RE: HTTP Tunnel question

[Stuart Stephen]

Hi all,

I have run into another problem. I can recieve messages from the server that
I am tunnelling to and send them to the applet fine. However it is proving
difficult to do things the other way round, when I want to send a message
from the applet to the
internal server I am having "java.io.EOFException: code expected" exceptions
appear.

The connection from the Applet is just a simple URLConnection. This is not
closed unless the applet closes or the user quits.

I have some tomcat logs to show you what is going wrong. I hope someone can
be of help here.

Thanks,
Stuart Stephen

start of servlet
ToApplet()
ToServer()
...Reading for Object Streams
java.io.EOFException: Expecting code
        at java.io.ObjectInputStream.peekCode(Unknown Source)
        at java.io.ObjectInputStream.readObject(Unknown Source)
        at java.io.ObjectInputStream.readObject(Unknown Source)
        at TestTunnel$ToApplet.run(TestTunnel.java:94)
>From ChatServer: "some random string object blah blah blah"
...Reading for Object Streams
java.io.EOFException: Expecting code
        at java.io.ObjectInputStream.peekCode(Unknown Source)
        at java.io.ObjectInputStream.readObject(Unknown Source)
        at java.io.ObjectInputStream.readObject(Unknown Source)
        at TestTunnel$ToApplet.run(TestTunnel.java:94)
java.io.EOFException: Expecting code
        at java.io.ObjectInputStream.peekCode(Unknown Source)
        at java.io.ObjectInputStream.readObject(Unknown Source)
        at java.io.ObjectInputStream.readObject(Unknown Source)
        at TestTunnel$ToApplet.run(TestTunnel.java:94)
etc...

My code is as follows.

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.ServletException.*;
import javax.servlet.UnavailableException.*;
import java.lang.Exception.*;
import java.io.*;
import java.util.*;
import java.net.*;

public class TestTunnel extends HttpServlet {

  // applet connections
  ObjectOutputStream objOut = null;
  ObjectInputStream objIn = null;

  // chatserver connections
  Socket socket = null;
  ObjectOutputStream sockObjOut = null;
  ObjectInputStream sockObjIn = null;

  ToApplet app = null;
  ToServer ser = null;

  protected void service(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException  {
    try {
      // get data stream from applet
      System.err.println("start of servlet");

      objOut = new ObjectOutputStream(res.getOutputStream());
      objIn = new ObjectInputStream(req.getInputStream());
      objOut.useProtocolVersion(objOut.PROTOCOL_VERSION_1);

      // create socket to chat server and the streams
      socket = new Socket("127.0.0.1", 3000);
      sockObjOut = new ObjectOutputStream(socket.getOutputStream());
      sockObjIn = new ObjectInputStream(socket.getInputStream());
      sockObjOut.useProtocolVersion(sockObjOut.PROTOCOL_VERSION_1);

      app = new ToApplet(objIn, sockObjOut);
      ser = new ToServer(sockObjIn, objOut);

      while(ser.connIsAlive() || app.connIsAlive()) {
        try {
          Thread.sleep(500);
        }
        catch(Exception ex) {
          ex.printStackTrace();
        }
      }

      System.err.println("end of servlet");
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }

  public void destroy() {
    try {
      objIn.close();
      objOut.close();
      sockObjIn.close();
      sockObjOut.close();
      socket.close();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }

  private class ToApplet extends Thread {
    ObjectOutputStream objOut = null;
    ObjectInputStream sockObjIn = null;
    boolean isAlive = true;

    public ToApplet(ObjectInputStream sockObjIn, ObjectOutputStream objOut)
{
      try {
        System.err.println("ToApplet()");
        this.objOut = objOut;
        this.sockObjIn = sockObjIn;
        this.start();
      }
      catch(Exception e) {
        e.printStackTrace();
      }
    }

    public void run() {
      try {
        Object obj = new Object();
        while(obj!=null) {
          try {
            System.err.println("...Reading for Object Streams");
            obj = sockObjIn.readObject();
            System.err.println("...Read Object Stream");
            write(obj);
          }
          catch(EOFException eof) {
            eof.printStackTrace();
          }
          catch(Exception ex) {
            ex.printStackTrace();
          }
        }
      }
      catch(Exception e) {
        e.printStackTrace();
      }
    }

    public boolean connIsAlive() {
      return isAlive;
    }

    public void write(Object msg) {
      try {
        System.err.println("ChatApplet: "+msg.toString());
        objOut.writeObject(msg);
        objOut.flush();
        objOut.reset();
      }
      catch(Exception e) {
        e.printStackTrace();
        isAlive = false;
      }
    }
  }

  private class ToServer extends Thread {
    ObjectInputStream objIn = null;
    ObjectOutputStream sockObjOut = null;
    boolean isAlive = true;

    public ToServer(ObjectInputStream objIn, ObjectOutputStream sockObjOut)
{
      try {
        System.err.println("ToServer()");
        this.objIn = objIn;
        this.sockObjOut = sockObjOut;
        this.start();
      }
      catch(Exception e) {
        e.printStackTrace();
      }
    }

    public void run() {
      try {
        Object obj = null;
        while((obj=objIn.readObject())!=null) {
          write(obj);
        }
      }
      catch(Exception e) {
        e.printStackTrace();
        isAlive = false;
      }
    }

    public boolean connIsAlive() {
      return isAlive;
    }

    public void write(Object msg) {
      try {
        System.err.println("ChatServer: "+msg.toString());
        sockObjOut.writeObject(msg);
        sockObjOut.flush();
        sockObjOut.reset();
      }
      catch(Exception e) {
        e.printStackTrace();
      }
    }
  }
}


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