Implementing Scalekit Django Auth

Scalekit Auth — Django

Reference repo: scalekit-inc/scalekit-django-auth-example

Project structure

auth_app/
├── scalekit_client.py   # ScalekitClient class + scalekit_client() singleton
├── views.py             # All auth + protected views
├── decorators.py        # @login_required, @permission_required('perm:name')
├── middleware.py        # ScalekitTokenRefreshMiddleware (auto token refresh)
└── urls.py              # URL patterns (app_name = 'auth_app')

scalekit_django_auth/
└── settings.py          # SCALEKIT_* settings, middleware registration, session config

Environment variables

SCALEKIT_ENV_URL=https://your-env.scalekit.io
SCALEKIT_CLIENT_ID=your-client-id
SCALEKIT_CLIENT_SECRET=your-client-secret
SCALEKIT_REDIRECT_URI=http://localhost:8000/auth/callback
# SCALEKIT_SCOPES is set directly in settings.py, not from env

SCALEKIT_ENV_URL also falls back to SCALEKIT_DOMAIN for backward compatibility. SCALEKIT_REDIRECT_URI has no trailing slash — this avoids Django redirect issues.

Django settings (settings.py)

Key non-obvious settings to include:

INSTALLED_APPS = [
    'django.contrib.contenttypes',
    'django.contrib.sessions',   # Required for session storage
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'auth_app',
]

MIDDLEWARE = [
    # ...
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'auth_app.middleware.ScalekitTokenRefreshMiddleware',  # MUST come after SessionMiddleware
    # ...
]

SESSION_ENGINE = 'django.contrib.sessions.backends.db'
SESSION_COOKIE_AGE = 3600
SESSION_COOKIE_HTTPONLY = True
SESSION_COOKIE_SAMESITE = 'Lax'
SESSION_SAVE_EVERY_REQUEST = True  # Required — ensures OAuth state persists across requests

SCALEKIT_ENV_URL = os.getenv('SCALEKIT_ENV_URL', os.getenv('SCALEKIT_DOMAIN', ''))
SCALEKIT_CLIENT_ID = os.getenv('SCALEKIT_CLIENT_ID', '')
SCALEKIT_CLIENT_SECRET = os.getenv('SCALEKIT_CLIENT_SECRET', '')
SCALEKIT_REDIRECT_URI = os.getenv('SCALEKIT_REDIRECT_URI', 'http://localhost:8000/auth/callback')
SCALEKIT_SCOPES = 'openid profile email offline_access'  # offline_access required for refresh token

LOGIN_URL = '/login'

SDK client (auth_app/scalekit_client.py)

Lazy singleton — always use scalekit_client(), never instantiate directly:

from auth_app.scalekit_client import scalekit_client

client = scalekit_client()  # raises ValueError with helpful message if env vars missing

SDK import paths:

from scalekit import ScalekitClient as SDKClient
from scalekit.common.scalekit import (
    AuthorizationUrlOptions,
    CodeAuthenticationOptions,
    TokenValidationOptions,
    LogoutUrlOptions,
)

Key methods on ScalekitClient:

Session storage schema

All auth state is stored in Django's session (no extra DB tables):

request.session['scalekit_user'] = {
    'sub', 'email', 'name', 'given_name', 'family_name',
    'preferred_username', 'claims'  # full access token claims dict
}
request.session['scalekit_tokens'] = {
    'access_token', 'refresh_token', 'id_token',
    'expires_at',   # ISO 8601 string (timezone-aware)
    'expires_in'    # int seconds
}
request.session['scalekit_roles'] = []        # from access token claims
request.session['scalekit_permissions'] = []  # from access token claims

Check authentication anywhere: request.session.get('scalekit_user') → truthy if logged in.

Auth flow

Login (login_view — GET /login/)

state = secrets.token_urlsafe(32)
request.session['oauth_state'] = state
request.session.save()  # Explicit save — required for state to survive redirect
auth_url = client.get_authorization_url(state=state)
# Pass auth_url to template; user clicks it to redirect to Scalekit

Callback (callback_view — GET /auth/callback)

1. Validate state param vs request.session['oauth_state'] → render error on mismatch
2. request.session.pop('oauth_state', None)
3. token_response = client.exchange_code_for_tokens(code)
4. user_obj = token_response.get('user', {}) — camelCase fields (givenName, familyName, id)
5. user_info = client.get_user_info(access_token) — snake_case claims for roles/permissions
6. Name resolution: user_obj.name → givenName + familyName → user_info claims → email
7. expires_at = timezone.now() + timedelta(seconds=expires_in)
8. Write scalekit_user, scalekit_tokens, scalekit_roles, scalekit_permissions to session
9. Redirect to auth_app:dashboard

Permission claim fallback chain (same as Node SDK):

permissions = (
    claims.get('permissions', []) or
    claims.get('https://scalekit.com/permissions', []) or
    claims.get('scalekit:permissions', []) or
    []
)

Logout (logout_view — GET /logout/)

logout_url = client.logout(access_token, id_token)
# post_logout_redirect_uri = SCALEKIT_REDIRECT_URI.replace('/auth/callback', '')
request.session.flush()     # Wipes entire session
return redirect(logout_url) # Server-side redirect (not JSON like Next.js)

Token refresh — middleware (auth_app/middleware.py)

ScalekitTokenRefreshMiddleware runs on every request. Skipped paths: /login, /auth/callback, /logout, /static/, /sessions/refresh-token

Buffer: 1 minute (vs 5 min in client is_token_expired helper).

Also available as a manual API endpoint: POST /sessions/refresh-token/ → JsonResponse.

Protecting views

from auth_app.decorators import login_required, permission_required

@login_required
def dashboard_view(request): ...         # Redirects to /login?next=<path> if unauthenticated

@permission_required('organization:settings')
def org_settings_view(request): ...      # Renders permission_denied.html with 403 if missing

URL configuration

# auth_app/urls.py — app_name = 'auth_app'
path('auth/callback', callback_view, name='callback'),  # No trailing slash — intentional
path('sessions/validate-token/', validate_token_view),   # POST only
path('sessions/refresh-token/', refresh_token_view),     # POST only

Use reverse('auth_app:dashboard') / {% url 'auth_app:login' %} in templates.

Route map

Install

pip install scalekit python-dotenv django
python manage.py migrate   # Creates session table (db.sqlite3, zero-config)
python manage.py runserver

Tactics

SameSite=Lax — never Strict

SESSION_COOKIE_SAMESITE = 'Lax' is correct. Do not change to 'Strict' — it drops the session cookie on the cross-origin redirect from Scalekit back to /auth/callback, so oauth_state is unavailable and the CSRF check fails on every login.

SESSION_SAVE_EVERY_REQUEST = True — why it matters

The OAuth flow involves at least two redirects. Without SESSION_SAVE_EVERY_REQUEST = True, the session containing oauth_state may not be written to the database before Django redirects to Scalekit, causing a state mismatch on the callback. This setting ensures session writes happen on every response.

@csrf_exempt on the callback view

The OAuth callback receives a GET request from Scalekit (an external origin). Django's CSRF middleware does not block GETs, but the OAuth state parameter already serves as the CSRF token for this flow. If you ever add a POST-based callback, exempt it explicitly:

from django.views.decorators.csrf import csrf_exempt

@csrf_exempt
def callback_view(request): ...

Deep link preservation

@login_required already appends ?next=<path> when redirecting. Read it in login_view and restore it after a successful callback:

# In login_view
next_url = request.GET.get('next', reverse('auth_app:dashboard'))
request.session['next'] = next_url
request.session.save()  # explicit save before redirect

# In callback_view — after writing session data
next_url = request.session.pop('next', reverse('auth_app:dashboard'))
if not next_url.startswith('/'):        # prevent open redirect
    next_url = reverse('auth_app:dashboard')
return redirect(next_url)

Cache-Control: no-store on protected views

Without this, the back button after logout serves a cached authenticated page:

from django.views.decorators.cache import never_cache

@never_cache
@login_required
def dashboard_view(request): ...

AJAX: 401 instead of redirect

If your frontend makes AJAX calls to protected views, return 401 instead of a redirect:

from functools import wraps
from django.http import JsonResponse

def login_required_ajax(f):
    @wraps(f)
    def decorated(request, *args, **kwargs):
        if not request.session.get('scalekit_user'):
            if request.headers.get('Accept') == 'application/json':
                return JsonResponse({'error': 'Authentication required'}, status=401)
            return redirect(f"{reverse('auth_app:login')}?next={request.path}")
        return f(request, *args, **kwargs)
    return decorated

Session fixation after login

Call request.session.cycle_key() immediately after writing session data in callback_view to prevent session fixation — an attacker who planted a known session ID before login cannot hijack the authenticated session:

# At the end of callback_view, after writing all session keys:
request.session.cycle_key()
return redirect(next_url)