Symfony 4 Generate Api Token from api login|register using email and password

Question

I'm using Symfony 4 "Custom Authentication System with Guard (API Token Example)"Custom Authentication System with Guard (API Token Example)

I want to generate api token when user register from other app(i.e Advance Rest Client) and then want to use this token to access other api's like get articles list.

There is no option to generate token or may be I can't find out.

Here is my code:

config/packages/security.yaml

security:
encoders:
    App\Entity\User:
        algorithm: bcrypt

# https://symfony.com/doc/current/security.html#where-do-users-come-from-user-providers
providers:
    # used to reload user from session & other features (e.g. switch_user)
    app_user_provider:
        entity:
            class: App\Entity\User
            #property: email
firewalls:
    dev:
        pattern: ^/(_(profiler|wdt)|css|images|js)/
        security: false
    api:
        pattern:    ^/api/
        stateless:  true
        anonymous:  false
        guard:
            authenticators:
                - App\Security\TokenAuthenticator
    main:
        pattern: ^/
        anonymous: true
        guard:
            authenticators:
                - App\Security\LoginFormAuthenticator
        logout:
            path:   app_logout

        # activate different ways to authenticate

        # http_basic: true
        # https://symfony.com/doc/current/security.html#a-configuring-how-your-users-will-authenticate

        # form_login: true
        # https://symfony.com/doc/current/security/form_login_setup.html

# Easy way to control access for large sections of your site
# Note: Only the *first* access control that matches will be used
access_control:
    - { path: ^/api, roles: [ IS_AUTHENTICATED_FULLY ] }
    - { path: ^/login$, roles: IS_AUTHENTICATED_ANONYMOUSLY }
    - { path: ^/admin, roles: ROLE_ADMIN }
    # - { path: ^/profile, roles: ROLE_USER }

Controller/RegistrationController.php

class RegistrationController extends AbstractController{

/**
 * @Route("/register/api", name="app_register_api")
 */
public function registerApi(Request $request, UserPasswordEncoderInterface $passwordEncoder, GuardAuthenticatorHandler $guardHandler, TokenAuthenticator $authenticator){

    $user = new User();
    $form = $this->createForm(RegistrationFormType::class, $user);
    $form->handleRequest($request);

    if ($form->isSubmitted() && $form->isValid()) {
        // encode the plain password
        $user->setPassword(
            $passwordEncoder->encodePassword(
                $user,
                $form->get('plainPassword')->getData()
            )
        );

        $entityManager = $this->getDoctrine()->getManager();
        $entityManager->persist($user);
        $entityManager->flush();

        // do anything else you need here, like send an email


        $data = $guardHandler->authenticateUserAndHandleSuccess(
            $user,
            $request,
            $authenticator,
            'api' // firewall name in security.yaml
        );

        return new JsonResponse($data, Response::HTTP_FORBIDDEN);
    }

}

}

Security/TokenAuthenticator.php

class TokenAuthenticator extends AbstractGuardAuthenticator
{
  private $em;

public function __construct(EntityManagerInterface $em)
{
    $this->em = $em;
}

/**
 * Called on every request to decide if this authenticator should be
 * used for the request. Returning false will cause this authenticator
 * to be skipped.
 */
public function supports(Request $request)
{
    return $request->headers->has('X-AUTH-TOKEN');
}

/**
 * Called on every request. Return whatever credentials you want to
 * be passed to getUser() as $credentials.
 */
public function getCredentials(Request $request)
{
    return [
        'token' => $request->headers->get('X-AUTH-TOKEN'),
    ];
}

public function getUser($credentials, UserProviderInterface $userProvider)
{
    $apiToken = $credentials['token'];

    if (null === $apiToken) {
        return;
    }

    // if a User object, checkCredentials() is called
    return $this->em->getRepository(User::class)
        ->findOneBy(['apiToken' => $apiToken]);
}

public function checkCredentials($credentials, UserInterface $user)
{
    // check credentials - e.g. make sure the password is valid
    // no credential check is needed in this case

    // return true to cause authentication success
    return true;
}

public function onAuthenticationSuccess(Request $request, TokenInterface $token, $providerKey)
{
    // on success, let the request continue
    return null;

}

public function onAuthenticationFailure(Request $request, AuthenticationException $exception)
{
    $data = [
        'message' => strtr($exception->getMessageKey(), $exception->getMessageData())

        // or to translate this message
        // $this->translator->trans($exception->getMessageKey(), $exception->getMessageData())
    ];

    return new JsonResponse($data, Response::HTTP_FORBIDDEN);
}

/**
 * Called when authentication is needed, but it's not sent
 */
public function start(Request $request, AuthenticationException $authException = null)
{
    $data = [
        // you might translate this message
        'message' => 'Authentication Required'
    ];

    return new JsonResponse($data, Response::HTTP_UNAUTHORIZED);
}

public function supportsRememberMe()
{
    return false;
}
}

Next problem is how to get user detail from token in articles api?

<?php

  namespace App\Controller\Rest;

  use Symfony\Component\HttpFoundation\Request;
  use Symfony\Component\HttpFoundation\Response;
  use FOS\RestBundle\Controller\FOSRestController;
  use FOS\RestBundle\Controller\Annotations as Rest;
  use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;

  use App\Entity\Article;
  use App\Form\ArticleType;
  use App\Service\ArticleService;

  class ArticleController extends FOSRestController
  {
     /**
          * @var ArticleService
    */
      private $articleService;
     /**
     * ArticleController constructor.
     * @param ArticleService $articleService
     */
     public function __construct(ArticleService $articleService)
    {
      $this->articleService = $articleService;
    }

/**
* Lists all Articles.
* http://sf4.local/api/articles
* @Rest\Get("/articles")
*
* @return Response
*/
public function getArticles()
 {
    $items = $this->articlesService->getAllArticles();
    return $this->handleView($this->view($items));
 }
}