.constructor cons = clobj.getdeclaredconstructor(sarg);
      arg[0]=ssock.accept();
      cons.newinstance(arg); // 创建httpproxy或其派生类的实例
    } catch (exception e) {
      socket esock = (socket)arg[0];
      try { esock.close(); } catch (exception ec) {}
    }
     }
   } catch (ioexception e) {
   }
      }

    // 测试用的简单main方法
    static public void main(string args[]) {
   system.out.println("在端口8080启动代理服务器/n");
   httpproxy.log=system.out;
   httpproxy.logging=false;
   httpproxy.startproxy(8080,httpproxy.class);
        }
      }