Django-REST: custom permission doesn't work - python

I'm trying to make a custom permission using this guide
views.py
class CustomModelList(generics.ListAPIView):
queryset = CustomModel.objects.all()
serializer_class = CustomModelSerializer
permission_classes = [IsAuthenticatedOrReadOnly, IsCustomOrReadOnly]
def get(self, request, format=None):
# some logic
def post(self, request, format=None):
# some logic
Just for experiment I've created this permission not to apply anyway
pesmissions.py
class IsCustomOrReadOnly(BasePermission):
def has_object_permission(self, request, view, obj):
return False
But when POST request sends to server it takes no effect -- I'm able to create new model instance.

I think that since you are using a list view, custom object level permissions are not checked automatically.
Also note that the generic views will only check the object-level permissions for views that retrieve a single model instance. If you require object-level filtering of list views, you'll need to filter the queryset separately. See the filtering documentation for more details.
You can try overriding the has_permission method instead and see if that works, or check the permissions manually.

Related

Make REST Framework require authentication for GET method

I'm working on an Django app that uses REST Framework together with Swagger. Also added some models, and one of them is called Example. Added some views based on mixins in views.py for the model previously mentioned.
In views.py, I've created two classes: ExampleList (that uses GET to get all the objects made out from that model and POST to add a new model) and ExampleIndividual, that uses methods such as individual GET, PUT and DELETE.
Anyways, this is how my ExampleList class looks like:
class ExampleList(mixins.ListModelMixin, mixins.CreateModelMixin, generics.GenericAPIView):
permission_classes = [IsAuthenticated]
queryset = ExampleModel.objects.all()
serializer_class = ExampleSerializer
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
In the settings.py file, in the REST_FRAMEWORK configuration, I've set:
'DEFAULT_AUTHENTICATION_CLASSES': [
'rest_framework.authentication.BasicAuthentication',
'rest_framework.authentication.SessionAuthentication',
]
Everything works fine at this moment. What I want to do, is, whenever I want to get the list of all objects from the Example model (access the get() method from the ExampleList() class, I want it to work only if I am authenticated (using the Authorize option from Swagger). If not, a status code like "FORBIDDEN" should be returned.
I tried using permission_classes = [IsAuthenticated] at the beginning of the method, but it didn't work. It seems that I can still GET all the objects without being authenticated into Swagger.
Any advice on how I can do that properly? Thank you.
Did you tried it with Token Authentication? With this method in each request made to the API, the token must be included in the Header Field Authorization. https://www.django-rest-framework.org/api-guide/authentication/#tokenauthentication to test it in Browser you can install an extension called Mod Header https://chrome.google.com/webstore/detail/modheader/idgpnmonknjnojddfkpgkljpfnnfcklj there you can include the token in the header field.

User can update or delete data which created by others

class StoryViewSet(viewsets.ModelViewSet):
serializer_class = StorySerializer
permission_classes = (permissions.IsAuthenticatedOrReadOnly,)
I have viewset with all CRUD functions. The problem is that user can edit or delete stories of another user, I found DjangoModelPermissionsOrAnonReadOnly in permissions, but I cannot even create. I am using author as foreign key in Storymodel. Also I am using rest_framework.authtoken. So, I think there is two options, create own permission or rewrite some permission. Which one is better?
Write a customer object-level permission. Here is an example:
class IsOwnerOrReadOnly(permissions.BasePermission):
"""
Object-level permission to only allow owners of an object to edit it.
"""
def has_object_permission(self, request, view, obj):
# Read permissions are allowed to any request,
# so we'll always allow GET, HEAD or OPTIONS requests.
if request.method in permissions.SAFE_METHODS:
return True
return obj.author == request.user
And include it to permission_classes list.

Django POST with ModelViewSet and ModelSerializer 405

How can I make a ModelViewSet accept the POST method to create an object? When I attempt to call the endpoint I get a 405 'Method "POST" not allowed.'.
Within views.py:
class AccountViewSet(viewsets.ModelViewSet):
"""An Account ModelViewSet."""
model = Account
serializer_class = AccountSerializer
queryset = Account.objects.all().order_by('name')
Within serializers.py:
class AccountSerializer(serializers.ModelSerializer):
name = serializers.CharField(required=False)
active_until = serializers.DateTimeField()
class Meta:
model = Account
fields = [
'name',
'active_until',
]
def create(self, validated_data):
with transaction.atomic():
Account.objects.create(**validated_data)
within urls.py:
from rest_framework import routers
router = routers.SimpleRouter()
router.register(
prefix=r'v1/auth/accounts',
viewset=AccountViewSet,
base_name='accounts',
)
Do I need to create a specific #action? my attempts to do so have yet to be successful. If that is the case what would the url = reverse('app:accounts-<NAME>') be such that I can call it from tests? I haven't found a full example (urls.py, views.py, serializers.py, and tests etc).
I discovered what the issue was, I had a conflicting route. There was a higher level endpoint registered before the AccountViewSet.
router.register(
prefix=r'v1/auth',
viewset=UserViewSet,
base_name='users',
)
router.register(
prefix=r'v1/auth/accounts',
viewset=AccountViewSet,
base_name='accounts',
)
Django runs through each URL pattern, in order, and stops at the first one that matches the requested URL.. I should have been ordered this way:
router.register(
prefix=r'v1/auth/accounts',
viewset=AccountViewSet,
base_name='accounts',
)
router.register(
prefix=r'v1/auth',
viewset=UserViewSet,
base_name='users',
)
despite the fact that reverse('appname:acccounts-list') worked, the underlying URL router still thought I was calling the UserViewSet.
From the docs:
A ViewSet class is simply a type of class-based View, that does not provide any method handlers such as .get() or .post(), and instead provides actions such as .list() and .create().
And here is a list of supported actions:
def list(self, request):
pass
def create(self, request):
pass
def retrieve(self, request, pk=None):
pass
def update(self, request, pk=None):
pass
def partial_update(self, request, pk=None):
pass
def destroy(self, request, pk=None):
pass
So no post is not directly supported but create is.
So your end point would be v1/auth/accounts/create when using the a router instead v1/auth/accounts/post.
I honestly prefer using class based or function based views when working with DRF. It resembles regular django views more closely and makes more sense to me when working with them. You woul write you views and urls pretty much like regular django urls and views.

Django REST Framework - can't override list in ListAPIView

I am using Django REST Framework to create an endpoint that will produce a PDF document. The PDF document will have information that corresponds to a particular Department. I have two desired functionalities -- to be able to download a PDF document, and to be able to preview the document within the browser.
Since the PDF document changes over time based on data that is added to the app, the document needs to be generated in real time when it is requested. As a first step, I'm trying to have the document be generated in a remote file storage location when the following endpoint is hit by a GET request:
departments/<department_pk>/result/preview
Since my endpoint should only take GET requests, I am using a ListAPIView. I'm trying to override the list method so that my custom document generation logic is executed, but it looks like the method is never called. How can I have some custom document generation logic be inserted into my endpoint, so that it is executed when the endpoint is hit by a GET request?
api/urls.py
url(r'^departments/(?P<department_pk>[0-9]+)/result/preview',
include(result_document_urls.result_document_preview_router.urls,
document_app/urls.py
result_document_preview_router = routers.DefaultRouter()
result_document_preview_router.register(r'^', ResultDocumentDetailView.as_view(),
base_name='Department')
document_app/views.py
class ResultDocumentDetailView(generics.ListAPIView):
queryset = Department.objects.all()
lookup_field = 'department_pk'
lookup_url_kwarg = 'department_pk'
def list(self, request, department_pk):
queryset = self.get_queryset()
import ipdb; ipdb.set_trace() # this break point is never hit
department = get_object_or_404(queryset, department_pk=department_pk)
...generate document logic...
return Response(status=status.HTTP_200_OK)
replace list method with below code, I think it will work
class ResultDocumentDetailView(generics.ListAPIView):
queryset = Department.objects.all()
lookup_field = 'department_pk'
lookup_url_kwarg = 'department_pk'
def list(self, request, *args, **kwargs):
queryset = self.get_queryset()
import ipdb; ipdb.set_trace() # this break point is never hit
department = get_object_or_404(
queryset, department_pk=kwargs.get('department_pk')
)
...generate document logic...
return Response(status=status.HTTP_200_OK)
for more reference see the overrinding method "list"
https://github.com/tomchristie/django-rest-framework/blob/master/rest_framework/mixins.py#L35
In your document_app/urls.py, you are incorrectly passing ResultDocumentDetailView as an argument instead of a viewset.
Router while registering accepts a ViewSet instead of an APIView.
There are two mandatory arguments to the register() method:
prefix - The URL prefix to use for this set of routes.
viewset - The viewset class.
Also, since you are only interested in the retrieve method, you can just create a ResultDocumentRetrieveView and add its corresponding url to your urls.py without the need of creating a ResultDocument router. (Routers are generally used when you want to handle both list and detail requests.)
class ResultDocumentRetrieveView(generics.RetrieveAPIView):
queryset = Department.objects.all()
lookup_field = 'department_pk'
lookup_url_kwarg = 'department_pk'
def retrieve(self, request, department_pk):
department = self.get_object()
...generate document logic...
return Response(status=status.HTTP_200_OK)
urls.py
url(r'^departments/(?P<department_pk>[0-9]+)/result/preview', ResultDocumentRetrieveView.as_view())

Django restframework test permissions

Which is the proper way to test object based permissions?
Sample:
from rest_framework import permissions
class IsOfficeAdmin(permissions.BasePermission):
def has_object_permission(self, request, view, obj):
office = obj
return office.admin == request.user
Which are the "asserts" that I shouldn't miss?
Do I need to create a view?
To your questions:
it's up to you to write the logic which will allow a user to access the object. As a result, you have to return a Boolean.
yes. You will specify to the view which permission classes you want to apply. In case of object permissions they will be queried on detail routes (get, update, delete)

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