SocketIo Overview

2020-04-18 145 words One minute

socket.io enable realtime, bidirectional communication for Nodejs

Backend

We use Express as backend framework.

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

const app = express();
const server = http.createServer(app);
const io = socket_io(server);

io.on('connection', (server_socket) => {
    // ...
}

Frontend

bring client side socket.io in your html file

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<script src="/socket.io/socket.io.js"></script>

connect in your frontend script file

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const clientSocket = io();

Function

Receive -> on()

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socket.on('<head>', (data) => {
    // deal with data
});

Send -> emit()

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socket.emit('<head>', data);

Send to all client socket except itself -> socket.broadcast.emit()

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socket.broadcast.emit('<head>', data);

Sent to all client socket include itself -> io.emit()

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io.emit('<head>', data);

Group socket together

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socket.join('<name>');

Send to a group

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socket.to('<name>').emit();
socket.broadcast.to('<name>').emit();
io.to('<name>').emit();