Node-js application that acts as a proxy between a client and a server, logging the traffic to the console

snoopProxy.js

var net = require('net');

HOST = '127.0.0.1'
PORT = 12345
LISTENPORT = 23456

var server = net.createServer( function(socket) {

	socket.on('data', function(data){
		console.log('CLIENT:', data);
	});

	var client = new net.Socket();

	client.on('data', function(data){
		console.log('SERVER:', data);
	});

	client.connect(PORT, HOST);

	client.pipe(socket);
	socket.pipe(client);

});

server.listen(LISTENPORT);

Example: Open up three terminals and type the following commands:
Terminal 1: node snoopProxy.js
Terminal 2: nc -l 12345
Terminal 3: nc 23456

Then use either instance of netcat to create some network traffic, notice that it is being logged as raw bytes (or a Buffer() object) in the node-js application