Node.js基础（二）

1. NodeJs操作Mongodb

1.1. 连接数据库

const mongoose = require("mongoose")
mongoose.connect("mongodb://127.0.0.1:27017/company-system")

1.2. 创建模型

const mongoose = require("mongoose")
const Schema = mongoose.Schemaconst UserType = {username:String,password:String,gender:Number,introduction:String,avatar:String,role:Number
}
const UserModel = mongoose.model("user",new Schema(UserType))
module.exports  = UserModel

1.3. 增加数据

UserModel.create({introduction,username,gender,avatar,password,role
})

1.4. 查询数据

UserModel.find({username:"wyb"},["username","role","introduction","password"]).sort({createTime:-1}).skip(10).limit(10)

1.5. 更新数据

UserModel.updateOne({ _id },{ introduction,username,gender,avatar })

1.6. 删除数据

UserModel.deleteOne({_id})

2. 登录鉴权

2.1. Cookie && Session

在这里插入图片描述

const express = require("express");
const session = require("express-session");
const MongoStore = require("connect-mongo");
const app = express();app.use(session({secret: "this is session", // 服务器生成 session 的签名resave: true, saveUninitialized: true, // 强制将为初始化的 session 存储cookie: {maxAge: 1000 * 60 * 10,// 过期时间secure: false, // true：只有 https 协议才能访问cookie},rolling: true, // true：超时前刷新，cookie 会重新计时；false：在超时前刷新多少次，都是按照第一次刷新开始计时。store: MongoStore.create({mongoUrl: 'mongodb://127.0.0.1:27017/kerwin_session',ttl: 1000 * 60 * 10 // 过期时间}),})
);app.use((req,res,next)=>{if(req.url==="/login"){next()return;}if(req.session.user){req.session.garbage = Date();next();} else{res.redirect("/login")   }
})

2.2. JSON Web Token (JWT)

在这里插入图片描述

代码实现

//jsonwebtoken 封装
const jsonwebtoken = require("jsonwebtoken")
const secret = "wyb- secret"
const JWT = {generate(value, exprires){return jsonwebtoken.sign(value, secret, {expiresIn: exprires})},verify(token){try {return jsonwebtoken.verify(token, secret)} catch(e) {return false}}
}
module.exports = JWT

//node中间件校验
app.use((req,res,next)=>{// 如果token有效 ,next() // 如果token过期了, 返回401错误if(req.url==="/login"){next()return;}const token = req.headers["authorization"].split(" ")[1]if(token) {const payload = JWT.verify(token)if(payload) {const newToken = JWT.generate({_id: payload._id,username: payload.username}, "1d")res.header("Authorization", newToken)next()} else {res.status(401).send({errCode: "-1", errorInfo: "token过期"})}}
})

// 生成token
const token = JWT.generate({_id: result[0]._id,username: result[0].username
}, "1d")
res.header("Authorization", token)

3. 文件上传管理

Multer 是一个 node.js 中间件，用于处理 multipart/form-data 类型的表单数据，它主要用于上传文件。

前端

const params = new FormData()
params.append('wybfile', file.file)
params.append('username', this.username)
const config = {headers: {"Content-Type":"multipart/form-data"}
}
http.post('/api/upload', params, config).then(res => {this.imgpath = 'http://localhost:3000' + res.data
})

Multer 会添加一个 body 对象以及 file 或 files 对象到 express 的 request 对象中。 body 对象包含表单的文本域信息，file 或 files 对象包含对象表单上传的文件信息。

后端

router.post('/upload', upload.single('wybfile'),function(req, res, next) {console.log(req.file)
})

4. 操作MySQL

const express = require('express')
const app = express()
const mysql2 = require('mysql2')
const port = 9000app.get('/', async (req, res) => {const config = getDBConfig()const promisePool = mysql2.createPool(config).promise();let user = await promisePool.query('select * from students');if (user[0].length) {// 存在用户res.send(user[0])} else {// 不存在res.send( {code: -2,msg: 'user not exsit',})}      
})
app.listen(port, () => {console.log(`Example app listening at http://localhost:${port}`)
})function getDBConfig() {return {host: '127.0.0.1',user: 'root',port: 3306,password: '',database: 'wyb_test',connectionLimit: 1 // 创建一个连接池}
}

查询：promisePool.query('select * from users');
插入：promisePool.query('INSERT INTO `users`(`id`,`name`,`age`, `password`) VALUES (?,?,?,?)',[null,"kerwin",100,"123456"]);
更新：promisePool.query(`UPDATE users SET name = ? ,age=? WHERE id = ?`,["xiaoming2",20,1])
删除：promisePool.query(`delete from users where id=?`,[1])

5. Socket编程

5.1. ws模块

服务端

const  WebSocket = require("ws")
WebSocketServer = WebSocket.WebSocketServer
const wss = new WebSocketServer({ port: 8080 });wss.on('connection', function connection(ws) {ws.on('message', function message(data, isBinary) {wss.clients.forEach(function each(client) {if (client !== ws && client.readyState === WebSocket.OPEN) {client.send(data, { binary: isBinary });}});});ws.send('欢迎加入聊天室');
});

客户端

let ws = new WebSocket("ws://localhost:8080")
ws.onopen = ()=>{console.log("open")
}
ws.onmessage = (evt)=>{console.log(evt.data)
}

5.2. 授权验证

// 前端
var ws = new WebSocket(`ws://localhost:8080?token=${localStorage.getItem("token")}`)
ws.onopen = () => {ws.send(JSON.stringify({type: WebSocketType.GroupList}))
}
ws.onmessage = (evt) => {console.log(evt.data)
}
// 后端
const WebSocket = require("ws");
const JWT = require('../util/JWT');
WebSocketServer = WebSocket.WebSocketServer
const wss = new WebSocketServer({ port: 8080 });wss.on('connection', function connection(ws, req) {const myURL = new URL(req.url, 'http://127.0.0.1:3000');const payload = JWT.verify(myURL.searchParams.get("token"))if (payload) {ws.user = payloadws.send(createMessage(WebSocketType.GroupChat, ws.user, "欢迎来到聊天室"))sendBroadList() //发送好友列表} else {ws.send(createMessage(WebSocketType.Error, null, "token过期"))}ws.on('message', function message(data, isBinary) {const messageObj = JSON.parse(data)switch (messageObj.type) {case WebSocketType.GroupList:ws.send(createMessage(WebSocketType.GroupList, ws.user, JSON.stringify(Array.from(wss.clients).map(item => item.user))))break;case WebSocketType.GroupChat:wss.clients.forEach(function each(client) {if (client !== ws && client.readyState === WebSocket.OPEN) {client.send(createMessage(WebSocketType.GroupChat, ws.user, messageObj.data));}});break;case WebSocketType.SingleChat:wss.clients.forEach(function each(client) {if (client.user.username === messageObj.to && client.readyState === WebSocket.OPEN) {client.send(createMessage(WebSocketType.SingleChat, ws.user, messageObj.data));}});break;}ws.on("close",function(){// 删除当前用户wss.clients.delete(ws.user)sendBroadList() //发送好用列表})});
});
const WebSocketType = {Error: 0, //错误GroupList: 1,//群列表GroupChat: 2,//群聊SingleChat: 3//私聊
}
function createMessage(type, user, data) {return JSON.stringify({type: type,user: user,data: data});
}function sendBroadList(){wss.clients.forEach(function each(client) {if (client.readyState === WebSocket.OPEN) {client.send(createMessage(WebSocketType.GroupList, client.user, JSON.stringify(Array.from(wss.clients).map(item => item.user))))}});
}

5.3. socket.io模块

服务端

const io = require('socket.io')(server);
io.on('connection', (socket) => {const payload = JWT.verify(socket.handshake.query.token)if (payload) {socket.user = payloadsocket.emit(WebSocketType.GroupChat, createMessage(socket.user, "欢迎来到聊天室"))sendBroadList() // 发送好友列表} else {socket.emit(WebSocketType.Error, createMessage(null, "token过期"))}socket.on(WebSocketType.GroupList, () => {socket.emit(WebSocketType.GroupList, createMessage(null, Array.from(io.sockets.sockets).map(item => item[1].user).filter(item=>item)));})socket.on(WebSocketType.GroupChat, (messageObj) => {socket.broadcast.emit(WebSocketType.GroupChat, createMessage(socket.user, messageObj.data));})socket.on(WebSocketType.SingleChat, (messageObj) => {Array.from(io.sockets.sockets).forEach(function (socket) {if (socket[1].user.username === messageObj.to) {socket[1].emit(WebSocketType.SingleChat, createMessage(socket[1].user, messageObj.data));}})})socket.on('disconnect', reason => {sendBroadList() // 发送好用列表});
});function sendBroadList() {io.sockets.emit(WebSocketType.GroupList, createMessage(null, Array.from(io.sockets.sockets).map(item => item[1].user).filter(item=>item)))
}
// 最后filter，是因为 有可能存在null的值

客户端

const WebSocketType = {Error: 0, //错误GroupList: 1, //群列表GroupChat: 2, //群聊SingleChat: 3 //私聊
}
const socket = io(`ws://localhost:3000?token=${localStorage.getItem("token")}`);
socket.on("connect",()=>{socket.emit(WebSocketType.GroupList)
})
socket.on(WebSocketType.GroupList, (messageObj) => {select.innerHTML = ""select.innerHTML = `<option value="all">all</option>` + messageObj.data.map(item => `<option value="${item.username}">${item.username}</option>`).join("")
})
socket.on(WebSocketType.GroupChat, (msg) => {console.log(msg)
})
socket.on(WebSocketType.SingleChat, (msg) => {console.log(msg)
})
socket.on(WebSocketType.Error, (msg) => {localStorage.removeItem("token")location.href = "/login"
})
send.onclick = () => {if (select.value === "all") {socket.emit(WebSocketType.GroupChat,{data: text.value})} else {socket.emit(WebSocketType.SingleChat,{data: text.value,to:select.value})}
}