Inhalt des Elterndokumentes soll nicht angezeigt werden

<?php
/*
Plugin Name: Redirect to subpage
Plugin URI: 
Description: This plugin redirects automatically to the first subpage of the current page if it has no contents and at least one subpage.
Version: 0.1
Author: Marcus Zelend
Author URI: http://marcus.zelend.de/
*/


function redirect_to_subpage($wp) {
	// calling a page?
	if (empty($wp->query_vars["page_id"]))
		return;
	
	$page_id = $wp->query_vars["page_id"];
	
	// get current page
	$current = get_page($page_id);
	
	// is page content empty?
	if(!empty($current->post_content))
		return;
		
	// get children of current page
	$children = get_pages("child_of=$page_id&sort_column=menu_order");
	
	// page has child pages?
	if(empty($children))
		return;
	
	// redirect to subpage:
	header("Location: " . get_permalink($children[0]->ID), true, 302);
	exit;
}
add_action('wp', 'redirect_to_subpage');