Generates a hash that uniquely identifies a user's permissions.

Parameters

\Drupal\Core\Session\AccountInterface $account: The user account for which to get the permissions hash.

Return value

string A permissions hash.

Overrides PermissionsHashGeneratorInterface::generate

File

core/lib/Drupal/Core/Session/PermissionsHashGenerator.php, line 36

Class

PermissionsHashGenerator

Generates and caches the permissions hash for a user.

Namespace

Drupal\Core\Session

Code

public function generate(AccountInterface $account) {
  // We can use a simple per-user static cache here because we already cache
  // the permissions more efficiently in the access policy processor. On top
  // of that, there is only a tiny chance of a hash being generated for more
  // than one account during a single request.
  $cid = 'permissions_hash_' . $account->id();
  // Retrieve the hash from the static cache if available.
  if ($static_cache = $this->static
    ->get($cid)) {
    return $static_cache->data;
  }
  // Otherwise hash the permissions and store them in the static cache.
  $calculated_permissions = $this->processor
    ->processAccessPolicies($account);
  $item = $calculated_permissions->getItem();
  // This should never happen, but in case nothing defined permissions for the
  // current user, even if empty, we need to have _some_ hash too.
  if ($item === FALSE) {
    $hash = 'no-access-policies';
  }
  elseif ($item->isAdmin()) {
    $hash = 'is-admin';
  }
  else {
    $permissions = $item->getPermissions();
    sort($permissions);
    $hash = $this->hash(serialize($permissions));
  }
  $this->static
    ->set($cid, $hash, Cache::PERMANENT, $calculated_permissions->getCacheTags());
  return $hash;
}

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