From a556b9cb426f2893cb6807299a94044d585b7c2c Mon Sep 17 00:00:00 2001
From: Christian Sauer <sauerc@gmail.com>
Date: Wed, 14 Sep 2016 18:01:30 -0400
Subject: [PATCH 1/2] Router doesn't work if prefix is blank, though project
 urls.py handles prefix

---
 tests/test_routers.py | 49 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/tests/test_routers.py b/tests/test_routers.py
index f45039f80..d28e301a0 100644
--- a/tests/test_routers.py
+++ b/tests/test_routers.py
@@ -1,5 +1,6 @@
 from __future__ import unicode_literals
 
+import json
 from collections import namedtuple
 
 from django.conf.urls import include, url
@@ -47,6 +48,21 @@ class MockViewSet(viewsets.ModelViewSet):
     serializer_class = None
 
 
+class EmptyPrefixSerializer(serializers.HyperlinkedModelSerializer):
+    class Meta:
+        model = RouterTestModel
+        fields = ('uuid', 'text')
+
+
+class EmptyPrefixViewSet(viewsets.ModelViewSet):
+    queryset = [RouterTestModel(id=1, uuid='111', text='First'), RouterTestModel(id=2, uuid='222', text='Second')]
+    serializer_class = EmptyPrefixSerializer
+
+    def get_object(self, *args, **kwargs):
+        index = int(self.kwargs['pk']) - 1
+        return self.queryset[index]
+
+
 notes_router = SimpleRouter()
 notes_router.register(r'notes', NoteViewSet)
 
@@ -56,11 +72,19 @@ kwarged_notes_router.register(r'notes', KWargedNoteViewSet)
 namespaced_router = DefaultRouter()
 namespaced_router.register(r'example', MockViewSet, base_name='example')
 
+empty_prefix_router = SimpleRouter()
+empty_prefix_router.register(r'', EmptyPrefixViewSet, base_name='empty_prefix')
+empty_prefix_urls = [
+    url(r'^', include(empty_prefix_router.urls)),
+]
+
 urlpatterns = [
     url(r'^non-namespaced/', include(namespaced_router.urls)),
     url(r'^namespaced/', include(namespaced_router.urls, namespace='example')),
     url(r'^example/', include(notes_router.urls)),
     url(r'^example2/', include(kwarged_notes_router.urls)),
+
+    url(r'^empty-prefix/', include(empty_prefix_urls)),
 ]
 
 
@@ -384,3 +408,28 @@ class TestDynamicListAndDetailRouter(TestCase):
 
     def test_inherited_list_and_detail_route_decorators(self):
         self._test_list_and_detail_route_decorators(SubDynamicListAndDetailViewSet)
+
+
+@override_settings(ROOT_URLCONF='tests.test_routers')
+class TestEmptyPrefix(TestCase):
+    def test_empty_prefix_list(self):
+        response = self.client.get('/empty-prefix/')
+        self.assertEqual(200, response.status_code)
+        self.assertEqual(
+            json.loads(response.content.decode('utf-8')),
+            [
+                {'uuid': '111', 'text': 'First'},
+                {'uuid': '222', 'text': 'Second'}
+            ]
+        )
+
+    def test_empty_prefix_detail(self):
+        response = self.client.get('/empty-prefix/1/')
+        self.assertEqual(200, response.status_code)
+        self.assertEqual(
+            json.loads(response.content.decode('utf-8')),
+            {
+                'uuid': '111',
+                'text': 'First'
+            }
+        )

From a372a8edea70260ebfb559f3d0bd692132cdfb40 Mon Sep 17 00:00:00 2001
From: Christian Sauer <sauerc@gmail.com>
Date: Thu, 15 Sep 2016 12:54:35 -0400
Subject: [PATCH 2/2] Check for empty router prefix; adjust URL accordingly

It's easiest to fix this issue after we have made the regex.  To try
to fix it before would require doing something different for List vs
Detail, which means we'd have to know which type of url we're
constructing before acting accordingly.
---
 rest_framework/routers.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/rest_framework/routers.py b/rest_framework/routers.py
index 4eec70bda..e2fbfa77b 100644
--- a/rest_framework/routers.py
+++ b/rest_framework/routers.py
@@ -83,6 +83,7 @@ class BaseRouter(object):
 
 
 class SimpleRouter(BaseRouter):
+
     routes = [
         # List route.
         Route(
@@ -258,6 +259,13 @@ class SimpleRouter(BaseRouter):
                     trailing_slash=self.trailing_slash
                 )
 
+                # If there is no prefix, the first part of the url is probably
+                #   controlled by project's urls.py and the router is in an app,
+                #   so a slash in the beginning will (A) cause Django to give
+                #   warnings and (B) generate URLS that will require using '//'.
+                if not prefix and regex[:2] == '^/':
+                    regex = '^' + regex[2:]
+
                 view = viewset.as_view(mapping, **route.initkwargs)
                 name = route.name.format(basename=basename)
                 ret.append(url(regex, view, name=name))