zip - Creating and serving zipped files with php

Question

I'm trying to use the following code to create a zip file from a directory and serve it to the user via an http download:

 // write the file
file_put_contents($path . "/index.html", $output);

// zip up the contents
chdir($path);
exec("zip -r {$course->name} ./");

$filename = "{$course->name}.zip";

header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename=' .urlencode($filename));
header('Content-Transfer-Encoding: binary');

readfile($filename);

I am able to create the zip file, but downloading it over http is not working. If I download the zip file that's created using an ftp client then Mac's Stuffit Expander unzips the files just fine, but if I download it over http, the mac unzipper creates an endless loop. What I mean by this is say the file I download is called course.zip, then unzipping the file gives course.zip.cpgz and unzipping that file gives course.zip again..and on and on.

Anyone have any ideas?

Thanks!

Answer 1

I had this problem and it turned out the downloaded zip file had a new line inserted at the very beginning.

Solved by using ob_clean and flush functions

    header("Pragma: public");
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Cache-Control: private",false);
    header("Content-Type: application/octet-stream");
    header("Content-Disposition: attachment; filename=".basename($archive_file_name));
    header("Content-Transfer-Encoding: binary");
    header("Content-Length: ".filesize($archive_file_name));
    ob_clean();
    flush();
    echo readfile("$archive_file_name");