Django

The Oso Django integration adopts Django conventions and provides middleware, view decorators and ORM integrations to make it easier to use Oso with Django.

Installation

The Oso Django integration is available on PyPI and can be installed using pip:

$ pip install django-oso==0.20.1

Usage

The django_oso Django plugin contains a reusable Django app that makes authorization with Oso and Django easy. To use, ensure django_oso is in INSTALLED_APPS:

INSTALLED_APPS = [
    'django_oso',
    ...
]

By default, django_oso will consider policy files as source code and restart the server on any changes. To prevent this, add the configuration option: OSO_RELOAD_SERVER = False to your application’s settings.py file.

To reload policies on each request in DEBUG mode without restarting the server, you can use the ReloadPolicyMiddleware as a complement to the above configuration change.

Loading policies

django_oso expects policy files to be included in the policy directory of each installed app. Upon startup, all .polar files found in that directory (or sub-directories) will be loaded using oso.Oso.load_file(). To load additional files outside of these directories, call load_file() on django_oso.oso.Oso.

Registering classes & models

Often, authorization rules will be expressed over Django models. Therefore, django_oso will register every model for each installed app upon startup as a class with Oso. The django.http.HttpRequest is also registered under HttpRequest. Django models are referenced in a Polar file using the syntax app_name::ModelName. If an app name contains ., for example django.contrib.auth, it will be referenced in Oso as django::contrib::auth.

Additional classes can be registered as needed using oso.Oso.register_class() on django_oso.oso.Oso.

Performing authorization

To authorize a request, use the django_oso.auth.authorize() function. It calls is_allowed(), but provides sensible defaults for working with Django. The actor defaults to request.user. The action defaults to the method of the request. resource must be provided.

django_oso.auth.authorize() can be used within route handlers, or in the data access layer, depending upon how you want to express authorization.

Here’s a basic example in a route:

def get_expense(request, id):
    try:
        expense = Expense.objects.get(pk=id)
    except Expense.DoesNotExist:
        return HttpResponseNotFound()

    authorize(request, expense, action="read")
    return HttpResponse(expense.json())

Requiring authorization on every request

Since authorize() is just a function call, it can be forgotten. To enforce authorization on every request, use the RequireAuthorization() middleware. Any view that does not call authorize() or skip_authorization() will raise an exception.

Route authorization

One common usage of django_oso.auth.authorize() is to perform authorization based on the request object. The authorize_request() decorator does this:

from django_oso.decorators import authorize_request

@authorize_request
def auth_route(request):
    pass

Rules can then be written using request attributes, like the path:

# Allow any actor to make a GET request to "/".
allow(_user: User, "GET", http_request: HttpRequest) if
    http_request.path = "/";

To enforce route authorization on all requests (the equivalent of decorating every route as we did above), use the RouteAuthorization() middleware during initialization.

Example

Check out the Django integration example app on GitHub.

API Reference

The Django API reference is automatically generated from the Oso Django library source files.


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