access_policy-1.0.x-dev/src/Cache/Context/UserFieldValuesCacheContext.php

<?php

namespace Drupal\access_policy\Cache\Context;

use Drupal\access_policy\Session\UserFieldValuesHashGeneratorInterface;
use Drupal\Core\Cache\CacheableMetadata;
use Drupal\Core\Cache\Context\CalculatedCacheContextInterface;
use Drupal\Core\Session\AccountProxyInterface;

/**
 * Defines the UserFieldValuesCacheContext service.
 *
 * Access rules compare values between the user and entity. That means that a
 * user's access is going to vary depending on their field values. If the policy
 * does not have access rules it will only use user.permissions.
 *
 * Cache context ID: 'user.field_values' (to vary by all observed fields of the
 * current user). Calculated cache context ID: 'user.field_values:%field_name',
 * e.g. 'user.field_value:field_department' (to vary by the values in the
 * department field).
 */
class UserFieldValuesCacheContext implements CalculatedCacheContextInterface {

  /**
   * The current user.
   *
   * @var \Drupal\Core\Session\AccountProxyInterface
   */
  protected $currentUser;

  /**
   * The access rule manager.
   *
   * @var \Drupal\access_policy\Session\UserFieldValuesHashGeneratorInterface
   */
  protected $hashGenerator;

  /**
   * Constructs a new UserFieldValuesCacheContext class.
   *
   * @param \Drupal\Core\Session\AccountProxyInterface $current_user
   *   The current user.
   * @param \Drupal\access_policy\Session\UserFieldValuesHashGeneratorInterface $hash_generator
   *   The user field values hash generator.
   */
  public function __construct(AccountProxyInterface $current_user, UserFieldValuesHashGeneratorInterface $hash_generator) {
    $this->currentUser = $current_user;
    $this->hashGenerator = $hash_generator;
  }

  /**
   * {@inheritdoc}
   */
  public static function getLabel() {
    return t("Account's fields observed by access rules.");
  }

  /**
   * {@inheritdoc}
   */
  public function getContext($field_name = NULL) {
    return $this->hashGenerator->generate($this->currentUser, $field_name);
  }

  /**
   * {@inheritdoc}
   */
  public function getCacheableMetadata($field_name = NULL) {
    $cacheable_metadata = new CacheableMetadata();
    $tags = ['user:' . $this->currentUser->id()];
    return $cacheable_metadata->setCacheTags($tags);
  }

}