如何在NodeJs中下载和解压缩内存中的zip文件? [英] How to download and unzip a zip file in memory in NodeJs?
问题描述
我想从互联网上下载一个zip文件并将其解压缩到内存而不保存到临时文件。我怎么能这样做?
I want to download a zip file from the internet and unzip it in memory without saving to a temporary file. How can I do this?
这是我试过的:
var url = 'http://bdn-ak.bloomberg.com/precanned/Comdty_Calendar_Spread_Option_20120428.txt.zip';
var request = require('request'), fs = require('fs'), zlib = require('zlib');
request.get(url, function(err, res, file) {
if(err) throw err;
zlib.unzip(file, function(err, txt) {
if(err) throw err;
console.log(txt.toString()); //outputs nothing
});
});
建议,我尝试使用adm-zip库和我仍然不能使这项工作:
As, suggested, I tried using the adm-zip library and I still cannot make this work:
var ZipEntry = require('adm-zip/zipEntry');
request.get(url, function(err, res, zipFile) {
if(err) throw err;
var zip = new ZipEntry();
zip.setCompressedData(new Buffer(zipFile.toString('utf-8')));
var text = zip.getData();
console.log(text.toString()); // fails
});
推荐答案
您需要一个可以处理缓冲区的库。最新版本的 adm-zip
将执行:
You need a library that can handle buffers. The latest version of adm-zip
will do:
npm install adm-zip
我的解决方案使用 http.get
方法,因为它返回缓冲区块。
My solution uses the http.get
method, since it returns Buffer chunks.
代码:
var file_url = 'http://notepad-plus-plus.org/repository/7.x/7.6/npp.7.6.bin.x64.zip';
var AdmZip = require('adm-zip');
var http = require('http');
http.get(file_url, function(res) {
var data = [], dataLen = 0;
res.on('data', function(chunk) {
data.push(chunk);
dataLen += chunk.length;
}).on('end', function() {
var buf = Buffer.alloc(dataLen);
for (var i = 0, len = data.length, pos = 0; i < len; i++) {
data[i].copy(buf, pos);
pos += data[i].length;
}
var zip = new AdmZip(buf);
var zipEntries = zip.getEntries();
console.log(zipEntries.length)
for (var i = 0; i < zipEntries.length; i++) {
if (zipEntries[i].entryName.match(/readme/))
console.log(zip.readAsText(zipEntries[i]));
}
});
});
想法是创建一个缓冲区数组,并在最后将它们连接成一个新缓冲区。这是因为缓冲区无法调整大小。
The idea is to create an array of buffers and concatenate them into a new one at the end. This is due to the fact that buffers cannot be resized.
更新
这是一个更简单的解决方案,它使用请求
模块通过设置 encoding:null
来获取缓冲区中的响应选项。它还遵循重定向并自动解析http / https。
This is a simpler solution that uses the request
module to obtain the response in a buffer, by setting encoding: null
in the options. It also follows redirects and resolves http/https automatically.
var file_url = 'https://github.com/mihaifm/linq/releases/download/3.1.1/linq.js-3.1.1.zip';
var AdmZip = require('adm-zip');
var request = require('request');
request.get({url: file_url, encoding: null}, (err, res, body) => {
var zip = new AdmZip(body);
var zipEntries = zip.getEntries();
console.log(zipEntries.length);
zipEntries.forEach((entry) => {
if (entry.entryName.match(/readme/i))
console.log(zip.readAsText(entry));
});
});
响应的正文
是一个缓冲区可以直接传递给 AdmZip
,简化整个过程。
The body
of the response is a buffer that can be passed directly to AdmZip
, simplifying the whole process.
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