6 files changed, 246 insertions, 31 deletions

diff --git a/rest_framework/__init__.py b/rest_framework/__init__.py
index 087808e0..2bd2991b 100644
--- a/rest_framework/__init__.py
+++ b/rest_framework/__init__.py
@@ -1,4 +1,4 @@
-__version__ = '2.3.7'
+__version__ = '2.3.8'
 
 VERSION = __version__  # synonym
 
diff --git a/rest_framework/compat.py b/rest_framework/compat.py
index 6f7447ad..b9d1dae6 100644
--- a/rest_framework/compat.py
+++ b/rest_framework/compat.py
@@ -47,6 +47,12 @@ try:
 except ImportError:
     django_filters = None
 
+# guardian is optional
+try:
+    import guardian
+except ImportError:
+    guardian = None
+
 
 # cStringIO only if it's available, otherwise StringIO
 try:
diff --git a/rest_framework/filters.py b/rest_framework/filters.py
index 4079e1bd..b8fe7f77 100644
--- a/rest_framework/filters.py
+++ b/rest_framework/filters.py
@@ -4,7 +4,7 @@ returned by list views.
 """
 from __future__ import unicode_literals
 from django.db import models
-from rest_framework.compat import django_filters, six
+from rest_framework.compat import django_filters, six, guardian
 from functools import reduce
 import operator
 
@@ -53,6 +53,7 @@ class DjangoFilterBackend(BaseFilterBackend):
                 class Meta:
                     model = queryset.model
                     fields = filter_fields
+                    order_by = True
             return AutoFilterSet
 
         return None
@@ -140,3 +141,24 @@ class OrderingFilter(BaseFilterBackend):
             return queryset.order_by(*ordering)
 
         return queryset
+
+
+class DjangoObjectPermissionsFilter(BaseFilterBackend):
+    """
+    A filter backend that limits results to those where the requesting user
+    has read object level permissions.
+    """
+    def __init__(self):
+        assert guardian, 'Using DjangoObjectPermissionsFilter, but django-guardian is not installed'
+
+    perm_format = '%(app_label)s.view_%(model_name)s'
+
+    def filter_queryset(self, request, queryset, view):
+        user = request.user
+        model_cls = queryset.model
+        kwargs = {
+            'app_label': model_cls._meta.app_label,
+            'model_name': model_cls._meta.module_name
+        }
+        permission = self.perm_format % kwargs
+        return guardian.shortcuts.get_objects_for_user(user, permission, queryset)
diff --git a/rest_framework/permissions.py b/rest_framework/permissions.py
index 1036663e..53184798 100644
--- a/rest_framework/permissions.py
+++ b/rest_framework/permissions.py
@@ -7,6 +7,7 @@ import warnings
 
 SAFE_METHODS = ['GET', 'HEAD', 'OPTIONS']
 
+from django.http import Http404
 from rest_framework.compat import oauth2_provider_scope, oauth2_constants
 
 
@@ -151,6 +152,65 @@ class DjangoModelPermissionsOrAnonReadOnly(DjangoModelPermissions):
     authenticated_users_only = False
 
 
+class DjangoObjectPermissions(DjangoModelPermissions):
+    """
+    The request is authenticated using Django's object-level permissions.
+    It requires an object-permissions-enabled backend, such as Django Guardian.
+
+    It ensures that the user is authenticated, and has the appropriate
+    `add`/`change`/`delete` permissions on the object using .has_perms.
+
+    This permission can only be applied against view classes that
+    provide a `.model` or `.queryset` attribute.
+    """
+
+    perms_map = {
+        'GET': [],
+        'OPTIONS': [],
+        'HEAD': [],
+        'POST': ['%(app_label)s.add_%(model_name)s'],
+        'PUT': ['%(app_label)s.change_%(model_name)s'],
+        'PATCH': ['%(app_label)s.change_%(model_name)s'],
+        'DELETE': ['%(app_label)s.delete_%(model_name)s'],
+    }
+
+    def get_required_object_permissions(self, method, model_cls):
+        kwargs = {
+            'app_label': model_cls._meta.app_label,
+            'model_name': model_cls._meta.module_name
+        }
+        return [perm % kwargs for perm in self.perms_map[method]]
+
+    def has_object_permission(self, request, view, obj):
+        model_cls = getattr(view, 'model', None)
+        queryset = getattr(view, 'queryset', None)
+
+        if model_cls is None and queryset is not None:
+            model_cls = queryset.model
+
+        perms = self.get_required_object_permissions(request.method, model_cls)
+        user = request.user
+
+        if not user.has_perms(perms, obj):
+            # If the user does not have permissions we need to determine if
+            # they have read permissions to see 403, or not, and simply see
+            # a 404 reponse.
+
+            if request.method in ('GET', 'OPTIONS', 'HEAD'):
+                # Read permissions already checked and failed, no need
+                # to make another lookup.
+                raise Http404
+
+            read_perms = self.get_required_object_permissions('GET', model_cls)
+            if not user.has_perms(read_perms, obj):
+                raise Http404
+
+            # Has read permissions.
+            return False
+
+        return True
+
+
 class TokenHasReadWriteScope(BasePermission):
     """
     The request is authenticated as a user and the token used has the right scope
diff --git a/rest_framework/runtests/settings.py b/rest_framework/runtests/settings.py
index b3702d0b..be721658 100644
--- a/rest_framework/runtests/settings.py
+++ b/rest_framework/runtests/settings.py
@@ -123,6 +123,21 @@ else:
         'provider.oauth2',
     )
 
+# guardian is optional
+try:
+    import guardian
+except ImportError:
+    pass
+else:
+    ANONYMOUS_USER_ID = -1
+    AUTHENTICATION_BACKENDS = (
+        'django.contrib.auth.backends.ModelBackend', # default
+        'guardian.backends.ObjectPermissionBackend',
+    )
+    INSTALLED_APPS += (
+        'guardian',
+    )
+
 STATIC_URL = '/static/'
 
 PASSWORD_HASHERS = (
diff --git a/rest_framework/tests/test_permissions.py b/rest_framework/tests/test_permissions.py
index e2cca380..d08124f4 100644
--- a/rest_framework/tests/test_permissions.py
+++ b/rest_framework/tests/test_permissions.py
@@ -1,18 +1,17 @@
 from __future__ import unicode_literals
-from django.contrib.auth.models import User, Permission
+from django.contrib.auth.models import User, Permission, Group
 from django.db import models
 from django.test import TestCase
+from django.utils import unittest
 from rest_framework import generics, status, permissions, authentication, HTTP_HEADER_ENCODING
+from rest_framework.compat import guardian
+from rest_framework.filters import DjangoObjectPermissionsFilter
 from rest_framework.test import APIRequestFactory
+from rest_framework.tests.models import BasicModel
 import base64
 
 factory = APIRequestFactory()
 
-
-class BasicModel(models.Model):
-    text = models.CharField(max_length=100)
-
-
 class RootView(generics.ListCreateAPIView):
     model = BasicModel
     authentication_classes = [authentication.BasicAuthentication]
@@ -144,45 +143,158 @@ class ModelPermissionsIntegrationTests(TestCase):
         self.assertEqual(list(response.data['actions'].keys()), ['PUT'])
 
 
-class OwnerModel(models.Model):
+class BasicPermModel(models.Model):
     text = models.CharField(max_length=100)
-    owner = models.ForeignKey(User)
 
+    class Meta:
+        app_label = 'tests'
+        permissions = (
+            ('view_basicpermmodel', 'Can view basic perm model'),
+            # add, change, delete built in to django
+        )
+
+# Custom object-level permission, that includes 'view' permissions
+class ViewObjectPermissions(permissions.DjangoObjectPermissions):
+    perms_map = {
+        'GET': ['%(app_label)s.view_%(model_name)s'],
+        'OPTIONS': ['%(app_label)s.view_%(model_name)s'],
+        'HEAD': ['%(app_label)s.view_%(model_name)s'],
+        'POST': ['%(app_label)s.add_%(model_name)s'],
+        'PUT': ['%(app_label)s.change_%(model_name)s'],
+        'PATCH': ['%(app_label)s.change_%(model_name)s'],
+        'DELETE': ['%(app_label)s.delete_%(model_name)s'],
+    }
+
+
+class ObjectPermissionInstanceView(generics.RetrieveUpdateDestroyAPIView):
+    model = BasicPermModel
+    authentication_classes = [authentication.BasicAuthentication]
+    permission_classes = [ViewObjectPermissions]
 
-class IsOwnerPermission(permissions.BasePermission):
-    def has_object_permission(self, request, view, obj):
-        return request.user == obj.owner
+object_permissions_view = ObjectPermissionInstanceView.as_view()
 
 
-class OwnerInstanceView(generics.RetrieveUpdateDestroyAPIView):
-    model = OwnerModel
+class ObjectPermissionListView(generics.ListAPIView):
+    model = BasicPermModel
     authentication_classes = [authentication.BasicAuthentication]
-    permission_classes = [IsOwnerPermission]
-
+    permission_classes = [ViewObjectPermissions]
 
-owner_instance_view = OwnerInstanceView.as_view()
+object_permissions_list_view = ObjectPermissionListView.as_view()
 
 
+@unittest.skipUnless(guardian, 'django-guardian not installed')
 class ObjectPermissionsIntegrationTests(TestCase):
     """
     Integration tests for the object level permissions API.
     """
+    @classmethod
+    def setUpClass(cls):
+        from guardian.shortcuts import assign_perm
+
+        # create users
+        create = User.objects.create_user
+        users = {
+            'fullaccess': create('fullaccess', 'fullaccess@example.com', 'password'),
+            'readonly': create('readonly', 'readonly@example.com', 'password'),
+            'writeonly': create('writeonly', 'writeonly@example.com', 'password'),
+            'deleteonly': create('deleteonly', 'deleteonly@example.com', 'password'),
+        }
+
+        # give everyone model level permissions, as we are not testing those
+        everyone = Group.objects.create(name='everyone')
+        model_name = BasicPermModel._meta.module_name
+        app_label = BasicPermModel._meta.app_label
+        f = '{0}_{1}'.format
+        perms = {
+            'view':   f('view', model_name),
+            'change': f('change', model_name),
+            'delete': f('delete', model_name)
+        }
+        for perm in perms.values():
+            perm = '{0}.{1}'.format(app_label, perm)
+            assign_perm(perm, everyone)
+        everyone.user_set.add(*users.values())
+
+        cls.perms = perms
+        cls.users = users
 
     def setUp(self):
-        User.objects.create_user('not_owner', 'not_owner@example.com', 'password')
-        user = User.objects.create_user('owner', 'owner@example.com', 'password')
+        from guardian.shortcuts import assign_perm
+        perms = self.perms
+        users = self.users
+
+        # appropriate object level permissions
+        readers = Group.objects.create(name='readers')
+        writers = Group.objects.create(name='writers')
+        deleters = Group.objects.create(name='deleters')
+
+        model = BasicPermModel.objects.create(text='foo')
+        
+        assign_perm(perms['view'], readers, model)
+        assign_perm(perms['change'], writers, model)
+        assign_perm(perms['delete'], deleters, model)
+
+        readers.user_set.add(users['fullaccess'], users['readonly'])
+        writers.user_set.add(users['fullaccess'], users['writeonly'])
+        deleters.user_set.add(users['fullaccess'], users['deleteonly'])
+
+        self.credentials = {}
+        for user in users.values():
+            self.credentials[user.username] = basic_auth_header(user.username, 'password')
+
+    # Delete
+    def test_can_delete_permissions(self):
+        request = factory.delete('/1', HTTP_AUTHORIZATION=self.credentials['deleteonly'])
+        response = object_permissions_view(request, pk='1')
+        self.assertEqual(response.status_code, status.HTTP_204_NO_CONTENT)
 
-        self.not_owner_credentials = basic_auth_header('not_owner', 'password')
-        self.owner_credentials = basic_auth_header('owner', 'password')
+    def test_cannot_delete_permissions(self):
+        request = factory.delete('/1', HTTP_AUTHORIZATION=self.credentials['readonly'])
+        response = object_permissions_view(request, pk='1')
+        self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
 
-        OwnerModel(text='foo', owner=user).save()
+    # Update
+    def test_can_update_permissions(self):
+        request = factory.patch('/1', {'text': 'foobar'}, format='json',
+            HTTP_AUTHORIZATION=self.credentials['writeonly'])
+        response = object_permissions_view(request, pk='1')
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(response.data.get('text'), 'foobar')
+
+    def test_cannot_update_permissions(self):
+        request = factory.patch('/1', {'text': 'foobar'}, format='json',
+            HTTP_AUTHORIZATION=self.credentials['deleteonly'])
+        response = object_permissions_view(request, pk='1')
+        self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)
+
+    def test_cannot_update_permissions_non_existing(self):
+        request = factory.patch('/999', {'text': 'foobar'}, format='json',
+            HTTP_AUTHORIZATION=self.credentials['deleteonly'])
+        response = object_permissions_view(request, pk='999')
+        self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)
+
+    # Read
+    def test_can_read_permissions(self):
+        request = factory.get('/1', HTTP_AUTHORIZATION=self.credentials['readonly'])
+        response = object_permissions_view(request, pk='1')
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
 
-    def test_owner_has_delete_permissions(self):
-        request = factory.delete('/1', HTTP_AUTHORIZATION=self.owner_credentials)
-        response = owner_instance_view(request, pk='1')
-        self.assertEqual(response.status_code, status.HTTP_204_NO_CONTENT)
+    def test_cannot_read_permissions(self):
+        request = factory.get('/1', HTTP_AUTHORIZATION=self.credentials['writeonly'])
+        response = object_permissions_view(request, pk='1')
+        self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)
 
-    def test_non_owner_does_not_have_delete_permissions(self):
-        request = factory.delete('/1', HTTP_AUTHORIZATION=self.not_owner_credentials)
-        response = owner_instance_view(request, pk='1')
-        self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
+    # Read list
+    def test_can_read_list_permissions(self):
+        request = factory.get('/', HTTP_AUTHORIZATION=self.credentials['readonly'])
+        object_permissions_list_view.cls.filter_backends = (DjangoObjectPermissionsFilter,)
+        response = object_permissions_list_view(request)
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(response.data[0].get('id'), 1)
+
+    def test_cannot_read_list_permissions(self):
+        request = factory.get('/', HTTP_AUTHORIZATION=self.credentials['writeonly'])
+        object_permissions_list_view.cls.filter_backends = (DjangoObjectPermissionsFilter,)
+        response = object_permissions_list_view(request)
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertListEqual(response.data, [])