Django REST - Access Policy

This project brings a declaritive, organized approach to managing access control in Django REST Framework projects. Each ViewSet or function-based view can be assigned an explicit policy for the exposed resource(s). No more digging through views or seralizers to understand access logic – it’s all in one place in a format that less technical stakeholders can understand. If you’re familiar with other declaritive access models, such as AWS’ IAM, the syntax will be familiar.

In short, you can start expressing your access rules like this:

class ArticleAccessPolicy(AccessPolicy):
    statements = [
        {
            "action": ["list", "retrieve"],
            "principal": "*",
            "effect": "allow"
        },
        {
            "action": ["publish", "unpublish"],
            "principal": ["group:editor"],
            "effect": "allow"
        }
    ]

This project has complete test coverage and the base AccessPolicy class is only ~150 lines of code: there’s no magic here.

Additionally, this project also provides FieldAccessMixin that can be added to a serializer to dynamically set fields to read_only, based on the access policy. Assign the appropriate access policy class inside the Meta declaration. See example below for how this works:

class UserAccountAccessPolicy(AccessPolicy):
    statements = [
        {"principal": "group:admin", "action": ["create", "update"], "effect": "allow"},
        {
            "principal": "group:dev",
            "action": ["update", "partial_update"],
            "effect": "allow",
        },
    ]

    field_permissions = {"read_only": [{"principal": "group:dev", "fields": "status"}]}

class UserAccountSerializer(FieldAccessMixin, serializers.ModelSerializer):
  class Meta:
    model = UserAccount
    fields = ["username", "first_name", "last_name", "status"]
    access_policy = UserAccountAccessPolicy

# Incoming POST/PUT/PATCH request from a user in group:dev...
# serializer = UserAccountSerializer(account, context={'request': request})
# print(serializer.fields["status"].read_only) -> True

⚠️ 1.0 Breaking Change ⚠️

See migration notes if your policy statements combine multiple conditions into boolean expressions.

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Documentation: https://rsinger86.github.io/drf-access-policy

Source Code: https://github.com/rsinger86/drf-access-policy

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Changelog

1.5 (March 2023)

• Adds Statement dataclass as alternative to dictionaries. Drops Python 3.5 support.

1.4 (March 2023)

• Fixes read-only scenario for FieldAccessMixin. Thanks @hungryseven!

1.3 (October 2022)

• Adds PermittedSlugRelatedField to re-use scope_queryset methods on policies. Thanks @bradydean!

1.2 (October 2022)

• Adds PermittedPkRelatedField to re-use scope_queryset methods on policies.

1.1.2 (July 2022)

• Fixes issue with boolean parser and shared request state. Thanks @mari8i!

1.1.1 (April 2022)

• Adds support for field-level permissions via a AccessPolicy.scope_fields(request, fields: dict, instance=None) method and the FieldAccessMixin. Thanks @gianpieropa!

1.1.0 (August 2021)

• Adds a mixin for explicitly defining a single access policy per ViewSet.

1.0.1 (July 2021)

• Fixes race condition between concurrent requests in evaluation of condition expressions. Thanks @goranpavlovic!

1.0.0 (July 2021)

• ⚠️ Breaking Change ⚠️
  • The condition element no longer supports the evaluation of multiple methods joined with boolean logic. These statements must be updated to use the new condition_expression element, which does support complex boolean logic.

0.9.2 (July 2021)

• Allow defining reusable_conditions module as a list. Thanks @HonakerM!

0.9.1 (July 2021)

• Fixes attribute error when request.user is None, which is the case when Django’s AuthenticationMiddleware is not used. If request.user is None, the user is anonymous.

0.9.0 (April 2021)

• Adds special admin and staff principal keys to match users with is_superuser and is_staff set to True. Thanks @BarnabasSzabolcs!

0.8.7 (February 2021)

• Fixed bug preventing argument being passed to custom condition method if “*” character used.

0.8.6 (January 2021)

• Adds missing requirement to setup.py. Thanks @daviddavis!

0.8.5 (January 2021)

• Adds support for boolean expressions in condition statement elements. Thanks @tanonl!

0.8.1 (October 2020)

• Fixes case where object has no action_map. Thanks @oguzhancelikarslan!
• Added missing info to docs. Thanks @hardntrash!

0.8.0 (September 2020)

• Workaround for quirk resulting in action not always being set. Thanks @oguzhancelikarslan!

0.7.0 (August 2020)

• Allows using HTTP method placeholders in action element of statements to match request.
  • For example, "action": ["<method:post>"] will match all POST requests.

0.6.2 (July 2020)

• Uses user.pk instead of user.id in user principal check, for compatibility with non-id primary keys.
• Fixes to documentation. Thanks @oguzhancelikarslan!

0.6.1 (June 2020)

• Replaces references to “delete” action with “destroy” in docs/tests, to be consistent with DRF’s ViewSet actions. Thanks @greenled!

0.6.0 (May 2020)

• Only call database-hitting get_user_group_values if needed in private method. Thanks KillianMeersman!
• Use prefetch_related_objects to ensure that user’s groups aren’t fetched more than once. Thanks filwaline!

0.5.1 (December 2019)

• Tox config updates and typo fixes in docs.

0.5.0 (September 2019)

• Add option to define re-usable custom conditions/permissions in a module that can be referenced by multiple policies.

0.4.2 (June 2019)

• Fixes readme format for Pypy display.

0.4.0 (June 2019)

• Allow passing arguments to condition methods, via condition values formatted as {method_name}:{arg_value}.

0.3.0 (May 2019)

• Adds special <safe_methods> action key that matches when the current request is an HTTP read-only method: HEAD, GET, OPTIONS.

0.2.0 (May 2019)

• Adds special authenticated and anonymous principal keys to match any authenticated user and any non-authenticated user, respectively. Thanks @bogdandm for discussion/advice!

0.1.0 (May 2019)

• Initial release

Testing

Tests are found in a simplified Django project in the /tests folder. Install the project requirements and do ./manage.py test to run them.

License

See License.