Merge master

1 files changed, 60 insertions, 0 deletions

diff --git a/rest_framework/permissions.py b/rest_framework/permissions.py
index 0c7b02ff..14bec42c 100644
--- a/rest_framework/permissions.py
+++ b/rest_framework/permissions.py
@@ -2,6 +2,7 @@
 Provides a set of pluggable permission policies.
 """
 from __future__ import unicode_literals
+from django.http import Http404
 from rest_framework.compat import oauth2_provider_scope, oauth2_constants
 
 SAFE_METHODS = ['GET', 'HEAD', 'OPTIONS']
@@ -141,6 +142,65 @@ 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