Simple http proxy

Question

What I'm trying to do is write an http proxy. It should resend client's requests unaltered to the designated http server (Host parameter in the request) , then stream the content back to the client. For certain responses (text/html) I'll need to alter the streams reaching the client. Can anyone help with some suggestions? I'm a bit stuck here, especially because the same code runs on linux (jdk 6) but with tons of broken pipe exceptions, and it won't send anything to the browser when the proxy runs on windows. Which is the best way to stream/process the response I get from the remote server?
Here's my code:
import java.io.*;
import java.net.*;
import java.util.logging.*;
public class Main {
public static void main(String[] args) throws IOException {
Daemon daemon = new Daemon(80);
Thread t = new Thread(daemon);
t.start();
//Main Listener thread
static class Daemon implements Runnable {
private ServerSocket server;
public Daemon(int port) throws IOException {
this.server = new ServerSocket(port);
public void run() {
System.out.println("LISTENING");
try {
for (;;) {
Socket s = server.accept();
System.out.println("Accepted connection from: " + s.getInetAddress());
Handler handler = new Handler(s);
Thread t = new Thread(handler);
t.start();
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
//Handles concurrent connections
static class Handler implements Runnable {
private Socket clientSocket;
public Handler(Socket clientSocket) {
this.clientSocket = clientSocket;
public void run() {
InputStream in = null;
try {
in = clientSocket.getInputStream();
int d;
//Read the HTTP request from client
StringBuilder requestBuilder = new StringBuilder();
while (((d = in.read()) != -1) && (in.available() > 0)) {
requestBuilder.append((char) d);
String request = requestBuilder.toString();
//Find to which host the rquest was directed to
InputStream temStream = new ByteArrayInputStream(request.getBytes());
BufferedReader reader = new BufferedReader(new InputStreamReader(temStream));
String line;
String host = "";
while ((line = reader.readLine()).length() > 0) {
if (line.split(": ")[0].toLowerCase().contains("host")) {
host = line.split(": ")[1];
break;
//Open a connection to the remote Http server
Socket remoteConnection = new Socket(host, 80);
//Write the request to the remote host
BufferedWriter serverWriter = new BufferedWriter(new OutputStreamWriter(remoteConnection.getOutputStream()));
serverWriter.write(request);
serverWriter.newLine();
serverWriter.flush();
//From here on problems start
BufferedInputStream serverStream = new BufferedInputStream(remoteConnection.getInputStream());
int i;
//Read data from remote server and stream it to the client
while ((i = serverStream.read()) != -1 && !(remoteConnection.isInputShutdown())) {
//This thing here throws a broken pipe exception on linux JKD 6
//On windows it won't even work
clientSocket.getOutputStream().write(i);
clientSocket.getOutputStream().flush();
clientSocket.close();
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
in.close();
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}

Answer 1

You're telnetting and HTTP'ing to the same port, right?
What do you mean no input? From the browser, from the server's point of view?
Or vice-versa?
All the details of how a proxy should work, is spelled out in the HTTP RFC doc. I can't recall the RFC number.
Do a Google on "HTTP RFC" and you'll probably find it.