let app = require('http').createServer() 
let io = require('socket.io')(app)

app.listen(3000); 

let io = require('socket.io')(app, { 
 serveClient: false
})

let app = require('http').createServer() 
let io = require('socket.io')() 
io.serveClient(false) 
io.listen(app) // 或者io.attach(app) 

let io = require('socket.io')(app, { 
 path: '/io'
})

let app = require('http').createServer() 
let io = require('socket.io')() 
io.path('/io') 
io.listen(app) 

let socket = io('http://localhost:3000?token=abc') 
socket.on('connect', () => { 
 console.log('connect')
})
socket.on('connect_error', err => { 
 socket.disconnect()
 console.log('connect_error', err)
})

let app = require('http').createServer() 
let io = require('socket.io')(app, { 
 allowRequest: (req, cb) => {
 if (req._query && req._query.token === 'abc') return cb(null, true)
 cb(null, false)
 }
});

let app = require('http').createServer() 
let io = require('socket.io')(app, { 
 origins: 'http://localhost:3000'
})

io.origins('http://localhost:*')

io.origins((origin, cb) => { 
 if (origin === 'http://localhost:3000/') return cb(null, true)
 cb(null, false)
})

let editSocket = io('edit.socket.test') 
let messageSocket = io('message.socket.test') 

let app = require('http').createServer() 
let io = require('socket.io')(app) 
let editServer = io.of('/edit') 
let messsageServer = io.of('/message') 
editServer.on('connection', socket => { 
 //编辑相关
})
messsageServer.on('connection', socket => { 
 /消息相关
})

let editSocket = io('socket.test/edit') 
let messageSocket = io('socket.test/message') 

let app = require('http').createServer() 
let io = require('socket.io')(app)

io.on('connection', socket => { 
 //编辑相关
 io.emit('edit:test')
 io.on('edit:test', data => {

 })
 //消息相关
 io.emit('message:test')
 io.on('message:test', data => {

 })
}

let app = require('http').createServer() 
let io = require('socket.io')(app)

io.sockets // io.of('/').sockets 
io.emit // 代理io.of('/').emit, 类似函数有'to', 'in', 'use', 'send', 'write', 'clients', 'compress' 

io.use((socket, next) => { 
 if (socket.request.headers.cookie) return next()
 next(new Error('Authentication error'))
})

socket.join('room name') //进入 
socket.leave('room name') //退出 

io.to('some room').emit('some event') // io.to与io.in同义，向某个聊天室的所有成员发送消息

socket.on('say to someone', (id, msg) => { 
 socket.broadcast.to(id).emit('my message', msg)
})

io.on('connection', socket => { 
 socket.emit('an event', { some: 'data' }) //普通消息

 socket.emit('ferret', 'tobi', function (data) { //应答消息
 console.log(data); // data will be 'woot'
 })
})

socket.on('ferret', (name, fn) => { 
 fn('woot')
})

// 客户端发送消息
socket.emit('hello', 'can you hear me?', 1, 2, 'abc');

// 向所有连接的客户端（除了自己)发送消息
socket.broadcast.emit('broadcast', 'hello friends!');

// 向game聊天室发送消息,自己不算
socket.to('game').emit('nice game', "let's play a game");

// 同时向game1和game2聊天室发送消息，自己不算
socket.to('game1').to('game2').emit('nice game', "let's play a game (too)");

// 向game聊天室的所有人发送消息
io.in('game').emit('big-announcement', 'the game will start soon');

// 发送消息到<socketid>客户端
socket.to(<socketid>).emit('hey', 'I just met you');

// 发送应答消息
socket.emit('question', 'do you think so?', function (answer) {});