Force downloading a file

<?php	
if($_GET){
	if($_GET['file']) {
		$filename = $_GET['file'];
		$download_path = "files/";
	}
 
	if(eregi("\.\.", $filename)) die("I'm sorry, you may not download that file.");
	$file = str_replace("..", "", $filename);
	if(eregi("\.ht.+", $filename)) die("I'm sorry, you may not download that file.");
	$file = "$download_path$file";
	if(!file_exists($file)) die("I'm sorry, the file doesn't seem to exist.");
	$type = filetype($file);
	$today = date("F j, Y, g:i a");
	$time = time();
 
	header("Content-type: $type");
	header("Content-Disposition: attachment;filename=$filename");
	header("Content-Transfer-Encoding: binary");
	header("Cache-Control: ");
	header("Pragma: ");
	set_time_limit(0);
	readfile($file);
}
?>