✨(entitlements) add Entitlements backend with Deploy Center support (#31)

This checks if the user has access to the app and can create calendars.

.github/workflows/calendars.yml

@@ -9,32 +9,6 @@ on:
       - "*"
 
 jobs:
-  check-changelog:
-    runs-on: ubuntu-latest
-    if: |
-      contains(github.event.pull_request.labels.*.name, 'noChangeLog') == false &&
-      github.event_name == 'pull_request'
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v6
-        with:
-          fetch-depth: 50
-      - name: Check that the CHANGELOG has been modified in the current branch
-        run: git diff --name-only ${{ github.event.pull_request.base.sha }} ${{ github.event.after }} | grep 'CHANGELOG.md'
-
-  lint-changelog:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v6
-      - name: Check CHANGELOG max line length
-        run: |
-          max_line_length=$(cat CHANGELOG.md | grep -Ev "^\[.*\]: https://github.com" | wc -L)
-          if [ $max_line_length -ge 80 ]; then
-            echo "ERROR: CHANGELOG has lines longer than 80 characters."
-            exit 1
-          fi
-
   lint-back:
     runs-on: ubuntu-latest
     defaults:

docs/entitlements.md

@@ -0,0 +1,246 @@
+# Entitlements System
+
+The entitlements system provides a pluggable backend architecture for
+checking whether a user is allowed to access the application. It
+integrates with the DeployCenter API in production and uses a local
+backend for development.
+
+Unlike La Suite Messages, Calendars only checks `can_access` — there
+is no admin permission sync.
+
+## Architecture
+
+```
+┌─────────────────────────────────────────────┐
+│       OIDC Authentication Backend           │
+│  post_get_or_create_user() — warms cache    │
+└──────────────┬──────────────────────────────┘
+               │
+┌──────────────▼──────────────────────────────┐
+│          UserMeSerializer                   │
+│    GET /users/me/ → { can_access: bool }    │
+└──────────────┬──────────────────────────────┘
+               │
+┌──────────────▼──────────────────────────────┐
+│            Service Layer                    │
+│       get_user_entitlements()               │
+└──────────────┬──────────────────────────────┘
+               │
+┌──────────────▼──────────────────────────────┐
+│       Backend Factory (singleton)           │
+│       get_entitlements_backend()            │
+└──────────────┬──────────────────────────────┘
+               │
+       ┌───────┴───────┐
+       │               │
+┌──────▼─────┐  ┌──────▼───────────────┐
+│   Local    │  │    DeployCenter      │
+│  Backend   │  │      Backend         │
+│ (dev/test) │  │ (production, cached) │
+└────────────┘  └──────────────────────┘
+```
+
+### Components
+
+- **Service layer** (`core/entitlements/__init__.py`): Public
+  `get_user_entitlements()` function and
+  `EntitlementsUnavailableError` exception.
+- **Backend factory** (`core/entitlements/factory.py`):
+  `@functools.cache` singleton that imports and instantiates the
+  configured backend class.
+- **Abstract base** (`core/entitlements/backends/base.py`): Defines
+  the `EntitlementsBackend` interface.
+- **Local backend** (`core/entitlements/backends/local.py`): Always
+  grants access. Used for local development.
+- **DeployCenter backend**
+  (`core/entitlements/backends/deploycenter.py`): Calls the
+  DeployCenter API with Django cache and stale fallback.
+
+### Integration points
+
+1. **OIDC login** (`core/authentication/backends.py`):
+   `post_get_or_create_user()` calls `get_user_entitlements()` with
+   `force_refresh=True` to warm the cache. Login always succeeds
+   regardless of `can_access` value — access is gated at API level
+   and in the frontend.
+2. **User API** (`core/api/serializers.py`): `UserMeSerializer`
+   exposes `can_access` as a field on `GET /users/me/`. Fail-open:
+   returns `True` when entitlements are unavailable.
+3. **Default calendar creation** (`core/signals.py`):
+   `provision_default_calendar` checks entitlements before creating a
+   calendar for a new user. Fail-closed: skips creation when
+   entitlements are unavailable.
+4. **CalDAV proxy** (`core/api/viewsets_caldav.py`): Blocks
+   `MKCALENDAR` and `MKCOL` methods for non-entitled users.
+   Other methods (PROPFIND, REPORT, GET, PUT, DELETE) are allowed
+   so that users invited to shared calendars can still use them.
+   Fail-closed: denies creation when entitlements are unavailable.
+5. **Import events** (`core/api/viewsets.py`): Blocks
+   `POST /calendars/import-events/` for non-entitled users.
+   Fail-closed: denies import when entitlements are unavailable.
+6. **Frontend** (`pages/index.tsx`, `pages/calendar.tsx`): Checks
+   `user.can_access` and redirects to `/no-access` when `false`.
+   Calendar creation uses MKCALENDAR via CalDAV proxy (no Django
+   endpoint).
+
+### Error handling
+
+- **Login is fail-open**: if the entitlements service is unavailable,
+  login succeeds and the cache warming is skipped.
+- **User API is fail-open**: if the entitlements service is
+  unavailable, `can_access` defaults to `True`.
+- **Calendar creation is fail-closed**: if the entitlements service
+  is unavailable, the default calendar is not created (avoids
+  provisioning resources for users who may not be entitled).
+- **CalDAV proxy MKCALENDAR/MKCOL is fail-closed**: if the
+  entitlements service is unavailable, calendar creation via CalDAV
+  is denied (returns 403).
+- **Import events is fail-closed**: if the entitlements service is
+  unavailable, ICS import is denied (returns 403).
+- The DeployCenter backend falls back to stale cached data when the
+  API is unavailable.
+- `EntitlementsUnavailableError` is only raised when the API fails
+  **and** no cache exists.
+
+## Configuration
+
+### Environment variables
+
+| Variable | Default | Description |
+|---|---|---|
+| `ENTITLEMENTS_BACKEND` | `core.entitlements.backends.local.LocalEntitlementsBackend` | Python import path of the backend class |
+| `ENTITLEMENTS_BACKEND_PARAMETERS` | `{}` | JSON object passed to the backend constructor |
+| `ENTITLEMENTS_CACHE_TIMEOUT` | `300` | Cache TTL in seconds |
+
+### DeployCenter backend parameters
+
+When using
+`core.entitlements.backends.deploycenter.DeployCenterEntitlementsBackend`,
+provide these in `ENTITLEMENTS_BACKEND_PARAMETERS`:
+
+```json
+{
+  "base_url": "https://deploycenter.example.com/api/v1.0/entitlements/",
+  "service_id": "calendar",
+  "api_key": "your-api-key",
+  "timeout": 10,
+  "oidc_claims": ["siret"]
+}
+```
+
+| Parameter | Required | Description |
+|---|---|---|
+| `base_url` | Yes | Full URL of the DeployCenter entitlements endpoint |
+| `service_id` | Yes | Service identifier in DeployCenter |
+| `api_key` | Yes | API key for `X-Service-Auth: Bearer` header |
+| `timeout` | No | HTTP timeout in seconds (default: 10) |
+| `oidc_claims` | No | OIDC claim names to forward as query params |
+
+### Example production configuration
+
+```bash
+ENTITLEMENTS_BACKEND=core.entitlements.backends.deploycenter.DeployCenterEntitlementsBackend
+ENTITLEMENTS_BACKEND_PARAMETERS='{"base_url":"https://deploycenter.example.com/api/v1.0/entitlements/","service_id":"calendar","api_key":"secret","timeout":10,"oidc_claims":["siret"]}'
+ENTITLEMENTS_CACHE_TIMEOUT=300
+```
+
+## Backend interface
+
+Custom backends must extend `EntitlementsBackend` and implement:
+
+```python
+class MyBackend(EntitlementsBackend):
+    def __init__(self, **kwargs):
+        # Receives ENTITLEMENTS_BACKEND_PARAMETERS as kwargs
+        pass
+
+    def get_user_entitlements(
+        self, user_sub, user_email, user_info=None, force_refresh=False
+    ):
+        # Return: {"can_access": bool}
+        # Raise EntitlementsUnavailableError on failure.
+        pass
+```
+
+## DeployCenter API
+
+The DeployCenter backend calls:
+
+```
+GET {base_url}?service_id=X&account_type=user&account_email=X
+```
+
+Headers: `X-Service-Auth: Bearer {api_key}`
+
+Query parameters include any configured `oidc_claims` extracted from
+the OIDC user_info response (e.g. `siret`).
+
+Expected response: `{"entitlements": {"can_access": true}}`
+
+## Access control flow
+
+The entitlements check follows a two-step approach: the backend
+exposes entitlements data, and the frontend gates access.
+
+### On login
+
+1. User authenticates via OIDC — login always succeeds
+2. `post_get_or_create_user` calls `get_user_entitlements()` with
+   `force_refresh=True` to warm the cache
+3. If entitlements are unavailable, a warning is logged but login
+   proceeds
+
+### On page load
+
+1. Frontend calls `GET /users/me/` which includes `can_access`
+2. If `can_access` is `false`, the frontend redirects to `/no-access`
+3. The user remains authenticated — they see the header, logo, and
+   their profile, but cannot use the app
+4. The `/no-access` page offers a logout button and a message to
+   contact support
+
+This approach ensures users always have a session (important for
+shared calendars and other interactions) while still gating access to
+the main application.
+
+### Caching behavior
+
+- The DeployCenter backend caches results in Django's cache framework
+  (key: `entitlements:user:{user_sub}`, TTL:
+  `ENTITLEMENTS_CACHE_TIMEOUT`).
+- On login, `force_refresh=True` bypasses the cache for fresh data.
+- If the API fails during a forced refresh, stale cached data is
+  returned as fallback.
+- Subsequent `GET /users/me/` calls use the cached value (no
+  `force_refresh`).
+
+## Frontend
+
+Users denied access see `/no-access` — a page using the main layout
+(header with logo and user profile visible) with:
+
+- A message explaining the app is not available for their account
+- A suggestion to contact support
+- A logout button
+
+The user is fully authenticated and can see their profile in the
+header, but cannot access calendars or events.
+
+## Key files
+
+| Area | Path |
+|------|------|
+| Service layer | `src/backend/core/entitlements/__init__.py` |
+| Backend factory | `src/backend/core/entitlements/factory.py` |
+| Abstract base | `src/backend/core/entitlements/backends/base.py` |
+| Local backend | `src/backend/core/entitlements/backends/local.py` |
+| DeployCenter backend | `src/backend/core/entitlements/backends/deploycenter.py` |
+| Auth integration | `src/backend/core/authentication/backends.py` |
+| User API serializer | `src/backend/core/api/serializers.py` |
+| Calendar gating (signal) | `src/backend/core/signals.py` |
+| CalDAV proxy gating | `src/backend/core/api/viewsets_caldav.py` |
+| Import events gating | `src/backend/core/api/viewsets.py` |
+| No-access page | `src/frontend/apps/calendars/src/pages/no-access.tsx` |
+| Homepage gate | `src/frontend/apps/calendars/src/pages/index.tsx` |
+| Calendar gate | `src/frontend/apps/calendars/src/pages/calendar.tsx` |
+| Tests | `src/backend/core/tests/test_entitlements.py` |

renovate.json

@@ -1,25 +0,0 @@
-{
-    "extends": ["github>suitenumerique/renovate-configuration"],
-    "dependencyDashboard": true,
-    "labels": ["dependencies", "noChangeLog"],
-    "packageRules": [
-        {
-            "groupName": "allowed redis versions",
-            "matchManagers": ["pep621"],
-            "matchPackageNames": ["redis"],
-            "allowedVersions": "<6.0.0"
-        },
-        {
-            "groupName": "allowed pylint versions",
-            "matchManagers": ["pep621"],
-            "matchPackageNames": ["pylint"],
-            "allowedVersions": "<4.0.0"
-        },
-        {
-            "description": "Disable requires-python updates - managed manually",
-            "matchManagers": ["pep621"],
-            "matchPackageNames": ["python"],
-            "enabled": false
-        }
-    ]
-}

src/backend/calendars/settings.py

@@ -133,6 +133,23 @@ class Base(Configuration):
         environ_prefix=None,
     )
 
+    # Entitlements
+    ENTITLEMENTS_BACKEND = values.Value(
+        "core.entitlements.backends.local.LocalEntitlementsBackend",
+        environ_name="ENTITLEMENTS_BACKEND",
+        environ_prefix=None,
+    )
+    ENTITLEMENTS_BACKEND_PARAMETERS = values.DictValue(
+        {},
+        environ_name="ENTITLEMENTS_BACKEND_PARAMETERS",
+        environ_prefix=None,
+    )
+    ENTITLEMENTS_CACHE_TIMEOUT = values.IntegerValue(
+        300,
+        environ_name="ENTITLEMENTS_CACHE_TIMEOUT",
+        environ_prefix=None,
+    )
+
     # Security
     ALLOWED_HOSTS = values.ListValue([])
     SECRET_KEY = SecretFileValue(None)

src/backend/core/api/permissions.py

@@ -1,9 +1,15 @@
 """Permission handlers for the calendars core app."""
 
+import logging
+
 from django.core import exceptions
 
 from rest_framework import permissions
 
+from core.entitlements import EntitlementsUnavailableError, get_user_entitlements
+
+logger = logging.getLogger(__name__)
+
 ACTION_FOR_METHOD_TO_PERMISSION = {
     "versions_detail": {"DELETE": "versions_destroy", "GET": "versions_retrieve"},
     "children": {"GET": "children_list", "POST": "children_create"},
@@ -60,6 +66,23 @@ class IsOwnedOrPublic(IsAuthenticated):
             return False
 
 
+class IsEntitled(IsAuthenticated):
+    """Allows access only to users with can_access entitlement.
+
+    Fail-closed: denies access when the entitlements service is
+    unavailable and no cached value exists.
+    """
+
+    def has_permission(self, request, view):
+        if not super().has_permission(request, view):
+            return False
+        try:
+            entitlements = get_user_entitlements(request.user.sub, request.user.email)
+            return entitlements.get("can_access", True)
+        except EntitlementsUnavailableError:
+            return False
+
+
 class AccessPermission(permissions.BasePermission):
     """Permission class for access objects."""
 

src/backend/core/api/serializers.py

@@ -7,6 +7,7 @@ from django.utils.translation import gettext_lazy as _
 from rest_framework import exceptions, serializers
 
 from core import models
+from core.entitlements import EntitlementsUnavailableError, get_user_entitlements
 
 
 class UserLiteSerializer(serializers.ModelSerializer):
@@ -108,18 +109,20 @@ class UserSerializer(serializers.ModelSerializer):
 class UserMeSerializer(UserSerializer):
     """Serialize users for me endpoint."""
 
+    can_access = serializers.SerializerMethodField(read_only=True)
+
     class Meta:
         model = models.User
-        fields = UserSerializer.Meta.fields
-        read_only_fields = UserSerializer.Meta.read_only_fields
+        fields = [*UserSerializer.Meta.fields, "can_access"]
+        read_only_fields = [*UserSerializer.Meta.read_only_fields, "can_access"]
 
-
-class CalendarCreateSerializer(serializers.Serializer):  # pylint: disable=abstract-method
-    """Serializer for creating a Calendar (CalDAV only, no Django model)."""
-
-    name = serializers.CharField(max_length=255)
-    color = serializers.CharField(max_length=7, required=False, default="")
-    description = serializers.CharField(required=False, default="")
+    def get_can_access(self, user) -> bool:
+        """Check entitlements for the current user."""
+        try:
+            entitlements = get_user_entitlements(user.sub, user.email)
+            return entitlements.get("can_access", True)
+        except EntitlementsUnavailableError:
+            return True  # fail-open
 
 
 class CalendarSubscriptionTokenSerializer(serializers.ModelSerializer):

src/backend/core/api/viewsets.py

@@ -18,7 +18,6 @@ from rest_framework.throttling import UserRateThrottle
 
 from core import models
 from core.services.caldav_service import (
-    CalendarService,
     normalize_caldav_path,
     verify_caldav_access,
 )
@@ -266,34 +265,15 @@ class ConfigView(drf.views.APIView):
 class CalendarViewSet(viewsets.GenericViewSet):
     """ViewSet for calendar operations.
 
-    create: Create a new calendar (CalDAV only, no Django record).
     import_events: Import events from an ICS file.
     """
 
     permission_classes = [IsAuthenticated]
-    serializer_class = serializers.CalendarCreateSerializer
 
-    def create(self, request):
-        """Create a new calendar via CalDAV.
-
-        POST /api/v1.0/calendars/
-        Body: { name, color?, description? }
-        Returns: { caldav_path }
-        """
-        serializer = serializers.CalendarCreateSerializer(data=request.data)
-        serializer.is_valid(raise_exception=True)
-
-        service = CalendarService()
-        caldav_path = service.create_calendar(
-            user=request.user,
-            name=serializer.validated_data["name"],
-            color=serializer.validated_data.get("color", ""),
-        )
-
-        return drf_response.Response(
-            {"caldav_path": caldav_path},
-            status=status.HTTP_201_CREATED,
-        )
+    def get_permissions(self):
+        if self.action == "import_events":
+            return [permissions.IsEntitled()]
+        return super().get_permissions()
 
     @action(
         detail=False,

src/backend/core/api/viewsets_caldav.py

@@ -12,6 +12,7 @@ from django.views.decorators.csrf import csrf_exempt
 
 import requests
 
+from core.entitlements import EntitlementsUnavailableError, get_user_entitlements
 from core.services.caldav_service import CalDAVHTTPClient, validate_caldav_proxy_path
 from core.services.calendar_invitation_service import calendar_invitation_service
 
@@ -29,7 +30,28 @@ class CalDAVProxyView(View):
     Authentication is handled via session cookies instead.
     """
 
-    def dispatch(self, request, *args, **kwargs):  # noqa: PLR0912  # pylint: disable=too-many-branches
+    @staticmethod
+    def _check_entitlements_for_creation(user):
+        """Check if user is entitled to create calendars.
+
+        Returns None if allowed, or an HttpResponse(403) if denied.
+        Fail-closed: denies if the entitlements service is unavailable.
+        """
+        try:
+            entitlements = get_user_entitlements(user.sub, user.email)
+            if not entitlements.get("can_access", True):
+                return HttpResponse(
+                    status=403,
+                    content="Calendar creation not allowed",
+                )
+        except EntitlementsUnavailableError:
+            return HttpResponse(
+                status=403,
+                content="Calendar creation not allowed",
+            )
+        return None
+
+    def dispatch(self, request, *args, **kwargs):  # noqa: PLR0912, PLR0911, PLR0915  # pylint: disable=too-many-branches,too-many-return-statements,too-many-statements
         """Forward all HTTP methods to CalDAV server."""
         # Handle CORS preflight requests
         if request.method == "OPTIONS":
@@ -45,6 +67,13 @@ class CalDAVProxyView(View):
         if not request.user.is_authenticated:
             return HttpResponse(status=401)
 
+        # Block calendar creation (MKCALENDAR/MKCOL) for non-entitled users.
+        # Other methods (GET, PROPFIND, REPORT, PUT, DELETE, etc.) are allowed
+        # so that users invited to shared calendars can still use them.
+        if request.method in ("MKCALENDAR", "MKCOL"):
+            if denied := self._check_entitlements_for_creation(request.user):
+                return denied
+
         # Build the CalDAV server URL
         path = kwargs.get("path", "")
 

src/backend/core/authentication/backends.py

@@ -4,12 +4,12 @@ import logging
 
 from django.conf import settings
 from django.core.exceptions import SuspiciousOperation
-from django.utils.translation import gettext_lazy as _
 
 from lasuite.oidc_login.backends import (
     OIDCAuthenticationBackend as LaSuiteOIDCAuthenticationBackend,
 )
 
+from core.entitlements import EntitlementsUnavailableError, get_user_entitlements
 from core.models import DuplicateEmailError
 
 logger = logging.getLogger(__name__)
@@ -51,3 +51,18 @@ class OIDCAuthenticationBackend(LaSuiteOIDCAuthenticationBackend):
             return self.UserModel.objects.get_user_by_sub_or_email(sub, email)
         except DuplicateEmailError as err:
             raise SuspiciousOperation(err.message) from err
+
+    def post_get_or_create_user(self, user, claims, is_new_user):
+        """Warm the entitlements cache on login (force_refresh)."""
+        try:
+            get_user_entitlements(
+                user_sub=user.sub,
+                user_email=user.email,
+                user_info=claims,
+                force_refresh=True,
+            )
+        except EntitlementsUnavailableError:
+            logger.warning(
+                "Entitlements unavailable for %s during login",
+                user.email,
+            )

src/backend/core/entitlements/__init__.py

@@ -0,0 +1,29 @@
+"""Entitlements service layer."""
+
+from core.entitlements.factory import get_entitlements_backend
+
+
+class EntitlementsUnavailableError(Exception):
+    """Raised when the entitlements backend cannot be reached or returns an error."""
+
+
+def get_user_entitlements(user_sub, user_email, user_info=None, force_refresh=False):
+    """Get user entitlements, delegating to the configured backend.
+
+    Args:
+        user_sub: The user's OIDC subject identifier.
+        user_email: The user's email address.
+        user_info: The full OIDC user_info dict (forwarded to backend).
+        force_refresh: If True, bypass backend cache and fetch fresh data.
+
+    Returns:
+        dict: {"can_access": bool}
+
+    Raises:
+        EntitlementsUnavailableError: If the backend cannot be reached
+            and no cache exists.
+    """
+    backend = get_entitlements_backend()
+    return backend.get_user_entitlements(
+        user_sub, user_email, user_info=user_info, force_refresh=force_refresh
+    )

src/backend/core/entitlements/backends/base.py

@@ -0,0 +1,27 @@
+"""Abstract base class for entitlements backends."""
+
+from abc import ABC, abstractmethod
+
+
+class EntitlementsBackend(ABC):
+    """Abstract base class that defines the interface for entitlements backends."""
+
+    @abstractmethod
+    def get_user_entitlements(
+        self, user_sub, user_email, user_info=None, force_refresh=False
+    ):
+        """Fetch user entitlements.
+
+        Args:
+            user_sub: The user's OIDC subject identifier.
+            user_email: The user's email address.
+            user_info: The full OIDC user_info dict (backends may
+                extract claims from it).
+            force_refresh: If True, bypass any cache and fetch fresh data.
+
+        Returns:
+            dict: {"can_access": bool}
+
+        Raises:
+            EntitlementsUnavailableError: If the backend cannot be reached.
+        """

src/backend/core/entitlements/backends/deploycenter.py

@@ -0,0 +1,120 @@
+"""DeployCenter (Espace Operateur) entitlements backend."""
+
+import logging
+
+from django.conf import settings
+from django.core.cache import cache
+
+import requests
+
+from core.entitlements import EntitlementsUnavailableError
+from core.entitlements.backends.base import EntitlementsBackend
+
+logger = logging.getLogger(__name__)
+
+
+class DeployCenterEntitlementsBackend(EntitlementsBackend):
+    """Backend that fetches entitlements from the DeployCenter API.
+
+    Args:
+        base_url: Full URL of the entitlements endpoint
+            (e.g. "https://dc.example.com/api/v1.0/entitlements/").
+        service_id: The service identifier in DeployCenter.
+        api_key: API key for X-Service-Auth header.
+        timeout: HTTP request timeout in seconds.
+        oidc_claims: List of OIDC claim names to extract from user_info
+            and forward as query params (e.g. ["siret"]).
+    """
+
+    def __init__(  # pylint: disable=too-many-arguments
+        self,
+        base_url,
+        service_id,
+        api_key,
+        *,
+        timeout=10,
+        oidc_claims=None,
+    ):
+        self.base_url = base_url
+        self.service_id = service_id
+        self.api_key = api_key
+        self.timeout = timeout
+        self.oidc_claims = oidc_claims or []
+
+    def _cache_key(self, user_sub):
+        return f"entitlements:user:{user_sub}"
+
+    def _make_request(self, user_email, user_info=None):
+        """Make a request to the DeployCenter entitlements API.
+
+        Returns:
+            dict | None: The response data, or None on failure.
+        """
+        params = {
+            "service_id": self.service_id,
+            "account_type": "user",
+            "account_email": user_email,
+        }
+
+        # Forward configured OIDC claims as query params
+        if user_info:
+            for claim in self.oidc_claims:
+                if claim in user_info:
+                    params[claim] = user_info[claim]
+
+        headers = {
+            "X-Service-Auth": f"Bearer {self.api_key}",
+        }
+
+        try:
+            response = requests.get(
+                self.base_url,
+                params=params,
+                headers=headers,
+                timeout=self.timeout,
+            )
+            response.raise_for_status()
+            return response.json()
+        except (requests.RequestException, ValueError):
+            email_domain = user_email.split("@")[-1] if "@" in user_email else "?"
+            logger.warning(
+                "DeployCenter entitlements request failed for user@%s",
+                email_domain,
+                exc_info=True,
+            )
+            return None
+
+    def get_user_entitlements(
+        self, user_sub, user_email, user_info=None, force_refresh=False
+    ):
+        """Fetch user entitlements from DeployCenter with caching.
+
+        On cache miss or force_refresh: fetches from the API.
+        On API failure: falls back to stale cache if available,
+        otherwise raises EntitlementsUnavailableError.
+        """
+        cache_key = self._cache_key(user_sub)
+
+        if not force_refresh:
+            cached = cache.get(cache_key)
+            if cached is not None:
+                return cached
+
+        data = self._make_request(user_email, user_info=user_info)
+
+        if data is None:
+            # API failed — try stale cache as fallback
+            cached = cache.get(cache_key)
+            if cached is not None:
+                return cached
+            raise EntitlementsUnavailableError(
+                "Failed to fetch user entitlements from DeployCenter"
+            )
+
+        entitlements = data.get("entitlements", {})
+        result = {
+            "can_access": entitlements.get("can_access", False),
+        }
+
+        cache.set(cache_key, result, settings.ENTITLEMENTS_CACHE_TIMEOUT)
+        return result

src/backend/core/entitlements/backends/local.py

@@ -0,0 +1,12 @@
+"""Local entitlements backend for development and testing."""
+
+from core.entitlements.backends.base import EntitlementsBackend
+
+
+class LocalEntitlementsBackend(EntitlementsBackend):
+    """Local backend that always grants access."""
+
+    def get_user_entitlements(
+        self, user_sub, user_email, user_info=None, force_refresh=False
+    ):
+        return {"can_access": True}

src/backend/core/entitlements/factory.py

@@ -0,0 +1,13 @@
+"""Factory for creating entitlements backend instances."""
+
+import functools
+
+from django.conf import settings
+from django.utils.module_loading import import_string
+
+
+@functools.cache
+def get_entitlements_backend():
+    """Return a singleton instance of the configured entitlements backend."""
+    backend_class = import_string(settings.ENTITLEMENTS_BACKEND)
+    return backend_class(**settings.ENTITLEMENTS_BACKEND_PARAMETERS)

src/backend/core/signals.py

@@ -9,6 +9,7 @@ from django.contrib.auth import get_user_model
 from django.db.models.signals import post_save
 from django.dispatch import receiver
 
+from core.entitlements import EntitlementsUnavailableError, get_user_entitlements
 from core.services.caldav_service import CalendarService
 
 logger = logging.getLogger(__name__)
@@ -27,6 +28,23 @@ def provision_default_calendar(sender, instance, created, **kwargs):  # pylint:
     if not settings.CALDAV_URL:
         return
 
+    # Check entitlements before creating calendar — fail-closed:
+    # never create a calendar if we can't confirm access.
+    try:
+        entitlements = get_user_entitlements(instance.sub, instance.email)
+        if not entitlements.get("can_access", True):
+            logger.info(
+                "Skipped calendar creation for %s (not entitled)",
+                instance.email,
+            )
+            return
+    except EntitlementsUnavailableError:
+        logger.warning(
+            "Entitlements unavailable for %s, skipping calendar creation",
+            instance.email,
+        )
+        return
+
     try:
         service = CalendarService()
         service.create_default_calendar(instance)

src/backend/core/tests/test_api_users.py

@@ -262,6 +262,7 @@ def test_api_users_retrieve_me_authenticated():
         "full_name": user.full_name,
         "short_name": user.short_name,
         "language": user.language,
+        "can_access": True,
     }
 
 

src/backend/core/tests/test_entitlements.py

@@ -0,0 +1,670 @@
+"""Tests for the entitlements module."""
+
+from unittest import mock
+
+from django.conf import settings
+from django.test import override_settings
+
+import pytest
+import requests
+import responses
+from rest_framework.status import (
+    HTTP_200_OK,
+    HTTP_207_MULTI_STATUS,
+    HTTP_403_FORBIDDEN,
+)
+from rest_framework.test import APIClient
+
+from core import factories
+from core.api.serializers import UserMeSerializer
+from core.authentication.backends import OIDCAuthenticationBackend
+from core.entitlements import EntitlementsUnavailableError, get_user_entitlements
+from core.entitlements.backends.deploycenter import DeployCenterEntitlementsBackend
+from core.entitlements.backends.local import LocalEntitlementsBackend
+from core.entitlements.factory import get_entitlements_backend
+
+# -- LocalEntitlementsBackend --
+
+
+def test_local_backend_always_grants_access():
+    """The local backend should always return can_access=True."""
+    backend = LocalEntitlementsBackend()
+    result = backend.get_user_entitlements("sub-123", "user@example.com")
+    assert result == {"can_access": True}
+
+
+def test_local_backend_ignores_parameters():
+    """The local backend should work regardless of parameters passed."""
+    backend = LocalEntitlementsBackend()
+    result = backend.get_user_entitlements(
+        "sub-123",
+        "user@example.com",
+        user_info={"some": "claim"},
+        force_refresh=True,
+    )
+    assert result == {"can_access": True}
+
+
+# -- Factory --
+
+
+@override_settings(
+    ENTITLEMENTS_BACKEND="core.entitlements.backends.local.LocalEntitlementsBackend",
+    ENTITLEMENTS_BACKEND_PARAMETERS={},
+)
+def test_factory_returns_local_backend():
+    """The factory should instantiate the configured backend."""
+    get_entitlements_backend.cache_clear()
+    backend = get_entitlements_backend()
+    assert isinstance(backend, LocalEntitlementsBackend)
+    get_entitlements_backend.cache_clear()
+
+
+@override_settings(
+    ENTITLEMENTS_BACKEND="core.entitlements.backends.local.LocalEntitlementsBackend",
+    ENTITLEMENTS_BACKEND_PARAMETERS={},
+)
+def test_factory_singleton():
+    """The factory should return the same instance on repeated calls."""
+    get_entitlements_backend.cache_clear()
+    backend1 = get_entitlements_backend()
+    backend2 = get_entitlements_backend()
+    assert backend1 is backend2
+    get_entitlements_backend.cache_clear()
+
+
+# -- get_user_entitlements public API --
+
+
+@override_settings(
+    ENTITLEMENTS_BACKEND="core.entitlements.backends.local.LocalEntitlementsBackend",
+    ENTITLEMENTS_BACKEND_PARAMETERS={},
+)
+def test_get_user_entitlements_with_local_backend():
+    """The public API should delegate to the configured backend."""
+    get_entitlements_backend.cache_clear()
+    result = get_user_entitlements("sub-123", "user@example.com")
+    assert result["can_access"] is True
+    get_entitlements_backend.cache_clear()
+
+
+# -- DeployCenterEntitlementsBackend --
+
+DC_URL = "https://deploy.example.com/api/v1.0/entitlements/"
+
+
+@responses.activate
+def test_deploycenter_backend_grants_access():
+    """DeployCenter backend should return can_access from API response."""
+    responses.add(
+        responses.GET,
+        DC_URL,
+        json={"entitlements": {"can_access": True}},
+        status=200,
+    )
+
+    backend = DeployCenterEntitlementsBackend(
+        base_url=DC_URL,
+        service_id="calendar",
+        api_key="test-key",
+    )
+    result = backend.get_user_entitlements("sub-123", "user@example.com")
+    assert result == {"can_access": True}
+
+    # Verify request was made with correct params and header
+    assert len(responses.calls) == 1
+    request = responses.calls[0].request
+    assert "service_id=calendar" in request.url
+    assert "account_email=user%40example.com" in request.url
+    assert request.headers["X-Service-Auth"] == "Bearer test-key"
+
+
+@responses.activate
+def test_deploycenter_backend_denies_access():
+    """DeployCenter backend should return can_access=False when API says so."""
+    responses.add(
+        responses.GET,
+        DC_URL,
+        json={"entitlements": {"can_access": False}},
+        status=200,
+    )
+
+    backend = DeployCenterEntitlementsBackend(
+        base_url=DC_URL,
+        service_id="calendar",
+        api_key="test-key",
+    )
+    result = backend.get_user_entitlements("sub-123", "user@example.com")
+    assert result == {"can_access": False}
+
+
+@responses.activate
+@override_settings(ENTITLEMENTS_CACHE_TIMEOUT=300)
+def test_deploycenter_backend_uses_cache():
+    """DeployCenter should use cached results when not force_refresh."""
+    responses.add(
+        responses.GET,
+        DC_URL,
+        json={"entitlements": {"can_access": True}},
+        status=200,
+    )
+
+    backend = DeployCenterEntitlementsBackend(
+        base_url=DC_URL,
+        service_id="calendar",
+        api_key="test-key",
+    )
+
+    # First call hits the API
+    result1 = backend.get_user_entitlements("sub-123", "user@example.com")
+    assert result1 == {"can_access": True}
+    assert len(responses.calls) == 1
+
+    # Second call should use cache
+    result2 = backend.get_user_entitlements("sub-123", "user@example.com")
+    assert result2 == {"can_access": True}
+    assert len(responses.calls) == 1  # No additional API call
+
+
+@responses.activate
+@override_settings(ENTITLEMENTS_CACHE_TIMEOUT=300)
+def test_deploycenter_backend_force_refresh_bypasses_cache():
+    """force_refresh=True should bypass cache and hit the API."""
+    responses.add(
+        responses.GET,
+        DC_URL,
+        json={"entitlements": {"can_access": True}},
+        status=200,
+    )
+    responses.add(
+        responses.GET,
+        DC_URL,
+        json={"entitlements": {"can_access": False}},
+        status=200,
+    )
+
+    backend = DeployCenterEntitlementsBackend(
+        base_url=DC_URL,
+        service_id="calendar",
+        api_key="test-key",
+    )
+
+    result1 = backend.get_user_entitlements("sub-123", "user@example.com")
+    assert result1["can_access"] is True
+
+    result2 = backend.get_user_entitlements(
+        "sub-123", "user@example.com", force_refresh=True
+    )
+    assert result2["can_access"] is False
+    assert len(responses.calls) == 2
+
+
+@responses.activate
+@override_settings(ENTITLEMENTS_CACHE_TIMEOUT=300)
+def test_deploycenter_backend_fallback_to_stale_cache():
+    """When API fails, should return stale cached value if available."""
+    responses.add(
+        responses.GET,
+        DC_URL,
+        json={"entitlements": {"can_access": True}},
+        status=200,
+    )
+
+    backend = DeployCenterEntitlementsBackend(
+        base_url=DC_URL,
+        service_id="calendar",
+        api_key="test-key",
+    )
+
+    # Populate cache
+    backend.get_user_entitlements("sub-123", "user@example.com")
+
+    # Now API fails
+    responses.replace(
+        responses.GET,
+        DC_URL,
+        body=requests.ConnectionError("Connection error"),
+    )
+
+    # force_refresh to hit API, but should fall back to cache
+    result = backend.get_user_entitlements(
+        "sub-123", "user@example.com", force_refresh=True
+    )
+    assert result == {"can_access": True}
+
+
+@responses.activate
+def test_deploycenter_backend_raises_when_no_cache():
+    """When API fails and no cache exists, should raise."""
+    responses.add(
+        responses.GET,
+        DC_URL,
+        body=requests.ConnectionError("Connection error"),
+    )
+
+    backend = DeployCenterEntitlementsBackend(
+        base_url=DC_URL,
+        service_id="calendar",
+        api_key="test-key",
+    )
+
+    with pytest.raises(EntitlementsUnavailableError):
+        backend.get_user_entitlements("sub-123", "user@example.com")
+
+
+@responses.activate
+def test_deploycenter_backend_sends_oidc_claims():
+    """DeployCenter should forward configured OIDC claims."""
+    responses.add(
+        responses.GET,
+        DC_URL,
+        json={"entitlements": {"can_access": True}},
+        status=200,
+    )
+
+    backend = DeployCenterEntitlementsBackend(
+        base_url=DC_URL,
+        service_id="calendar",
+        api_key="test-key",
+        oidc_claims=["organization"],
+    )
+
+    backend.get_user_entitlements(
+        "sub-123",
+        "user@example.com",
+        user_info={"organization": "org-42", "other": "ignored"},
+    )
+
+    request = responses.calls[0].request
+    assert "organization=org-42" in request.url
+    assert "other" not in request.url
+
+
+# -- Auth backend integration --
+
+
+pytestmark = pytest.mark.django_db
+
+
+def test_auth_backend_warms_cache_on_login():
+    """post_get_or_create_user should call get_user_entitlements with force_refresh."""
+    user = factories.UserFactory()
+    backend = OIDCAuthenticationBackend()
+
+    with mock.patch(
+        "core.authentication.backends.get_user_entitlements",
+        return_value={"can_access": True},
+    ) as mock_ent:
+        backend.post_get_or_create_user(user, {"sub": "x"}, is_new_user=False)
+        mock_ent.assert_called_once_with(
+            user_sub=user.sub,
+            user_email=user.email,
+            user_info={"sub": "x"},
+            force_refresh=True,
+        )
+
+
+def test_auth_backend_login_succeeds_when_access_denied():
+    """Login should succeed even when can_access is False (gated in frontend)."""
+    user = factories.UserFactory()
+    backend = OIDCAuthenticationBackend()
+
+    with mock.patch(
+        "core.authentication.backends.get_user_entitlements",
+        return_value={"can_access": False},
+    ):
+        # Should not raise — user logs in, frontend gates access
+        backend.post_get_or_create_user(user, {}, is_new_user=False)
+
+
+def test_auth_backend_login_succeeds_when_entitlements_unavailable():
+    """Login should succeed when entitlements service is unavailable."""
+    user = factories.UserFactory()
+    backend = OIDCAuthenticationBackend()
+
+    with mock.patch(
+        "core.authentication.backends.get_user_entitlements",
+        side_effect=EntitlementsUnavailableError("unavailable"),
+    ):
+        # Should not raise
+        backend.post_get_or_create_user(user, {}, is_new_user=False)
+
+
+# -- UserMeSerializer (can_access field) --
+
+
+def test_user_me_serializer_includes_can_access_true():
+    """UserMeSerializer should include can_access=True when entitled."""
+    user = factories.UserFactory()
+    with mock.patch(
+        "core.api.serializers.get_user_entitlements",
+        return_value={"can_access": True},
+    ):
+        data = UserMeSerializer(user).data
+    assert data["can_access"] is True
+
+
+def test_user_me_serializer_includes_can_access_false():
+    """UserMeSerializer should include can_access=False when not entitled."""
+    user = factories.UserFactory()
+    with mock.patch(
+        "core.api.serializers.get_user_entitlements",
+        return_value={"can_access": False},
+    ):
+        data = UserMeSerializer(user).data
+    assert data["can_access"] is False
+
+
+def test_user_me_serializer_can_access_fail_open():
+    """UserMeSerializer should return can_access=True when entitlements unavailable."""
+    user = factories.UserFactory()
+    with mock.patch(
+        "core.api.serializers.get_user_entitlements",
+        side_effect=EntitlementsUnavailableError("unavailable"),
+    ):
+        data = UserMeSerializer(user).data
+    assert data["can_access"] is True
+
+
+# -- Signals integration --
+
+
+@override_settings(
+    CALDAV_URL="http://caldav:80",
+    ENTITLEMENTS_BACKEND="core.entitlements.backends.local.LocalEntitlementsBackend",
+    ENTITLEMENTS_BACKEND_PARAMETERS={},
+)
+def test_signal_skips_calendar_when_not_entitled():
+    """Calendar should NOT be created when entitlements deny access."""
+    get_entitlements_backend.cache_clear()
+
+    with (
+        mock.patch(
+            "core.signals.get_user_entitlements",
+            return_value={"can_access": False},
+        ) as mock_ent,
+        mock.patch("core.signals.CalendarService") as mock_svc,
+    ):
+        factories.UserFactory()
+        mock_ent.assert_called_once()
+        mock_svc.assert_not_called()
+
+    get_entitlements_backend.cache_clear()
+
+
+@override_settings(
+    CALDAV_URL="http://caldav:80",
+    ENTITLEMENTS_BACKEND="core.entitlements.backends.local.LocalEntitlementsBackend",
+    ENTITLEMENTS_BACKEND_PARAMETERS={},
+)
+def test_signal_skips_calendar_when_entitlements_unavailable():
+    """Calendar should NOT be created when entitlements are unavailable (fail-closed)."""
+    get_entitlements_backend.cache_clear()
+
+    with (
+        mock.patch(
+            "core.signals.get_user_entitlements",
+            side_effect=EntitlementsUnavailableError("unavailable"),
+        ),
+        mock.patch("core.signals.CalendarService") as mock_svc,
+    ):
+        factories.UserFactory()
+        mock_svc.assert_not_called()
+
+    get_entitlements_backend.cache_clear()
+
+
+@override_settings(
+    CALDAV_URL="http://caldav:80",
+    ENTITLEMENTS_BACKEND="core.entitlements.backends.local.LocalEntitlementsBackend",
+    ENTITLEMENTS_BACKEND_PARAMETERS={},
+)
+def test_signal_creates_calendar_when_entitled():
+    """Calendar should be created when entitlements grant access."""
+    get_entitlements_backend.cache_clear()
+
+    with (
+        mock.patch(
+            "core.signals.get_user_entitlements",
+            return_value={"can_access": True},
+        ),
+        mock.patch("core.signals.CalendarService") as mock_svc,
+    ):
+        factories.UserFactory()
+        mock_svc.return_value.create_default_calendar.assert_called_once()
+
+    get_entitlements_backend.cache_clear()
+
+
+# -- CalDAV proxy entitlements enforcement --
+
+
+@pytest.mark.django_db
+class TestCalDAVProxyEntitlements:  # pylint: disable=no-member
+    """Tests for entitlements enforcement in the CalDAV proxy."""
+
+    @responses.activate
+    def test_mkcalendar_blocked_when_not_entitled(self):
+        """MKCALENDAR should return 403 when user has can_access=False."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        with mock.patch(
+            "core.api.viewsets_caldav.get_user_entitlements",
+            return_value={"can_access": False},
+        ):
+            response = client.generic(
+                "MKCALENDAR",
+                "/api/v1.0/caldav/calendars/test@example.com/new-cal/",
+            )
+
+        assert response.status_code == HTTP_403_FORBIDDEN
+
+    @responses.activate
+    def test_mkcol_blocked_when_not_entitled(self):
+        """MKCOL should return 403 when user has can_access=False."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        with mock.patch(
+            "core.api.viewsets_caldav.get_user_entitlements",
+            return_value={"can_access": False},
+        ):
+            response = client.generic(
+                "MKCOL",
+                "/api/v1.0/caldav/calendars/test@example.com/new-cal/",
+            )
+
+        assert response.status_code == HTTP_403_FORBIDDEN
+
+    @responses.activate
+    def test_mkcalendar_blocked_when_entitlements_unavailable(self):
+        """MKCALENDAR should return 403 when entitlements service
+        is unavailable (fail-closed)."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        with mock.patch(
+            "core.api.viewsets_caldav.get_user_entitlements",
+            side_effect=EntitlementsUnavailableError("unavailable"),
+        ):
+            response = client.generic(
+                "MKCALENDAR",
+                "/api/v1.0/caldav/calendars/test@example.com/new-cal/",
+            )
+
+        assert response.status_code == HTTP_403_FORBIDDEN
+
+    @responses.activate
+    def test_mkcalendar_allowed_when_entitled(self):
+        """MKCALENDAR should be forwarded when user has can_access=True."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        responses.add(
+            responses.Response(
+                method="MKCALENDAR",
+                url=f"{caldav_url}/api/v1.0/caldav/calendars/test@example.com/new-cal/",
+                status=201,
+                body="",
+            )
+        )
+
+        with mock.patch(
+            "core.api.viewsets_caldav.get_user_entitlements",
+            return_value={"can_access": True},
+        ):
+            response = client.generic(
+                "MKCALENDAR",
+                "/api/v1.0/caldav/calendars/test@example.com/new-cal/",
+            )
+
+        assert response.status_code == 201
+        assert len(responses.calls) == 1
+
+    @responses.activate
+    def test_propfind_allowed_when_not_entitled(self):
+        """PROPFIND should work for non-entitled users (shared calendars)."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        responses.add(
+            responses.Response(
+                method="PROPFIND",
+                url=f"{caldav_url}/api/v1.0/caldav/",
+                status=HTTP_207_MULTI_STATUS,
+                body='<?xml version="1.0"?><multistatus xmlns="DAV:"></multistatus>',
+                headers={"Content-Type": "application/xml"},
+            )
+        )
+
+        # No entitlements mock needed — PROPFIND should not check entitlements
+        response = client.generic("PROPFIND", "/api/v1.0/caldav/")
+
+        assert response.status_code == HTTP_207_MULTI_STATUS
+
+    @responses.activate
+    def test_report_allowed_when_not_entitled(self):
+        """REPORT should work for non-entitled users (shared calendars)."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        responses.add(
+            responses.Response(
+                method="REPORT",
+                url=f"{caldav_url}/api/v1.0/caldav/calendars/other@example.com/cal-id/",
+                status=HTTP_207_MULTI_STATUS,
+                body='<?xml version="1.0"?><multistatus xmlns="DAV:"></multistatus>',
+                headers={"Content-Type": "application/xml"},
+            )
+        )
+
+        response = client.generic(
+            "REPORT",
+            "/api/v1.0/caldav/calendars/other@example.com/cal-id/",
+        )
+
+        assert response.status_code == HTTP_207_MULTI_STATUS
+
+    @responses.activate
+    def test_put_allowed_when_not_entitled(self):
+        """PUT (event creation/update in shared calendar) should work
+        for non-entitled users."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        caldav_url = settings.CALDAV_URL
+        responses.add(
+            responses.Response(
+                method="PUT",
+                url=f"{caldav_url}/api/v1.0/caldav/calendars/other@example.com/cal-id/event.ics",
+                status=HTTP_200_OK,
+                body="",
+            )
+        )
+
+        response = client.generic(
+            "PUT",
+            "/api/v1.0/caldav/calendars/other@example.com/cal-id/event.ics",
+            data=b"BEGIN:VCALENDAR\nEND:VCALENDAR",
+            content_type="text/calendar",
+        )
+
+        assert response.status_code == HTTP_200_OK
+
+
+# -- import_events entitlements enforcement --
+
+
+@pytest.mark.django_db
+class TestImportEventsEntitlements:  # pylint: disable=no-member
+    """Tests for entitlements enforcement on import_events endpoint."""
+
+    def test_import_events_blocked_when_not_entitled(self):
+        """import_events should return 403 when user has
+        can_access=False."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        with mock.patch(
+            "core.api.permissions.get_user_entitlements",
+            return_value={"can_access": False},
+        ):
+            response = client.post(
+                "/api/v1.0/calendars/import-events/",
+                data={},
+                format="multipart",
+            )
+
+        assert response.status_code == HTTP_403_FORBIDDEN
+
+    def test_import_events_blocked_when_entitlements_unavailable(self):
+        """import_events should return 403 when entitlements service
+        is unavailable (fail-closed)."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        with mock.patch(
+            "core.api.permissions.get_user_entitlements",
+            side_effect=EntitlementsUnavailableError("unavailable"),
+        ):
+            response = client.post(
+                "/api/v1.0/calendars/import-events/",
+                data={},
+                format="multipart",
+            )
+
+        assert response.status_code == HTTP_403_FORBIDDEN
+
+    def test_import_events_allowed_when_entitled(self):
+        """import_events should proceed normally when user has
+        can_access=True (will fail on validation, not entitlements)."""
+        user = factories.UserFactory(email="test@example.com")
+        client = APIClient()
+        client.force_login(user)
+
+        with mock.patch(
+            "core.api.permissions.get_user_entitlements",
+            return_value={"can_access": True},
+        ):
+            # No file or caldav_path — should fail with 400, not 403
+            response = client.post(
+                "/api/v1.0/calendars/import-events/",
+                data={},
+                format="multipart",
+            )
+
+        # Should pass entitlements check but fail on missing caldav_path
+        assert response.status_code == 400

src/frontend/apps/calendars/src/features/auth/types.ts

@@ -9,4 +9,5 @@ export interface User {
   id: string;
   email: string;
   language: string;
+  can_access: boolean;
 }

src/frontend/apps/calendars/src/features/calendar/api.ts

@@ -4,21 +4,6 @@
 
 import { fetchAPI, fetchAPIFormData } from "@/features/api/fetchApi";
 
-/**
- * Create a new calendar via Django API (CalDAV only).
- */
-export const createCalendarApi = async (data: {
-  name: string;
-  color?: string;
-  description?: string;
-}): Promise<{ caldav_path: string }> => {
-  const response = await fetchAPI("calendars/", {
-    method: "POST",
-    body: JSON.stringify(data),
-  });
-  return response.json();
-};
-
 /**
  * Subscription token for iCal export.
  */

src/frontend/apps/calendars/src/features/calendar/contexts/CalendarContext.tsx

@@ -17,7 +17,6 @@ import type {
   CalDavCalendarCreate,
 } from "../services/dav/types/caldav-service";
 import type { CalendarApi } from "../components/scheduler/types";
-import { createCalendarApi } from "../api";
 import {
   addToast,
   ToasterItem,
@@ -191,15 +190,15 @@ export const CalendarContextProvider = ({
       params: CalDavCalendarCreate,
     ): Promise<{ success: boolean; error?: string }> => {
       try {
-        // Use Django API to create calendar (CalDAV only)
-        await createCalendarApi({
-          name: params.displayName,
-          color: params.color,
-          description: params.description,
-        });
-        // Refresh CalDAV calendars list to show the new calendar
-        await refreshCalendars();
-        return { success: true };
+        const result = await caldavService.createCalendar(params);
+        if (result.success) {
+          await refreshCalendars();
+          return { success: true };
+        }
+        return {
+          success: false,
+          error: result.error || "Failed to create calendar",
+        };
       } catch (error) {
         console.error("Error creating calendar:", error);
         return {
@@ -208,7 +207,7 @@ export const CalendarContextProvider = ({
         };
       }
     },
-    [refreshCalendars],
+    [caldavService, refreshCalendars],
   );
 
   const updateCalendar = useCallback(

src/frontend/apps/calendars/src/features/i18n/translations.json

@@ -9,6 +9,11 @@
         "title": "You don't have the necessary permissions to access this page.",
         "button": "Home"
       },
+      "no_access": {
+        "title": "Your login was successful, but this application is not available for your account.",
+        "description": "If you think this is a mistake, please contact support.",
+        "button": "Logout"
+      },
       "common": {
         "cancel": "Cancel"
       },
@@ -445,6 +450,11 @@
         "title": "Vous n'avez pas les permissions nécessaires pour accéder à cette page.",
         "button": "Accueil"
       },
+      "no_access": {
+        "title": "Votre connexion a réussi, mais cette application n'est pas disponible pour votre compte.",
+        "description": "Si vous pensez qu'il s'agit d'une erreur, veuillez contacter le support.",
+        "button": "Se déconnecter"
+      },
       "file_download_modal": {
         "error": {
           "no_url_or_title": "Ce fichier n'a pas d'URL ou de titre. "

src/frontend/apps/calendars/src/pages/calendar.tsx

@@ -28,6 +28,14 @@ export default function CalendarPage() {
     return <SpinnerPage />;
   }
 
+  // Redirect to no-access if not entitled
+  if (user.can_access === false) {
+    if (typeof window !== "undefined") {
+      window.location.href = "/no-access";
+    }
+    return <SpinnerPage />;
+  }
+
   return (
     <>
       <Head>

src/frontend/apps/calendars/src/pages/index.tsx

@@ -27,6 +27,10 @@ export default function HomePage() {
 
   useEffect(() => {
     if (user) {
+      if (user.can_access === false) {
+        window.location.href = "/no-access";
+        return;
+      }
       const attemptedUrl = sessionStorage.getItem(
         SESSION_STORAGE_REDIRECT_AFTER_LOGIN_URL
       );
@@ -52,14 +56,6 @@ export default function HomePage() {
         </ToasterItem>
       );
     }
-    if (failure === "user_cannot_access_app") {
-      addToast(
-        <ToasterItem type="error">
-          <span className="material-icons">lock</span>
-          <span>{t("authentication.error.user_cannot_access_app")}</span>
-        </ToasterItem>
-      );
-    }
   }, []);
 
   if (user) {

src/frontend/apps/calendars/src/pages/no-access.tsx

@@ -0,0 +1,41 @@
+import { MainLayout } from "@gouvfr-lasuite/ui-kit";
+import { Button } from "@gouvfr-lasuite/cunningham-react";
+import { useTranslation } from "react-i18next";
+
+import { logout } from "@/features/auth/Auth";
+import { GlobalLayout } from "@/features/layouts/components/global/GlobalLayout";
+import { HeaderRight } from "@/features/layouts/components/header/Header";
+import { GenericDisclaimer } from "@/features/ui/components/generic-disclaimer/GenericDisclaimer";
+import { DynamicCalendarLogo } from "@/features/ui/components/logo";
+
+export default function NoAccessPage() {
+  const { t } = useTranslation();
+  return (
+    <GenericDisclaimer
+      message={t("no_access.title")}
+      imageSrc="/assets/403-background.png"
+    >
+      <p>{t("no_access.description")}</p>
+      <Button onClick={() => logout()}>{t("no_access.button")}</Button>
+    </GenericDisclaimer>
+  );
+}
+
+NoAccessPage.getLayout = function getLayout(page: React.ReactElement) {
+  return (
+    <GlobalLayout>
+      <MainLayout
+        enableResize={false}
+        hideLeftPanelOnDesktop={true}
+        icon={
+          <div className="calendars__header__left">
+            <DynamicCalendarLogo variant="header" />
+          </div>
+        }
+        rightHeaderContent={<HeaderRight />}
+      >
+        {page}
+      </MainLayout>
+    </GlobalLayout>
+  );
+};