socket.io 'on' doesn't get fired with Nodejs server-CodePudding

server.js

const express_l = require('express');
const path_l    = require('path');
const app_l     = express_l();
const http_l    = require('http');

const server_l   = http_l.createServer( app_l);

const socketio_l = require('socket.io');
const io_l = socketio_l( server_l);

app_l.use( express_l.static( path_l.join( __dirname, 'public')) );

io_l.on( "connection", argSocket => { console.log('New websocket connection!'); });

var PORT = 3000 || process.env.PORT;

server_l.listen( PORT, ()=>{ console.log(`from express server on port ${PORT}!`) });

main.js

const socket = io_l();

chat.html

...
...
  <script src = "/socket.io/socket.io.js"> </script>
  <script src = "js/main.js"> </script>
</body>
</html>

package.json

{
  "name": "chatcord",
  "version": "1.0.0",
  "description": "Realtime chat application built with Nodejs",
  "main": "server.js",
  "scripts": {
    "start": "node server",
    "dev": "nodemon server"  
  },
  "author": "xyz",
  "license": "MIT",
  "dependencies": {
    "express": "^4.18.1",
    "moment": "^2.29.3",
    "socket.io": "^4.5.1"
  },
  "devDependencies": {
    "nodemon": "^2.0.16"
  }
}

Now, when I refresh http://localhost:3000/ in browser, I don't see the console.log statement from the on function of socket.io.

Where am I going wrong? Please point out.

CodePudding user response：

Your initialization is wrong. You have create an new instance of the socket io server and then call it. Check the documentation for more. https://socket.io/get-started/chat#integrating-socketio

const { Server } = require("socket.io");
const io = new Server(server);

io.on('connection', (socket) => {
  console.log('a user connected');
});

Hopefully this helps.

CodePudding user response：

this is from socket io documentation https://socket.io/get-started/chat

const express = require('express');
const app = express();
const http = require('http');
const server = http.createServer(app);
const { Server } = require("socket.io");
const io = new Server(server);

io.on("connection", async (socket) => {
  console.log("someone connected to socket")
  //add listener here
  socket.on("chat",(data)=> {
    console.log(data)
  })
});

httpServer.listen(port, host, () => {
 console.log(`Server running on http://${host}:${port}`);
});

also this is the emit cheatsheet maybe useful for you https://socket.io/docs/v3/emit-cheatsheet/

CodePudding user response：

You're consoling on nodejs server so check your terminal for the output of the console. You need to research how emitting events works in socket (helping material)