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。
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
你可以使用https://github.com/douzi8/ajax-request#download
request.download('http://res.m.ctrip.com/html5/Content/images/57.png',
function(err, res, body) {}
);
其他回答
你可以使用https://github.com/douzi8/ajax-request#download
request.download('http://res.m.ctrip.com/html5/Content/images/57.png',
function(err, res, body) {}
);
超时解决方案,防止内存泄漏:
下面的代码是基于Brandon Tilley的回答:
var http = require('http'),
fs = require('fs');
var request = http.get("http://example12345.com/yourfile.html", function(response) {
if (response.statusCode === 200) {
var file = fs.createWriteStream("copy.html");
response.pipe(file);
}
// Add timeout.
request.setTimeout(12000, function () {
request.abort();
});
});
当您得到一个错误时,不要创建文件,并倾向于使用超时在X秒后关闭您的请求。
2022年底编辑:
Node v18及以上版本自带自带的Fetch API支持。使用它。
最初的回答:
对于支持承诺的节点,与其他答案相比,一个简单的(部分)Fetch API的Node shim只需要少量额外的代码:
const fs = require(`fs`);
const http = require(`http`);
const https = require(`https`);
module.exports = function fetch(url) {
return new Promise((resolve, reject) => {
const data = [];
const client = url.startsWith("https") ? https : http;
client
.request(url, (res) => {
res.on(`data`, (chunk) => data.push(chunk));
res.on(`end`, () => {
const asBytes = Buffer.concat(data);
const asString = asBytes.toString(`utf8`);
resolve({
arrayBuffer: async () => asBytes,
json: async () => JSON.parse(asString),
text: async () => asString,
});
});
res.on(`error`, (e) => reject(e));
})
.end();
});
};
你可以用它来做任何你需要的事情,使用普通的fetch语法:
const fetch = require(`./tiny-fetch.js`);
fetch(`https://placekitten.com/200/300`)
.then(res => res.arrayBuffer())
.then(bytes => fs.writeFileSync(`kitten.jpg`, bytes))
.catch(e => console.error(e));
fetch(`https://jsonplaceholder.typicode.com/todos/1`)
.then(res => res.json())
.then(obj => console.log(obj))
.catch(e => console.error(e));
// etc.
var fs = require('fs'),
request = require('request');
var download = function(uri, filename, callback){
request.head(uri, function(err, res, body){
console.log('content-type:', res.headers['content-type']);
console.log('content-length:', res.headers['content-length']);
request(uri).pipe(fs.createWriteStream(filename)).on('close', callback);
});
};
download('https://www.cryptocompare.com/media/19684/doge.png', 'icons/taskks12.png', function(){
console.log('done');
});
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()