WordPress实现文章按最新评论时间排序

function comment_meta_add($post_ID) {
// 发布新文章或修改文章，更新/添加commentTime字段值
global $wpdb;
if(!wp_is_post_revision($post_ID)) {
if( !update_post_meta($post_ID, 'commentTime', time()) ) {
add_post_meta($post_ID, 'commentTime', time());
}
}
}

function comment_meta_update($comment_ID) {
// 发布新评论更新commentTime字段值
$comment = get_comment($comment_ID);
$my_post_id = $comment->comment_post_ID;
update_post_meta($my_post_id, 'commentTime', time());
}

function comment_meta_delete($post_ID) {
// 删除文章同时删除commentTime字段
global $wpdb;
if(!wp_is_post_revision($post_ID)) {
delete_post_meta($post_ID, 'commentTime');
}
}
add_action('save_post', 'comment_meta_add');
add_action('delete_post', 'comment_meta_delete');
add_action('comment_post', 'comment_meta_update');