public function init() {
        // Attach Event to EventManager
        $events = StaticEventManager::getInstance ();

        // Add event of authentication before dispatch
        $events->attach ( 'Zend\Mvc\Controller\AbstractActionController', 'dispatch', array (
                $this,
                'authPreDispatch'
        ), 110 );
}
public function authPreDispatch($event){
    $target = $event->getTarget ();
    $serviceLocator = $target->getServiceLocator();
    // Do what ever you want to check the user's identity
    $url = $event->getRouter ()->assemble ( array (
                        "controller" => "<controller>"
                ), array (
                        'name' => '<route name>'
                ) );
    $response = $event->getResponse ();
            $response->setHeaders ( $response->getHeaders ()->addHeaderLine ( 'Location', $url ) ));
            $response->setStatusCode ( 302 );
            $response->sendHeaders ();
            exit ();
    }