Merge pull request #3 from yscumc/master

Middleware polishing.

session_security/middleware.py

@@ -14,6 +14,7 @@
 
 from django import http
 from django.contrib.auth import logout
+from django.core.urlresolvers import reverse
 
 from settings import *
 
@@ -48,8 +49,17 @@ def update_last_activity(self, request, now):
         last_activity = request.session['_session_security']
         server_idle_for = (now - last_activity).seconds
 
-        if 'idleFor' in request.GET:
-            client_idle_for = int(request.GET['idleFor'])
+        if (request.path == reverse('session_security_ping') and
+                'idleFor' in request.GET):
+            # Gracefully ignore non-integer values
+            try:
+                client_idle_for = int(request.GET['idleFor'])
+            except ValueError:
+                return
+
+            # Disallow negative values, causes problems with delta calculation
+            if client_idle_for < 0:
+                client_idle_for = 0
 
             if client_idle_for < server_idle_for:
                 # Client has more recent activity than we have in the session