ExpressionExtension for KnpMenu/KnpMenuBundle

ExpressionExtension.php

<?php

namespace MyApp\Menu;

use Knp\Menu\Factory\ExtensionInterface;
use Knp\Menu\ItemInterface;
use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
use Symfony\Component\Security\Core\Authentication\AuthenticationTrustResolverInterface;
use Symfony\Component\Security\Core\Role\RoleHierarchyInterface;
use Symfony\Component\Security\Core\SecurityContextInterface;

/**
 * @author Kevin Bond <kevinbond@gmail.com>
 */
class ExpressionExtension implements ExtensionInterface
{
    private $expressionLanguage;
    private $securityContext;
    private $roleHierarchy;
    private $trustResolver;
    private $variables;

    public function __construct(
        ExpressionLanguage $expressionLanguage,
        SecurityContextInterface $securityContext,
        RoleHierarchyInterface $roleHierarchy,
        AuthenticationTrustResolverInterface $trustResolver
    )
    {
        $this->expressionLanguage = $expressionLanguage;
        $this->securityContext = $securityContext;
        $this->roleHierarchy = $roleHierarchy;
        $this->trustResolver = $trustResolver;
    }

    /**
     * {@inheritDoc}
     */
    public function buildOptions(array $options)
    {
        $variables = $this->getVariables();

        if (!empty($options['display']) && !is_bool($options['display'])) {
            $options['display'] = (bool) $this->expressionLanguage->evaluate($options['display'], $variables);
        }

        if (!empty($options['displayChildren']) && !is_bool($options['displayChildren'])) {
            $options['displayChildren'] = (bool) $this->expressionLanguage->evaluate($options['displayChildren'], $variables);
        }

        if (!empty($options['extras']['expression_translation_params'])) {
            foreach ($options['extras']['expression_translation_params'] as $key => $value) {
                $options['extras']['translation_params'][$key] = $this->expressionLanguage->evaluate($value, $variables);
            }
        }

        return $options;
    }

    /**
     * {@inheritDoc}
     */
    public function buildItem(ItemInterface $item, array $options)
    {
    }

    // code should be sync with Sensio\Bundle\FrameworkExtraBundle\EventListener\SecurityListener::getVariables
    private function getVariables()
    {
        if (is_array($this->variables)) {
            return $this->variables;
        }

        $token = $this->securityContext->getToken();
        $roles = $this->roleHierarchy->getReachableRoles($token->getRoles());

        return $this->variables = array(
            'token' => $token,
            'user' => $token->getUser(),
            'object' => null,
            'roles' => array_map(function ($role) { return $role->getRole(); }, $roles),
            'trust_resolver' => $this->trustResolver,
            'security_context' => $this->securityContext,
        );
    }
}

services.yml

myapp.menu.factory_extension.expression:
    class: Hammond\Website\Menu\ExpressionExtension
    arguments:
        - @sensio_framework_extra.security.expression_language
        - @security.context
        - @security.role_hierarchy
        - @security.authentication.trust_resolver
    public: false
    tags:
        - { name: knp_menu.factory_extension, priority: -20 }