Php - Tạo xml sitemap động theo dữ liệu !

<?php
    header('Content-type: application/xml');

    require_once '../common/settings.php'; // database settings
    require_once PROJECT_PATH . '/lib/php_adodb_v5.18/adodb.inc.php';
    require_once PROJECT_PATH . '/lib/small_blog_v0.8.0/smallblog.php'; // custom blogging engine
    require_once PROJECT_PATH . '/lib/utils/utils.php'; // utility functions: date_decode, now

// configuration
    $url_prefix = 'http://www.pontikis.net/blog/';
    $blog_timezone = 'UTC';
    $timezone_offset = '+00:00';
    $W3C_datetime_format_php = 'Y-m-d\Th:i:s'; // See http://www.w3.org/TR/NOTE-datetime
    $null_sitemap = '<urlset><url><loc></loc></url></urlset>';

    $blog = new smallblog();  // custom blogging engine
    $res = $blog->db_connect($blog_db_settings);
    if($res === false) {
        echo $null_sitemap;
        exit; // Database connection error...
    } else {

        // get all posts meta-data
        $posts = $blog->getPosts(0, 0, '', '', '', now($blog_timezone));
        if($posts === false) {
            echo $null_sitemap;
            exit; // Error retreiving posts...
        }

        $len = count($posts);
        for($i = 0; $i < $len; $i++) {
            // entities encode URL according http://www.sitemaps.org/protocol.html#escaping
            $posts[$i]['url'] = $url_prefix . htmlspecialchars($posts[$i]['url']);
            // convert dates to W3C datetime format http://www.sitemaps.org/protocol.html#xmlTagDefinitions
            $posts[$i]['date_updated'] = date_decode($posts[$i]['date_updated'], $blog_timezone, $W3C_datetime_format_php) . $timezone_offset;
        }

        // retrieve max date
        $max_date = $posts[0]['date_updated'];
    }

    $output = '<?xml version="1.0" encoding="UTF-8"?>' . "\n";
    $output .= '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">' . "\n";
    echo $output;
?>
<url>
    <loc>http://www.pontikis.net/blog/</loc>
    <lastmod><?php print $max_date ?></lastmod>
    <changefreq>daily</changefreq>
</url>
<url>
    <loc>http://www.pontikis.net/blog/archive/</loc>
    <lastmod><?php print $max_date ?></lastmod>
    <changefreq>daily</changefreq>
</url>
<?php for($i = 0; $i < $len; $i++) { ?>
<url>
    <loc><?php print $posts[$i]['url'] ?></loc>
    <lastmod><?php print $posts[$i]['date_updated'] ?></lastmod>
</url>
<?php } ?>
</urlset>