Nodejs+koa.js实现服务端内容（超级详细

npm i koa koa-router koa-bodyparser nodemon

project
│   README.md
│   .env    
│   package.json
└───src
│   └───app  // 服务端代码实现
│    │   │   index.ts  // 引入koa及相关内容，导出 
│    │   │   config.ts  // 导出.env中的环境变量
│    │   │   database.ts  // 连接数据库
│    │   │   
│    └───controller // 对应的业务处理层
│    └───middleware  // 中间件
│    └───router  // 匹配 路由
│    └───service  // SQL相关操作
│    └───type
│     │   main.ts // 服务端启动文件
│   
└───node_modules
    │   ...

mysqld --initialize

./mysqld --initialize

systemctl start mysqld

systemctl status mysqld

mysqladmin -u root password "new_password";

./mysql -u root -p
Enter password:*******

npm i mysql2

"scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "cross-env NODE_ENV=development nodemon ./src/main.ts"
  },

const app = require('./app')
const config = require('./app/config') // config中读取了.env中配置的环境变量

app.listen(config.port, () => {
  console.log('8001 OK')
})

const mysql = require('mysql2')
const config = require('./config')

const connections = mysql.createPool({
  host: config.sql_host,
  user: config.user,
  port: config.sql_port,
  password: config.password,
  database: config.database
})

connections.getConnection((err: any, conn: any) => {
  conn.connect((err: any) => {
    if (err) {
      console.log('sql error')
    } else {
      console.log('sql OK')
    }
  })
})

module.exports = connections.promise()

const koa = require('koa')
//解析请求参数的
const bodyParser = require('koa-bodyparser')
const routers = require('../router/index') //整合所有的页面统一返回路由
const errorHandler = require('./error-handle') //处理错误函数

const app = new koa()

app.on('error', errorHandler)
app.use(bodyParser()) //解析请求参数的
// 调用router.routes()来组装匹配好的路由，返回一个合并好的中间件
Object.keys(routers).map(item => {
  app.use(routers[item].routes())
  app.use(
    routers[item].allowedMethods({
      // throw: true, // 抛出错误，代替设置响应头状态
      // notImplemented: () => '不支持当前请求所需要的功能',
      // methodNotAllowed: () => '不支持的请求方式'
    })
  )
})
// 调用router.allowedMethods()获得一个中间件
// 当发送了不符合的请求时，会返回 `405 Method Not Allowed` 或 `501 Not Implemented`

module.exports = app

const Router = require('koa-router')
//controller中定义了对应接口的处理方法
const { login, create, getUserInfo, userLogout } = require('../controller/user') 
//接口参数验证自定义中间件
const { verifyUser, verifyLogin, verifyToken } = require('../middleware/user') 
const userRouter = new Router({ prefix: '/api' })

userRouter.post('/create', verifyUser, create)
userRouter.post('/login', verifyLogin, login)
userRouter.post('/logout', userLogout)
userRouter.get('/userInfo', verifyToken, getUserInfo)

module.exports = userRouter

const service = require('../service/user')
var jwt = require('jsonwebtoken')
import { UserRes } from '../type/user'
import { CommonRes } from '../type/common'

class UserController {
  // 登录
  async login(ctx: any) {
    // 获取用户请求参数
    const user = ctx.request.body
    let token = jwt.sign(user, 'shhhhh', {
      expiresIn: 60 * 60 * 24
    })
    const result: CommonRes = {
      code: 200,
      message: '登录成功！',
      token: token
    }
    // 返回数据
    ctx.body = result
  }
  // 登出
  async userLogout(ctx: any) {
    const result: CommonRes = {
      code: 200,
      message: '登出成功'
    }
    // 返回数据
    ctx.body = result
  }
  // 创建账户
  async create(ctx: any) {
    // 获取用户请求参数
    const user = ctx.request.body
    // 查数据库
    const result: CommonRes = await service.create(user) //数据库操作创建账号
    // 返回数据
    ctx.body = result
  }
 
  
}

module.exports = new UserController()

// 只做数据库处理操作
const connection = require('../app/database')
import { UserReq } from '../type/user'
import { CommonRes } from '../type/common'

class UserService {
  async create(user: UserReq) {
    const { username, password } = user
    const statement = `INSERT INTO users (name, password) VALUES (?, ?);`
    const createUsersTable = `CREATE TABLE IF NOT EXISTS users(
	id INT PRIMARY KEY AUTO_INCREMENT,
	username VARCHAR(20) NOT NULL UNIQUE,
	password VARCHAR(50) NOT NULL,
	createAt TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
	updateAt TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP`
    try {
      const createResq = await connection.query(createUsersTable)
    } catch (error) {
      console.log(error)
    }
    const result = await connection.execute(statement, [username, password])
    const res: CommonRes = {
      code: 200,
      message: '创建成功'
    }
    // 将user 存储到数据库
    return res
  }

  //查询用户是否存在
  async getUserByName(name: string) {
    const statement = `SELECT * FROM users WHERE name = ?;`
    const result = await connection.execute(statement, [name])
    return result
  }
}

module.exports = new UserService()