Create zip files.

gistfile1.php

<?php

function create_zip($path, $save_as)
{
    if (!extension_loaded('zip'))
        throw new ErrorException('Extension ZIP has not been compiled or loaded in php.');
    else if(!file_exists($path))
        throw new ErrorException('The file/path you want to zip doesn\'t exist!');


    $zip = new ZipArchive();
    if (!$zip->open($save_as, ZIPARCHIVE::CREATE))
        throw new ErrorException('Could not create zip file!');

    $ignore = array('.','..');
    if($path == dirname($save_as))
        $ignore[] = basename($save_as);

    $path = str_replace('\\', '/', realpath($path));

    if (is_dir($path)) {
        $files = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST);
        foreach ($files as $file) {
            $file = str_replace('\\', '/', $file);

            if( in_array(substr($file, strrpos($file, '/')+1), $ignore )) continue;

            $file = realpath($file);
            if (is_dir($file)) {
                $zip->addEmptyDir(str_replace($path . '/', '', $file . '/'));
            }
            else if (is_file($file)) {
                $zip->addFromString(str_replace($path . '/', '', $file), file_get_contents($file));
            }
        }
    }
    else if (is_file($path)) {
        $zip->addFromString(basename($path), file_get_contents($path));
    }

    return $zip->close();
}

$zip = create_zip('/path/to/zip/', '/path/to/save.zip');

?>