节点：通过请求下载zip，Zip已损坏 [英] Node: Downloading a zip through Request, Zip being corrupted

问题描述

我正在使用优秀的请求库来下载Node中的文件以获取小命令行工具I正在努力。请求完全适用于拉入单个文件，没有任何问题，但它不适用于ZIP。

I'm using the excellent Request library for downloading files in Node for a small command line tool I'm working on. Request works perfectly for pulling in a single file, no problems at all, but it's not working for ZIPs.

例如，我正在尝试下载 Twitter Bootstrap 存档，位于URL：

For example, I'm trying to download the Twitter Bootstrap archive, which is at the URL:

http://twitter.github.com/bootstrap/assets/bootstrap.zip

代码的相关部分是：

var fileUrl = "http://twitter.github.com/bootstrap/assets/bootstrap.zip";
var output = "bootstrap.zip";
request(fileUrl, function(err, resp, body) {
  if(err) throw err;
  fs.writeFile(output, body, function(err) {
    console.log("file written!");
  }
}

I我已经尝试将编码设置为二进制，但没有运气。实际的zip是~74KB，但是当通过上面的代码下载时它是~134KB并且双击Finder来提取它，我得到错误：

I've tried setting the encoding to "binary" too but no luck. The actual zip is ~74KB, but when downloaded through the above code it's ~134KB and on double clicking in Finder to extract it, I get the error:

无法将bootstrap解压缩到nodetest（错误21 - 是目录）

Unable to extract "bootstrap" into "nodetest" (Error 21 - Is a directory)

我觉得这是一个编码问题但不知道从哪里开始。

I get the feeling this is an encoding issue but not sure where to go from here.

推荐答案

是的，问题在于编码。当你等待整个转移完成 body 默认强制转换为字符串。你可以告诉请求通过将编码选项设置为<$ c来为您提供缓冲区 $ c> null ：

Yes, the problem is with encoding. When you wait for the whole transfer to finish body is coerced to a string by default. You can tell request to give you a Buffer instead by setting the encoding option to null:

var fileUrl = "http://twitter.github.com/bootstrap/assets/bootstrap.zip";
var output = "bootstrap.zip";
request({url: fileUrl, encoding: null}, function(err, resp, body) {
  if(err) throw err;
  fs.writeFile(output, body, function(err) {
    console.log("file written!");
  });
});

另一个更优雅的解决方案是使用 pipe（）将响应指向文件可写流：

Another more elegant solution is to use pipe() to point the response to a file writable stream:

request('http://twitter.github.com/bootstrap/assets/bootstrap.zip')
  .pipe(fs.createWriteStream('bootstrap.zip'))
  .on('close', function () {
    console.log('File written!');
  });

一个班轮总是获胜：）

pipe（）返回目标流（本例中为WriteStream），因此您可以收听其 close 事件在写入文件时收到通知。

pipe() returns the destination stream (the WriteStream in this case), so you can listen to its close event to get notified when the file was written.

这篇关于节点：通过请求下载zip，Zip已损坏的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！