Restrict View Content Hook

/**
 * Restrict View Content Hook
 * This code snippet will restrict users / authors from getting
 * points when their post that is set for sale is viewed by someone
 * who has not paid for it.
 * @verion 1.0
 */
add_filter( 'mycred_add', 'mycred_restrict_view_content', 10, 3 );
function mycred_restrict_view_content( $reply, $request, $mycred ) {

    // Only applicable for view content hook
    if ( $reply === false || ! in_array( $request['ref'], array( 'view_content', 'view_content_author' ) ) )
        return $reply;

    // Get post and user IDs
    $post_id = absint( $request['ref_id'] );

    // User viewing content
    if ( $request['ref'] == 'view_content' )
        $user_id = absint( $request['user_id'] );
    else
        $user_id = absint( $request['data']['cui'] );

    // Get the sell content module
    $sell_content = new myCRED_Sell_Content_Module();

    // If post is for sale but has not been bought by user, decline payouts.
    if ( $sell_content->for_sale( $post_id ) && ! $sell_content->user_paid( $user_id, $post_id ) )
        return false;

    return $reply;

}