Day15 [实作] 使用 Socket.io 建立聊天室

实作

聊天室 server 端，使用 SSL
聊天室 client 端，使用 SSL

为什麽要使用 Socket.io

使用webSocket
1. 建立在 TCP 协议之上
2. 资料格式比较轻量
3. 可以发送文字，也可以发送二进位资料
有房间的概念
跨平台(浏览器/IOS/Android/…)，跨语言

服务器端实作

建立专案

cd Desktop/WebRTC/sample
mkdir socketio-chartroom
cd socketio-chartroom
touch server.js
npm init --yes
npm install express socket.io

产生本地端开发用SSL凭证
1. 安装 mkcert
2. 开启终端机 cd 到专案下
3. mkcert -install
4. mkcert 0.0.0.0 localhost 127.0.0.1 ::1
5. mv 0.0.0.0+3-key.pem key.pem & mv 0.0.0.0+3.pem cert.pem

在 server.js 加入以下程序码

'use strict'

const https = require('https')
const fs = require('fs')
const express = require('express')
const socketIo = require('socket.io')

const app = express()

const options = {
  key: fs.readFileSync('key.pem'),
  cert: fs.readFileSync('cert.pem'),
}

const https_server = https.createServer(options, app)
https_server.listen(4443, '0.0.0.0')

const io = socketIo(https_server, {
  cors: true,
})

// 收到使用者连线
io.sockets.on('connection', (socket) => {
  console.log(socket.id, '已连线')

  socket.on('message', (room, data) => {
    io.in(room).emit('message', room, data)
  })

  socket.on('join', (room) => {
    socket.join(room)
    socket.emit('joined', room, socket.id)
  })

  socket.on('leave', (room) => {
    socket.leave(room)
    socket.to(room).emit('bye', room, socket.id)
    socket.emit('leave', room, socket.id)
  })
})

使用者端实作

在专案内新增一个 client 资料夹及以下结构

client
├── index.html
└── js
    └── client.js

在 index.html 中加入

<html>
  <head>
    <title>Chat Room</title>
  </head>
  <body>
    <table align="center">
      <h1 style="text-align: center">聊天室</h1>
      <tr>
        <td>
          <label for="username">UserName: </label>
          <input type="text" id="username" />
        </td>
      </tr>
      <tr>
        <td>
          <label for="room">room: </label><input type="text" id="room" />
          <button id="connect">Connect</button>
          <button id="leave" disabled>Leave</button>
        </td>
      </tr>
      <tr>
        <td>
          <label for="output">Content: </label><br />
          <textarea disabled style="line-height: 1.5" id="output" rows="10" cols="100"></textarea>
        </td>
      </tr>
      <tr>
        <td>
          <label for="input">Input: </label><br />
          <textarea disabled id="input" rows="3" cols="100"></textarea>
        </td>
      </tr>
      <tr>
        <td>
          <button id="send">Send</button>
        </td>
      </tr>
    </table>

    <script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/4.0.1/socket.io.js"></script>
    <script src="./js/client.js"></script>
  </body>
</html>

在 client.js 中加入

'use strict'

const userName = document.querySelector('input#username')
const inputRoom = document.querySelector('input#room')
const btnConnect = document.querySelector('button#connect')
const btnLeave = document.querySelector('button#leave')
const outputArea = document.querySelector('textarea#output')
const inputArea = document.querySelector('textarea#input')
const btnSend = document.querySelector('button#send')

let socket
let room

btnConnect.onclick = () => {
  socket = io('wss://localhost:4443')

  socket.on('joined', (room, id) => {
    btnConnect.disabled = true
    btnLeave.disabled = false
    inputArea.disabled = false
    btnSend.disabled = false
  })

  socket.on('leave', (room, id) => {
    btnConnect.disabled = false
    btnLeave.disabled = true
    inputArea.disabled = true
    btnSend.disabled = true

    socket.disconnect()
  })

  socket.on('message', (room, data) => {
    console.log(room, data)
    outputArea.scrollTop = outputArea.scrollHeight
    outputArea.value = outputArea.value + data + '\n'
  })

  socket.on('disconnect', (reason) => {
    btnConnect.disabled = false
    btnLeave.disabled = true
    inputArea.disabled = true
    btnSend.disabled = true
  })

  room = inputRoom.value
  socket.emit('join', room)
}

btnSend.onclick = () => {
  let data = inputArea.value
  data = userName.value + ':' + data
  socket.emit('message', room, data)
  inputArea.value = ''
}

btnLeave.onclick = () => {
  room = inputRoom.value
  socket.emit('leave', room)
}

inputArea.onkeypress = (event) => {
  if (event.keyCode === 13) {
    let data = inputArea.value
    data = userName.value + ':' + data
    socket.emit('message', room, data)
    inputArea.value = ''
    event.preventDefault()
  }
}