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Tweaks and docs to object-level model permissions.

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Tom Christie 2013-09-10 21:00:13 +01:00
parent 75fb4b02b4
commit 5970baa201
5 changed files with 235 additions and 130 deletions
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46
docs/api-guide/filtering.md
View File

@ -257,6 +257,49 @@ The `ordering` attribute may be either a string or a list/tuple of strings.
---
## DjangoObjectPermissionsFilter
The `DjangoObjectPermissionsFilter` is intended to be used together with the [`django-guardian`][guardian] package, with custom `'view'` permissions added. The filter will ensure that querysets only returns objects for which the user has the appropriate view permission.
This filter class must be used with views that provide either a `queryset` or a `model` attribute.
If you're using `DjangoObjectPermissionsFilter`, you'll probably also want to add an appropriate object permissions class, to ensure that users can only operate on instances if they have the appropriate object permissions. The easiest way to do this is to subclass `DjangoObjectPermissions` and add `'view'` permissions to the `perms_map` attribute.
A complete example using both `DjangoObjectPermissionsFilter` and `DjangoObjectPermissions` might look something like this.
**permissions.py**:
class CustomObjectPermissions(permissions.DjangoObjectPermissions):
"""
Similar to `DjangoObjectPermissions`, but adding 'view' permissions.
"""
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'],
}
**views.py**:
class EventViewSet(viewsets.ModelViewSet):
"""
Viewset that only lists events if user has 'view' permissions, and only
allows operations on individual events if user has appropriate 'view', 'add',
'change' or 'delete' permissions.
"""
queryset = Event.objects.all()
serializer = EventSerializer
filter_backends = (filters.DjangoObjectPermissionsFilter,)
permission_classes = (myapp.permissions.CustomObjectPermissions,)
For more information on adding `'view'` permissions for models, see the [relevant section][view-permissions] of the `django-guardian` documentation, and [this blogpost][view-permissions-blogpost].
---
# Custom generic filtering
You can also provide your own generic filtering backend, or write an installable app for other developers to use.
@ -281,5 +324,8 @@ We could achieve the same behavior by overriding `get_queryset()` on the views,
[cite]: https://docs.djangoproject.com/en/dev/topics/db/queries/#retrieving-specific-objects-with-filters
[django-filter]: https://github.com/alex/django-filter
[django-filter-docs]: https://django-filter.readthedocs.org/en/latest/index.html
[guardian]: http://pythonhosted.org/django-guardian/
[view-permissions]: http://pythonhosted.org/django-guardian/userguide/assign.html
[view-permissions-blogpost]: http://blog.nyaruka.com/adding-a-view-permission-to-django-models
[nullbooleanselect]: https://github.com/django/django/blob/master/django/forms/widgets.py
[search-django-admin]: https://docs.djangoproject.com/en/dev/ref/contrib/admin/#django.contrib.admin.ModelAdmin.search_fields

16
docs/api-guide/permissions.md
View File

@ -122,6 +122,20 @@ To use custom model permissions, override `DjangoModelPermissions` and set the `
Similar to `DjangoModelPermissions`, but also allows unauthenticated users to have read-only access to the API.
## DjangoObjectPermissions
This permission class ties into Django's standard [object permissions framework][objectpermissions] that allows per-object permissions on models. In order to use this permission class, you'll also need to add a permission backend that supports object-level permissions, such as [django-guardian][guardian].
When applied to a view that has a `.model` property, authorization will only be granted if the user *is authenticated* and has the *relevant per-object permissions* and *relevant model permissions* assigned.
* `POST` requests require the user to have the `add` permission on the model instance.
* `PUT` and `PATCH` requests require the user to have the `change` permission on the model instance.
* `DELETE` requests require the user to have the `delete` permission on the model instance.
Note that `DjangoObjectPermissions` **does not** require the `django-guardian` package, and should support other object-level backends equally well.
As with `DjangoModelPermissions` you can use custom model permissions by overriding `DjangoModelPermissions` and setting the `.perms_map` property. Refer to the source code for details. Note that if you add a custom `view` permission for `GET`, `HEAD` and `OPTIONS` requests, you'll probably also want to consider adding the `DjangoObjectPermissionsFilter` class to ensure that list endpoints only return results including objects for which the user has appropriate view permissions.
## TokenHasReadWriteScope
This permission class is intended for use with either of the `OAuthAuthentication` and `OAuth2Authentication` classes, and ties into the scoping that their backends provide.
@ -220,7 +234,9 @@ The [Composed Permissions][composed-permissions] package provides a simple way t
[authentication]: authentication.md
[throttling]: throttling.md
[contribauth]: https://docs.djangoproject.com/en/1.0/topics/auth/#permissions
[objectpermissions]: https://docs.djangoproject.com/en/dev/topics/auth/customizing/#handling-object-permissions
[guardian]: https://github.com/lukaszb/django-guardian
[get_objects_for_user]: http://pythonhosted.org/django-guardian/api/guardian.shortcuts.html#get-objects-for-user
[django-oauth-plus]: http://code.larlet.fr/django-oauth-plus
[django-oauth2-provider]: https://github.com/caffeinehit/django-oauth2-provider
[2.2-announcement]: ../topics/2.2-announcement.md

37
rest_framework/filters.py
View File

@ -23,22 +23,6 @@ class BaseFilterBackend(object):
raise NotImplementedError(".filter_queryset() must be overridden.")
class ObjectPermissionReaderFilter(BaseFilterBackend):
"""
A filter backend that limits results to those where the requesting user
has read object level permissions.
"""
def __init__(self):
assert guardian, 'Using ObjectPermissionReaderFilter, but django-guardian is not installed'
def filter_queryset(self, request, queryset, view):
user = request.user
model_cls = queryset.model
model_name = model_cls._meta.module_name
permission = 'read_' + model_name
return guardian.shortcuts.get_objects_for_user(user, permission, queryset)
class DjangoFilterBackend(BaseFilterBackend):
"""
A filter backend that uses django-filter.
@ -156,3 +140,24 @@ 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)

45
rest_framework/permissions.py
View File

@ -152,10 +152,10 @@ class DjangoModelPermissionsOrAnonReadOnly(DjangoModelPermissions):
authenticated_users_only = False
class DjangoObjectLevelModelPermissions(DjangoModelPermissions):
class DjangoObjectPermissions(DjangoModelPermissions):
"""
The request is authenticated using `django.contrib.auth` permissions.
See: https://docs.djangoproject.com/en/dev/topics/auth/#permissions
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.
@ -164,21 +164,22 @@ class DjangoObjectLevelModelPermissions(DjangoModelPermissions):
provide a `.model` or `.queryset` attribute.
"""
actions_map = {
'GET': ['read_%(model_name)s'],
'OPTIONS': ['read_%(model_name)s'],
'HEAD': ['read_%(model_name)s'],
'POST': ['add_%(model_name)s'],
'PUT': ['change_%(model_name)s'],
'PATCH': ['change_%(model_name)s'],
'DELETE': ['delete_%(model_name)s'],
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.actions_map[method]]
return [perm % kwargs for perm in self.perms_map[method]]
def has_object_permission(self, request, view, obj):
model_cls = getattr(view, 'model', None)
@ -190,10 +191,24 @@ class DjangoObjectLevelModelPermissions(DjangoModelPermissions):
perms = self.get_required_object_permissions(request.method, model_cls)
user = request.user
check = user.has_perms(perms, obj)
if not check:
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
return user.has_perms(perms, obj)
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):

47
rest_framework/tests/test_permissions.py
View File

@ -2,9 +2,10 @@ from __future__ import unicode_literals
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 ObjectPermissionReaderFilter
from rest_framework.filters import DjangoObjectPermissionsFilter
from rest_framework.test import APIRequestFactory
from rest_framework.tests.models import BasicModel
import base64
@ -148,33 +149,48 @@ class BasicPermModel(models.Model):
class Meta:
app_label = 'tests'
permissions = (
('read_basicpermmodel', 'Can view basic perm model'),
('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 = [permissions.DjangoObjectLevelModelPermissions]
permission_classes = [ViewObjectPermissions]
object_permissions_view = ObjectPermissionInstanceView.as_view()
class ObjectPermissionListView(generics.ListAPIView):
model = BasicPermModel
authentication_classes = [authentication.BasicAuthentication]
permission_classes = [permissions.DjangoObjectLevelModelPermissions]
permission_classes = [ViewObjectPermissions]
object_permissions_list_view = ObjectPermissionListView.as_view()
if guardian:
from guardian.shortcuts import assign_perm
class ObjectPermissionsIntegrationTests(TestCase):
@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 = {
@ -190,7 +206,7 @@ if guardian:
app_label = BasicPermModel._meta.app_label
f = '{0}_{1}'.format
perms = {
'read': f('read', model_name),
'view': f('view', model_name),
'change': f('change', model_name),
'delete': f('delete', model_name)
}
@ -203,6 +219,7 @@ if guardian:
cls.users = users
def setUp(self):
from guardian.shortcuts import assign_perm
perms = self.perms
users = self.users
@ -213,7 +230,7 @@ if guardian:
model = BasicPermModel.objects.create(text='foo')
assign_perm(perms['read'], readers, model)
assign_perm(perms['view'], readers, model)
assign_perm(perms['change'], writers, model)
assign_perm(perms['delete'], deleters, model)
@ -234,7 +251,7 @@ if guardian:
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_404_NOT_FOUND)
self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
# Update
def test_can_update_permissions(self):
@ -250,6 +267,12 @@ if guardian:
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'])
@ -264,14 +287,14 @@ if guardian:
# Read list
def test_can_read_list_permissions(self):
request = factory.get('/', HTTP_AUTHORIZATION=self.credentials['readonly'])
object_permissions_list_view.cls.filter_backends = (ObjectPermissionReaderFilter,)
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 = (ObjectPermissionReaderFilter,)
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, [])