Zip Folder PHP

gistfile1.php

<?php
    //Get the directory to zip
    $filename_no_ext= $_GET['directtozip'];

    // we deliver a zip file
    header("Content-Type: archive/zip");

    // filename for the browser to save the zip file
    header("Content-Disposition: attachment; filename=$filename_no_ext".".zip");

    // get a tmp name for the .zip
    $tmp_zip = tempnam ("tmp", "tempname") . ".zip";

    //change directory so the zip file doesnt have a tree structure in it.
    chdir('user_uploads/'.$_GET['directtozip']);
   
    // zip the stuff (dir and all in there) into the tmp_zip file
    exec('zip '.$tmp_zip.' *');
   
    // calc the length of the zip. it is needed for the progress bar of the browser
    $filesize = filesize($tmp_zip);
    header("Content-Length: $filesize");

    // deliver the zip file
    $fp = fopen("$tmp_zip","r");
    echo fpassthru($fp);

    // clean up the tmp zip file
    unlink($tmp_zip);
?>
<a href="zip_folders.php?directtozip=THE USERS DIRECTORY">Download All As Zip</a>