Prevent subscriber saving in observer newsletter_subscriber_save_before Magento - magento

Question

I created an Observer to monitor the event subscriber_save_before. In this observer I handle a new field, the value of that is saved, but if some errors occurs I wanna the record not to be saved and to display only my error message. The throwException seems not to do the trick. The only method I think could work is to force the email field to null but wasn't able to achieve this.
In the subscriberController.php (Mage Core) I have this:
$email = (string) $this->getRequest()->getPost('email');
try {
if (!Zend_Validate::is($email, 'EmailAddress')) {
Mage::throwException($this->__('Please enter a valid email address.'));
}
This is my code (not working):
public function NewsletterSaveSubscriber($observer)
{
$subscriber = $observer->getEvent()->getSubscriber();
$name = Mage::app()->getRequest()->getParam('subscriber_name');
// server side validation
// no name specified
if (!Zend_Validate::is(trim($name), 'NotEmpty')) {
$session = Mage::getSingleton('core/session');
try {
Mage::throwException(Mage::helper('newsletter')->__('The name field cannot be empty!'));
} catch (Mage_Core_Exception $e) {
$session->addException($e, Mage::helper('newsletter')->__('There was a problem: %s', $e->getMessage()));
}
$observer->getRequest()->setPost('email', ''); // this code doesn't work
Mage::app()->getRequest()->setPost('email', ''); // this too
// Ohh nooo! The subscriber is stored :-(
return $this;
}
// save the name
$name = htmlspecialchars($name);
$subscriber->setSubscriberName($name);
return $this;
}

Answer 1

This will solve your probem:
//Error Message
$session = Mage::getSingleton('core/session');
$session->getMessages(true);
$session->addError(Mage::helper('cartware_automaticreview')->__('Could´t save.'));
// Ohh nooo! The subscriber is not stored :)
$controller = $observer->getControllerAction()->setFlag('',Mage_Core_Controller_Varien_Action::FLAG_NO_DISPATCH,true);
$controller->getResponse()->setRedirect(Mage::app()->getRequest()->getServer('HTTP_REFERER'));
return;
Good luck!