Symfony2 KnpMenu TwitterBootstrap switch user menu

Builder.php

<?php

namespace Ormigo\Bundle\BackofficeBundle\Menu;

use Knp\Menu\FactoryInterface;
use Symfony\Component\DependencyInjection\ContainerAware;

use Ormigo\Bundle\UserBundle\Model\User\UserQuery;
use Symfony\Component\Security\Core\Role\SwitchUserRole;

class Builder extends ContainerAware
{
    public function mainMenu(FactoryInterface $factory)
    {
        $menu = $factory->createItem('root');
        $menu->setCurrentUri($this->container->get('request')->getRequestUri());

        $menu->addChild('Dashboard', array(
            'uri' => '#',
        ));
        $menu->addChild('Demo View', array(
            'route' => 'demo',
        ));

        return $menu;
    }

    public function switchUserMenu(FactoryInterface $factory)
    {
        $menu = $factory->createItem('root');
        $menu->setAttributes(array(
            'class' => 'pull-right',
            'dropdown' => true,
            'divider_append' => true,
        ));
        $menu->setLabel('Switch User');

        $securityContext = $this->container->get('security.context');
        if ($securityContext->isGranted('ROLE_ALLOWED_TO_SWITCH') or $securityContext->isGranted('ROLE_PREVIOUS_ADMIN')) {
            // The current (may be switched) username.
            $username = $securityContext->getToken()->getUser()->getUsername();

            // The actual user, if switched, retrieve the correct one.
            $actualUser = $securityContext->getToken()->getUser();
            foreach ($securityContext->getToken()->getRoles() as $role) {
                if ($role instanceof SwitchUserRole) {
                    $actualUser = $role->getSource();
                    break;
                }
            }

            foreach (UserQuery::create()->find() as $eachUser) {
                // only show links to different users
                if ($username !== $eachUser->getUsername()) {
                    $menu->addChild($eachUser->getUsername(), array('uri' => '?_switch_user='.$eachUser->getUsername()));
                }
            }

            $menu->addChild($actualUser->getUsername(), array('uri' => '?_switch_user=_exit'));
        }

        return $menu;
    }
}

example.png

menu_bootstrap.html.twig

{% extends "knp_menu.html.twig"  %}

{% block list %}
{% import "knp_menu.html.twig" as macros %}

{% set is_dropdown = listAttributes.dropdown|default(false) %}
{% set divider_prepend = listAttributes.divider_prepend|default(false) %}
{% set divider_append = listAttributes.divider_append|default(false) %}

{# unset bootstrap specific attributes #}
{% set listAttributes = listAttributes|merge({'dropdown': null, 'divider_prepend': null, 'divider_append': null }) %}

{% if item.hasChildren and options.depth is not sameas(0) and item.displayChildren %}
    {% if is_dropdown %}
        <ul{{ macros.attributes(listAttributes)}}>
            {% if divider_prepend %}
            <li class="divider-vertical"></li>
            {% endif %}
            <li class="dropdown">
                <a href="#" class="dropdown-toggle" data-toggle="dropdown">{{ item.label }} <b class="caret"></b></a>
                <ul class="dropdown-menu">
                    {{ block('children') }}
                </ul>
            </li>
            {% if divider_append %}
            <li class="divider-vertical"></li>
            {% endif %}
        </ul>
    {% else %}
        {{ parent() }}
    {% endif %}
{% endif %}
{% endblock %}

services.yml

services:
    twitter_bootstrap.menu_renderer:
        class: Ormigo\Bundle\BackofficeBundle\Menu\TwitterBootstrapRenderer
        arguments:
            - @twig
            - 'BackofficeBundle:Menu:menu_bootstrap.html.twig'
        tags:
            - { name: knp_menu.renderer, alias: bootstrap }

TwitterBootstrapRenderer.php

<?php

namespace Ormigo\Bundle\BackofficeBundle\Menu;

use Knp\Menu\ItemInterface;
use Knp\Menu\Renderer\TwigRenderer;

class TwitterBootstrapRenderer extends TwigRenderer
{
    public function render(ItemInterface $item, array $options = array())
    {
        $options = array_merge(
            array('currentClass' => 'active'),
            $options
        );

        if ('root' === $item->getName()) {
            $item->setAttribute('class', trim('nav '.$item->getAttribute('class')));
        }

        return parent::render($item, $options);
    }
}

last missing bit is the example how to actually render the menu.
{{ knp_menu_render('main', {}, 'bootstrap') }}
more info in documentation:
https://github.com/KnpLabs/KnpMenuBundle/blob/master/Resources/doc/custom_renderer.md

@fralex:
services.yml should have one more argument, @knp_menu.matcher

services:
    twitter_bootstrap.menu_renderer:
        class: Ormigo\Bundle\BackofficeBundle\Menu\TwitterBootstrapRenderer
        arguments:
            - @twig
            - 'BackofficeBundle:Menu:menu_bootstrap.html.twig'
            - @knp_menu.matcher
        tags:
            - { name: knp_menu.renderer, alias: bootstrap }

in fact, you don't need custom renderer at all. you can achieve this just in menu builder:

$sub = $menu->addChild('Sub', array(
    'uri' => '#',
    'linkAttributes' => array(
        'class' => 'dropdown-toggle',
        'data-toggle' => 'dropdown',
    ),
    'childrenAttributes' => array(
        'class' => 'dropdown-menu',
    ),
    'attributes' => array(
        'class' => 'dropdown',
    ),
));
foreach ($subMenuItems as $item) {
    $sub->addChild($item['name'], array(
        'route' => $item['route'],
    ));
}