Implement single sign out via CAS.

application/modules/auth/controllers/IndexController.php

@@ -50,8 +50,12 @@ class Auth_IndexController extends App_Controller_Action {
 	
 	public function validateAction()
 	{
-		$auth = Unl_Auth::getInstance();
-		$auth->pushAdapter($this->_getCasAdapter());
+        $auth = Unl_Auth::getInstance();
+		$casAdapter = $this->_getCasAdapter();
+		if ($this->_getParam('logoutRequest')) {
+			$casAdapter->handleLogoutRequest($this->_getParam('logoutRequest'));
+		}
+		$auth->pushAdapter($casAdapter);
 		
 		try {
 			$result = $auth->authenticate();
@@ -64,6 +68,8 @@ class Auth_IndexController extends App_Controller_Action {
 	        if (!$user) {
 	            $user = Auth_UserModel::fetchNewFromLdap($auth->getIdentity());
 	        }
+		} else {
+			Zend_Auth::getInstance()->clearIdentity();
 		}
 		
 		$session = new Zend_Session_Namespace(__CLASS__);