如何在自定义WordPress主题中添加对客户端提供的alt文本的支持？

function custom_add_image_alt_text($content) {
    global $post;
    
    if (preg_match_all('/<img[^>]+>/i', $content, $matches)) {
        foreach ($matches[0] as $img) {
            if (preg_match('/alt="(.*?)"/i', $img, $alt)) {
                $image_id = attachment_url_to_postid($img);
                
                if ($image_id) {
                    $image_alt = get_post_meta($image_id, '_wp_attachment_image_alt', true);
                    
                    if (!$image_alt) {
                        $new_img = str_replace($alt[1], '', $img);
                        $content = str_replace($img, $new_img, $content);
                    }
                }
            }
        }
    }
    
    return $content;
}
add_filter('the_content', 'custom_add_image_alt_text');