Fix request formdata handling (#5800)

* Rename 'wsgi' request test to more accurate 'http'

* Test duplicate request stream parsing

* Fix setting post/files on the underlying request

rest_framework/request.py

@@ -278,10 +278,11 @@ class Request(object):
             else:
                 self._full_data = self._data
 
-            # copy data & files refs to the underlying request so that closable
-            # objects are handled appropriately.
-            self._request._post = self.POST
-            self._request._files = self.FILES
+            # if a form media type, copy data & files refs to the underlying
+            # http request so that closable objects are handled appropriately.
+            if is_form_media_type(self.content_type):
+                self._request._post = self.POST
+                self._request._files = self.FILES
 
     def _load_stream(self):
         """

tests/test_request.py

@@ -13,6 +13,7 @@ from django.contrib.auth.middleware import AuthenticationMiddleware
 from django.contrib.auth.models import User
 from django.contrib.sessions.middleware import SessionMiddleware
 from django.core.files.uploadedfile import SimpleUploadedFile
+from django.http.request import RawPostDataException
 from django.test import TestCase, override_settings
 from django.utils import six
 
@@ -137,6 +138,11 @@ class MockView(APIView):
         return Response(status=status.HTTP_500_INTERNAL_SERVER_ERROR)
 
 
+class EchoView(APIView):
+    def post(self, request):
+        return Response(status=status.HTTP_200_OK, data=request.data)
+
+
 class FileUploadView(APIView):
     def post(self, request):
         filenames = [file.temporary_file_path() for file in request.FILES.values()]
@@ -149,6 +155,7 @@ class FileUploadView(APIView):
 
 urlpatterns = [
     url(r'^$', MockView.as_view()),
+    url(r'^echo/$', EchoView.as_view()),
     url(r'^upload/$', FileUploadView.as_view())
 ]
 
@@ -271,24 +278,64 @@ class TestSecure(TestCase):
         assert request.scheme == 'https'
 
 
-class TestWSGIRequestProxy(TestCase):
-    def test_attribute_access(self):
-        wsgi_request = factory.get('/')
-        request = Request(wsgi_request)
+class TestHttpRequest(TestCase):
+    def test_attribute_access_proxy(self):
+        http_request = factory.get('/')
+        request = Request(http_request)
 
         inner_sentinel = object()
-        wsgi_request.inner_property = inner_sentinel
+        http_request.inner_property = inner_sentinel
         assert request.inner_property is inner_sentinel
 
         outer_sentinel = object()
         request.inner_property = outer_sentinel
         assert request.inner_property is outer_sentinel
 
-    def test_exception(self):
+    def test_exception_proxy(self):
         # ensure the exception message is not for the underlying WSGIRequest
-        wsgi_request = factory.get('/')
-        request = Request(wsgi_request)
+        http_request = factory.get('/')
+        request = Request(http_request)
 
         message = "'Request' object has no attribute 'inner_property'"
         with self.assertRaisesMessage(AttributeError, message):
             request.inner_property
+
+    @override_settings(ROOT_URLCONF='tests.test_request')
+    def test_duplicate_request_stream_parsing_exception(self):
+        """
+        Check assumption that duplicate stream parsing will result in a
+        `RawPostDataException` being raised.
+        """
+        response = APIClient().post('/echo/', data={'a': 'b'}, format='json')
+        request = response.renderer_context['request']
+
+        # ensure that request stream was consumed by json parser
+        assert request.content_type.startswith('application/json')
+        assert response.data == {'a': 'b'}
+
+        # pass same HttpRequest to view, stream already consumed
+        with pytest.raises(RawPostDataException):
+            EchoView.as_view()(request._request)
+
+    @override_settings(ROOT_URLCONF='tests.test_request')
+    def test_duplicate_request_form_data_access(self):
+        """
+        Form data is copied to the underlying django request for middleware
+        and file closing reasons. Duplicate processing of a request with form
+        data is 'safe' in so far as accessing `request.POST` does not trigger
+        the duplicate stream parse exception.
+        """
+        response = APIClient().post('/echo/', data={'a': 'b'})
+        request = response.renderer_context['request']
+
+        # ensure that request stream was consumed by form parser
+        assert request.content_type.startswith('multipart/form-data')
+        assert response.data == {'a': ['b']}
+
+        # pass same HttpRequest to view, form data set on underlying request
+        response = EchoView.as_view()(request._request)
+        request = response.renderer_context['request']
+
+        # ensure that request stream was consumed by form parser
+        assert request.content_type.startswith('multipart/form-data')
+        assert response.data == {'a': ['b']}