Follow-up Comments Notification Without a Plug-in

Question

I'm trying to find the code to insert in my Comments.php to add the functionality of "Follow-up Comments Notification" but I can't find it.

I can't use a plug-in because it's for a theme that I'm starting to develop for a client and he doesn't want to use plug-ins. I know there has to be a way because I've been told that some themes come with that feature but I don't seem to understand where that piece of code is.

Any help or suggestions will be greatly appreciated.

Cheers

Answer 1

It's quite simple, just hook a function on comment_post in which you check if the comment is a reply and send the author of the parent comment an email:

add_action('comment_post', 'notify_author_of_reply', 10, 2);

function notify_author_of_reply($comment_id, $approved){
  if($approved){
    $comment = get_comment($comment_id);
    if($comment->comment_parent){
      $parent_comment = get_comment($comment->comment_parent);
      wp_mail($parent_comment->comment_author_email, 'Hello', 'Dude you got a reply...');
    }
  }
}

For handling unsubscriptions, you can add store emails of people who don't want notifications inside an option (and check if $parent_comment->comment_author_email is not within that list in the function above).