ENT-325 Create a LogoutView that can redirect to a specified target

common/djangoapps/student/tests/test_views.py

@@ -157,22 +157,36 @@ class LogoutTests(TestCase):
         self.client.post(reverse('oauth2:capture'), data, follow=True)
         self.assertListEqual(self.client.session[AUTHORIZED_CLIENTS_SESSION_KEY], [oauth_client.client_id])
 
-    def assert_logout_redirects(self):
+    def assert_logout_redirects_to_root(self):
         """ Verify logging out redirects the user to the homepage. """
         response = self.client.get(reverse('logout'))
         self.assertRedirects(response, '/', fetch_redirect_response=False)
 
-    def test_switch(self):
+    def assert_logout_redirects_with_target(self):
+        """ Verify logging out with a redirect_url query param redirects the user to the target. """
+        url = '{}?{}'.format(reverse('logout'), 'redirect_url=/courses')
+        response = self.client.get(url)
+        self.assertRedirects(response, '/courses', fetch_redirect_response=False)
+
+    def test_switch_default(self):
+        """ Verify the IDA logout functionality is disabled if the associated switch is disabled. """
+        LogoutViewConfiguration.objects.create(enabled=False)
+        oauth_client = self.create_oauth_client()
+        self.authenticate_with_oauth(oauth_client)
+        self.assert_logout_redirects_to_root()
+
+    def test_switch_with_redirect_url(self):
         """ Verify the IDA logout functionality is disabled if the associated switch is disabled. """
         LogoutViewConfiguration.objects.create(enabled=False)
         oauth_client = self.create_oauth_client()
         self.authenticate_with_oauth(oauth_client)
-        self.assert_logout_redirects()
+        self.assert_logout_redirects_with_target()
 
     def test_without_session_value(self):
         """ Verify logout works even if the session does not contain an entry with
         the authenticated OpenID Connect clients."""
-        self.assert_logout_redirects()
+        self.assert_logout_redirects_to_root()
+        self.assert_logout_redirects_with_target()
 
     def test_client_logout(self):
         """ Verify the context includes a list of the logout URIs of the authenticated OpenID Connect clients.

common/djangoapps/student/views.py

@@ -31,7 +31,7 @@ from django.http import HttpResponse, HttpResponseBadRequest, HttpResponseForbid
 from django.shortcuts import redirect
 from django.utils.encoding import force_bytes, force_text
 from django.utils.translation import ungettext
-from django.utils.http import base36_to_int, urlsafe_base64_encode, urlencode
+from django.utils.http import base36_to_int, is_safe_url, urlsafe_base64_encode, urlencode
 from django.utils.translation import ugettext as _, get_language
 from django.views.decorators.csrf import csrf_exempt, ensure_csrf_cookie
 from django.views.decorators.http import require_POST, require_GET
@@ -2672,7 +2672,21 @@ class LogoutView(TemplateView):
     template_name = 'logout.html'
 
     # Keep track of the page to which the user should ultimately be redirected.
-    target = reverse_lazy('cas-logout') if settings.FEATURES.get('AUTH_USE_CAS') else '/'
+    default_target = reverse_lazy('cas-logout') if settings.FEATURES.get('AUTH_USE_CAS') else '/'
+
+    @property
+    def target(self):
+        """
+        If a redirect_url is specified in the querystring for this request, and the value is a url
+        with the same host, the view will redirect to this page after rendering the template.
+        If it is not specified, we will use the default target url.
+        """
+        target_url = self.request.GET.get('redirect_url')
+
+        if target_url and is_safe_url(target_url, self.request.META.get('HTTP_HOST')):
+            return target_url
+        else:
+            return self.default_target
 
     def dispatch(self, request, *args, **kwargs):  # pylint: disable=missing-docstring
         # We do not log here, because we have a handler registered to perform logging on successful logouts.