socket.io官网中使用express实现了一个最简单的IM即时聊天,今天我们使用koa来实现一下

框架准备

1.确保你本地已经安装好了nodejs和npm,使用koa要求node版本>7.6

2.在你需要的位置新建一个文件夹(官网的简单命名为chat-example)

3.进入项目目录,创建package.json文件:

{
 "name": "socket-chat-example",
 "version": "0.0.1",
 "description": "my first socket.io app",
 "dependencies": {}
}

4.命令行中使用npm安装,执行以下命令

npm install --save koa koa-router http fs socket.io

接下来直接上代码

项目目录下直接新建index.js

var Koa = require('koa');
var app = new Koa();
const Router = require('koa-router');
const fs = require('fs');
const server = require('http').createServer(app.callback());
const io = require('socket.io')(server);
 
// 首页路由
let router = new Router();
router.get('/', ctx => {
  ctx.response.type = 'html';
  ctx.response.body = fs.createReadStream('./index.html');
});
app.use(router.routes());
 
// socket连接
io.on('connection', (socket) => {
  socket.on('chat message', (msg) => {
    console.log('message: '+msg);
    io.emit('chat message', msg);
  });
  socket.on('disconnect', () => {
    console.log('user disconnected');
  });
});
 
// 监听端口
server.listen(3000, () => {
  console.log('listening on *:3000');
});

重点:socket的连接方式是先建立server,它的获取方式不再是:

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

而变成了:

const server = require('http').createServer(app.callback());
const io = require('socket.io')(server);

node8之后,function(){} 可以简化为 () => {},写法上更加的简洁页面index.html

<!doctype html>
<html>
 <head>
  <title>Socket.IO chat</title>
  <style>
   * { margin: 0; padding: 0; box-sizing: border-box; }
   body { font: 13px Helvetica, Arial; }
   form { background: #000; padding: 3px; position: fixed; bottom: 0; width: 100%; }
   form input { border: 0; padding: 10px; width: 90%; margin-right: .5%; }
   form button { width: 9%; background: rgb(130, 224, 255); border: none; padding: 10px; }
   #messages { list-style-type: none; margin: 0; padding: 0; }
   #messages li { padding: 5px 10px; }
   #messages li:nth-child(odd) { background: #eee; }
  </style>
 </head>
 <body>
  <ul id="messages"></ul>
  <form action="">
   <input id="m" autocomplete="off" /><button>Send</button>
  </form>
  <script src="/socket.io/socket.io.js"></script>
  <script src="https://code.jquery.com/jquery-1.11.1.js"></script>
   <script>
     $(function () {
       var socket = io();
       $('form').submit(function(){
         socket.emit('chat message', $('#m').val());
         $('#m').val('');
         return false;
       });
       socket.on('chat message', function(msg){
         $('#message').append($('<li>').text(msg));
       });
     });
   </script>
 </body>
</html>

index.html和官网的一样,不做任何改动

最后执行node index.js,打开浏览器,输入http://localhost:3000就可以实现最简单的聊天了

01-07 16:27