php header issue when downloading zip

Question

I'm trying to make php download a .zip file using this code:

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

$file is right.

I have two problem with this script:

1. If I use header('Content-Length: ' . filesize($file)); the download is corrupt with 0 bytes file. If I comment this line, the download looks good on ubuntu.

2. If I use mac OS to download this file, after opening the .zip it extracts .cpgz file (for what I read is when the zip is corrupt)

I've tried all kind of headers to make this work, but the problem is always on that header. My question is: how can I make this work on all OS?

Answer 1

I use this for the purpose of downloading any kind of file using one generic PHP-script:

$base = "/path/to/downloadable/files";
$file = "myArchive.zip"; // or anything else

if(file_exists($base.$file)){        
    header('Content-Description: Download');
    header('Content-Type: '.mime_content_type($base.$file));
    header('Content-Disposition: attachment; filename="'.basename($file).'"');
    header('Content-Transfer-Encoding: binary');
    header('Connection: Keep-Alive');
    header('Expires: 0');
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
    header('Content-Length: ' . filesize($base.$file));
    echo file_get_contents($base.$file);
}

This works fine for me with almost every kind of file (including .zip).