Lightweight "node-http-proxy" HTTP/WS Proxy Server

HTTP-WS-Proxy.js

// Node Modules 
////////////////////////////////////////////////////////////////////////////////
var http_m = require("http");

// 3rd Party Modules 
////////////////////////////////////////////////////////////////////////////////
var http_proxy_m = require("http-proxy");

// Utilities
////////////////////////////////////////////////////////////////////////////////
var cookie_parser = function(cookies_, name)
{
	var compare = new RegExp(name+"=\\d+;?", "g")
	, cookies = cookies_ || ""
	, result;

	if(result = cookies.match(compare)) {
		return result[0].replace(name+"=", "");
	} else {
		return undefined;
	}
}

var attach_cookie = function(res, cookie)
{
	res.setHeader("set-cookie", cookie.k+"="+cookie.v+"; path=/; HttpOnly;");	
}

// Web Socket Configs
////////////////////////////////////////////////////////////////////////////////

// In-Memory cookie-to-proxy cache
var ws_cookies = {};

// Array of proxy nodes
var ws_nodes = [
	{host: "127.0.0.1", port: 8001}
	, {host: "127.0.0.1", port: 8002}
// On creation, map the pairs to new HttpProxy objects
].map(function(pair) {return new http_proxy_m.HttpProxy({target: pair});});

var handle_ws = function(req, res)
{
	// Parse the request for a ws session cookie
	var cookie = cookie_parser(req.headers.cookie, "ws");
	
	// Handles cookie creation and attachment
	if(!cookie) {
		cookie = Math.floor(Math.random()*9999999999999);
		attach_cookie(res, {k: "ws", v: cookie});
	}
	
	// Handle cookie => proxy association
	if(!ws_cookies[cookie]) {
		var proxy = ws_nodes.shift()
		ws_cookies[cookie] = proxy;
		ws_nodes.push(proxy);
	}

	// init proxy
	ws_cookies[cookie].proxyRequest(req, res);
}

// This handler is attached to the proxy server (see below)
var handle_ws_upgrade = function(req, socket, head)
{
	// Since the socket.io handshake begins with HTTP, 
	// we can assume there is a cookie (and return if there isn't)
	var cookie = cookie_parser(req.headers.cookie, "ws");
	if(!cookie) {return;}

	ws_cookies[cookie].proxyWebSocketRequest(req, socket, head);
	console.log("WebSocket client on", ws_cookies[cookie].target.port);
}

// REST API Configs
////////////////////////////////////////////////////////////////////////////////
var api_cookies = {};
var api_nodes = [
	  {host: "127.0.0.1", port: 9001}
	, {host: "127.0.0.1", port: 9002}
// On creation, map the pairs to new HttpProxy objecs
].map(function(pair) {return new http_proxy_m.HttpProxy({target: pair});});

var handle_api = function(req, res)
{
	var proxy = api_nodes.shift();
	proxy.proxyRequest(req, res);
	api_nodes.push(proxy);
	console.log("HTTP client on", proxy.target.port);
}

// Error Configs
////////////////////////////////////////////////////////////////////////////////
var handle_error = function(req, res) {res.end();}

// Proxy Server Configs
////////////////////////////////////////////////////////////////////////////////
var server = http_m.createServer(function(req, res) {	
	switch(req.headers.host) {
	case "ws.app.com":
		handle_ws(req, res);
		break;
	case "api.app.com":
		handle_api(req, res);
		break;
	default:
		handle_error(req, res);
		break;
	}
});

server.on("upgrade", handle_ws_upgrade);
server.listen(80);