Tech Tips: Node.js Reverse Proxy

Summary

In this post I'll show how to create a simple reverse proxy server in Node.js.

Environmentals

The scenario here is front-ending an app server (in this case Genesys Mobility Services (GMS) with a proxy to only forward application-specific REST API requests to GMS over HTTPS. The proxy also acts as a general web server as well - also over HTTPS.

Code

var path = require('path');
var fs = require('fs'); 
var gms = 'https://svr2:3443';
 
var express = require('express');
var app = express();
var privateKey = fs.readFileSync('./key.pem'); 
var certificate = fs.readFileSync('./cert.pem'); 
var credentials = {key: privateKey, cert: certificate};
var https = require('https');
var httpsServer = https.createServer(credentials, app);
 
var httpProxy = require('http-proxy');
var proxy = httpProxy.createProxyServer({
 secure : false,
 target : gms
});
 
httpsServer.on('upgrade', function (req, socket, head) {
   proxy.ws(req, socket, head);
});
 
proxy.on('error', function (err, req, res) {
 console.log(err);
 try {
  res.writeHead(500, {
   'Content-Type': 'text/plain'
  });
  res.end('Error: ' + err.message);
 } catch(err) {
  console.log(err);
 }
});
 
app.use(express.static(path.join(__dirname, 'public')));
 
app.all("/genesys/*", function(req, res) {
 proxy.web(req, res);
});
 
httpsServer.listen(8443);

Lines 1-11: Set up a HTTPS server with Express. The proxy target is specified in Line 3.
Lines 13-17: Set up the Proxy. I'm using a self-signed certificate on Svr 2, so 'secure' is set to false to support that.
Lines 19-21: Configure the HTTPS server use the Proxy to proxy websockets.
Line 35: Serve up static content (HTML, CSS, Javascript) from the 'public' directory for general requests to this server.
Lines 37-39: Proxy any requests that are specifically to the GMS REST API, both HTTPS and WSS traffic.

Source: https://github.com/joeywhelan/Revproxy/

Tuesday, February 20, 2018

Node.js Reverse Proxy

Summary

Environmentals

Code