# 2.1.5 在express中使用Socket.io

## Server(app.js)

```javascript
const app= require('express')()
const server = require('http').Server(app);
const io = require('socket.io')(server)

server.listen(80)
// 警告：app.listen(80)在这里没起作用，可能有端口被占用情况

app.get('/',(req,res)=>{
    res.sendFile(__dirname+'/index.html')
})

io.on('connection',(socket)=>{
    socket.emit('news',{hello:'world'}
    socket.on('my other event',(data)=>{
        console.log(data)
    })
})
```

## Client(index.html)

```markup
<script src="/socket.io/socket.io.js"></script>
<script>
    const socket= io.connect('http://localhost')
    socket.on('news',(data)=>{
        console.log(data)

        socket.emit('my other event',{my:'data'})
    })
</script>
```


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