Why is my dependency container variable undefined when I try to register csrf middleware for all routes in Slim? - slim

Question

I am trying to register middleware for all routes to protect against csrf in Slim. I have installed the files for Slim csrf protection using composer and I have added the dependency to my dependencies file, but when I try to register the middleware in my middleware file, I get an error telling me that my dependency container variable is undefined.
I am a programming newbie and do not understand how to troubleshoot things within a framework. So I have just tried fiddling with it.
Dependency in dependencies.php:
$container['csrf'] = function ($c) {
return new \Slim\Csrf\Guard;
};
Register middleware in middleware.php:
use Slim\App;
return function (App $app) {
$app->add($container['csrf']);
};
It should work, especially considering I literally did exactly what the documentation says to do in order to set this up, but when I refresh my page after I get a notice message telling me $container is not defined. Because I am completely new to using a framework I could really use some insight. Thanks.

Answer 1

The App is not the container itself; it holds the container, so you need to get at it first.
Try:
return function (App $app) {
$app->add($app->getContainer()->get('csrf'));
};
Note that I've also used the get() method on the container for retrieval. This is the method that PSR-11 uses and so will work with a variety of containers. Using array access to retrieve items from the container is Pimple specific.