Support new MIDDLEWARE Django 1.10 Setting (#623)

oauth2client/contrib/django_util/__init__.py

@@ -52,6 +52,9 @@ Add the helper to your INSTALLED_APPS:
 
 This helper also requires the Django Session Middleware, so
 ``django.contrib.sessions.middleware`` should be in INSTALLED_APPS as well.
+MIDDLEWARE or MIDDLEWARE_CLASSES (in Django  versions <1.10) should also
+contain the string 'django.contrib.sessions.middleware.SessionMiddleware'.
+
 
 Add the client secrets created earlier to the settings. You can either
 specify the path to the credentials file in JSON format
@@ -338,13 +341,23 @@ class OAuth2Settings(object):
         info = _get_oauth2_client_id_and_secret(settings_instance)
         self.client_id, self.client_secret = info
 
-        if ('django.contrib.sessions.middleware.SessionMiddleware'
-           not in settings_instance.MIDDLEWARE_CLASSES):
+        # Django 1.10 deprecated MIDDLEWARE_CLASSES in favor of MIDDLEWARE
+        middleware_settings = getattr(settings_instance, 'MIDDLEWARE', None)
+        if middleware_settings is None:
+            middleware_settings = getattr(
+                settings_instance, 'MIDDLEWARE_CLASSES', None)
+        if middleware_settings is None:
             raise exceptions.ImproperlyConfigured(
-                  'The Google OAuth2 Helper requires session middleware to '
-                  'be installed. Edit your MIDDLEWARE_CLASSES setting'
-                  ' to include \'django.contrib.sessions.middleware.'
-                  'SessionMiddleware\'.')
+                'Django settings has neither MIDDLEWARE nor MIDDLEWARE_CLASSES'
+                'configured')
+
+        if ('django.contrib.sessions.middleware.SessionMiddleware' not in
+                middleware_settings):
+            raise exceptions.ImproperlyConfigured(
+                'The Google OAuth2 Helper requires session middleware to '
+                'be installed. Edit your MIDDLEWARE_CLASSES or MIDDLEWARE '
+                'setting to include \'django.contrib.sessions.middleware.'
+                'SessionMiddleware\'.')
         (self.storage_model, self.storage_model_user_property,
          self.storage_model_credentials_property) = _get_storage_model()
 

tests/contrib/django_util/test_django_util.py

@@ -101,6 +101,20 @@ class OAuth2SetupTest(unittest.TestCase):
                 object.__new__(django_util.OAuth2Settings),
                 django.conf.settings)
 
+    def test_no_middleware(self):
+        django.conf.settings.MIDDLEWARE_CLASSES = None
+        with self.assertRaises(exceptions.ImproperlyConfigured):
+            django_util.OAuth2Settings.__init__(
+                object.__new__(django_util.OAuth2Settings),
+                django.conf.settings)
+
+    def test_middleware_no_classes(self):
+        django.conf.settings.MIDDLEWARE = (
+            django.conf.settings.MIDDLEWARE_CLASSES)
+        django.conf.settings.MIDDLEWARE_CLASSES = None
+        # primarily testing this doesn't raise an exception
+        django_util.OAuth2Settings(django.conf.settings)
+
     def test_storage_model(self):
         STORAGE_MODEL = {
             'model': 'tests.contrib.django_util.models.CredentialsModel',