[apache] Apache and Node.js on the Same Server

I combined the answer above with certbot SSL cert and CORS access-control-allow-headers and got it working so I thought I would share the results.

Apache httpd.conf added to the bottom of the file:

LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_http_module modules/mod_proxy_http.so

Apache VirtualHost settings (doc root for PHP is under Apache and SSL with Certbot, while node.js/socket.io site runs on port 3000 - and uses SSL cert from Apache) Also notice the node.js site uses the proxy for the folder /nodejs, socket.io, and ws (websockets):

<IfModule mod_ssl.c>
<VirtualHost *:443>
    ServerName www.example.com
    ServerAlias www.example.com
    DocumentRoot /var/html/www.example.com
    ErrorLog /var/html/log/error.log
    CustomLog /var/html/log/requests.log combined
    SSLCertificateFile /etc/letsencrypt/live/www.example.com/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/www.example.com/privkey.pem
    Include /etc/letsencrypt/options-ssl-apache.conf

    RewriteEngine On
    RewriteCond %{REQUEST_URI}  ^socket.io          [NC]
    RewriteCond %{QUERY_STRING} transport=websocket [NC]
    RewriteRule /{.*}       ws://localhost:3000/$1  [P,L]

    RewriteCond %{HTTP:Connection} Upgrade [NC]
    RewriteRule /(.*) ws://localhost:3000/$1 [P,L]

    ProxyPass /nodejs http://localhost:3000/
    ProxyPassReverse /nodejs http://localhost:3000/

    ProxyPass /socket.io http://localhost:3000/socket.io
    ProxyPassReverse /socket.io http://localhost:3000/socket.io

    ProxyPass /socket.io ws://localhost:3000/socket.io
    ProxyPassReverse /socket.io ws://localhost:3000/socket.io

</VirtualHost>
</IfModule>

Then my node.js app (app.js):

var express = require('express');
var app = express();
    app.use(function(req, res, next) {
        res.header("Access-Control-Allow-Origin", "*");
        res.header("Access-Control-Allow-Headers", "X-Requested-With");
        res.header("Access-Control-Allow-Headers", "Content-Type");
        res.header("Access-Control-Allow-Methods", "PUT, GET, POST, DELETE, OPTIONS");
        next();
    });
var http = require('http').Server(app);
var io = require('socket.io')(http);

http.listen({host:'0.0.0.0',port:3000});

I force a ip4 listener, but that is optional - you can substitute:

http.listen(3000);

node.js app (app.js) code continues with:

io.of('/nodejs').on('connection', function(socket) {
    //optional settings:
    io.set('heartbeat timeout', 3000); 
    io.set('heartbeat interval', 1000);

    //listener for when a user is added
    socket.on('add user', function(data) {
         socket.join('AnyRoomName');
         socket.broadcast.emit('user joined', data);
    });

    //listener for when a user leaves
    socket.on('remove user', function(data) {
         socket.leave('AnyRoomName');
         socket.broadcast.emit('user left', data);
    });

    //sample listener for any other function
    socket.on('named-event', function(data) {
         //code....
         socket.broadcast.emit('named-event-broadcast', data);
    });

    // add more listeners as needed... use different named-events...
});

finally, on the client side (created as nodejs.js):

//notice the /nodejs path
var socket = io.connect('https://www.example.com/nodejs');

//listener for user joined
socket.on('user joined', function(data) {
    // code... data shows who joined...
});

//listener for user left
socket.on('user left', function(data) {
    // code... data shows who left...
});

// sample listener for any function:
socket.on('named-event-broadcast', function(data) {
    // this receives the broadcast data (I use json then parse and execute code)
    console.log('data1=' + data.data1);
    console.log('data2=' + data.data2);
});

// sample send broadcast json data for user joined:
socket.emit('user joined', {
    'userid': 'userid-value',
    'username':'username-value'
});

// sample send broadcast json data for user left 
//(I added the following with an event listener for 'beforeunload'):
// socket.emit('user joined', {
//     'userid': 'userid-value',
//     'username':'username-value'
// });

// sample send broadcast json data for any named-event:
socket.emit('named-event', {
    'data1': 'value1',
    'data2':'value2'
});

In this example when the JS loads, it will emit to the socket a "named-event" sending the data in JSON to the node.js/socket.io server.

Using the io and socket on the server under path /nodejs (connected by client), receives the data an then resends it as a broadcast. Any other users in the socket would receive the data with their listener "named-event-broadcast". Note that the sender does not receive their own broadcast.