class SessionManager in Drupal 10

Manages user sessions.

This class implements the custom session management code inherited from Drupal 7 on top of the corresponding Symfony component. Regrettably the name NativeSessionStorage is not quite accurate. In fact the responsibility for storing and retrieving session data has been extracted from it in Symfony 2.1 but the class name was not changed.

@todo In fact the NativeSessionStorage class already implements all of the functionality required by a typical Symfony application. Normally it is not necessary to subclass it at all. In order to reach the point where Drupal can use the Symfony session management unmodified, the code implemented here needs to be extracted either into a dedicated session handler proxy (e.g. sid-hashing) or relocated to the authentication subsystem.

Hierarchy

• class \Drupal\Core\Session\SessionManager extends \Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage implements \Drupal\Core\Session\SessionManagerInterface uses \Drupal\Core\DependencyInjection\DependencySerializationTrait

1 string reference to 'SessionManager'

core.services.yml in core/core.services.yml

core/core.services.yml

1 service uses SessionManager

session_manager in core/core.services.yml

Drupal\Core\Session\SessionManager

File

core/lib/Drupal/Core/Session/SessionManager.php, line 27

Namespace

Drupal\Core\Session

class SessionManager extends NativeSessionStorage implements SessionManagerInterface {
  use DependencySerializationTrait;

  /**
   * The request stack.
   *
   * @var \Symfony\Component\HttpFoundation\RequestStack
   */
  protected $requestStack;

  /**
   * The database connection to use.
   *
   * @var \Drupal\Core\Database\Connection
   */
  protected $connection;

  /**
   * The session configuration.
   *
   * @var \Drupal\Core\Session\SessionConfigurationInterface
   */
  protected $sessionConfiguration;

  /**
   * Whether a lazy session has been started.
   *
   * @var bool
   */
  protected $startedLazy;

  /**
   * The write safe session handler.
   *
   * @todo: This reference should be removed once all database queries
   *   are removed from the session manager class.
   *
   * @var \Drupal\Core\Session\WriteSafeSessionHandlerInterface
   */
  protected $writeSafeHandler;

  /**
   * Constructs a new session manager instance.
   *
   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
   *   The request stack.
   * @param \Drupal\Core\Database\Connection $connection
   *   The database connection.
   * @param \Drupal\Core\Session\MetadataBag $metadata_bag
   *   The session metadata bag.
   * @param \Drupal\Core\Session\SessionConfigurationInterface $session_configuration
   *   The session configuration interface.
   * @param \Symfony\Component\HttpFoundation\Session\Storage\Proxy\AbstractProxy|Symfony\Component\HttpFoundation\Session\Storage\Handler\NativeSessionHandler|\SessionHandlerInterface|null $handler
   *   The object to register as a PHP session handler.
   *   @see \Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage::setSaveHandler()
   */
  public function __construct(RequestStack $request_stack, Connection $connection, MetadataBag $metadata_bag, SessionConfigurationInterface $session_configuration, $handler = NULL) {
    $options = [];
    $this->sessionConfiguration = $session_configuration;
    $this->requestStack = $request_stack;
    $this->connection = $connection;
    parent::__construct($options, $handler, $metadata_bag);
  }

  /**
   * {@inheritdoc}
   */
  public function start() : bool {
    if (($this->started || $this->startedLazy) && !$this->closed) {
      return $this->started;
    }
    $request = $this->requestStack
      ->getCurrentRequest();
    $this
      ->setOptions($this->sessionConfiguration
      ->getOptions($request));
    if ($this->sessionConfiguration
      ->hasSession($request)) {

      // If a session cookie exists, initialize the session. Otherwise the
      // session is only started on demand in save(), making
      // anonymous users not use a session cookie unless something is stored in
      // $_SESSION. This allows HTTP proxies to cache anonymous pageviews.
      $result = $this
        ->startNow();
    }
    if (empty($result)) {

      // Initialize the session global and attach the Symfony session bags.
      $_SESSION = [];
      $this
        ->loadSession();

      // NativeSessionStorage::loadSession() sets started to TRUE, reset it to
      // FALSE here.
      $this->started = FALSE;
      $this->startedLazy = TRUE;
      $result = FALSE;
    }
    return $result;
  }

  /**
   * Forcibly start a PHP session.
   *
   * @return bool
   *   TRUE if the session is started.
   */
  protected function startNow() {
    if ($this
      ->isCli()) {
      return FALSE;
    }
    if ($this->startedLazy) {

      // Save current session data before starting it, as PHP will destroy it.
      $session_data = $_SESSION;
    }
    $result = parent::start();

    // Restore session data.
    if ($this->startedLazy) {
      $_SESSION = $session_data;
      $this
        ->loadSession();
    }
    return $result;
  }

  /**
   * {@inheritdoc}
   */
  public function save() {
    if ($this
      ->isCli()) {

      // We don't have anything to do if we are not allowed to save the session.
      return;
    }
    if ($this
      ->isSessionObsolete()) {

      // There is no session data to store, destroy the session if it was
      // previously started.
      if ($this
        ->getSaveHandler()
        ->isActive()) {
        $this
          ->destroy();
      }
    }
    else {

      // There is session data to store. Start the session if it is not already
      // started.
      if (!$this
        ->getSaveHandler()
        ->isActive()) {
        $this
          ->startNow();
      }

      // Write the session data.
      parent::save();
    }
    $this->startedLazy = FALSE;
  }

  /**
   * {@inheritdoc}
   */
  public function regenerate($destroy = FALSE, $lifetime = NULL) : bool {

    // Nothing to do if we are not allowed to change the session.
    if ($this
      ->isCli()) {
      return FALSE;
    }

    // Drupal will always destroy the existing session when regenerating a
    // session. This is inline with the recommendations of @link https://cheatsheetseries.owasp.org/cheatsheets/Session_Management_Cheat_Sheet.html#renew-the-session-id-after-any-privilege-level-change
    // OWASP session management cheat sheet. @endlink
    $destroy = TRUE;

    // Cannot regenerate the session ID for non-active sessions.
    if (\PHP_SESSION_ACTIVE !== session_status()) {

      // Ensure the metadata bag has been stamped. If the parent::regenerate()
      // is called prior to the session being started it will not refresh the
      // metadata as expected.
      $this
        ->getMetadataBag()
        ->stampNew($lifetime);
      return FALSE;
    }
    return parent::regenerate($destroy, $lifetime);
  }

  /**
   * {@inheritdoc}
   */
  public function delete($uid) {

    // Nothing to do if we are not allowed to change the session.
    if (!$this->writeSafeHandler
      ->isSessionWritable() || $this
      ->isCli()) {
      return;
    }
    $this->connection
      ->delete('sessions')
      ->condition('uid', $uid)
      ->execute();
  }

  /**
   * {@inheritdoc}
   */
  public function destroy() {
    if ($this
      ->isCli()) {
      return;
    }

    // Symfony suggests using Session::invalidate() instead of session_destroy()
    // however the former calls session_regenerate_id(TRUE), which while
    // destroying the current session creates a new ID; Drupal has historically
    // decided to only set sessions when absolutely necessary (e.g., to increase
    // anonymous user cache hit rates) and as such we cannot use the Symfony
    // convenience method here.
    session_destroy();

    // Unset the session cookies.
    $session_name = $this
      ->getName();
    $cookies = $this->requestStack
      ->getCurrentRequest()->cookies;

    // setcookie() can only be called when headers are not yet sent.
    if ($cookies
      ->has($session_name) && !headers_sent()) {
      $params = session_get_cookie_params();
      setcookie($session_name, '', REQUEST_TIME - 3600, $params['path'], $params['domain'], $params['secure'], $params['httponly']);
      $cookies
        ->remove($session_name);
    }
  }

  /**
   * {@inheritdoc}
   */
  public function setWriteSafeHandler(WriteSafeSessionHandlerInterface $handler) {
    $this->writeSafeHandler = $handler;
  }

  /**
   * Returns whether the current PHP process runs on CLI.
   *
   * Command line clients do not support cookies nor sessions.
   *
   * @return bool
   */
  protected function isCli() {
    return PHP_SAPI === 'cli';
  }

  /**
   * Determines whether the session contains user data.
   *
   * @return bool
   *   TRUE when the session does not contain any values and therefore can be
   *   destroyed.
   */
  protected function isSessionObsolete() {
    $used_session_keys = array_filter($this
      ->getSessionDataMask());
    return empty($used_session_keys);
  }

  /**
   * Returns a map specifying which session key is containing user data.
   *
   * @return array
   *   An array where keys correspond to the session keys and the values are
   *   booleans specifying whether the corresponding session key contains any
   *   user data.
   */
  protected function getSessionDataMask() {
    if (empty($_SESSION)) {
      return [];
    }

    // Start out with a completely filled mask.
    $mask = array_fill_keys(array_keys($_SESSION), TRUE);

    // Ignore the metadata bag, it does not contain any user data.
    $mask[$this->metadataBag
      ->getStorageKey()] = FALSE;

    // Ignore attribute bags when they do not contain any data.
    foreach ($this->bags as $bag) {
      $key = $bag
        ->getStorageKey();
      $mask[$key] = !empty($_SESSION[$key]);
    }
    return array_intersect_key($mask, $_SESSION);
  }

}