User Email Comment Notifications in WordPress

I’ve been using the “Subscribe To Comments Reloaded” for a few years. Although the core features worked fine, some items like email security (especially Google reCAPTCHA) seemed to stop working.

After a lot of research and testing, I came up with an easier solution that is super lightweight and doesn’t require a plugin. You’ll just update your child theme’s “functions.php” file.

The code below does four things:

1. Sets up the emails to be sent in HTML.
2. Emails a commenter when their comment is approved.
3. Emails a commenter when someone replies to their comment.
4. Allows you to customize the “Your comment is awaiting moderation” text as well as adds an “awaiting-moderation” class to this text to help you stylize this alert.

// =========================================================================
//  Comment Notifications &  Moderation Notice
// =========================================================================

// Set HTML mail content type
function set_html_content_type() {
  return 'text/html';
}

// Notify commenter when comment is approved
add_action('wp_set_comment_status', 'notify_comment_author_on_approval', 10, 2);
function notify_comment_author_on_approval($comment_id, $comment_status) {
  if ($comment_status == 'approve') {
    $comment = get_comment($comment_id);
    $email = $comment->comment_author_email;
    $post = get_post($comment->comment_post_ID);
    $subject = 'Your comment on ' . $post->post_title . ' was approved';
    $message = 'Hi ' . $comment->comment_author . ',<br><br>';
    $message .= 'Your comment on "' . $post->post_title . '" has been approved!<br><br>';
    $message .= '<a href="' . get_comment_link($comment) . '">View your comment here</a>.<br><br>';
    $message .= 'Thanks,<br>';
    $message .= 'YOUR NAME<br>';
    $message .= get_bloginfo('name');

    add_filter('wp_mail_content_type', 'set_html_content_type');
    wp_mail($email, $subject, $message);
    remove_filter('wp_mail_content_type', 'set_html_content_type');
  }
}

// Notify commenter when comment is replied to
add_action('comment_post', 'notify_comment_author_on_reply', 10, 2);
function notify_comment_author_on_reply($comment_id, $comment_approved) {
  $comment = get_comment($comment_id);
  if ($comment->comment_parent) {
    $parent_comment = get_comment($comment->comment_parent);
    $email = $parent_comment->comment_author_email;
    $post = get_post($comment->comment_post_ID);
    $subject = 'Someone replied to your comment on ' . $post->post_title;
    $message = 'Hi ' . $parent_comment->comment_author . ',<br><br>';
    $message .= 'Someone has replied to your comment on "' . $post->post_title . '"!<br><br>';
    $message .= '<a href="' . get_comment_link($comment) . '">View your reply here</a>.<br><br>';
    $message .= 'Thanks,<br>';
    $message .= 'YOUR NAME<br>';
    $message .= get_bloginfo('name');

    add_filter('wp_mail_content_type', 'set_html_content_type');
    wp_mail($email, $subject, $message);
    remove_filter('wp_mail_content_type', 'set_html_content_type');
  }
}

// Customize 'Your comment is awaiting moderation.' text
add_filter( 'gettext', function( $text ) {
  if ( 'Your comment is awaiting moderation.' === $text ) {
    $text = '<span class="awaiting-moderation">Thanks! you\'ll be notified you once your comment has been approved.</span>';
  }
  return $text;
});

Caveats

• Change the “YOUR NAME” in the code above to your name, or remove this line completely.
• This doesn’t allow users to unsubscribe or manage email subscriptions to your posts.
• Make sure you’re doing any updates to “functions.php” in a child theme.
• You’ll need to make sure that email is processing properly.

Recommendations on preventing spam:

• Install the free Spam Destroyer by Ryan Hellyer.
• Add Google’s reCAPTCHA to your security plugin, or use something like Advanced Google reCAPTCHA to add reCAPTCHA to your site.
• Go through your “Discussion” settings and follow the recommendations to help prevent spam.