Check expiration date instead of the expired flag (#394)

extra/modules/quota.py

@@ -16,6 +16,8 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 # 02110-1301  USA
 
+from datetime import datetime
+
 from quixote import get_request, get_publisher
 from quixote.errors import AccessError
 
@@ -97,4 +99,11 @@ def is_locked():
     return get_boolean_quota('x-asec-locked')
 
 def is_expired():
-    return get_boolean_quota('x-asec-expired')
+    t = get_request().get_header('x-asec-expiration-date')
+    if not t:
+        return False
+    try:
+        expiration_date = datetime.strptime(t, '%Y-%m-%dT%H:%M:%S.%f')
+    except ValueError:
+        return False
+    return expiration_date < datetime.now()