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
下载.js(即/project/utils/ Download.js)
const fs = require('fs');
const request = require('request');
const download = (uri, filename, callback) => {
request.head(uri, (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);
});
};
module.exports = { download };
app.js
...
// part of imports
const { download } = require('./utils/download');
...
// add this function wherever
download('https://imageurl.com', 'imagename.jpg', () => {
console.log('done')
});
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");
}
});
}
下载.js(即/project/utils/ Download.js)
const fs = require('fs');
const request = require('request');
const download = (uri, filename, callback) => {
request.head(uri, (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);
});
};
module.exports = { download };
app.js
...
// part of imports
const { download } = require('./utils/download');
...
// add this function wherever
download('https://imageurl.com', 'imagename.jpg', () => {
console.log('done')
});
说到处理错误,监听请求错误甚至更好。我甚至会通过检查响应代码来验证。这里认为只有200个响应代码成功,但其他代码可能很好。
const fs = require('fs');
const http = require('http');
const download = (url, dest, cb) => {
const file = fs.createWriteStream(dest);
const request = http.get(url, (response) => {
// check if response is success
if (response.statusCode !== 200) {
return cb('Response status was ' + response.statusCode);
}
response.pipe(file);
});
// close() is async, call cb after close completes
file.on('finish', () => file.close(cb));
// check for request error too
request.on('error', (err) => {
fs.unlink(dest, () => cb(err.message)); // delete the (partial) file and then return the error
});
file.on('error', (err) => { // Handle errors
fs.unlink(dest, () => cb(err.message)); // delete the (partial) file and then return the error
});
};
尽管这段代码相对简单,但我建议使用request模块,因为它处理更多http不支持的协议(你好,HTTPS!)。
可以这样做:
const fs = require('fs');
const request = require('request');
const download = (url, dest, cb) => {
const file = fs.createWriteStream(dest);
const sendReq = request.get(url);
// verify response code
sendReq.on('response', (response) => {
if (response.statusCode !== 200) {
return cb('Response status was ' + response.statusCode);
}
sendReq.pipe(file);
});
// close() is async, call cb after close completes
file.on('finish', () => file.close(cb));
// check for request errors
sendReq.on('error', (err) => {
fs.unlink(dest, () => cb(err.message)); // delete the (partial) file and then return the error
});
file.on('error', (err) => { // Handle errors
fs.unlink(dest, () => cb(err.message)); // delete the (partial) file and then return the error
});
};
编辑:
要使它与https兼容,请更改
const http = require('http');
to
const http = require('https');
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。