Fixed #26601 -- Improved middleware per DEP 0005.

Thanks Tim Graham for polishing the patch, updating the tests, and
writing documentation. Thanks Carl Meyer for shepherding the DEP.

2 files changed, 27 insertions, 16 deletions

diff --git a/tests/middleware_exceptions/middleware.py b/tests/middleware_exceptions/middleware.py
index 944dd8910d..6871d9556e 100644
--- a/tests/middleware_exceptions/middleware.py
+++ b/tests/middleware_exceptions/middleware.py
@@ -1,8 +1,10 @@
 from __future__ import unicode_literals
 
 from django.http import HttpResponse
+from django.utils.deprecation import MiddlewareMixin
 
 
-class ProcessExceptionMiddleware(object):
+class ProcessExceptionMiddleware(MiddlewareMixin):
+
     def process_exception(self, request, exception):
         return HttpResponse('Exception caught')
diff --git a/tests/middleware_exceptions/tests.py b/tests/middleware_exceptions/tests.py
index ef9d19fe21..13b33632f8 100644
--- a/tests/middleware_exceptions/tests.py
+++ b/tests/middleware_exceptions/tests.py
@@ -8,6 +8,7 @@ from django.template import engines
 from django.template.response import TemplateResponse
 from django.test import RequestFactory, SimpleTestCase, override_settings
 from django.test.utils import patch_logger
+from django.utils.deprecation import MiddlewareMixin
 
 
 class TestException(Exception):
@@ -15,13 +16,14 @@ class TestException(Exception):
 
 
 # A middleware base class that tracks which methods have been called
-class TestMiddleware(object):
-    def __init__(self):
+class TestMiddleware(MiddlewareMixin):
+    def __init__(self, get_response=None):
         self.process_request_called = False
         self.process_view_called = False
         self.process_response_called = False
         self.process_template_response_called = False
         self.process_exception_called = False
+        self.get_response = get_response
 
     def process_request(self, request):
         self.process_request_called = True
@@ -115,7 +117,11 @@ class NoResponseMiddleware(TestMiddleware):
         super(NoResponseMiddleware, self).process_response(request, response)
 
 
-@override_settings(ROOT_URLCONF='middleware_exceptions.urls')
+@override_settings(
+    ROOT_URLCONF='middleware_exceptions.urls',
+    MIDDLEWARE_CLASSES=['django.middleware.common.CommonMiddleware'],
+    MIDDLEWARE=None,
+)
 class BaseMiddlewareExceptionTest(SimpleTestCase):
 
     def setUp(self):
@@ -492,12 +498,10 @@ class MiddlewareTests(BaseMiddlewareExceptionTest):
         # Check that the right middleware methods have been invoked
         self.assert_middleware_usage(middleware, True, True, True, True, False)
 
-    @override_settings(
-        MIDDLEWARE_CLASSES=['middleware_exceptions.middleware.ProcessExceptionMiddleware'],
-    )
+    @override_settings(MIDDLEWARE=['middleware_exceptions.middleware.ProcessExceptionMiddleware'])
     def test_exception_in_render_passed_to_process_exception(self):
         # Repopulate the list of middlewares since it's already been populated
-        # by setUp() before the MIDDLEWARE_CLASSES setting got overridden
+        # by setUp() before the MIDDLEWARE setting got overridden.
         self.client.handler.load_middleware()
         response = self.client.get('/middleware_exceptions/exception_in_render/')
         self.assertEqual(response.content, b'Exception caught')
@@ -868,7 +872,7 @@ class RootUrlconfTests(SimpleTestCase):
 
 class MyMiddleware(object):
 
-    def __init__(self):
+    def __init__(self, get_response=None):
         raise MiddlewareNotUsed
 
     def process_request(self, request):
@@ -877,7 +881,7 @@ class MyMiddleware(object):
 
 class MyMiddlewareWithExceptionMessage(object):
 
-    def __init__(self):
+    def __init__(self, get_response=None):
         raise MiddlewareNotUsed('spam eggs')
 
     def process_request(self, request):
@@ -887,6 +891,7 @@ class MyMiddlewareWithExceptionMessage(object):
 @override_settings(
     DEBUG=True,
     ROOT_URLCONF='middleware_exceptions.urls',
+    MIDDLEWARE=['django.middleware.common.CommonMiddleware'],
 )
 class MiddlewareNotUsedTests(SimpleTestCase):
 
@@ -897,9 +902,7 @@ class MiddlewareNotUsedTests(SimpleTestCase):
         with self.assertRaises(MiddlewareNotUsed):
             MyMiddleware().process_request(request)
 
-    @override_settings(MIDDLEWARE_CLASSES=[
-        'middleware_exceptions.tests.MyMiddleware',
-    ])
+    @override_settings(MIDDLEWARE=['middleware_exceptions.tests.MyMiddleware'])
     def test_log(self):
         with patch_logger('django.request', 'debug') as calls:
             self.client.get('/middleware_exceptions/view/')
@@ -909,9 +912,7 @@ class MiddlewareNotUsedTests(SimpleTestCase):
             "MiddlewareNotUsed: 'middleware_exceptions.tests.MyMiddleware'"
         )
 
-    @override_settings(MIDDLEWARE_CLASSES=[
-        'middleware_exceptions.tests.MyMiddlewareWithExceptionMessage',
-    ])
+    @override_settings(MIDDLEWARE=['middleware_exceptions.tests.MyMiddlewareWithExceptionMessage'])
     def test_log_custom_message(self):
         with patch_logger('django.request', 'debug') as calls:
             self.client.get('/middleware_exceptions/view/')
@@ -926,3 +927,11 @@ class MiddlewareNotUsedTests(SimpleTestCase):
         with patch_logger('django.request', 'debug') as calls:
             self.client.get('/middleware_exceptions/view/')
         self.assertEqual(len(calls), 0)
+
+
+@override_settings(
+    MIDDLEWARE_CLASSES=['django.middleware.common.CommonMiddleware'],
+    MIDDLEWARE=None,
+)
+class MiddlewareNotUsedMiddlewareClassesTests(MiddlewareNotUsedTests):
+    pass