Recursively zip files with PHP

This function is useful for zipping files/directories when you only have FTP access to a site, and for when you are using a web host ‘File Manager’ which bugs out on permissions or otherwise.

function Zip($source, $destination)
{
    if (!extension_loaded('zip') || !file_exists($source)) {
        return false;
    }
    $zip = new ZipArchive();
    if (!$zip->open($destination, ZIPARCHIVE::CREATE)) {
        return false;
    }
    $source = str_replace('\', '/', realpath($source));
    if (is_dir($source) === true)
    {
        $files = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($source), RecursiveIteratorIterator::SELF_FIRST);
        foreach ($files as $file)
        {
            $file = str_replace('\', '/', $file);
            // Ignore "." and ".." folders
            if( in_array(substr($file, strrpos($file, '/')+1), array('.', '..')) )
                continue;
            $file = realpath($file);
            if (is_dir($file) === true)
            {
                $zip->addEmptyDir(str_replace($source . '/', '', $file . '/'));
            }
            else if (is_file($file) === true)
            {
                $zip->addFromString(str_replace($source . '/', '', $file), file_get_contents($file));
            }
        }
    }
    else if (is_file($source) === true)
    {
        $zip->addFromString(basename($source), file_get_contents($source));
    }
    return $zip->close();
}

Zip('/folder/to/compress/', './compressed.zip');