PHP : Muat-naik fail dari URL

<?php 
$PHP_SELF = $_SERVER['PHP_SELF']; 

if ($_GET[xfer]) { 
if ($_POST[from] == "") { 
print "You forgot to enter a url."; 
} else { 
copy("$_POST[from]", "$_POST[to]"); 
$size = round((filesize($_POST[to])/1000000), 3); 
print "transfer complete.<br> 
<a><a href=\"$_POST[from]\">$_POST[from]</a><br> 
<a><a href=\"$_POST[to]\">$_POST[to]</a> : $size MB"; 
} 
} else { 
print "<form action=\"$PHP_SELF?xfer=true\" method=post> 
from(http://): <input name='from' value=''><br> 
to(filename): <input name='to'><br> 
<input type=submit value=\"transload\">"; 
} 
?>