connect style middleware to proxy requests to another server

proxy.js

/**
 * Simple proxy intended to be used as middleware to direct parts
 * of an HTTP namespace to other servers.  
 *
 * Copyright (c) 2011, Stella Laurenzo
 */
var util=require('util'),
	url=require('url'),
	http=require('http'),
	armor=require('./armor');

function makeAppendDestination(baseUrl) {
	return function(request) {
		//console.log('Request: ' + util.inspect(request));
		return baseUrl + request.url;
	};
}
 
module.exports=function(destination) {
	if (typeof destination==='string')
		destination=makeAppendDestination(destination);
	
	return function(req, res, next) {
		var newUrl=destination(req),
			parsed=url.parse(newUrl),
			port=parsed.port;
			
		//console.log('url: ' + util.inspect(parsed));
		if (!port) {
			if (parsed.protocol==='http:') port=80;
			else if (parsed.protocol==='https:') port=443;
			else port=80;
		}
		
		var client=http.createClient(port, parsed.hostname),
			clientRequest=client.request(req.method, 
				parsed.pathname + (parsed.search||''),
				req.headers);
		
		// Error handling
		var a=armor(next)
			.enlist(client)
			.enlist(clientRequest, clientRequest.end.bind(clientRequest));
		
		// Patch through the response
		clientRequest.on('response', function(pxres) {
			pxres.on('data', function(chunk) {
				res.write(chunk, 'binary');
			}.armor(a));
			pxres.on('end', function() {
				res.end();
			}.armor(a));
			res.writeHead(pxres.statusCode, pxres.headers);
		}.armor(a));
		
		// Patch through the request
		req.on('data', function(chunk) {
			clientRequest.write(chunk, 'binary');
		}.armor(a));
		req.on('end', function() {
			clientRequest.end();
		}.armor(a));
	};
};