Extract URLs from Webpage

<?php

// by seidbenseid
// from arabia.io
// algerian HaXoor

function get_all_urls ($url) {
    if (function_exists ("curl_exec")) {
        $ch = curl_init ($url);
        curl_setopt ($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt ($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 6.1; rv:35.0) Gecko/20100101 Firefox/35.0");
        curl_setopt ($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt ($ch, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt ($ch, CURLOPT_HEADER, false);
        curl_setopt ($ch, CURLOPT_ENCODING, false);
        $data = curl_exec ($ch);
    }
    else
        $data = file_get_contents ($url);

    $urls = array ();

    if (preg_match_all ('#<a\s*(.*?)>#i', $data, $attrs)) {
        foreach ($attrs[1] as $attr) {
            if (preg_match ('#href\s*=\s*(\'|")(.*?)(\'|")#i', $attr, $href)) {
                if ($href[2] && !in_array ($href[2], $urls))
                    $urls[] = $href[2];
            }
        }
    }

    return $urls;
}

?>