PHP dowload file (following redirects)

download_file.php

<?php
function download_file($url, $filename){
	$ch = curl_init($url);
	if (is_writable(dirname($filename))) {
		$fp = fopen($filename, "w");
		curl_setopt($ch, CURLOPT_FILE, $fp);
		curl_setopt($ch, CURLOPT_HEADER, 0);
		curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); 
		curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); 
		curl_exec($ch);
		curl_close($ch);
		fclose($fp);
	} else {
	    echo 'The file ($filename) is not writable';
	    die();
	}
}
?>