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forms – PHP ZIP files on the fly

Posted by: admin April 23, 2020 Leave a comment


What’s the easiest way to zip, say 2 files, from a folder on the server and force download? Without saving the “zip” to the server.

    $zip = new ZipArchive();
   //the string "file1" is the name we're assigning the file in the archive
$zip->addFile(file_get_contents($filepath1), 'file1'); //file 1 that you want compressed
$zip->addFile(file_get_contents($filepath2), 'file2'); //file 2 that you want compressed
$zip->addFile(file_get_contents($filepath3), 'file3'); //file 3 that you want compressed
echo $zip->file(); //this sends the compressed archive to the output buffer instead of writing it to a file.

Can someone verify:
I have a folder with test1.doc, test2.doc, and test3.doc

with the above example – file1 (file2 and file3) might just be test1.doc, etc.

do I have to do anything with “$filepath1”? Is that the folder directory that holds the 3 docs?

Sorry for my basic question..

How to&Answers:

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
header('Content-Type: application/zip');
header('Content-Length: ' . filesize($file));
header('Content-Disposition: attachment; filename="file.zip"');

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');


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

$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.


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.


To create ZIP files on the fly (in memory), you can use ZipFile class from phpMyAdmin:

An example of how to use it in your own application:

Note: Your ZIP files will be limited by PHP’s memory limit, resulting in corrupted archive if you exceed the limit.


If you want to insert the ‘Content-Length’ do it like this:

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

I don’t know why, but it crashes if you put it in the same line.