Update CAS auth adapter to support single sign out.

library/App/Controller/Action.php

@@ -21,7 +21,13 @@ class App_Controller_Action extends Unl_Controller_Action
         $session = new Zend_Session_Namespace(__CLASS__);
         
         if (!array_key_exists('unl_sso', $_COOKIE)) {
-        	return;
+	        // Only passively check for a login once per hour (per user)
+	        if ($session->lastCasCheck > time() - 60*60) {
+	            return;
+	        }
+            $session->lastCasCheck = time();
+        } else {
+        	$session->lastCasCheck = 0;
         }
         
     	// The auth module is doing its thing (probably an active login or logout). Let it be.
@@ -29,12 +35,6 @@ class App_Controller_Action extends Unl_Controller_Action
     		return;
     	}
     	
-    	// Only passively check for a login once per hour (per user)
-    	if ($session->lastCasCheck > time() - 60*60) {
-            return;
-    	}
-    	
-        $session->lastCasCheck = time();
     	
     	
     	// Do a passive authentication check
@@ -55,6 +55,9 @@ class App_Controller_Action extends Unl_Controller_Action
         
         $casAdapter = new Unl_Auth_Adapter_Cas($serviceUrl, 'https://login.unl.edu/cas', $this->_getParam('ticket'));
         $casAdapter->setGateway();
-        $this->_redirect($casAdapter->getLoginUrl());
+        
+        if ($casAdapter->isTicketExpired()) {
+            $this->_redirect($casAdapter->getLoginUrl());
+        }
     }
 }