$url = "https://glasgow.social/@neil.rss";
$basename = basename($url);
$cache_file = "cache/$basename";
if(!file_exists($cache_file)) {
        $data = file_get_contents($url);
        file_put_contents($cache_file, $data);
} else {
        $cache_ts = filemtime($cache_file);
        if($cache_ts >= strtotime("-5 minutes")) {
                $data = file_get_contents($cache_file);
        } else {
                $data = file_get_contents($url);
                file_put_contents($cache_file, $data);
        }
}

$posts = new SimpleXmlElement($data);

echo "<ul>";
foreach($posts->channel->item as $p) {

        $allowed_post = false;
        foreach($p->category as $hash_tag) {
                if(strtolower($hash_tag) == "glasgow")
                        $allowed_post = true;
        }
        if(!$allowed_post)
                continue;

        echo "<li><strong><a target='new' href='{$p->link}'>{$p->title}</a></strong><br />";
        echo $p->description;
        echo "</li>";
}
echo "</ul>";