如何在不使用第三方库的情况下使用Node.js下载文件?

我不需要什么特别的东西。我只想从给定的URL下载文件,然后将其保存到给定的目录。


当前回答

const download = (url, path) => new Promise((resolve, reject) => {
http.get(url, response => {
    const statusCode = response.statusCode;

    if (statusCode !== 200) {
        return reject('Download error!');
    }

    const writeStream = fs.createWriteStream(path);
    response.pipe(writeStream);

    writeStream.on('error', () => reject('Error writing to file!'));
    writeStream.on('finish', () => writeStream.close(resolve));
});}).catch(err => console.error(err));

其他回答

没有库,它可能是错误的,只是指出。以下是一些例子:

不能处理http重定向,比如这个url https://calibre-ebook.com/dist/portable,它是二进制的。 http模块不能https url,你将得到协议“https:”不支持。

以下是我的建议:

调用系统工具,如wget或curl 使用一些类似node-wget-promise的工具,使用起来也非常简单。 Var wget = require('node-wget-promise'); wget(“http://nodejs.org/images/logo.svg”);

如果您正在使用express,请使用res.download()方法。否则使用fs模块。

app.get('/read-android', function(req, res) {
   var file = "/home/sony/Documents/docs/Android.apk";
    res.download(file) 
}); 

(or)

   function readApp(req,res) {
      var file = req.fileName,
          filePath = "/home/sony/Documents/docs/";
      fs.exists(filePath, function(exists){
          if (exists) {     
            res.writeHead(200, {
              "Content-Type": "application/octet-stream",
              "Content-Disposition" : "attachment; filename=" + file});
            fs.createReadStream(filePath + file).pipe(res);
          } else {
            res.writeHead(400, {"Content-Type": "text/plain"});
            res.end("ERROR File does NOT Exists.ipa");
          }
        });  
    }
const download = (url, path) => new Promise((resolve, reject) => {
http.get(url, response => {
    const statusCode = response.statusCode;

    if (statusCode !== 200) {
        return reject('Download error!');
    }

    const writeStream = fs.createWriteStream(path);
    response.pipe(writeStream);

    writeStream.on('error', () => reject('Error writing to file!'));
    writeStream.on('finish', () => writeStream.close(resolve));
});}).catch(err => console.error(err));

现代版本(ES6, Promise, Node 12。X +)适用于https/http。它还支持重定向302和301。我决定不使用第三方库,因为它可以很容易地使用标准Node.js库。

// download.js
import fs from 'fs'
import https from 'https'
import http from 'http'
import { basename } from 'path'
import { URL } from 'url'

const TIMEOUT = 10000

function download (url, dest) {
  const uri = new URL(url)
  if (!dest) {
    dest = basename(uri.pathname)
  }
  const pkg = url.toLowerCase().startsWith('https:') ? https : http

  return new Promise((resolve, reject) => {
    const request = pkg.get(uri.href).on('response', (res) => {
      if (res.statusCode === 200) {
        const file = fs.createWriteStream(dest, { flags: 'wx' })
        res
          .on('end', () => {
            file.end()
            // console.log(`${uri.pathname} downloaded to: ${path}`)
            resolve()
          })
          .on('error', (err) => {
            file.destroy()
            fs.unlink(dest, () => reject(err))
          }).pipe(file)
      } else if (res.statusCode === 302 || res.statusCode === 301) {
        // Recursively follow redirects, only a 200 will resolve.
        download(res.headers.location, dest).then(() => resolve())
      } else {
        reject(new Error(`Download request failed, response status: ${res.statusCode} ${res.statusMessage}`))
      }
    })
    request.setTimeout(TIMEOUT, function () {
      request.abort()
      reject(new Error(`Request timeout after ${TIMEOUT / 1000.0}s`))
    })
  })
}

export default download

感谢安德烈·特卡琴科,我修改了他的要点

将其包含在另一个文件中并使用

const download = require('./download.js')
const url = 'https://raw.githubusercontent.com/replace-this-with-your-remote-file'
console.log('Downloading ' + url)

async function run() {
  console.log('Downloading file')
  try {
    await download(url, 'server')
    console.log('Download done')
  } catch (e) {
    console.log('Download failed')
    console.log(e.message)
  }
}

run()

Vince Yuan的代码很棒,但似乎有问题。

function download(url, dest, callback) {
    var file = fs.createWriteStream(dest);
    var request = http.get(url, function (response) {
        response.pipe(file);
        file.on('finish', function () {
            file.close(callback); // close() is async, call callback after close completes.
        });
        file.on('error', function (err) {
            fs.unlink(dest); // Delete the file async. (But we don't check the result)
            if (callback)
                callback(err.message);
        });
    });
}