How to share variables to all views (including behavior) in twig? - symfony

Question

I have this controller action:
public function index(Request $request)
{
$start = $request->get('start', 0);
$limit = $request->get('limit', 10);
$articles = $this->articleRepository->all($start, $limit);
$navigation = $this->menu->build()->render(new RenderStrategyBootstrap4());
return $this->render('article/index.html.twig', [
'articles' => $articles,
'navigation'=>$navigation
]);
}
I build a menu with:
$navigation = $this->menu->build()->render(new RenderStrategyBootstrap4());
Now this is high level behavior and I do not want to render this for every action there is. Is there a way in Symfony to move this behavior to a sort of view composer (like in Laravel?) and then share the variable with the view?
Or is there no way and do I need to create a base controller?

Answer 1

You could create a Custom Twig Extension as described here: https://symfony.com/doc/current/templating/twig_extension.html
There you can register a custom Twig Function like this:
public function getFunctions()
{
return array('renderNavigation' => new TwigFunction(
'renderNavigation',
array($this, 'renderNavigation'),
array('needs_environment' => true, 'is_safe' => array('html'))
);
}
public function renderNavigation(Environment $twig)
{
/* ... */
return $twig->render(/* ... */);
}
Then you can use the function in every template like {{ renderNavigation() }}
Since the Twig Extension itself is a service you can inject whatever service else you need (like RequestStack, EntityManager and so on) and even cache expensive operations within the extension if you need to function to be run more than once.