joplin-notes/joplin notion extension/Web Development/nodejs/socket.io.md

socket.io

• Using with http module

    const PORT = process.env.PORT || 8080;
  
    const httpServer = require("http").createServer();
    const socketIO = require("socket.io");
  
    const io = socketIO(httpServer, {
      cors: { origin: "*" },
    });
  
    // when client connects to the server
    io.on("connection", (socket) => {
      console.log(`user connected ${socket.id}`);
      io.emit("requestKey");
  
      // when listening to custom event named 'message'
      socket.on("message", (msgObjs) => {
    	// here using socket.broadcast.emit will send message to all client except the one who originally sent to server
  
    	for (let msgObj of msgObjs) {
    	  const id = msgObj.sid;
    	  io.to(id).emit("message", msgObj.message, socket.id);
    	}
  
    	// socket.broadcast.emit(
    	//   "message",
    	//   `${socket.id.substr(0, 2)} said ${message}`
    	// );
  
    	// to send to all including OP, use io.emit
    	// and for particular client use
    	// io.to(socket.id). emit("event", data);
      });
  

 

• Using with express

    const express = require('express');
    const app = express();
    const socketIO = require('socket.io');
  
    const PORT = process.env.PORT || 8080;
    const keys = [];
  
    // Serve your application on a specific route using Express
    app.get('/', (req, res) => {
      res.sendFile(__dirname + '/index.html'); // Replace 'index.html' with your HTML file
    });
  
    // Create the HTTP server using Express
    const server = app.listen(PORT, () => {
      console.log(`Server is running on port ${PORT}`);
    });
  
    // Initialize Socket.io by passing the HTTP server instance
    const io = socketIO(server, {
      cors: { origin: "*" },
    });
  
    // Socket.io logic
    io.on("connection", (socket) => {
      console.log(`User connected: ${socket.id}`);
      io.emit("requestKey");
  
      // ... (rest of your Socket.io logic)
    });