Proxy Server!!!

[gautham kasinath]

Hi! I am trying to develop a proxy server.. any one there with a design..
I wrote a piece of code for the same but it is not working.
Regds
Gautham Kasinath

[Frank Carver]

Do you mean a proxy server for any particular protocol, or just a "port replicator" which forwards all traffic to another port?
What went wrong with the code you wrote? Did it give any errors or exceptions?

[gautham kasinath]

Hi! Well the code is something like a port forwarder.. well I am behind a proxy / firewall so I made my code connect to that proxy and my browser connect to my server.. what ever the request it is transferred to my connection with the proxy I am behind.. Here is the code:

import java.net.*;
import java.io.*;
import java.util.*;
final class serverConstants
{
    public static int intServerPort = 9000; // Constant Server Port
    public static String strServerIP = "http://192.168.200.111"; // Constant Server IP
    public static ServerSocket sSoc; // Server Socket
}
final class toIspServer extends Thread
{
    private DataOutputStream toIspServer;
    private DataInputStream  fromClient;
    
    public toIspServer(DataOutputStream toIspServer, DataInputStream fromClient)
    {
        // Initialise Streams
        //
        this.toIspServer = toIspServer;
        this.fromClient  = fromClient;
    }
    
    public void run()
    {
        System.out.println("This is the toIspServer Thread");
        
        String strFromClient = "";
        
        try
        {
            while(( strFromClient = fromClient.readLine()) != "")
            {
                // Write to Server Request from Client
                //
                toIspServer.writeBytes(strFromClient);
                System.out.println("To Server : "+strFromClient);
            }
        }
        catch(Exception exp)
        {
        }
    }
}
final class fromIspServer extends Thread
{
    private DataInputStream fromIspServer;
    private DataOutputStream  toClient;
    
    public fromIspServer(DataOutputStream toClient, DataInputStream fromIspServer)
    {
        // Initialise Streams
        //
        this.toClient      = toClient;
        this.fromIspServer = fromIspServer;
    }
    
    public void run()
    {
        System.out.println("This is the FromIspServer Thread ");
        
        String strFromIspServer = "";
        
        try
        {
            while(( strFromIspServer = fromIspServer.readLine()) != "")
            {
                System.out.println("From Server : "+strFromIspServer);
                
                //Write to Client data from Server
                //
                toClient.writeBytes(strFromIspServer);
            }
        }
        catch(Exception exp)
        {
        }
    }
}
class ConnectToServer extends Thread
{
    private Socket cSoc;
    
    DataOutputStream toIspServer; // Stream to Write to the Main Server
    DataInputStream  fromIspServer; // Stream to Read from the Main Server
    
    DataOutputStream outMyClient; // Stream to Write to Client
    DataInputStream inMyClient; // Stream to Read from Client
    
    public ConnectToServer(Socket cSoc, DataOutputStream toIspServer, DataInputStream fromIspServer ) throws IOException
    {
        // Initialise the Data Streams
        //
        this.cSoc = cSoc;
        this.fromIspServer = fromIspServer;
        this.toIspServer = toIspServer;
        
        outMyClient = new DataOutputStream(cSoc.getOutputStream());
        inMyClient = new DataInputStream(cSoc.getInputStream());
    }
    
    public void run()
    {
        System.out.println("The Socket from Client is : "+cSoc);
        
        // Start the Receiver Thread fro this Client
        //
        new toIspServer(toIspServer, inMyClient).start();
        
        //Start the Transmitter Thread for this Client
        //
        new fromIspServer(outMyClient, fromIspServer).start();
    }
}
public class proxyServer
{
    private static Socket proxySoc;
    
    public static void main(String a[])
    {
        DataOutputStream toIspServer; // Stream to Write to Main Server
        DataInputStream fromIspServer; // Stream to Read from Main Server
        
        try
        {
            serverConstants.sSoc = new ServerSocket(serverConstants.intServerPort);
            
            try
            {
                // Connect to the ISP / Main Server / Main Proxy Server
                //
                proxySoc = new Socket("my proxy ip",90);
            }
            catch(Exception e)
            {
                System.out.println("Error Conneting to ISP Server : "+e.getMessage());
            }
            
            toIspServer = new DataOutputStream(proxySoc.getOutputStream());
            
            fromIspServer = new DataInputStream(proxySoc.getInputStream());
            
            System.out.println("Server Started Waiting for Connections....");
            
            // Accept Connections from Clients on New threads.
            //
            for(;  [img]http://www.javaranch.com/ubb/wink.gif[/img]  (new ConnectToServer(serverConstants.sSoc.accept(), toIspServer, fromIspServer )).start();
        }
        catch(Exception exp)
        {
            System.out.println("Exception in conneting to my Clients : "+exp.getMessage());
        }
    }
}

added UBB CODE tags to help maintain code formatting
[This message has been edited by Frank Carver (edited January 10, 2001).]