basic reverse proxy middleware in comparison to the node-http-proxy module

example_with_middleware.js

var http = require('http');
var createProxyMiddleware = require('./proxy_middleware');

/*
/etc/hosts

127.0.0.1    hostA
127.0.0.1    hostB
*/

function getSocketPathForHostname (hostName) {
	return __dirname+'/sockets/' + hostName;
}

var hostAproxyMiddleware = createProxyMiddleware(getSocketPathForHostname('hostA'))
var hostBproxyMiddleware = createProxyMiddleware(getSocketPathForHostname('hostB'))

var proxyServer = http.createServer().listen(80);
proxyServer.on('request', function (req, res) {
	var hostName = req.headers.host.split(':')[0];
	if (hostName == 'hostA') {
		hostAproxyMiddleware(req, res);
	}
	if (hostName == 'hostB') {
		hostBproxyMiddleware(req, res);
	}
});

example_with_npm_module.js

var http = require('http');
var httpProxy = require('http-proxy');

/*
/etc/hosts

127.0.0.1    hostA
127.0.0.1    hostB
*/

function getSocketPathForHostname (hostName) {
	return __dirname+'/sockets/' + hostName;
}

function createProxyWithSocketPathAsTargetForHostName (hostName) {
	var options = {
	    target: {
	        socketPath: getSocketPathForHostname(hostName)
	    },
	    ws: true,
	    xfwd: true,
	    secure: false
	};
	var proxy = httpProxy.createProxyServer(options);
	proxy.on('error', function (err, req, res) {
		// implement!
	});
	return proxy;
}

var hostAproxy = createProxyWithSocketPathAsTargetForHostName('hostA')
var hostBproxy = createProxyWithSocketPathAsTargetForHostName('hostB')

var proxyServer = http.createServer().listen(80);

proxyServer.on('request', function(req, res) {
	var hostName = req.headers.host.split(':')[0];
	if (hostName == 'hostA') {
		hostAproxy.web(req, res);
	}
	if (hostName == 'hostB') {
		hostBproxy.web(req, res);
	}
});

proxy_middleware.js

var url = require('url');
var http = require('http');

module.exports = function createMiddleware (socketPath) {
    return function proxyMiddleware (req, res) {
        console.log('request ' + req.url);
        req.pause();

        var options = url.parse(req.url);
        options.socketPath = socketPath;
        options.headers = req.headers;
        options.headers['x-forwarded-for'] = req.connection.remoteAddress;
        options.method = req.method;
        options.agent = false;

        var proxy = http.request(options, function(appRes) {
                appRes.pause();
                res.writeHeader(appRes.statusCode, appRes.headers);
                appRes.pipe(res);
                appRes.resume();
        });
        proxy.on('error', function (e) {
            console.error('problem with request:', e.message);
            res.end('500 Internal server error');
        });
        req.pipe(proxy);
        req.resume();
    };
};