In CakePHP, the beforeFilter callback method is triggered before an action is executed in a controller. This method can be used to perform additional tasks before the action is executed, such as authentication or authorization checks.

Here’s an example of how you can use the beforeFilter method in a CakePHP controller:

class UsersController extends AppController {
  public function beforeFilter(Event $event) {
    // Allow users to register and log in without being logged in
    $this->Auth->allow(['add', 'login']);
  }
}

In this example, the beforeFilter method is used to allow users to access the add and login actions without being logged in.

The beforeFilter method can also be used to set variables or configure components that will be used by all actions in the controller. For example:

class UsersController extends AppController {
  public function beforeFilter(Event $event) {
    // Set the page title
    $this->set('title', 'Users');
    // Load the Users model
    $this->loadModel('Users');
  }
}

Note: The beforeFilter method is just one of several callback methods available in CakePHP controllers. Other callback methods include beforeRender, afterFilter, and shutdown. These methods can be used to perform additional tasks before or after certain controller events.