permissions.py

Permissions

Authentication or identification by itself is not usually sufficient to gain access to information or code. For that, the entity requesting access must have authorization.

— Apple Developer Documentation

Together with authentication and throttling, permissions determine wheter a request should be granted or denied access.

Permission checks are always run at the very start of the view, before any other code is allowed to proceed. Permission checks will typically use the authentication information in the request.user and request.auth properties to determine if the incoming request should be permitted.

How permissions are determined

Permissions in REST framework are always defined as a list of permission classes.

Before running the main body of the view each permission in the list is checked. If any permission check fails an exceptions.PermissionDenied exception will be raised, and the main body of the view will not run.

Object level permissions

REST framework permissions also support object-level permissioning. Object level permissions are used to determine if a user should be allowed to act on a particular object, which will typically be a model instance.

Object level permissions are run by REST framework's generic views when .get_object() is called. As with view level permissions, an exceptions.PermissionDenied exception will be raised if the user is not allowed to act on the given object.

Setting the permission policy

The default permission policy may be set globally, using the DEFAULT_PERMISSION_CLASSES setting. For example.

REST_FRAMEWORK = {
    'DEFAULT_PERMISSION_CLASSES': (
        'rest_framework.permissions.IsAuthenticated',
    )
}

You can also set the authentication policy on a per-view basis, using the APIView class based views.

class ExampleView(APIView):
    permission_classes = (IsAuthenticated,)

    def get(self, request, format=None):
        content = {
            'status': 'request was permitted'
        }
        return Response(content)

Or, if you're using the @api_view decorator with function based views.

@api_view('GET')
@permission_classes(IsAuthenticated)
def example_view(request, format=None):
    content = {
        'status': 'request was permitted'
    }
    return Response(content)

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API Reference

IsAuthenticated

The IsAuthenticated permission class will deny permission to any unauthenticated user, and allow permission otherwise.

This permission is suitable if you want your API to only be accessible to registered users.

IsAdminUser

The IsAdminUser permission class will deny permission to any user, unless user.is_staffis True in which case permission will be allowed.

This permission is suitable is you want your API to only be accessible to a subset of trusted administrators.

IsAuthenticatedOrReadOnly

The IsAuthenticatedOrReadOnly will allow authenticated users to perform any request. Requests for unauthorised users will only be permitted if the request method is one of the "safe" methods; GET, HEAD or OPTIONS.

This permission is suitable if you want to your API to allow read permissions to anonymous users, and only allow write permissions to authenticated users.

DjangoModelPermissions

This permission class ties into Django's standard django.contrib.auth model permissions. When applied to a view that has a .model property, authorization will only be granted if the user has the relevant model permissions assigned.

• POST requests require the user to have the add permission on the model.
• PUT and PATCH requests require the user to have the change permission on the model.
• DELETE requests require the user to have the delete permission on the model.

The default behaviour can also be overridden to support custom model permissions. For example, you might want to include a view model permission for GET requests.

To use custom model permissions, override DjangoModelPermissions and set the .perms_map property. Refer to the source code for details.

The DjangoModelPermissions class also supports object-level permissions. Third-party authorization backends such as django-guardian that provide object-level permissions should work just fine with DjangoModelPermissions without any custom configuration required.

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Custom permissions

To implement a custom permission, override BasePermission and implement the .has_permission(self, request, view, obj=None) method.

The method should return True if the request should be granted access, and False otherwise.