ouput the contents of a folder for download

I want to output the file contents of a folder to a php page and provide a link for them to be downloaded. This is what I have so far but I cannot get a filename or get it to iterate through all the files in a folder. <?php $dir = "mydirectory"; // Open a known directory, and proceed to read its contents if (is_dir($dir)) { if ($dh = opendir($dir)) { while (($file = readdir($dh)) !== false) { echo filetype($file) . "\n"; echo filesize($file); } closedir($dh); } } ?>