Merge pull request #2278 from edx/cdodge/session-inactivity-timeout

add middleware to be able to expire inactive sessions after N seconds

cms/djangoapps/contentstore/tests/tests.py

+"""
+This test file will test registration, login, activation, and session activity timeouts
+"""
+import time
+
 from django.test.utils import override_settings
 from django.core.cache import cache
 from django.core.urlresolvers import reverse
+from django.conf import settings
 
 from contentstore.tests.utils import parse_json, user, registration, AjaxEnabledTestClient
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
@@ -188,6 +194,29 @@ class AuthTestCase(ContentStoreTestCase):
 
         # Logged in should work.
 
+    @override_settings(SESSION_INACTIVITY_TIMEOUT_IN_SECONDS=1)
+    def test_inactive_session_timeout(self):
+        """
+        Verify that an inactive session times out and redirects to the
+        login page
+        """
+        self.create_account(self.username, self.email, self.pw)
+        self.activate_user(self.email)
+
+        self.login(self.email, self.pw)
+
+        # make sure we can access courseware immediately
+        resp = self.client.get_html('/course')
+        self.assertEquals(resp.status_code, 200)
+
+        # then wait a bit and see if we get timed out
+        time.sleep(2)
+
+        resp = self.client.get_html('/course')
+
+        # re-request, and we should get a redirect to login page
+        self.assertRedirects(resp, settings.LOGIN_REDIRECT_URL + '?next=/course')
+
 
 class ForumTestCase(CourseTestCase):
     def setUp(self):

cms/envs/common.py

@@ -174,6 +174,9 @@ MIDDLEWARE_CLASSES = (
 
     # catches any uncaught RateLimitExceptions and returns a 403 instead of a 500
     'ratelimitbackend.middleware.RateLimitMiddleware',
+
+    # for expiring inactive sessions
+    'session_inactivity_timeout.middleware.SessionInactivityTimeout',
 )
 
 ############# XBlock Configuration ##########

common/djangoapps/session_inactivity_timeout/middleware.py

+"""
+Middleware to auto-expire inactive sessions after N seconds, which is configurable in
+settings.
+
+To enable this feature, set in a settings.py:
+
+  SESSION_INACTIVITY_TIMEOUT_IN_SECS = 300
+
+This was taken from StackOverflow (http://stackoverflow.com/questions/14830669/how-to-expire-django-session-in-5minutes)
+"""
+from datetime import datetime, timedelta
+from django.conf import settings
+from django.contrib import auth
+
+LAST_TOUCH_KEYNAME = 'SessionInactivityTimeout:last_touch'
+
+
+class SessionInactivityTimeout(object):
+    """
+    Middleware class to keep track of activity on a given session
+    """
+    def process_request(self, request):
+        """
+        Standard entry point for processing requests in Django
+        """
+        if not hasattr(request, "user") or not request.user.is_authenticated():
+            #Can't log out if not logged in
+            return
+
+        timeout_in_seconds = getattr(settings, "SESSION_INACTIVITY_TIMEOUT_IN_SECONDS", None)
+
+        # Do we have this feature enabled?
+        if timeout_in_seconds:
+            # what time is it now?
+            utc_now = datetime.utcnow()
+
+            # Get the last time user made a request to server, which is stored in session data
+            last_touch = request.session.get(LAST_TOUCH_KEYNAME)
+
+            # have we stored a 'last visited' in session? NOTE: first time access after login
+            # this key will not be present in the session data
+            if last_touch:
+                # compute the delta since last time user came to the server
+                time_since_last_activity = utc_now - last_touch
+
+                # did we exceed the timeout limit?
+                if time_since_last_activity > timedelta(seconds=timeout_in_seconds):
+                    # yes? Then log the user out
+                    del request.session[LAST_TOUCH_KEYNAME]
+                    auth.logout(request)
+                    return
+
+            request.session[LAST_TOUCH_KEYNAME] = utc_now

lms/djangoapps/courseware/tests/test_navigation.py

+"""
+This test file will run through some LMS test scenarios regarding access and navigation of the LMS
+"""
+import time
+from django.conf import settings
+
 from django.core.urlresolvers import reverse
 from django.test.utils import override_settings
 
@@ -37,6 +43,28 @@ class TestNavigation(ModuleStoreTestCase, LoginEnrollmentTestCase):
             self.create_account(username, email, password)
             self.activate_user(email)
 
+    @override_settings(SESSION_INACTIVITY_TIMEOUT_IN_SECONDS=1)
+    def test_inactive_session_timeout(self):
+        """
+        Verify that an inactive session times out and redirects to the
+        login page
+        """
+        email, password = self.STUDENT_INFO[0]
+        self.login(email, password)
+
+        # make sure we can access courseware immediately
+        resp = self.client.get(reverse('dashboard'))
+        self.assertEquals(resp.status_code, 200)
+
+        # then wait a bit and see if we get timed out
+        time.sleep(2)
+
+        resp = self.client.get(reverse('dashboard'))
+
+        # re-request, and we should get a redirect to login page
+        self.assertRedirects(resp, settings.LOGIN_REDIRECT_URL + '?next=' + reverse('dashboard'))
+
+
     def test_redirects_first_time(self):
         """
         Verify that the first time we click on the courseware tab we are

lms/envs/common.py

@@ -654,6 +654,9 @@ MIDDLEWARE_CLASSES = (
 
     # For A/B testing
     'waffle.middleware.WaffleMiddleware',
+
+    # for expiring inactive sessions
+    'session_inactivity_timeout.middleware.SessionInactivityTimeout',
 )
 
 ############################### Pipeline #######################################