socket.io in nodejs code example

Example 1: create a web server node js w socket.io

var app = require('express')();
var http = require('http').createServer(app);
var io = require('socket.io')(http);

app.get('/', (req, res) => {
  // Ran when a GET request to path '/'
  res.sendFile(__dirname + '/index.html');
});

io.on('connection', (socket) => {
  // Ran when a socket connected
});

http.listen(3000, () => {
  // Ran when server is ready to take requestes
});

Example 2: how to run socket.io server

const express = require("express");
const http = require("http");
const socketIo = require("socket.io");
const port = process.env.PORT || 8001;
const index = require("./routes/index");
const app = express();
app.use(index);
const server = http.createServer(app);
const io = socketIo(server); // < Interesting!
const getApiAndEmit = "TODO";

Example 3: js socket.emit

const socket = io('ws://localhost:3000');
socket.on('connect', () => {  
  // either with send()  
  socket.send('Hello!');
  // or with emit() and custom event names  
  socket.emit('salutations', 'Hello!', { 'mr': 'john' }, Uint8Array.from([1, 2, 3, 4]));});
// handle the event sent with socket.send()
socket.on('message', data => {
  console.log(data);
});
// handle the event sent with socket.emit()
socket.on('greetings', (elem1, elem2, elem3) => {
  console.log(elem1, elem2, elem3);
});

Example 4: socket io node js

npm install socket.io

Example 5: socket io nodejs

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);app.get('/', (req, res) => {  res.sendFile(__dirname + '/index.html');});io.on('connection', (socket) => {  console.log('a user connected');});server.listen(3000, () => {  console.log('listening on *:3000');});

Example 6: node socket.io send

io.on('connect', onConnect);

function onConnect(socket){

  // sending to the client
  socket.emit('hello', 'can you hear me?', 1, 2, 'abc');

  // sending to all clients except sender
  socket.broadcast.emit('broadcast', 'hello friends!');

  // sending to all clients in 'game' room except sender
  socket.to('game').emit('nice game', "let's play a game");

  // sending to all clients in 'game1' and/or in 'game2' room, except sender
  socket.to('game1').to('game2').emit('nice game', "let's play a game (too)");

  // sending to all clients in 'game' room, including sender
  io.in('game').emit('big-announcement', 'the game will start soon');

  // sending to all clients in namespace 'myNamespace', including sender
  io.of('myNamespace').emit('bigger-announcement', 'the tournament will start soon');

  // sending to a specific room in a specific namespace, including sender
  io.of('myNamespace').to('room').emit('event', 'message');

  // sending to individual socketid (private message)
  io.to(`${socketId}`).emit('hey', 'I just met you');

  // WARNING: `socket.to(socket.id).emit()` will NOT work, as it will send to everyone in the room
  // named `socket.id` but the sender. Please use the classic `socket.emit()` instead.

  // sending with acknowledgement
  socket.emit('question', 'do you think so?', function (answer) {});

  // sending without compression
  socket.compress(false).emit('uncompressed', "that's rough");

  // sending a message that might be dropped if the client is not ready to receive messages
  socket.volatile.emit('maybe', 'do you really need it?');

  // specifying whether the data to send has binary data
  socket.binary(false).emit('what', 'I have no binaries!');

  // sending to all clients on this node (when using multiple nodes)
  io.local.emit('hi', 'my lovely babies');

  // sending to all connected clients
  io.emit('an event sent to all connected clients');

};