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[英]How to download multiple files bundled into one zip files in Node js?
[英]How to download files one by one in node js?
我正在嘗試使用請求庫下載多個文件,我需要一個一個地下載它們,並顯示一個進度欄,文件鏈接存儲在一個數組中,該數組將它們傳遞給函數以開始下載
const request = require('request')
const fs = require('fs')
const ProgressBar = require('progress')
async function downloadFiles(links) {
for (let link of links) {
let file = request(link)
file.on('response', (res) => {
var len = parseInt(res.headers['content-length'], 10);
console.log();
bar = new ProgressBar(' Downloading [:bar] :rate/bps :percent :etas', {
complete: '=',
incomplete: ' ',
width: 20,
total: len
});
file.on('data', (chunk) => {
bar.tick(chunk.length);
})
file.on('end', () => {
console.log('\n');
})
})
file.pipe(fs.createWriteStream('./downloads/' + Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15)))
}
}
let links = ['https://speed.hetzner.de/100MB.bin', 'https://speed.hetzner.de/100MB.bin', 'https://speed.hetzner.de/100MB.bin', 'https://speed.hetzner.de/100MB.bin']
downloadFiles(links)
到目前為止,這就是我所得到的,問題是請求是異步的,我嘗試使用async / await,但是那樣我無法使進度條正常工作。 如何使文件一次被下載並具有進度欄?
根據我對async.queue
評論,這就是我要寫的方式。 您可以根據需要dl.downloadFiles([])
調用dl.downloadFiles([])
,它只會一次又一次地提取添加到隊列中的所有內容。
const request = require('request')
const async = require('async')
const fs = require('fs')
const ProgressBar = require('progress')
class Downloader {
constructor() {
this.q = async.queue(this.singleFile, 1);
// assign a callback
this.q.drain(function() {
console.log('all items have been processed');
});
// assign an error callback
this.q.error(function(err, task) {
console.error('task experienced an error', task);
});
}
downloadFiles(links) {
for (let link of links) {
this.q.push(link);
}
}
singleFile(link, cb) {
let file = request(link);
let bar;
file.on('response', (res) => {
const len = parseInt(res.headers['content-length'], 10);
console.log();
bar = new ProgressBar(' Downloading [:bar] :rate/bps :percent :etas', {
complete: '=',
incomplete: ' ',
width: 20,
total: len
});
file.on('data', (chunk) => {
bar.tick(chunk.length);
})
file.on('end', () => {
console.log('\n');
cb();
})
})
file.pipe(fs.createWriteStream('./downloads/' + Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15)))
}
}
const dl = new Downloader();
dl.downloadFiles([
'https://speed.hetzner.de/100MB.bin',
'https://speed.hetzner.de/100MB.bin'
]);
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