WebSocket Server

Setup

Install the dependencies:

yarn init -y && \
yarn add express ws cors

Simple HTTP Server with Express

// main.js
const express = require('express');

const cors = require('cors');
const morgan = require('morgan');

const app = express();

app.use(cors({ origin: process.env.CORS_ORIGIN || '*' }));

app.use(helmet());

app.use(express.json());

app.use(morgan('dev'));

app.post('/login', (req, res, next) => {
  res.json({ token: '123456' });
});
app.listen(process.env.PORT || 3000, () => {
  console.log('Server started on port 3000');
});

to simplify the process of setting up a simple HTTP server I use the Express framework.

WebSocket Server handling events

//ws.js
function onError(ws, err) {
  console.error(`onError: ${err.message}`);
}

function onMessage(ws, data) {
  console.log(`onMessage: ${data}`);
  ws.send(`recebido!`);
}

function onConnection(ws, req) {
  ws.on('message', (data) => onMessage(ws, data));
  ws.on('error', (error) => onError(ws, error));
  console.log(`onConnection`);
}

module.exports = (server) => {
  const wss = new WebSocket.Server({
    server
  });

  wss.on('connection', onConnection);

  console.log(`WebSocketis running!`);
  return wss;
};

the code above, I've set some default events to handle. The onError event is called when an error occurs. The onMessage event is called when a message is received. The onConnection event is called when a new connection is established. Web socket server ?

(Express Server)+(WebSocket Server) = la especilidad ✨

//main.js
// main.js
const express = require('express');
const cors = require('cors');
const appWS = require('./ws');

    ...

const server =app.listen(process.env.PORT || 3000, () => {
  console.log('Server started on port 3000');
});

appWs(server);

And voila!

A simple HTTP server with WebSocket support.

$ node main.js
Server started on port 3000

how to Test

I use the Hoppscotch library to test my real time applications. 😉