Express and WebSocket listening on the same port

Question

I have an app.js which is used to trigger two events when some POST data are received:

1. Insert POST data into a database
2. Send a message to a client us

Answer 1

Based on your code and comments, here's a super simple example of how it would work together.

First, the http-server.js - a typical express app, except that we do not start the server with app.listen():

'use strict';

let fs = require('fs');
let express = require('express');
let app = express();
let bodyParser = require('body-parser');

app.use(bodyParser.json());

// Let's create the regular HTTP request and response
app.get('/', function(req, res) {

  console.log('Get index');
  fs.createReadStream('./index.html')
  .pipe(res);
});

app.post('/', function(req, res) {

  let message = req.body.message;
  console.log('Regular POST message: ', message);
  return res.json({

    answer: 42
  });
});

module.exports = app;

Now, the ws-server.js example, where we create the WSS server from a node native http.createServer(). Now, note that this is where we import the app, and give this native http.createServer the app instance to use.

Start the app with PORT=8080 node ws-server.js :

(Note you're launching the second, socket related, file (ws-server) not the first, http related, file (http-server).)

'use strict';

let WSServer = require('ws').Server;
let server = require('http').createServer();
let app = require('./http-server');

// Create web socket server on top of a regular http server
let wss = new WSServer({

  server: server
});

// Also mount the app here
server.on('request', app);

wss.on('connection', function connection(ws) {
 
  ws.on('message', function incoming(message) {
    
    console.log(`received: ${message}`);
    
    ws.send(JSON.stringify({

      answer: 42
    }));
  });
});


server.listen(process.env.PORT, function() {

  console.log(`http/ws server listening on ${process.env.PORT}`);
});

Finally, this sample index.html will work by creating both a POST and a Socket "request" and display the response:

  



  
Socket message response: 
  

  

  
POST message response: 
  

  

Note you'll need a quite recent browser, one that has both WebSocket and fetch APIs for this client side part, but it's irrelevant anyway, it just gives you the gist of it.