Added EdxOpenIdConnectLogoutView (#21)

IDAs can now use this view, instead of making their own, to facilitate logouts.

ECOM-2345

auth_backends/__init__.py

@@ -3,4 +3,4 @@
  These package is designed to be used primarily with Open edX Django projects, but should be compatible with non-edX
  projects as well.
 """
-__version__ = '0.4.0'  # pragma: no cover
+__version__ = '0.5.0'  # pragma: no cover

auth_backends/backends.py

@@ -55,6 +55,11 @@ def USER_INFO_URL(self):  # pylint: disable=invalid-name
         """ URL of the auth provider's user info endpoint. """
         return '{0}/user_info/'.format(self.setting('URL_ROOT'))
 
+    @property
+    def logout_url(self):
+        """ URL of the auth provider's logout page. """
+        return self.setting('LOGOUT_URL')
+
     def user_data(self, _access_token, *_args, **_kwargs):
         # Include decoded id_token fields in user data.
         return self.id_token

auth_backends/tests/mixins.py

@@ -2,13 +2,21 @@
 
 from django.contrib.auth import get_user, get_user_model
 from django.core.urlresolvers import reverse
+from social.apps.django_app.default.models import UserSocialAuth
 
+PASSWORD = 'test'
 User = get_user_model()
 
 
 class LogoutViewTestMixin(object):
     """ Mixin for tests of the LogoutRedirectBaseView children. """
 
+    def create_user(self):
+        """ Create a new user. """
+        user = User.objects.create_user('test', password=PASSWORD)
+        UserSocialAuth.objects.create(user=user, provider='edx-oidc', uid=user.username)
+        return user
+
     def get_logout_url(self):
         """ Returns the URL of the logout view. """
         return reverse('logout')
@@ -22,28 +30,23 @@ def assert_authentication_status(self, is_authenticated):
         user = get_user(self.client)
         self.assertEqual(user.is_authenticated(), is_authenticated)
 
-    def test_redirect_url(self):
-        """ Verify the view redirects to the correct URL. """
-        response = self.client.get(self.get_logout_url())
-        self.assertRedirects(response, self.get_redirect_url(), fetch_redirect_response=False)
-
     def test_x_frame_options_header(self):
         """ Verify no X-Frame-Options header is set in the resposne. """
         response = self.client.get(self.get_logout_url())
         self.assertNotIn('X-Frame-Options', response)
 
     def test_logout(self):
-        """ Verify the user is logged out of the current session. """
+        """ Verify the user is logged out of the current session and redirected to the appropriate URL. """
         self.client.logout()
         self.assert_authentication_status(False)
 
-        password = 'test'
-        user = User.objects.create_user('test', password=password)
-        self.client.login(username=user.username, password=password)
+        user = self.create_user()
+        self.client.login(username=user.username, password=PASSWORD)
         self.assert_authentication_status(True)
 
-        self.client.get(self.get_logout_url())
+        response = self.client.get(self.get_logout_url())
         self.assert_authentication_status(False)
+        self.assertRedirects(response, self.get_redirect_url(), fetch_redirect_response=False)
 
     def test_no_redirect(self):
         """ Verify the view does not redirect if the no_redirect querystring parameter is set. """

auth_backends/tests/test_backends.py

@@ -13,6 +13,7 @@ class EdXOpenIdConnectTests(OpenIdConnectTestMixin, OAuth2Test):
 
     backend_path = 'auth_backends.backends.EdXOpenIdConnect'
     url_root = 'http://www.example.com'
+    logout_url = 'http://www.example.com/logout/'
     issuer = url_root
     expected_username = 'test_user'
     fake_locale = 'en_US'
@@ -28,6 +29,7 @@ def extra_settings(self):
         settings.update({
             'SOCIAL_AUTH_{0}_URL_ROOT'.format(self.name): self.url_root,
             'SOCIAL_AUTH_{0}_ISSUER'.format(self.name): self.issuer,
+            'SOCIAL_AUTH_{0}_LOGOUT_URL'.format(self.name): self.logout_url,
         })
         return settings
 
@@ -69,3 +71,7 @@ def test_get_user_claims(self, token_type):
             headers = {'Authorization': '{token_type} {token}'.format(token_type=expected_token_type,
                                                                       token=self.fake_access_token)}
             mock_get_json.assert_called_once_with(self.backend.USER_INFO_URL, headers=headers)
+
+    def test_logout_url(self):
+        """ Verify the property returns the configured logout URL. """
+        self.assertEqual(self.backend.logout_url, self.logout_url)

auth_backends/tests/test_views.py

@@ -1,26 +1,14 @@
 """ Tests for the views module. """
 
-from django.conf.urls import url
 from django.core.urlresolvers import reverse
 from django.test import TestCase, override_settings
 
 from auth_backends.tests.mixins import LogoutViewTestMixin
 from auth_backends.urls import auth_urlpatterns
-from auth_backends.views import LogoutRedirectBaseView
 
 LOGOUT_REDIRECT_URL = 'https://www.example.com/logout/'
 
-urlpatterns = auth_urlpatterns + [
-    url(r'^logout/$', LogoutRedirectBaseView.as_view(url=LOGOUT_REDIRECT_URL), name='logout'),
-]
-
-
-@override_settings(ROOT_URLCONF=__name__)
-class LogoutRedirectBaseViewTests(LogoutViewTestMixin, TestCase):
-    """ Tests for LogoutRedirectBaseView. """
-
-    def get_redirect_url(self):
-        return LOGOUT_REDIRECT_URL
+urlpatterns = auth_urlpatterns
 
 
 @override_settings(ROOT_URLCONF=__name__)
@@ -31,3 +19,11 @@ def test_redirect(self):
         """ Verify the view redirects to the edX OIDC login page. """
         response = self.client.get(reverse('login'))
         self.assertRedirects(response, reverse('social:begin', args=['edx-oidc']), fetch_redirect_response=False)
+
+
+@override_settings(ROOT_URLCONF=__name__, SOCIAL_AUTH_EDX_OIDC_LOGOUT_URL=LOGOUT_REDIRECT_URL)
+class EdxOpenIdConnectLogoutView(LogoutViewTestMixin, TestCase):
+    """ Tests for EdxOpenIdConnectLogoutView. """
+
+    def get_redirect_url(self):
+        return LOGOUT_REDIRECT_URL

auth_backends/urls.py

@@ -4,9 +4,10 @@
 """
 from django.conf.urls import url, include
 
-from auth_backends.views import EdxOpenIdConnectLoginView
+from auth_backends.views import EdxOpenIdConnectLoginView, EdxOpenIdConnectLogoutView
 
 auth_urlpatterns = [  # pylint: disable=invalid-name
     url(r'^login/$', EdxOpenIdConnectLoginView.as_view(), name='login'),
+    url(r'^logout/$', EdxOpenIdConnectLogoutView.as_view(), name='logout'),
     url('', include('social.apps.django_app.urls', namespace='social')),
 ]

auth_backends/views.py

@@ -1,11 +1,15 @@
 """ Authentication views. """
+import logging
 
 from django.contrib.auth import logout
 from django.core.urlresolvers import reverse_lazy
 from django.http import HttpResponse
 from django.utils.decorators import method_decorator
 from django.views.decorators.clickjacking import xframe_options_exempt
 from django.views.generic import RedirectView
+from social.apps.django_app.utils import load_strategy, load_backend
+
+logger = logging.getLogger(__name__)
 
 
 class LogoutRedirectBaseView(RedirectView):
@@ -24,9 +28,12 @@ class LogoutRedirectBaseView(RedirectView):
     authorization server's logout page. This allows signout to be triggered by the authorization server.
     """
     permanent = False
+    user = None
 
     @method_decorator(xframe_options_exempt)
     def dispatch(self, request, *args, **kwargs):
+        # Keep track of the user so that child classes have access to it after logging out.
+        self.user = request.user
         logout(request)
 
         if request.GET.get('no_redirect'):
@@ -43,3 +50,12 @@ class EdxOpenIdConnectLoginView(RedirectView):
     permanent = False
     query_string = True
     url = reverse_lazy('social:begin', args=['edx-oidc'])
+
+
+class EdxOpenIdConnectLogoutView(LogoutRedirectBaseView):
+    """ Logout view for projects utilizing edX OpenID Connect for single sign-on. """
+
+    def get_redirect_url(self, *args, **kwargs):
+        strategy = load_strategy(self.request)
+        backend = load_backend(strategy, 'edx-oidc', None)
+        return backend.logout_url

test_settings.py

@@ -44,6 +44,12 @@
 SOCIAL_AUTH_EDX_OIDC_KEY = 'dummy-key'
 SOCIAL_AUTH_EDX_OIDC_SECRET = 'dummy-secret'
 SOCIAL_AUTH_EDX_OIDC_ID_TOKEN_DECRYPTION_KEY = 'dummy-secret'
+SOCIAL_AUTH_EDX_OIDC_LOGOUT_URL = 'http://example.com/logout/'
 
 EXTRA_SCOPE = []
 COURSE_PERMISSIONS_CLAIMS = []
+
+AUTHENTICATION_BACKENDS = (
+    'auth_backends.backends.EdXOpenIdConnect',
+    'django.contrib.auth.backends.ModelBackend',
+)