ZF2 navigation permission listener.php

<?php
/**
 * Attach in Module::onBootstrap()
 * <code>
 * $navigationRbacListener = $target->getServiceManager()->get('NavigationRbacListener');
 * $target->getEventManager()->getSharedManager()->attach(
 *     'Zend\View\Helper\Navigation\AbstractHelper',
 *     'isAllowed',
 *     [$navigationRbacListener, 'hasPermission']
 * );
 * </code>
 */

namespace Application\Listener;


use Zend\EventManager\Event;
use Zend\Navigation\Page\AbstractPage;
use ZfcRbac\Service\AuthorizationService;

/**
 * Inject AuthorizationService via Factory
 */
class NavigationRbacListener
{
    /** @var AuthorizationService */
    private $_authorizationService;

    public function __construct(AuthorizationService $authorizationService)
    {
        $this->_authorizationService = $authorizationService;
    }

    public function hasPermission(Event $e)
    {
        $page = $e->getParam('page');

        if (!$page instanceof AbstractPage) {
            return true;
        }

        $permission = $page->getPermission();

        if (null === $permission) {
            return true;
        }

        $e->stopPropagation();

        return $this->_authorizationService->isGranted($permission);
    }
}