From 4a9dcfa76089143bbeb5cd43fa3a406365d89e96 Mon Sep 17 00:00:00 2001
From: bwreilly <benwreilly@gmail.com>
Date: Fri, 6 Sep 2013 11:01:31 -0500
Subject: [PATCH] added guardian as optional requirement, stubbed out
 object-level permission class

---
 docs/index.md                            | 1 +
 rest_framework/compat.py                 | 6 ++++++
 rest_framework/permissions.py            | 7 ++++++-
 rest_framework/tests/test_permissions.py | 1 +
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/docs/index.md b/docs/index.md
index e0a2e911b..d83fbff1f 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -42,6 +42,7 @@ The following packages are optional:
 * [django-filter][django-filter] (0.5.4+) - Filtering support.
 * [django-oauth-plus][django-oauth-plus] (2.0+) and [oauth2][oauth2] (1.5.211+) - OAuth 1.0a support.
 * [django-oauth2-provider][django-oauth2-provider] (0.2.3+) - OAuth 2.0 support.
+* [django-guardian][django-guardian] (1.1.1+) - Object level permissions support.
 
 **Note**: The `oauth2` Python package is badly misnamed, and actually provides OAuth 1.0a support.  Also note that packages required for both OAuth 1.0a, and OAuth 2.0 are not yet Python 3 compatible.
 
diff --git a/rest_framework/compat.py b/rest_framework/compat.py
index 6f7447add..b9d1dae6b 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/permissions.py b/rest_framework/permissions.py
index 1036663e0..6d213ba12 100644
--- a/rest_framework/permissions.py
+++ b/rest_framework/permissions.py
@@ -7,7 +7,7 @@ import warnings
 
 SAFE_METHODS = ['GET', 'HEAD', 'OPTIONS']
 
-from rest_framework.compat import oauth2_provider_scope, oauth2_constants
+from rest_framework.compat import oauth2_provider_scope, oauth2_constants, guardian
 
 
 class BasePermission(object):
@@ -151,6 +151,11 @@ class DjangoModelPermissionsOrAnonReadOnly(DjangoModelPermissions):
     authenticated_users_only = False
 
 
+class DjangoObjectLevelModelPermissions(DjangoModelPermissions):
+    def __init__(self):
+        assert guardian, 'Using DjangoObjectLevelModelPermissions, but guardian is not installed'
+
+
 class TokenHasReadWriteScope(BasePermission):
     """
     The request is authenticated as a user and the token used has the right scope
diff --git a/rest_framework/tests/test_permissions.py b/rest_framework/tests/test_permissions.py
index e2cca3808..d1171cce5 100644
--- a/rest_framework/tests/test_permissions.py
+++ b/rest_framework/tests/test_permissions.py
@@ -4,6 +4,7 @@ from django.db import models
 from django.test import TestCase
 from rest_framework import generics, status, permissions, authentication, HTTP_HEADER_ENCODING
 from rest_framework.test import APIRequestFactory
+from rest_framework.compat import guardian
 import base64
 
 factory = APIRequestFactory()