Having trouble to set $_SESSION['lang'] - slim-3

Question

Im facing a though nut to crack here... Hope someone out there can help me out !? :-)
Im making a site with slim3, where im trying to setup localization based on this course over at CodeCourse and it seem's that im having troubles to set my session properly, since im using DI-Bridge whereas he is not...
I can't seem to figure out, WHY it fails accordingly to the stacktrace !?
Can anyone help perhaps?
Here's my contaner.php
use function DI\get;
use Interop\Container\ContainerInterface;
use Slim\Csrf\Guard;
use Slim\Flash\Messages;
use Slim\Views\Twig;
use Slim\Views\TwigExtension;
use Illuminate\Translation\Translator;
use Illuminate\Translation\FileLoader;
use Illuminate\Filesystem\Filesystem;
//use Noodlehaus\Config;
use app\views\extensions\TranslationExtension;
use app\handlers\auth\Auth;
use app\handlers\errors\NotFoundHandler;
use app\models\data\About;
use app\models\data\Contact;
use app\models\data\Framework;
use app\models\data\Project;
use app\models\data\Service;
use app\models\data\Site;
use app\models\data\Testimonial;
use app\models\data\User;
use app\validation\contracts\ValidatorInterface;
use app\validation\Validator;
use app\validation\domain\DomainCheck;
use app\validation\email\EmailAvailable;
use app\validation\password\MatchesPassword;
return [
/**
* attaching : XX ->
*/
/* ROUTER */
'router' => get(Slim\Router::class),
/* 404 ERROR */
'notFoundHandler' => function(ContainerInterface $c) {
return new NotFoundHandler ($c->get(Twig::class));
},
/* AUTH */
Auth::class => function (ContainerInterface $c) {
return new Auth;
},
/* CSRF */
Guard::class => function (ContainerInterface $c) {
return new Guard;
},
/* FLASH */
Messages::class => function (ContainerInterface $c) {
return new Messages;
},
/* VALIDATOR */
ValidatorInterface::class => function (ContainerInterface $c) {
return new Validator;
},
/* TRANSLATOR */
Translator::class => function (ContainerInterface $c) {
$fallback = $c->get('settings.translations.fallback');
$loader = new FileLoader(
new Filesystem(), $c->get('settings.translations.path')
);
$translator = new Translator($loader, $_SESSION['lang'] ?? $fallback);
$translator->setFallback($fallback);
return $translator;
},
/* TWIG */
Twig::class => function (ContainerInterface $c) {
$view = new Twig(__DIR__ . '/../resources/views', [
'cache' => false
]);
$view->addExtension(new TwigExtension(
$c->get('router'),
$c->get('request')->getUri()
));
$view->addExtension(new TranslationExtension(
$c->get(Translator::class)
));
$view->getEnvironment()->addGlobal('flash', $c->get(Messages::class));
$view->getEnvironment()->addGlobal('auth', [
'check' => $c->get(Auth::class)->check(),
'user' => $c->get(Auth::class)->user(),
]);
return $view;
},
/**
* attaching : RESPECT -> VALIDATION -> CUSTOM RULES
*/
/* DOMAIN */
DomainCheck::class => function (ContainerInterface $c) {
return new DomainCheck;
},
/* EMAIL */
EmailAvailable::class => function (ContainerInterface $c) {
return new EmailAvailable;
},
/* PASSWORD */
MatchesPassword::class => function (ContainerInterface $c) {
return new MatchesPassword ($c->get(password));
},
/**
* attaching : MODELS ->
*/
/* ABOUT */
About::class => function (ContainerInterface $c) {
return new About;
},
/* CONTACT */
Contact::class => function (ContainerInterface $c) {
return new Contact;
},
/* FRAMEWORK */
Framework::class => function (ContainerInterface $c) {
return new Framework;
},
/* PROJECT */
Project::class => function (ContainerInterface $c) {
return new Project;
},
/* SERVICE */
Service::class => function (ContainerInterface $c) {
return new Service;
},
/* SITE */
Site::class => function (ContainerInterface $c) {
return new Site;
},
/* TESTIMONIAL */
Testimonial::class => function (ContainerInterface $c) {
return new Testimonial;
},
/* USER */
User::class => function (ContainerInterface $c) {
return new User;
},
];
and here's my TranslationController.php
<?php
namespace App\Controllers;
use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;
use Slim\Router;
class TranslationController {
/**
* #param Request $request
* #param Response $response
* #param Router $router
* #param $args
*
* #return mixed
*/
public function switch(Request $request, Response $response, Router $router, $args) {
if (isset($args['lang'])) {
$_SESSION['lang'] = $args['lang'];
}
return $response->withRedirect($router->pathFor('home'));
}
}
plus the route for translate:
<?php
/**
* adding to view : LOCALIZATION
*/
$app->get('/translate/{lang}', ['app\controllers\TranslationController', 'switch'])->setName('translate.switch');
and finally, here's is the error stacktrace

Answer 1

I don't have much experience with PHP DI, but I would suggest removing the $args argument and get the param via the $request->getAttribute('lang') instead.
<?php
namespace App\Controllers;
use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;
use Slim\Router;
class TranslationController {
/**
* #param Request $request
* #param Response $response
* #param Router $router
* #param $args
*
* #return mixed
*/
public function switch(Request $request, Response $response, Router $router) {
$_SESSION['lang'] = $request->getAttribute('lang');
return $response->withRedirect($router->pathFor('home'));
}
}

Answer 2

after a litte bit more examination and try/correct, this is what ended up solving it! :
public function switch(Request $request, Response $response, Router $router, $lang) {
if (isset($lang)) {
$_SESSION['lang'] = $lang;
}
return $response->withRedirect($router->pathFor('home'));
}