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\",
 \"de ion\": \"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>
  < >Socket.IO chat</ >
  <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>
  <  src=\"/socket.io/socket.io.js\"></ >
  <  src=\"https://code.jquery.com/jquery-1.11.1.js\"></ >
   < >
     $(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));
       });
     });
   </ >
 </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

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。

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