node实例分析

Posted 2021-02-14 senjer

http

const http = require(‘http‘)
const querystring = require(‘querystring‘)

const server = http.createServer((req, res) => {
    const method = req.method
    const url = req.url
    const path = url.split(‘?‘)[0]
    const query = querystring.parse(url.split(‘?‘)[1])

    // 设置返回格式为 JSON
    res.setHeader(‘Content-type‘, ‘application/json‘)

    // 返回的数据
    const resData = {
        method,
        url,
        path,
        query
    }

    // 返回
    if (method === ‘GET‘) {
        res.end(
            JSON.stringify(resData)
        )
    }
    if (method === ‘POST‘) {
        let postData = ‘‘
        req.on(‘data‘, chunk => {
            postData += chunk.toString()
        })
        req.on(‘end‘, () => {
            resData.postData = postData
            // 返回
            res.end(
                JSON.stringify(resData)
            )
        })
    }
})

server.listen(8000)
console.log(‘OK‘)

mysql

const mysql = require(‘mysql‘)

// 创建链接对象
const con = mysql.createConnection({
    host: ‘localhost‘,
    user: ‘root‘,
    password: ‘Mysql_2018‘,
    port: ‘3306‘,
    database: ‘myblog‘
})

// 开始连接
con.connect()

// 执行 sql 语句
const sql = `insert into blogs (title, content, createtime, author) values (‘标题C‘, ‘内容C‘,1546871704408, ‘zhangsan‘)`
con.query(sql, (err, result) => {
    if (err) {
        console.error(err)
        return
    }
    console.log(result)
})

// 关闭连接
con.end()

pm2

pm2.conf.json

{
    "apps": {
        "name": "pm2-test-server",
        "script": "app.js",
        "watch": true,
        "ignore_watch": [
            "node_modules",
            "logs"
        ],
        "instances": 4,
        "error_file": "logs/err.log",
        "out_file": "logs/out.log",
        "log_date_format": "YYYY-MM-DD HH:mm:ss"
    }
}

package.json

{
  "name": "pm2-test",
  "version": "1.0.0",
  "description": "",
  "main": "app.js",
  "scripts": {
    "test": "echo "Error: no test specified" && exit 1",
    "dev": "cross-env NODE_ENV=dev nodemon app.js",
    "prd": "cross-env NODE_ENV=production pm2 start pm2.conf.json"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "cross-env": "^5.2.0",
    "nodemon": "^1.18.9"
  }
}

redis

const redis = require(‘redis‘)

// 创建客户端
const redisClient = redis.createClient(6379, ‘127.0.0.1‘)
redisClient.on(‘error‘, err => {
    console.error(err)
})

// 测试
redisClient.set(‘myname‘, ‘zhangsan2‘, redis.print)
redisClient.get(‘myname‘, (err, val) => {
    if (err) {
        console.error(err)
        return
    }
    console.log(‘val ‘, val)

    // 退出
    redisClient.quit()
})

stream

// 标准输入输出
// process.stdin.pipe(process.stdout)

// 复制文件
const fs = require(‘fs‘)
const path = require(‘path‘)

const fileName1 = path.resolve(__dirname, ‘data.txt‘)
const fileName2 = path.resolve(__dirname, ‘data-bak.txt‘)

const readStream = fs.createReadStream(fileName1)
const writeStream = fs.createWriteStream(fileName2)

readStream.pipe(writeStream)

readStream.on(‘data‘, chunk => {
     console.log(chunk.toString())
 })
 readStream.on(‘end‘, () => {
     console.log(‘copy done‘)
 })

// 读取服务器文件
const http = require(‘http‘)
const fs = require(‘fs‘)
const path = require(‘path‘)
const fileName1 = path.resolve(__dirname, ‘data.txt‘)
const server = http.createServer((req, res) => {
    if (req.method === ‘GET‘) {
        const readStream = fs.createReadStream(fileName1)
        readStream.pipe(res)
    }
})
server.listen(8000)