Cleanup Interface

When to Use

Implement CleanupInterface when your event plugin needs to perform cleanup operations after all successor actions complete, such as restoring switched user accounts, releasing resources, or processing accumulated state.

Decision

Cleanup Need	Implement CleanupInterface	Why
Account switching	Yes	Must restore original user context
Resource locks	Yes	Release file handles, database locks
Accumulated state	Yes	Process batched data after all actions
Token processing	Yes	Apply collected tokens back to event object
Temporary changes	Yes	Revert temporary system state

Pattern

use Drupal\eca\Plugin\CleanupInterface;

class MyEvent extends EventBase implements CleanupInterface {

  /**
   * Static storage for event state during execution.
   */
  protected static array $eventStates = [];

  /**
   * {@inheritdoc}
   */
  public function cleanupAfterSuccessors(): void {
    switch ($this->getDerivativeId()) {

      case 'account_switch':
        // Restore original user account
        if ($original_account = array_pop(self::$eventStates)) {
          $this->accountSwitcher->switchBack();
        }
        break;

      case 'token_collection':
        // Process accumulated tokens
        if (!($event_data = array_pop(self::$eventStates))) {
          return;
        }

        $token_name = $this->configuration['token_name'] ?? NULL;
        if ($token_name && $this->tokenService->hasTokenData($token_name)) {
          $collected_data = $this->tokenService->getTokenData($token_name);
          $this->applyCollectedData($event_data['event'], $collected_data);
        }
        break;

      case 'resource_lock':
        // Release locked resources
        if ($lock_id = array_pop(self::$eventStates)) {
          $this->lockBackend->release($lock_id);
        }
        break;
    }
  }

  /**
   * Store state for cleanup (call this in your event dispatcher).
   */
  public static function storeEventState($event, array $data): void {
    self::$eventStates[] = [
      'event' => $event,
      'data' => $data,
      'timestamp' => time(),
    ];
  }
}

Common Mistakes

• Wrong: Not using static storage → Right: State lost between registration and cleanup
• Wrong: Missing cleanup → Right: Resources remain locked, accounts not restored
• Wrong: Complex logic in cleanup → Right: Should be simple state restoration
• Wrong: Not checking if state exists → Right: Errors when cleanup called without setup
• Wrong: Forgetting to pop from stack → Right: Memory leak over time

See Also

• Token Receiver Interface for token preservation
• Event Plugin Basics for event structure
• Service Injection for cleanup services

References: - Core: /modules/contrib/eca/src/Plugin/CleanupInterface.php - Example: /modules/contrib/eca/modules/content/src/Plugin/ECA/Event/ContentEntityEvent.php