Get remote file size using php.

gistfile1.php

<?php
    function getRemoteFileSize($url) {
        $info = get_headers($url,1);
 
        if (is_array($info['Content-Length'])) {
            $info = end($info['Content-Length']);
        }
        else {
            $info = $info['Content-Length'];
        }
 
        return $info;
    }
?>