Call function in controller using service symfony 5 - symfony

Question

I tried to call a function in a controller using service:
#BookManager.php
<?php
namespace App\Service;
use App\Entity\BookContent;
use Doctrine\ORM\EntityManagerInterface;
class BookManager
{
protected $entityManager;
public function __construct(EntityManagerInterface $entityManager)
{
$this->entityManager = $entityManager;
}
public function getBookTitle(string $page){
return $this->entityManager->getRepository(BookContent::class)
>findOneBy(["page"=>$page])->getTitle();
}
In service.yml
....
services:
book.manager:
class: App\Service\BookManager
arguments: ['#doctrine.orm.entity_manager']
public: true
Finally I call it in Controller ;
$pageName = $this->container->get('request_stack')->getMasterRequest()->get('_route');
$bookTitle = $this->container->get('book.manager')->getBookTitle($pageName);
But I get this error
Service "book.manager" not found: even though it exists in the app's container, the container inside "App\Controller\HomeController" is a smaller service locator that only knows about the "doctrine", "form.factory", "http_kernel", "parameter_bag", "request_stack", "router", "security.authorization_checker", "security.csrf.token_manager", "security.token_storage", "serializer", "session" and "twig" services. Try using dependency injection instead.
Any idea?
EDIT
it's work when I use dependency injection but only when I do query with $id
$this->entityManager->getRepository(BookContent::class)-
>findOneById(["id"=>$id])->getTitle();
when I do it with findOneBy(["page"=>$page]) I get this error:
Impossible to access an attribute ("title") on a null variable.

Answer 1

By default Symfony 5 will autowire/auto configure your services. You can remove the book.manager from your service.yaml.
You can then use dependency injection in your controllers to access your services, like this for example:
<?php
namespace App\Controller;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\Annotation\Route;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use App\Service\BookManager; //<-- Add use
class YourController extends AbstractController
{
/**
* #Route("/", name="home")
*/
public function index(Request $request, BookManager $bookManager): Response
{
$pageName = $request->attributes->get('_route');
$bookTitle = $bookManager->getBookTitle($pageName);
return ...
}
}