Related articles

  • P01: Node.js tutorial from a practical perspective
  • P02: Basic node usage
  • P03: Node built-in module PATH
  • P04: Buffer for nodeAPI
  • P05: Events of node built-in module
  • P06: Node built-in module FS (1)
  • P07: Node built-in module FS (2)
  • P08: Node implements static server ~ create project
  • P09: Node implements static server ~ Hello HTTP
  • P10: Node implements static server ~ static file or folder reading

Now that we have a basic understanding of how Node works, let’s implement a system function that reads files or folders

Mining pit record

  • Chinese output garbled characters 
    res.statusCode = 200
res.setHeader('Content-Type'.'text/plain')
res.end('Ahh and gaha.')
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    • Chinese garbled characters appear in the output
    res.writeHead(200, { 'Content-Type': 'text/plain; charset=utf-8' })
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    or

    res.writeHead(200, { 'Context-Type': 'text/plain' })
res.write('<head><meta charset="utf-8"/></head>')
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  • File reading mode

    Node allows you to read and output files in two ways

    • One: Read and return as a file stream. Fast = recommended
    fs.createReadStream(filePath).pipe(res)
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    • Two: Reading the file in its entirety and then returning its contents together is simply a poor use of the API = slow
    fs.readFile(filePath, (err, data) => {
    if (err) return
    res.end(data)
})
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Read a file or folder

  • Blah, blah, code

Require (‘./config/defaultConfig’) updated to the following

Module. exports = {// hostname:'127.0.0.1', // port: 6969, // current folder root: process.cwd()}Copy the code
Const HTTP = require(const HTTP = require('http'Const chalk = require()'chalk')
    
    const path = require('path')
    const fs = require('fs'Const conf = require()'./config/defaultConfig') // Create a server instance const server = http.createserver ((rep, res) => {// Get path const filePath = path.join(conf.root, Stat (filePath, (err, stats) => {// Set public header res.writehead (200, {'Content-Type': 'text/plain; charset=utf-8' })
        if(err) {// statusCode res.statuscode = 404 // the prompt text res.end(' could not be found${filePath} is 404`)
    
          return
        }
        ifRes.statuscode = 200 fs.createreadStream (filePath).pipe(res)} (stats.isfile ()) {res.statusCode = 200 fs.createreadStream (filePath).pipe(res)}else if(stats.isdirectory ()) {fs.readdir(filePath, (err, files) => {if (err) return
            res.statusCode = 200
    
            res.end(files.join(', 'Listen (conf.port, conf.hostname, () => {const addr = 'http://${conf.hostname}:${conf.port}`
    
      console.info(`server startd at ${chalk.green(addr)}`)})Copy the code

Code optimization

  • The above code has many callbacks, and the code is bloated and unreadable. Let’s use asynchrony to remove the callback for optimization

    • require-atomic-updatesNote the restriction esLint has on this item, for which the argument await is used 
      const fs = require('fs')

const promisify = require('util').promisify
const stat = promisify(fs.stat)
const readdir = promisify(fs.readdir)

module.exports = async function(rep, res, Const awaitRes = await res awaitres. writeHead(200, {'Content-Type': 'text/plain; charset=utf-8' })
  try {
    const stats = await stat(filePath)
    ifStatusCode = 200 fs.createreadStream (filePath).pipe(awaitRes)} (stats.isfile () {awaitres.statusCode = 200 fs.createreadStream (filePath).pipe(awaitRes)}else if(stats.isdirectory ()) {// If it is a folder, Const file = readdir(filePath) awaitres.statusCode = 200 awaitres.end (file.join()', ')}} catch (ex) {// Awaitres.statusCode = 404 // The prompt text awaitres.end (' is not found${filePath} is 404`)
  }
}

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  • The app.js file is changed to

    Const HTTP = require(const HTTP = require('http'Const chalk = require()'chalk')

const path = require('path')

const route = require('./header/route'Const conf = require()'./config/defaultConfig') // Create a server instance const server = http.createserver ((rep, res) => {// Get path const filePath = path.join(conf.root, Rep. url) route(rep, res, filePath)}) server.listen(conf.port, conf.hostname, () => { const addr = `http://${conf.hostname}:${conf.port}`

  console.info(`server startd at ${chalk.green(addr)}`)})Copy the code

  • So far, hash path input is implemented to read/forward/backward files or folders

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