Trying to remove post thumbnail with plugin

Question

I have a plugin that need to remove the post thumbnail under certain conditions. Tried to hook to "get_post_metadata" filter but the code doesn't seem to work.

Here's my code:

public function helper() {
    ...
    add_filter('get_post_metadata', array($this, 'removeThumbnail'), 999, 4);
    ...
}

public function removeThumbnail($metadata, $object_id, $meta_key, $single) {
    return ( isset($meta_key) && '_thumbnail_id' === $meta_key ) ? false : $metadata;
}

My class is initialized on the_content hook.

However, it doesn't remove the featured image in the post. Any insights and ideas how to make it happen?

Answer 1

I found where the problem was. The code was attached to the the_content hook which runs after the thumbnail is generated.

Attached the code to post_thumbnail_html and it works now.