gdk/public/sitemap-xml.php

<?php

/**
 * sitemap xml
 */

function gdk_sitemap_xml_api_handlers($template)
{
    $hook = explode('-', get_query_var('sitemap'));
    if (isset($hook[0]) && $hook[0] === 'gdk') {
        if (isset($hook[1])) {
            status_header(404);
            header('HTTP/1.0 404 Not Found');
            $GLOBALS['wp_query']->set_404();
            include get_query_template('404');
            exit;
        }

        $sitemap = get_transient('gdk-sitemap');
        if (false === $sitemap || empty($sitemap)) {
            $sitemap = gdk_create_sitemap();
            set_transient('gdk-sitemap', $sitemap);
        }

        header("Content-type: text/xml");
        echo $sitemap;
        return;
    }

    return $template;
}

add_filter('template_include', 'gdk_sitemap_xml_api_handlers', 99);

function gdk_create_sitemap()
{
    if (str_replace('-', '', get_option('gmt_offset')) < 10) {
        $tempo = '-0' . str_replace('-', '', get_option('gmt_offset'));
    } else {
        $tempo = get_option('gmt_offset');
    }
    if (strlen($tempo) == 3) {$tempo = $tempo . ':00';}
    $postsForSitemap = get_posts(array(
        'numberposts' => -1,
        'orderby'     => 'modified',
        'post_type'   => array('post'),
        'order'       => 'DESC',
    ));
    $sitemap = '';
    $sitemap .= '<?xml version="1.0" encoding="UTF-8"?>';
    $sitemap .= "\n" . '<urlset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">' . "\n";
    $sitemap .= "\t" . '<url>' . "\n" .
    "\t\t" . '<loc>' . esc_url(home_url('/')) . '</loc>' .
    "\n\t\t" . '<lastmod>' . date("Y-m-d\TH:i:s", current_time('timestamp', 0)) . $tempo . '</lastmod>' .
        "\n\t\t" . '<changefreq>daily</changefreq>' .
        "\n\t\t" . '<priority>1.0</priority>' .
        "\n\t" . '</url>' . "\n";
    foreach ($postsForSitemap as $post) {
        setup_postdata($post);
        $postdate = explode(" ", $post->post_modified);
        $sitemap .= "\t" . '<url>' . "\n" .
        "\t\t" . '<loc>' . get_permalink($post->ID) . '</loc>' .
            "\n\t\t" . '<lastmod>' . $postdate[0] . 'T' . $postdate[1] . $tempo . '</lastmod>' .
            "\n\t\t" . '<changefreq>Weekly</changefreq>' .
            "\n\t\t" . '<priority>0.5</priority>' .
            "\n\t" . '</url>' . "\n";
    }
    $sitemap .= '</urlset>';
    return $sitemap;
}