nodejs常用内置模块、路由、静态资源服务

其他 2020-08-13 10:09:05 阅读次数: 0

一、node常用内置模块

这里介绍几个常用的内置模块：url, querystring, http, events, fs, stream, readline, crypto, zlib

1、url

1.1 parse

url.parse(urlString[, parseQueryString[, slashesDenoteHost]])

const url = require('url')
const urlString = 'https://www.baidu.com:443/ad/index.html?id=8&name=mouse#tag=110'
const parsedStr = url.parse(urlString)
console.log(parsedStr)

运行结果
在这里插入图片描述

1.2 format

url.format(urlObject)

const url = require('url')
const urlObject = {
  protocol: 'https:',
  slashes: true,
  auth: null,
  host: 'www.baidu.com:443',
  port: '443',
  hostname: 'www.baidu.com',
  hash: '#tag=110',
  search: '?id=8&name=mouse',
  query: { id: '8', name: 'mouse' },
  pathname: '/ad/index.html',
  path: '/ad/index.html?id=8&name=mouse',
  href: 'https://www.baidu.com:443/ad/index.html?id=8&name=mouse#tag=110'
}
const parsedObj = url.format(urlObject)
console.log(parsedObj)

在这里插入图片描述

1.3 resolve

url.resolve(from, to)

const url = require('url')
var a = url.resolve('/one/two/three', 'four')
var b = url.resolve('http://example.com/', '/one')
var c = url.resolve('http://example.com/one', '/two')
console.log(a + "," + b + "," + c)

在这里插入图片描述

2、querystring

2.1 parse

querystring.parse(str[, sep[, eq[, options]]])

const querystring = require('querystring')
var qs = 'x=3&y=4'
var parsed = querystring.parse(qs)
console.log(parsed)

在这里插入图片描述

2.2 stringify

querystring.stringify(obj[, sep[, eq[, options]]])

const querystring = require('querystring')
var qo = {
  x: 3,
  y: 4
}
var parsed = querystring.stringify(qo)
console.log(parsed)

在这里插入图片描述

2.3 escape/unescape

querystring.escape(str)

const querystring = require('querystring')
var str = 'id=3&city=北京&url=https://www.baidu.com'
var escaped = querystring.escape(str)
console.log(escaped)

在这里插入图片描述
querystring.unescape(str)

const querystring = require('querystring')
var str = 'id%3D3%26city%3D%E5%8C%97%E4%BA%AC%26url%3Dhttps%3A%2F%2Fwww.baidu.com'
var unescaped = querystring.unescape(str)
console.log(unescaped)

在这里插入图片描述

3、http/https

3.1 get

var http = require('http')
var https = require('https')

// 1、接口 2、跨域
const server = http.createServer((request, response) => {
  var url = request.url.substr(1)

  var data = ''

  response.writeHeader(200, {
    'content-type': 'application/json;charset=utf-8',
    'Access-Control-Allow-Origin': '*'
  })

  https.get(`https://m.lagou.com/listmore.json${url}`, (res) => {

    res.on('data', (chunk) => {
      data += chunk
    })

    res.on('end', () => {
      response.end(JSON.stringify({
        ret: true,
        data
      }))
    })
  })

})

server.listen(8080, () => {
  console.log('localhost:8080')
})

3.2 post：服务器提交（攻击）

const https = require('https')
const querystring = require('querystring')

const postData = querystring.stringify({
  province: '上海',
  city: '上海',
  district: '宝山区',
  address: '同济支路199号智慧七立方3号楼2-4层',
  latitude: 43.0,
  longitude: 160.0,
  message: '求购一条小鱼',
  contact: '13666666',
  type: 'sell',
  time: 1571217561
})

const options = {
  protocol: 'https:',
  hostname: 'ik9hkddr.qcloud.la',
  method: 'POST',
  port: 443,
  path: '/index.php/trade/add_item',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded',
    'Content-Length': Buffer.byteLength(postData)
  }
}

function doPost() {
  let data

  let req = https.request(options, (res) => {
    res.on('data', chunk => data += chunk)
    res.on('end', () => {
      console.log(data)
    })
  })

  req.write(postData)
  req.end()
}

// setInterval(() => {
//   doPost()
// }, 1000)

3.3 跨域：jsonp

const http = require('http')
const url = require('url')

const app = http.createServer((req, res) => {
  let urlObj = url.parse(req.url, true)

  switch (urlObj.pathname) {
    case '/api/user':
      res.end(`${urlObj.query.cb}({"name": "gp145"})`)
      break
    default:
      res.end('404.')
      break
  }
})

app.listen(8080, () => {
  console.log('localhost:8080')
})

3.4 跨域：CORS

const http = require('http')
const url = require('url')
const querystring = require('querystring')

const app = http.createServer((req, res) => {
  let data = ''
  let urlObj = url.parse(req.url, true)

  res.writeHead(200, {
    'content-type': 'application/json;charset=utf-8',
    'Access-Control-Allow-Origin': '*'
  })

  req.on('data', (chunk) => {
    data += chunk
  })

  req.on('end', () => {
    responseResult(querystring.parse(data))
  })

  function responseResult(data) {
    switch (urlObj.pathname) {
      case '/api/login':
        res.end(JSON.stringify({
          message: data
        }))
        break
      default:
        res.end('404.')
        break
    }
  }
})

app.listen(8080, () => {
  console.log('localhost:8080')
})

3.5 跨域：middleware（http-proxy-middware）

const http = require('http')
const proxy = require('http-proxy-middleware')

http.createServer((req, res) => {
  let url = req.url

  res.writeHead(200, {
    'Access-Control-Allow-Origin': '*'
  })

  if (/^\/api/.test(url)) {
    let apiProxy = proxy('/api', { 
      target: 'https://m.lagou.com',
      changeOrigin: true,
      pathRewrite: {
        '^/api': ''
      }
    })

    // http-proy-middleware 在Node.js中使用的方法
    apiProxy(req, res)
  } else {
    switch (url) {
      case '/index.html':
        res.end('index.html')
        break
      case '/search.html':
        res.end('search.html')
        break
      default:
        res.end('[404]page not found.')
    }
  }
}).listen(8080)

3.6 爬虫

const https = require('https')
const http = require('http')
const cheerio = require('cheerio')

http.createServer((request, response) => {
  response.writeHead(200, {
    'content-type': 'application/json;charset=utf-8'
  })

  const options = {
    protocol: 'https:',
    hostname: 'maoyan.com',
    port: 443,
    path: '/',
    method: 'GET'
  }

  const req = https.request(options, (res) => {
    let data = ''
    res.on('data', (chunk) => {
      data += chunk
    })

    res.on('end', () => {
      filterData(data)
    })
  })

  function filterData(data) {
    let $ = cheerio.load(data)
    let $movieList = $('.movie-item')
    let movies = []
    $movieList.each((index, value) => {
      movies.push({
        title: $(value).find('.movie-title').attr('title'),
        score: $(value).find('.movie-score i').text(),
      })
    })

    response.end(JSON.stringify(movies))
  }

  req.end()
}).listen(9000)

4、Events

const EventEmitter = require('events')

class MyEventEmitter extends EventEmitter {}

const event = new MyEventEmitter()

event.on('play', (movie) => {
  console.log(movie)
})

event.emit('play', '我和我的祖国')
event.emit('play', '中国机长')

5、File System

const fs = require('fs')
const fsP = require('fs').promises

// 创建文件夹
fs.mkdir('./logs', (err) => {
  console.log('done.')
})

// 文件夹改名
fs.rename('./logs', './log', () => {
  console.log('done')
})

// 删除文件夹
fs.rmdir('./log', () => {
  console.log('done.')
})

// 写内容到文件里
fs.writeFile(
  './logs/log1.txt',
  'hello',
  // 错误优先的回调函数
  (err) => {
    if (err) {
      console.log(err.message)
    } else {
      console.log('文件创建成功')
    }
  }
)

// 给文件追加内容
fs.appendFile('./logs/log1.txt', '\nworld', () => {
  console.log('done.')
})

// 读取文件内容
fs.readFile('./logs/log1.txt', 'utf-8', (err, data) => {
  console.log(data)
})

// 删除文件
fs.unlink('./logs/log1.txt', (err) => {
  console.log('done.')
})

// 批量写文件
for (var i = 0; i < 10; i++) {
  fs.writeFile(`./logs/log-${i}.txt`, `log-${i}`, (err) => {
    console.log('done.')
  })
}

// 读取文件/目录信息
fs.readdir('./', (err, data) => {
  data.forEach((value, index) => {
    fs.stat(`./${value}`, (err, stats) => {
      // console.log(value + ':' + stats.size)
      console.log(value + ' is ' + (stats.isDirectory() ? 'directory' : 'file'))
    })
  })
})

// 同步读取文件
try {
  const content = fs.readFileSync('./logs/log-1.txt', 'utf-8')
  console.log(content)
  console.log(0)
} catch (e) {
  console.log(e.message)
}

console.log(1)

// 异步读取文件：方法一
fs.readFile('./logs/log-0.txt', 'utf-8', (err, content) => {
  console.log(content)
  console.log(0)
})
console.log(1)

// 异步读取文件：方法二
fs.readFile('./logs/log-0.txt', 'utf-8').then(result => {
  console.log(result)
})

// 异步读取文件：方法三
function getFile() {
  return new Promise((resolve) => {
    fs.readFile('./logs/log-0.txt', 'utf-8', (err, data) => {
      resolve(data)
    })
  })
}

;(async () => {
  console.log(await getFile())
})()

// 异步读取文件：方法四
const fsp = fsP.readFile('./logs/log-1.txt', 'utf-8').then((result) => {
  console.log(result)
})

console.log(fsP)

// watch 监测文件变化
fs.watch('./logs/log-0.txt', () => {
  console.log(0)
})

6、Stream文件流

const fs = require('fs')

const readstream = fs.createReadStream('./note.txt')
const writestream = fs.createWriteStream('./note2.txt')

writestream.write(readstream)

7、Zlib压缩

const fs = require('fs')
const zlib = require('zlib')

const gzip = zlib.createGzip()

const readstream = fs.createReadStream('./note.txt')
const writestream = fs.createWriteStream('./note2.txt')

readstream
  .pipe(gzip)
  .pipe(writestream)

writestream.write(readstream)

8、ReadLine接收输入框里键盘输入的内容

const readline = require('readline')

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
})

rl.question('What do you think of Node.js? ', (answer) => {
  // TODO: Log the answer in a database
  console.log(`Thank you for your valuable feedback: ${answer}`)

  rl.close()
})

9、Crypto加密

const crypto = require('crypto')

const secret = 'abcdefg'
const hash = crypto.createHmac('sha256', secret)  //sha256 非对称加密算法  sha1是对称加密
                   .update('I love you')
                   .digest('hex')//编码格式 hex是16进制
console.log(hash)

转换的编码位数不会变
在这里插入图片描述

二、路由

const http = require('http')
const fs = require('fs')

const app = http.createServer((req, res) => {
  let url = req.url

  switch(url) {
    case '/home':
      res.end('home page.')
      break
    case '/style.css':
      fs.readFile('./style.css', (err, page) => {
        res.end(page)
      })
      break
    case '/script.js':
      fs.readFile('./script.js', (err, page) => {
        res.end(page)
      })
      break
    case '/banner8.jpg':
      fs.readFile('./banner8.jpg', 'binary', (err, page) => {
        res.write(page, 'binary')
        res.end()
      })
      break
    default:
      fs.readFile('./404.html', (err, page) => {
        res.end(page)
      })
  }
})

app.listen(8080, () => {
  console.log('localhost: 8080')
})

目录结构
在这里插入图片描述

三、静态资源服务

1 readStaticFile

const http = require('http')
const fs = require('fs')
const url = require('url')
const mime = require('mime')
const path = require('path')

function readStaticFile(res, filePathName) {
  //mime 类型
  var ext = path.parse(filePathName).ext

  var mimeType = mime.getType(ext)

  fs.readFile(filePathName, (err, data) => {
    if (err) {
      res.writeHead(404, {
        'Content-Type': 'text/plain'
      })
      res.end('page not found.')
    } else {
      res.writeHead(200, {
        'Content-Type': mimeType
      })
      res.end(data)
    }
  })
}

const app = http.createServer((req, res) => {
  var urlObj = url.parse(req.url)
  var urlPathName = urlObj.pathname

  var filePathName = path.join(__dirname, '/public', urlPathName)

    (res, filePathName)
  res.writeHead(200, {
    'Content-Type': 'application/json'
  })
  res.end(JSON.stringify({
    name: 'gp19'
  }))
})

app.listen(8081, () => {
  console.log('localhost: 8081')
})

https://lurongtao.gitee.io/felixbooks-gp19-node.js/basics/01-Node.js%E5%9F%BA%E7%A1%80.html在这里插入图片描述

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