add_filter('wpcf7_validate', function ($result, $tags) {

    // 1. 检查 referer（来源）
    if (!isset($_SERVER['HTTP_REFERER']) || strpos($_SERVER['HTTP_REFERER'], $_SERVER['HTTP_HOST']) === false) {
        $result->invalidate('', 'Spam detected');
        return $result;
    }

    // 2. 检查 user agent（很多机器人是空的）
    if (empty($_SERVER['HTTP_USER_AGENT'])) {
        $result->invalidate('', 'Spam detected');
        return $result;
    }

    // 3. 屏蔽常见垃圾邮箱域名
    if (isset($_POST['txtemail'])) {
        $email = $_POST['txtemail'];
        if (preg_match('/@(mail\.ru|legenmail\.com|cialis-otc\.com|bekommenmail\.com)$/i', $email)) {
            $result->invalidate('txtemail', 'Spam email domain blocked');
            return $result;
        }
    }

    return $result;

}, 10, 2);<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="https://www.homeykitchencabinet.com/wp-sitemap-index.xsl" ?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><sitemap><loc>https://www.homeykitchencabinet.com/wp-sitemap-posts-post-1.xml</loc></sitemap><sitemap><loc>https://www.homeykitchencabinet.com/wp-sitemap-posts-page-1.xml</loc></sitemap><sitemap><loc>https://www.homeykitchencabinet.com/wp-sitemap-posts-product-1.xml</loc></sitemap><sitemap><loc>https://www.homeykitchencabinet.com/wp-sitemap-taxonomies-category-1.xml</loc></sitemap><sitemap><loc>https://www.homeykitchencabinet.com/wp-sitemap-taxonomies-post_tag-1.xml</loc></sitemap><sitemap><loc>https://www.homeykitchencabinet.com/wp-sitemap-taxonomies-product_cat-1.xml</loc></sitemap><sitemap><loc>https://www.homeykitchencabinet.com/wp-sitemap-users-1.xml</loc></sitemap></sitemapindex>