/**
* Redirect to a specific page
*
* @param Mage_Adminhtml_Controller_Action $controller
*/
protected function _redirect($controller, $url = null)
{
$controller->setFlag('', Mage_Core_Controller_Varien_Action::FLAG_NO_DISPATCH, true);
if (null === $url) {
$url = Mage::getSingleton('adminhtml/url')->getUrl('*/*/denied');
} elseif (is_array($url)) {
$url = Mage::getSingleton('adminhtml/url')->getUrl(array_shift($url), $url);
} elseif (false === strpos($url, 'http', 0)) {
$url = Mage::getSingleton('adminhtml/url')->getUrl($url);
}
Mage::app()->getResponse()->setRedirect($url);
}