page creator to leave comments ONLY

Question

I am trying to set it so that the person who created a Page is the ONLY one who can comment on that particular page. This will be a logged in person. I haven't had any luck with Role Editor Plugins.

Answer 1

There's probably a way to do this via one of the meta cap filters, but off the top of my head you could use the comments_open filter to check if the currently logged in user is the author of the post and change the output of the comments_open() function accordingly.

I'm on the patio, so can't test, but something like this should work:

add_filter( 'comments_open', 'wpse158190_comments_open', 10, 2 );
function wpse158190_comments_open( $open, $post_id ) {
  global $current_user;
  get_currentuserinfo();
  $post = get_post( $post_id ); // 'global $post;' may also work here
  if ( $current_user->ID == $post->post_author ) return TRUE;
}

Edit:

As noted in comments, the above will also disallow anyone but the author from seeing comments.

Looking through the comment_form() function in core, I don't see a very clean way to accomplish this. You could run a late hook of the comment_form_default_fields filter in order to remove the fields:

add_filter( 'comment_form_default_fields', 'wpse158195_comment_form_default_fields', 99 );
function wpse158195_comment_form_default_fields( $fields ) {
  global $current_user;
  get_currentuserinfo();
  $post = get_post( $post_id ); // 'global $post;' may also work here
  if ( $current_user->ID != $post->post_author ) unset $fields;
  return $fields
}

However, I suspect this will leave a useless "Leave a reply" heading and "Post Comment" button. You could hide these by injecting some CSS on the page via the comment_form_before action:

add_action( 'comment_form_before', 'wpse158195_comment_form_before' );
function 158195_comment_form_before() {
  global $current_user;
  get_currentuserinfo();
  $post = get_post( $post_id ); // 'global $post;' may also work here
  if ( $current_user->ID != $post->post_author ) : ?>
    <style type="text/css">
      #respond.comment-respond { display: none; }
    </style>
  <?php endif;
}

Answer 2

Yes it is working 100%. Here is the total plugin if anyone else needs it...

add_filter( 'comment_form_default_fields', 'wpse158195_comment_form_default_fields', 99 );
function wpse158195_comment_form_default_fields( $fields ) {
  global $current_user;
  get_currentuserinfo();
  $post = get_post( $post_id ); // 'global $post;' may also work here
  if ( $current_user->ID != $post->post_author ) unset ($fields);
  return $fields;
}

add_action( 'comment_form_before', 'wpse158195_comment_form_before' );
function wpse158195_comment_form_before() {
  global $current_user;
  get_currentuserinfo();
  $post = get_post( $post_id ); // 'global $post;' may also work here
  if ( $current_user->ID != $post->post_author ) : ?>
    <style type="text/css">
      #respond.comment-respond { display: none; }
      .comment-reply-link { display: none; }
    </style>
  <?php endif;
}

Thank You so much karpstrucking