How to run socketIO server together with main server on nodejs

Question

Currently, we have a main server that is being hosted on localhost:3000 but to run our socket.io function, we need to run it on the same server. However, we need to run it separately (npm start separately). Is there a way to run it together or on the same server without it crashing?

Answer 1

You cannot run socket.io in a separate process, but on the same port as some other web server in some other process. The OS will not allow that as only one process can have a listening server on a specific port. If they are in the same process, that's easy as pie as socket.io is built to share an http server in the same process (one listening server internally, traffic divided between the two uses). But, not from separate processes.

To do that, you'd have to use something like nginx on your port 3000 to proxy plain web requests to one server on some other port say 3001 and socket.io requests to another server on some other port say 3002. The client would only deal with port 3000 and nginx would direct the traffic to the right server on different ports.

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I'm thinking that when you say "npm start separately" , you must have some other problem you're trying to solve with that statement and we could probably help with a better way to solve that actual problem (if you disclosed what that actual requirement is) while keeping socket.io and the http server in the same process and thus no need for a proxy to divide the traffic between two separate servers.

For example, you could start up your web server with no socket.io server started and then you could tell your web server process to start up the socket.io server later. Or you could start both the web server and socket.io server in the same process at initialization time, but have a temporary server configuration that blocks incoming socket.io connections until some other requirement is met.

But, without understanding what the real requirement is, you're just lobbing us an XY problem where you describe your attempted solution rather than the actual problem that needs to be solved. When we explain that your attempted solution is the wrong way to go, we need to know what the real problem is to help further.

Answer 2

This is simple SocketIo Server Code. It's not a client code.
You have to download SocketIO at npm.

const express = require('express');
const http = require('http');
const SocketIo = require('socket.io');

const app = express();

app.set('view engine', 'pug');
app.set('views', __dirname + '\\views');
app.use('/public', express.static(__dirname + '/public'));

app.get('/', (req, res) => res.render('home'));

const handleListen = () => console.log('Listening on http://localhost:3000');

const httpServer = http.createServer(app);
const wsServer = SocketIo(httpServer);

wsServer.on('connection', (socket) => {
  console.log('someone joined!')
  socket.on('join_room', (roomName) => {
    socket.join(roomName);
    socket.to(roomName).emit('welcome');
  });
});

httpServer.listen(3000, handleListen);

For more Info visit official documentation. https://socket.io/get-started/chat