PHP ZIP files on the fly

Question

Unfortunately w/ PHP 5.3.4-dev and Zend Engine v2.3.0 on CentOS 5.x I couldn't get the code above to work. An "Invalid or unitialized Zip object" error message was all I could get. So, in order to make it work, I had to use following snippet (taken from the example by Jonathan Baltazar on PHP.net manual, at the ZipArchive::open page):

// Prepare File
$file = tempnam("tmp", "zip");
$zip = new ZipArchive();
$zip->open($file, ZipArchive::OVERWRITE);

// Stuff with content
$zip->addFromString('file_name_within_archive.ext', $your_string_data);
$zip->addFile('file_on_server.ext', 'second_file_name_within_archive.ext');

// Close and send to users
$zip->close();
header('Content-Type: application/zip');
header('Content-Length: ' . filesize($file));
header('Content-Disposition: attachment; filename="file.zip"');
readfile($file);
unlink($file); 

I know this is different than working w/ memory only - unless you have your tmp area in ram ;-) - but maybe this can help out someone else, who's struggling with the solution above, like I was; and for which performance penalty is not an issue.

Your code is very close. You need to use the file name instead of the file contents.

$zip->addFile(file_get_contents($filepath1), 'file1');

should be

$zip->addFile($filepath1, 'file1');

http://us3.php.net/manual/en/function.ziparchive-addfile.php

If you need to add files from a variable instead of a file you can use the addFromString function.

$zip->addFromString( 'file1', $data );

If you have access to the zip commandline utility you can try

<?php
$zipped_data = `zip -q - files`;
header('Content-type: application/zip');
header('Content-Disposition: attachment; filename="download.zip"');
echo $zipped_data;
?>

where files is the things you want to zip and zip the location to the zip executable.

This assumes Linux or similar, of course. In Windows you might be able to do similar with another compression tool, I guess.

There's also a zip extension, usage shown here.

This works for me (nothing is written to disk)

$tmp_file = tmpfile(); //temp file in memory
$tmp_location = stream_get_meta_data($tmp_file)['uri']; //"location" of temp file

$zip = new ZipArchive;
$res = $zip->open($tmp_location, ZipArchive::CREATE);
$zip->addFile($filepath1, 'file1');
$zip->close();

header('Content-type: application/zip');
header('Content-Disposition: attachment; filename="download.zip"');
echo(file_get_contents($tmp_location));

maraspin's Answer is what I tried. Strangely, I got it working by removing the header line that references the file size:

header('Content-Length: ' . filesize($file));

With the above change, the code works like a breeze! Without this change, I used to get the following error message:

End-of-central-directory signature not found. Either this file is not a zipfile, or it constitutes one disk of a multi-part archive. In the latter case the central directory and zipfile comment will be found on the last disk(s) of this archive.

Test environment:

OS: Ubuntu 10.10 Browser: Firefox And the default LAMP stack.