Extract a file from a ZIP string

Question

I have a BASE64 string of a zip file that contains one single XML file.

Any ideas on how I could get the contents of the XML file without having to deal with files on the disk?

I would like very much to keep the whole process in the memory as the XML only has 1-5k.

It would be annoying to have to write the zip, extract the XML and then load it up and delete everything.

Answer 1

I had a similar problem, I ended up doing it manually.
https://www.pkware.com/documents/casestudies/APPNOTE.TXT

This extracts a single file (just the first one), no error/crc checks, assumes deflate was used.

// zip in a string $data = file_get_contents('test.zip');  // magic $head = unpack("Vsig/vver/vflag/vmeth/vmodt/vmodd/Vcrc/Vcsize/Vsize/vnamelen/vexlen", substr($data,0,30)); $filename = substr($data,30,$head['namelen']); $raw = gzinflate(substr($data,30+$head['namelen']+$head['exlen'],$head['csize']));  // first file uncompressed and ready to use file_put_contents($filename,$raw); 

Answer 2

After some hours of research I think it's surprisingly not possible do handle a zip without a temporary file:

1. The first try with php://memory will not work, beacuse it's a stream that cannot be read by functions like file_get_contents() or ZipArchive::open(). In the comments is a link to the php-bugtracker for the lack of documentation of this problem.
2. There is a stream support ZipArchive with ::getStream() but as stated in the manual, it only supports reading operation on an opened file. So you cannot build a archive on-the-fly with that.
3. The zip:// wrapper is also read-only: Create ZIP file with fopen() wrapper

4. I also did some attempts with the other php wrappers/protocolls like

    file_get_contents("zip://data://text/plain;base64,{$base64_string}#test.txt")  $zip->open("php://filter/read=convert.base64-decode/resource={$base64_string}")  $zip->open("php://filter/read=/resource=php://memory") 

   but for me they don't work at all, even if there are examples like that in the manual. So you have to swallow the pill and create a temporary file.

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Original Answer:

This is just the way of temporary storing. I hope you manage the zip handling and parsing of xml on your own.

Use the php php://memory (doc) wrapper. Be aware, that this is only usefull for small files, because its stored in the memory - obviously. Otherwise use php://temp instead.

<?php  // the decoded content of your zip file $text = 'base64 _decoded_ zip content';  // this will empty the memory and appen your zip content $written = file_put_contents('php://memory', $text);  // bytes written to memory var_dump($written);  // new instance of the ZipArchive $zip = new ZipArchive;  // success of the archive reading var_dump(true === $zip->open('php://memory'));