Comment Approve - Add custom function when comment is approved

Question

I would like to save some PHP memory when quering category page (like 5000 products at once) with average review rating, so I would like to save average rating of reviews every time I will manually approve new comment.

I would like to accomplish, whenever I click on "APPROVE" button in administration, it will run these php scripts.

function average_rating() {
global $wpdb;

$post_id = get_the_ID();

$ratings = $wpdb->get_results("

    SELECT $wpdb->commentmeta.meta_value

    FROM $wpdb->commentmeta

    INNER JOIN $wpdb->comments on $wpdb->comments.comment_id=$wpdb->commentmeta.comment_id

    WHERE $wpdb->commentmeta.meta_key='rating' 

    AND $wpdb->comments.comment_post_id=$post_id 

    AND $wpdb->comments.comment_approved = 1

    and trim(coalesce($wpdb->commentmeta.meta_value, '')) <>''

    ");

$counter = 0;

$average_rating = 0;    

if ($ratings) {

    foreach ($ratings as $rating) {

        $average_rating = $average_rating + $rating->meta_value;

        $counter++;

    } 

    //round the average to the nearast 1/2 point

    return (round(($average_rating/$counter)*2,0)/2);  

} else {

    //no ratings

    return '0';

}

}

 $ar = average_rating();
 add_post_meta( $post->ID, 'summary', $ar );

Answer 1

Sadly there are no hooks or filters that you could use in edit-comments.php. You'd have to build your own admin page with a custom button and use wp_set_comment_status( $comment, 'approve' ); to approve comment and do whatever you need to do...

EDIT: I was wrong - there's the wp_set_comment_status action inside wp_set_comment_status function https://wpseek.com/function/wp_set_comment_status/

do_action( 'wp_set_comment_status', $comment->comment_ID, $comment_status );

So you can just do:

add_action('wp_set_comment_status','average_rating',10,2);

and add to your function

function average_rating($comment_id, $comment_status) {
   if ($comment_status == 'approve') {
      .....rest of your code