LAMP:如何从远程URL /文件创建.Zip并将其流式传输到客户端

With external services like S3 for object storage, the old problem of providing custom zip archives of stored files gets a bit more complicated. One way would be for a web server to copy all the resources to temporary local files, compile them into a .zip, then return the zip to the user, but this is slow and resource intensive.

Can this be done similarly to the solution for local files? e.g. can you curl the files, pipe them into zip in streaming mode, then out to the user on the fly?

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译文

使用S3等外部服务进行对象存储,提供存储文件的自定义zip存档的旧问题会更多 复杂。 一种方法是让Web服务器将所有资源复制到临时本地文件,将它们编译成.zip,然后将zip返回给用户,但这很慢且资源密集。</ p>

< p>这可以与解决方案? 例如 你可以 curl </ code>这些文件,在流媒体模式下将它们导入 zip </ code>,然后直接发送给用户吗?</ p>
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1个回答

Yes — you can have zip operate on a set of fifos rather than a set of files. Here’s the code:

$sh = 'mkfifo a.jpg b.jpg ; '.                     // 1
  'curl -s some_service.com/a.jpg > a.jpg & ' .    // 2
  'curl -s some_service.com/b.jpg > b.jpg & ' .    // 
  'zip -FI - a.jpg b.jpg | cat > out.fifo';        // 3

// Open output fifo & curl-zip task pipe
posix_mkfifo('out.fifo', 0777);                    // 4
$pipe_output = popen('cat out.fifo', 'r');         //
$pipe_curlzip = popen($sh, 'r');                   //

It works as follows:

  1. We have two remote files: some_service.com/a.jpg and some_service.com/b.jpg – we create a fifo for each, each fifo having the name of the corresponding file as we wish it to appear in our zip file. So for some_service.com/a.jpg, we create a fifo called a.jpg.
  2. Kick off two curl tasks to feed the remote files a.jpg and b.jpg into each’s respective fifo. These curl tasks will hang until something reads from their output fifos, so we run them in the background (&).
  3. Start our zip task, giving it our two fifos as input. We cat its streaming output into a third fifo – out.fifo – to allow our PHP process to stream the file to the user.
  4. Kick things off.

It's then just a matter of reading what comes out of out.fifo and sending it to the user:

header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="Download.zip"');

while (!feof($pipe_output)) {
    echo fread($pipe_output, 128);   // Your magic number here
}
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