Socket.io-based app running through node proxy server disconnecting all sockets whenever one disconnects

I made a basic chat app using node.js, express and socket.io. It's not too different from the tutorial chat app for socket.io, it simply emits events between connected clients. When I ran it on port 3001 on my server, it worked fine.

Then I made a proxy server app using node-http-proxy which listens on port 80 and redirects traffic based on the requested url to various independent node apps I have running on different ports. Pretty straightforward. But something is breaking. Whenever anyone disconnects, every single socket dis- and re-connects. This is bad for my chat app, which has connection-based events. The client consoles all show:

WebSocket connection to 'ws://[some socket info]' failed: Connection closed before receiving a handshake response

Here's what I think are the important parts of my code.

proxy-server.js

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

//create proxy template object with websockets enabled
var proxy = httpProxy.createProxyServer({ws: true});

//check the header on request and return the appropriate port to proxy to
function sites (req) {
    //webapps get their own dedicated port
    if (req == 'mychatwebsite.com') {return 'http://localhost:3001';}
    else if (req == 'someothersite.com') {return 'http://localhost:3002';}
    //static sites are handled by a vhost server on port 3000
    else {return 'http://localhost:3000';}
}

//create node server on port 80 and proxy to ports accordingly
http.createServer(function (req, res) {
    proxy.web(req, res, { target: sites(req.headers.host) });
}).listen(80);

chat-app.js

/*
...other modules
*/
var express = require("express");
var app = exports.app = express(); //I probably don't need "exports.app" anymore
var http = require("http").Server(app);
var io = require("socket.io")(http);

io.on("connection", function (socket) {
  /*
  ...fun socket.on and io.emit stuff
  */
  socket.on("disconnect", function () {
    //say bye
  });
});

http.listen(3001, function () {
  console.log("listening on port 3001");
});

Now from what I've read on socket.io's site, I might need to use something to carry the socket traffic through my proxy server. I thought that node-http-proxy did that for me with the {ws: true} option as it states in their docs, but apparently it doesn't work like I thought it would. socket.io mentions three different things:

• sticky session based on node's built in cluster module


• socket.io-redis , which allows separate socket.io instances to talk to each other


• socket.io-emitter , which allows socket.io to talk to non-socket.io processes

I have exactly no idea what any of this means or does. I am accidentally coding way above my skill level here, and I have no idea which of these tools will solve my problem (if any) or even what the cause of my problem really is.

_{Obligatory apology: I'm new to node.js, so please forgive me.}

^{Also obligatory: I know other apps like nginx can solve a lot of my issues, but my goal is to learn and understand how to use this set of tools before I go picking up new ones. And, the less apps I use, the better.}