Content of ProxyConnection.java extracted from proxy.jar

package proxy;
 
import java.net.*;
import java.io.*;
import java.util.*;
import java.text.DateFormat;
 
class ProxyConnection extends Thread {
 
 final boolean textimageProxy = false;
 OutputStream f, content = null;
 Socket fromClient;
 
 ProxyConnection(Socket s) {
  fromClient=s;
  start();
 }
 
 public static synchronized void println(String s) {
   System.out.println(s);
   if (Proxy.out != null) Proxy.out.println(s);
 }
 
	 static void filter(buffer in)
			{
				String test = in.toString();
				String ustring = test.toUpperCase();
 
				int i=0, j;
 
			search:
				while (ustring != null)
				{   if ((i = ustring.indexOf("<A", i))==-1) break search;
 
					do
					{
						if ((i = ustring.indexOf(">", i))==-1) break search;
						i++;
						if ((j = ustring.indexOf("<", i))==-1) j = ustring.length(); // not correct 100%!
					}
					while (ustring.substring(i, j).trim().length()==0);
					if (Proxy.wordSet.contains(ustring.substring(i, j).trim()))
					{  
					   in.buf[j-1]='#';
					}
				}
			}
 
 
 
 
 public void run() {
  Proxy.clientCount++;
  buffer abuf = new buffer();
  DataInputStream clientIn = null;
  DataOutputStream clientOut = null;
  DataInputStream serverIn = null;
  DataOutputStream serverOut = null;
  Socket toServer = null;
  String filename ="";
  File dir = null;
  int responseCode = 500;
  long lastModified = 0;
  int hashcode = 0;
  long time0 = new Date().getTime();
  try {
	fromClient.setTcpNoDelay(true);
	clientIn = new DataInputStream(fromClient.getInputStream());
	clientOut = new DataOutputStream(fromClient.getOutputStream());
 
	String line, length ="";
	boolean first = true;
	abuf.clear();
	while (((line = clientIn.readLine()) != null) && (line.trim().length() != 0))
    { if (first)
		{
			first = false;
			String [] request = line.split(" ");
			if (!request[2].startsWith("HTTP"))
			{
				abuf.clear();
				abuf.insert("HTTP/1.0 501 Not Implemented\r\n");
				abuf.writeStream(clientOut);
				clientOut.flush();
				throw new Exception("bad request");
			}
			println(getName()+" fetching "+request[1]);
            hashcode = request[1].toUpperCase().hashCode();
			URI server = new URI(request[1]);
			try
			{
				if (!Proxy.tunnel)
				{
					int port=server.getPort(); if (port == -1) { port = 80; }
					if ((server.getHost() == null)&&(fromClient.getLocalPort() == port)) {	
						abuf.clear();
						abuf.insert("HTTP/1.0 404 Not Found\r\n");
						abuf.writeStream(clientOut);
						clientOut.flush();
						throw new Exception("missing host in proxy mode");
					}
					toServer = new Socket(server.getHost(),port);
				} else toServer = new Socket(Proxy.tunnel_host,Proxy.tunnel_port);			
			}
			catch (UnknownHostException e)
			{  
				abuf.clear();
				abuf.insert("HTTP/1.0 404 Not Found\r\n");
				abuf.writeStream(clientOut);
				clientOut.flush();
				throw e;
			}
			println(getName()+" connecting to "+toServer);
 
			serverIn = new DataInputStream(toServer.getInputStream());
			serverOut = new DataOutputStream(toServer.getOutputStream());
 
			String path = server.getPath()+(server.getRawQuery()==null ? "" :"?"+server.getRawQuery())+(server.getRawFragment()==null ? "" :"#"+server.getRawFragment());
			filename = server.getPath();
 
			if (path.length() == 0) path ="/";
			dir =  new File(Proxy.cache+"/"+server.getHost());
			if (!dir.exists()) 	dir.mkdir();
 
			if (filename.endsWith("/"))	{ filename += "index.htm"; }
			filename = dir.toString()+filename.charAt(0)+filename.substring(1).replace('/','.')+(server.getRawQuery()==null ? "" :"^"+server.getRawQuery().hashCode());
 
			if (!Proxy.tunnel) line = request[0]+" "+path+" "+request[2];
		}
	  abuf.insert(line+"\r\n");
	  if (line.startsWith("Content-Length:"))
	  {   length = line.substring(15).trim();  // 15 è la lunghezza di "Content-Length:"
	  }
    }  // end of while
	abuf.insert("\r\n");
 
	f = new FileOutputStream(dir.toString()+"/"+getName()+".log");
	abuf.writeStream(f);
	int fc = abuf.size;
	abuf.writeStream(serverOut);	
	int r0, nc=0;
	if (length.length() > 0)  
		while ((nc != Integer.parseInt(length))&&((r0 = abuf.readStream(clientIn)) > 0))
		{   nc+=r0;
			abuf.writeStream(f);
			abuf.writeStream(serverOut);
		}
	println(getName()+" "+(fc+nc)+" bytes from client");
	serverOut.flush();
// tutti i bytes sono stati inviati al server
 
	long contentLength = -1;
	String type =""; first =true;
	abuf.clear();
	while (((line = serverIn.readLine()) != null) && (line.trim().length() != 0))
    { 
	  abuf.insert(line+"\r\n");
	  if (first)
	  { first = false;
        String [] response = line.split(" ");	    
		if ((response.length < 3)||!response[0].startsWith("HTTP")) break; // il server ha risposto in modo non HTTP...
		responseCode = Integer.parseInt(response[1]);
		println(getName()+" response code: "+responseCode);
	  }
 
	  if (line.startsWith("Last-Modified:"))
	  {	  
//          lastModified=new Date(line.substring(14).trim()).getTime();  // 14 è la lunghezza di "Last-Modified:"
			try
			{
			  lastModified = DateFormat.getDateInstance().parse(line.substring(14).trim()).getTime(); // 14 è la lunghezza di "Last-Modified:"				
			}
			catch (java.text.ParseException ex)
			{
			}
	  }
 
	  if (line.startsWith("Content-Type:"))
	  {   type = line.substring(13).trim().split("/")[0];  // 13 è la lunghezza di "Content-Type:"
		  println(getName()+" type: "+type);
	  }
    }
	abuf.insert("\r\n");
	abuf.writeStream(f);
 
// esempio di intervento del proxy: solo testi e immagini vengono inviati verso il client:
// BEGIN
	if (textimageProxy)
	{
		if (type.length() != 0)
		{
			if (!(type.startsWith("text")||type.startsWith("image")))
			{ abuf.clear();
			  abuf.insert("HTTP/1.0 404 Not Found\r\n");
			  abuf.writeStream(clientOut);
			  println(getName()+" cancelling request");
			  clientOut.flush();
			  throw new RuntimeException("Proxy filter cancelled request");
			}
		}
	}
// END
 
	abuf.writeStream(clientOut);
	if (responseCode == 200)
	{
		content = new FileOutputStream(filename);
    }
 
	int r1, ns=abuf.size;
	while ((r1 = abuf.readStream(serverIn)) > 0)
	{   ns+=r1;
		if (content != null) abuf.writeStream(content);
// esempio di intervento del proxy: cerca gli iperlink che contengono le parole listate nel file list.txt
// in caso positivo i testi dei link sono alterati con il simbolo #
// BEGIN
		if (Proxy.wordSet != null)
		{
			if (type.startsWith("text")) filter(abuf);
		}
// END
		abuf.writeStream(clientOut);
	}
	println(getName()+" "+ns+" bytes from server");
	if (content != null)
	{	content.close();
		if (lastModified != 0)
		{  new File(filename).setLastModified(lastModified);
		}
	}
 
    clientOut.flush();
  } catch(SocketException e) {
	println(getName()+" "+e.getMessage());  // for some reason the client has closed the connection...
  } catch(UnknownHostException e) {
	println(getName()+" Unknown host: "+e.getMessage());
  } catch(Exception e) {
    println(getName());e.printStackTrace(System.err);
  } finally {
   try {
	if (f != null) f.close();
    if (clientIn != null) clientIn.close();
    if (clientOut != null) clientOut.close();
    if (serverIn != null) serverIn.close();
    if (serverOut != null) serverOut.close();
    if (fromClient != null) fromClient.close();
    if (toServer != null) toServer.close();
	Proxy.clientCount--;
	println(getName()+" quitting after "+((new Date().getTime())-time0)+ "ms");
	if (Proxy.out != null) Proxy.out.flush();
   } catch(Exception e) {
       println(getName()+"exception during quitting...");e.printStackTrace(System.err);
   }
  }
 }
} // ProxyConnection