[Day 7] 零碳運算 - 接通互聯網的另一端

15th鐵人賽

kingkenleung

團隊沙培小子

2023-09-22 23:59:45

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socket.io 在伺服器的設置

又要擴充node_module了，這次請在終端輸入npm install socket.io，以安裝socket.io。然後，在原先的index.js中修改幾筆，使之變成—

const express = require('express');
const app = express();

// This part is new!
const http = require('http');
const server = http.createServer(app);
const { Server } = require('socket.io');
const io = new Server(server);

const PORT = 3000;

io.on('connection', (socket) => {
    console.log("User is connected")

    socket.on('disconnect', () => {
        console.log('User disconnected');
    });
})

app.use("/", express.static("public"));

// It is no longer app.listen()!
server.listen(PORT, () => console.log(`Server listening on port: ${PORT}`));

socket.io 於客戶端的設置

客戶端比較容易，參考官方網站，我們只需利用CDN就可將socket.io放在網頁上。完成後的index.html像這樣：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>零碳運算</title>

</head>

<body>
    <h1>零碳運算</h1>
    <input></input>
    <input type="button" value="send"></input>

    <!-- socket.io from CDN -->
    <script src="https://cdn.socket.io/4.6.0/socket.io.min.js"
        integrity="sha384-c79GN5VsunZvi+Q/WObgk2in0CbZsHnjEqvFxC5DxHn9lTfNce2WW6h2pH6u/kF+"
        crossorigin="anonymous"></script>

    <!-- our client-side script -->
    <script src="script.js" defer></script>
</body>

</html>

然後，我們便可以在script.js 中加入socket.io的接通咒語。
const socket = io();

就是這樣，就接通了互聯網的另一端—你可以在伺服器的終端實時看到客戶端的人何時連接，何時斷開，這已超越了以往倚賴HTTP通訊所能做的了。