Dynamically created zip files by ZipStream in PHP

Question

I have a PHP site with a lot of media files and users need to be able to download multiple files at a time as a .zip. I'm trying to use ZipStream to serve the zips on the fly with "store" compression so I don't actually have to create a zip on the server, since some of the files are huge and it's prohibitively slow to compress them all.

This works great and the resulting files can be opened by every zip program I've tried with no errors except for OS X's default unzipping program, Archive Utility. You double click the .zip file and Archive Utility decides it doesn't look a real zip and instead compresses into a .cpgz file.

Using unzip or ditto in the OS X terminal or StuffIt Expander unzips the file with no problem but I need the default program (Archive Utility) to work for the sake of our users.

What sort of things (flags, etc.) in otherwise acceptable zip files can trip Archive Utility into thinking a file isn't a valid zip?

I've read this question, which seems to describe a similar issue but I don't have any of the general purpose bitfield bits set so it's not the third bit issue and I'm pretty sure I have valid crc-32's because when I don't, WinRAR throws a fit.

I'm happy to post some code or a link to a "bad" zip file if it would help but I'm pretty much just using ZipStream, forcing it into "large file mode" and using "store" as the compression method.

Edit - I've tried the "deflate" compression algorithm as well and get the same results so I don't think it's the "store". It's also worth pointing out that I'm pulling down the files one a time from a storage server and sending them out as they arrive so a solution that requires all the files to be downloaded before sending anything isn't going to be viable (extreme example is 5GB+ of 20MB files. User can't wait for all 5GB to transfer to zipping server before their download starts or they'll think it's broken)

Here's a 140 byte, "store" compressed, test zip file that exhibits this behavior: http://teknocowboys.com/test.zip

Answer 1

It's an old question but I leave what it worked for me just in case it helps someone else. When setting the options you need set Zero header to true and enable zip 64 to false (this will limit the archive to archive to 4 Gb though):

$options->setZeroHeader(true);
$opt->setEnableZip64(false)

Everything else as described by Forer. Solution found on https://github.com/maennchen/ZipStream-PHP/issues/71

Answer 2

use ob_clean(); and flush();

Example :

    $file =  __UPLOAD_PATH . $projectname . '/' . $fileName;

    $zipname = "watherver.zip"
    $zip = new ZipArchive(); 
    $zip_full_path_name = __UPLOAD_PATH . $projectname . '/' . $zipname;
    $zip->open($zip_full_path_name, ZIPARCHIVE::CREATE);
    $zip->addFile($file); // Adding one file for testing
    $zip->close();

    if(file_exists($zip_full_path_name)){
        header('Content-type: application/zip');
        header('Content-Disposition: attachment; filename="'.$zipname.'"');
        ob_clean();
        flush();
        readfile($zip_full_path_name);
        unlink($zip_full_path_name);
    }

Answer 3

I've had this exact issue but with a different cause.

In my case the php generated zip would open from the command line, but not via finder in OSX.

I had made the mistake of allowing some HTML content into the output buffer prior to creating the zip file and sending that back as the response.

<some html></....>
<?php

// Output a zip file...

The command line unzip program was evidently tolerant of this but the Mac unarchive function was not.

Answer 4

The InfoZip commandline tool I'm using, both on Windows and Linux, uses version 20 for the zip's "version needed to extract" field. This is needed on PHP as well, as the default compression is the Deflate algorithm. Thus the "version needed to extract" field should really be 0x0014. If you alter the "(6 << 8) +3" code in the referenced ZipStream class to just "20", you should get a valid Zip file across platforms.

The author is basically telling you that the zip file was created in OS/2 using the HPFS file system, and the Zip version needed predates InfoZip 1.0. Not many implementations know what to do about that one any longer ;)

Answer 5

No idea. If the external ZipString class doesn't work, try another option. The PHP ZipArchive extension won't help you, since it doesn't support streaming but only ever writes to files.

But you could try the standard Info-zip utility. It can be invoked from within PHP like this:

#header("Content-Type: archive/zip");
passthru("zip -0 -q -r - *.*");

That would lead to an uncompressed zip file directly send back to the client.

If that doesn't help, then the MacOS zip frontend probably doesn't like uncompressed stuff. Remove the -0 flag then.

Answer 6

For those using ZipStream in Symfony, here's your solution: https://stackoverflow.com/a/44706446/136151

use Symfony\Component\HttpFoundation\StreamedResponse;
use Aws\S3\S3Client;    
use ZipStream;

//...

/**
 * @Route("/zipstream", name="zipstream")
 */
public function zipStreamAction()
{
    //test file on s3
    $s3keys = array(
      "ziptestfolder/file1.txt"
    );

    $s3Client = $this->get('app.amazon.s3'); //s3client service
    $s3Client->registerStreamWrapper(); //required

    $response = new StreamedResponse(function() use($s3keys, $s3Client) 
    {

        // Define suitable options for ZipStream Archive.
        $opt = array(
                'comment' => 'test zip file.',
                'content_type' => 'application/octet-stream'
              );
        //initialise zipstream with output zip filename and options.
        $zip = new ZipStream\ZipStream('test.zip', $opt);

        //loop keys useful for multiple files
        foreach ($s3keys as $key) {
            // Get the file name in S3 key so we can save it to the zip 
            //file using the same name.
            $fileName = basename($key);

            //concatenate s3path.
            $bucket = 'bucketname';
            $s3path = "s3://" . $bucket . "/" . $key;        

            //addFileFromStream
            if ($streamRead = fopen($s3path, 'r')) {
              $zip->addFileFromStream($fileName, $streamRead);        
            } else {
              die('Could not open stream for reading');
            }
        }

        $zip->finish();

    });

    return $response;
}

If your controller action response is not a StreamedResponse, you are likely going to get a corrupted zip containing html as I found out.