/*
 * Copyright (c) 2004 David Flanagan.  All rights reserved.
 * This code is from the book Java Examples in a Nutshell, 3nd Edition.
 * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
 * You may study, use, and modify it for any non-commercial purpose,
 * including teaching and use in open-source projects.
 * You may distribute it non-commercially as long as you retain this notice.
 * For a commercial use license, or to purchase the book, 
 * please visit http://www.davidflanagan.com/javaexamples3.
 */
package je3.net;
import java.io.*;
import java.net.*;

/**
 * This program is a very simple Web server.  When it receives a HTTP request
 * it sends the request back as the reply.  This can be of interest when
 * you want to see just what a Web client is requesting, or what data is
 * being sent when a form is submitted, for example.
 **/
public class HttpMirror {
    public static void main(String args[]) {
        try {
            // Get the port to listen on
            int port = Integer.parseInt(args[0]);
            // Create a ServerSocket to listen on that port.
            ServerSocket ss = new ServerSocket(port);
            // Now enter an infinite loop, waiting for & handling connections.
            for(;;) {
                // Wait for a client to connect.  The method will block;
		// when it returns the socket will be connected to the client
                Socket client = ss.accept();

                // Get input and output streams to talk to the client 
                BufferedReader in = new BufferedReader(
			       new InputStreamReader(client.getInputStream()));
                PrintWriter out = new PrintWriter(client.getOutputStream());

                // Start sending our reply, using the HTTP 1.1 protocol
                out.print("HTTP/1.1 200 \r\n");        // Version & status code
                out.print("Content-Type: text/plain\r\n"); // The type of data
		out.print("Connection: close\r\n");        // Will close stream
                out.print("\r\n");                         // End of headers

                // Now, read the HTTP request from the client, and send it
                // right back to the client as part of the body of our
                // response.  The client doesn't disconnect, so we never get
                // an EOF.  It does sends an empty line at the end of the
                // headers, though.  So when we see the empty line, we stop
                // reading.  This means we don't mirror the contents of POST
                // requests, for example.  Note that the readLine() method 
		// works with Unix, Windows, and Mac line terminators.
                String line;
                while((line = in.readLine()) != null) {
                    if (line.length() == 0) break;
                    out.print(line + "\r\n");
                }

                // Close socket, breaking the connection to the client, and
		// closing the input and output streams
		out.close();     // Flush and close the output stream
		in.close();      // Close the input stream
                client.close();  // Close the socket itself
            } // Now loop again, waiting for the next connection
        }
        // If anything goes wrong, print an error message
        catch (Exception e) {
            System.err.println(e);
            System.err.println("Usage: java HttpMirror <port>");
        }
    }
}