TestAccessBlock.php

<?php

namespace Drupal\block_test\Plugin\Block;

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Block\BlockBase;
use Drupal\Core\Cache\Cache;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\State\StateInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Provides a block to test access.
 *
 * @Block(
 *   id = "test_access",
 *   admin_label = @Translation("Test block access")
 * )
 */
class TestAccessBlock extends BlockBase implements ContainerFactoryPluginInterface {
    
    /**
     * The state service.
     */
    protected $state;
    
    /**
     * Tests the test access block.
     *
     *
     * @param array $configuration
     *   The plugin configuration, i.e. an array with configuration values keyed
     *   by configuration option name. The special key 'context' may be used to
     *   initialize the defined contexts by setting it to an array of context
     *   values keyed by context names.
     * @param string $plugin_id
     *   The plugin_id for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\State\StateInterface $state
     *   The state.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, StateInterface $state) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->state = $state;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('state'));
    }
    
    /**
     * {@inheritdoc}
     */
    protected function blockAccess(AccountInterface $account) {
        return $this->state
            ->get('test_block_access', FALSE) ? AccessResult::allowed()->setCacheMaxAge(0) : AccessResult::forbidden()->setCacheMaxAge(0);
    }
    
    /**
     * {@inheritdoc}
     */
    public function build() {
        return [
            '#markup' => 'Hello test world',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCacheMaxAge() {
        return Cache::PERMANENT;
    }

}