Parse robots.txt file for sitemaps

robots.php

<?php

function robotsFile($url){

    $file = file_get_contents($url);

    $pattern = '/Sitemap: ([^\s]+)/';
    preg_match_all($pattern, $file, $match);

    $results = array();
    foreach($match[1] as $key => $url){
        $results[] = $url;
    }

    return $results;
}

print_r(robotsFile("https://www.cnn.com/robots.txt"));