How do I load the user object?

Question

I need to get the global $user object in Drupal 8. I did $account = \Drupal::currentUser(); in the definition of getSubscribedEvents() (a static method) inside a class file.

I get the following error when running drush cr:

exception
[error] 'Drupal\Core\DependencyInjection\ContainerNotInitializedException' with message '\Drupal::$container is not initialized yet. \Drupal::setContainer() must be called with a real container.' in /Applications/MAMP/htdocs/drupal-8.0.x-dev/core/lib/Drupal.php:129

What is wrong in my code?

Answer 1

You can not get the current user in getSubscribedEvents()

That is not possible and not needed. There is no container at this point.

The only thing you may do in there is returned a list of events you want to register to. This information is then stored in the compiled container and must be identical for all requests, it must not be conditional.

Any logic needs to be inside the methods you register there.

Answer 2

Since you are using a getSubscribedEvents() static method, I get you are implementing an event subscriber. In this case, you don't access \Drupal::currentUser() (and any static method returning a service that \Drupal exposes) in that method since it would be getting called too early, when Drupal has not yet initialized the dependency container.
That static method is supposed to return a static array describing the events to which the module wants to subscribe; the methods used to subscribe to the events will eventually take a different action basing on the user currently logged-in, and the user permissions that user account has.

Event subscribers are services, and as such they get their dependency injected. Instead of using \Drupal::currentUser(), you define @current_user as one of the arguments of your service, which is what the authentication_subscriber service does.

class: Drupal\Core\EventSubscriber\AuthenticationSubscriber
arguments:
  - '@authentication'
  - '@current_user'
tags:
  - { name: event_subscriber }

If you look at AuthenticationSubscriber::__construct(), you will see how it gets the current user object.

public function __construct(AuthenticationProviderInterface $authentication_provider, AccountProxyInterface $account_proxy) {
  $this->authenticationProvider = $authentication_provider;
  $this->filter = ($authentication_provider instanceof AuthenticationProviderFilterInterface) ? $authentication_provider : NULL;
  $this->challengeProvider = ($authentication_provider instanceof AuthenticationProviderChallengeInterface) ? $authentication_provider : NULL;
  $this->accountProxy = $account_proxy;
}

In your case, I would use the following code.

mymodule.services.yml

services:
  mymodule.eventsubscriber:
    class: Drupal\mymodule\EventSubscriber\MyModuleSubscriber
    arguments:
      - '@current_user'
    tags:
      - { name: event_subscriber }

src/EventSubscriber/MyModuleSubscriber.php

namespace Drupal\mymodule\EventSubscriber;

use Symfony\Component\EventDispatcher\EventSubscriberInterface;

class MymoduleSubscriber implements EventSubscriberInterface {

  /**
   * {@inheritdoc}
   */
  static function getSubscribedEvents() {
    // Return the array describing the events to which you subscribe.
  }

  public function __construct(AccountProxyInterface $account_proxy) {
    $this->accountProxy = $account_proxy;
  }

}

Notice that @current_user is an instance of AccountProxyInterface, so for example, you can check the user has some user permissions with $this->accountProxy->hasPermission().

Answer 3

You have to use namespace for load the current user object.

// Load the current user.
$user = \Drupal\user\Entity\User::load(\Drupal::currentUser()->id());

// get field data from that user

$email = $user->get('mail')->value;
$name = $user->get('name')->value;

Answer 4

Here is my whole piece of code which works fine now:

Inside my_module.service.yml

services:
  myModule.event_subscriber:
    class: Drupal\my_module\EventSubscriber\MymoduleSubscriber

    tags:
      - {name: event_subscriber}

Inside MymoduleSubscriber.php

<?php

namespace Drupal\my_module\EventSubscriber;

use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

class myModule implements EventSubscriberInterface {



  public function xyz(GetResponseEvent $event) {
    $user_id = $this->accountProxy->id();
    if($user_id) {
    }
  }
  /**
   * {@inheritdoc}
   */
  static function getSubscribedEvents() {
    $events[KernelEvents::REQUEST][] = array('xyz');
    return $events;

  }

  public function __construct() {
    $user = \Drupal::currentUser();
    $this->accountProxy = $user;
  }

}