django-rest-framework-roles

Simplifies Role Based Access Control_ in django-rest-framework_.

Why would I use this?

You have more than one type of user in your data model and you have business logic that diverges depending on the type of user. You do not want to organize your API by role because that is not very RESTful. You do not want to manually type out a lot of conditional branching around user roles.

Modeling Requirements

• You must have one Group for each role
• A User cannot belong to more than one of the Groups corresponding to each role

Installation

.. code:: bash

$ pip install django-rest-framework-roles

Configuration

• VIEWSET_METHOD_REGISTRY A tuple of DRF methods to override. Defaults to:

.. code:: python

    (
        "get_queryset",
        "get_serializer_class",
        "perform_create",
        "perform_update",
        "perform_destroy",
    )

• ROLE_GROUPS A tuple of Group names that correspond 1-to-1 with user roles. Defaults to:

.. code:: python

    [group.name.lower() for group in Group.objects.all()]

It's recommended to define ROLE_GROUPS in settings to avoid a database lookup on every request.

Usage

Add the mixin to any ViewSet:

.. code:: python

from drf_roles.mixins import RoleViewSetMixin

class MyViewSet(RoleViewSetMixin, ModelViewSet):
    # ...

For each of the methods specified in VIEWSET_METHOD_REGISTRY a role-scoped method will be generated on your ViewSet.

Parameterizing

For example, let’s say you have three groups named *Takers*, *Leavers* &
*Gods*. Let’s also say you included ``"get_queryset"`` in the
``VIEWSET_METHOD_REGISTRY``.

When a *Taker* user hits an endpont on the ViewSet, the call to
``get_queryset`` will be rerouted to a call to
``get_queryset_for_takers``.

When a *Leaver* user hits an endpont on the ViewSet, the call to
``get_queryset`` will be rerouted to a call to
``get_queryset_for_leavers``.

When a *God* user hits an endpont on the ViewSet, the call to
``get_queryset`` will be rerouted to a call to
``get_queryset_for_gods``.

You can implement each of these methods on your ViewSet to return a
different queryset for each type of user.

Not Parameterizing

You can also not implement one or more of these methods, in which case the default call will be executed. For example, with our same set of groups and with "get_serializer_class" included in the role registry, let’s say you did not implement get_serializer_class_for_takers. When a Taker user hits an endpoint on the ViewSet, the default implementation of get_serializer_class will be executed and return serializer_class.

In this case, you would want to be sure that you have a serializer_class defined on your ViewSet! Otherwise Django REST Framework will complain. It is a good idea to always define a default queryset and serializer_class with least privilege (e.g: Model.objects.none()).

Roadmap

• Some projects require even further parameterization. For example, you may need to use a different serializer_class depending on the user's role and the request method.
• There may be a more pleasant way to express the parameterization in code. For example, it may be more pleasing to use nested classes instead of renaming the methods.

Further Reading

• Role-Based Access Control with Django Rest Framework_
• Computer Lab_

.. _Role Based Access Control: https://en.wikipedia.org/wiki/Role-based_access_control .. _django-rest-framework: http://www.django-rest-framework.org/ .. _Role-Based Access Control with Django Rest Framework: http://computerlab.io/2016/08/17/django-rest-framework-roles/ .. _Computer Lab: http://computerlab.io