add system check for sync/async webhook views (#33)

* add deployment check for sync/async webhook views

* change to non-deploy check

* remove missing function

* add back stash

* update readme

* update changelog

* reword

* eh, add system back

Author: joshuadavidthomas

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project attempts to adhere to [Semantic Versioning](https://semver.org/
 ### Added
 
 - Added `SyncWebhookView`, a synchronous counterpart to `AsyncWebhookView` for Django applications running under WSGI. Works with `SyncGitHubAPI` and synchronous event handlers to provide a fully synchronous workflow for processing GitHub webhooks.
+- Added system check to prevent mixing async and sync webhook views in the same project (`django_github_app.E001`).
 
 ### Changed
 

README.md

@@ -438,6 +438,19 @@ issues = await repo.aget_issues(params={"state": "open"})
 - `owner`: Repository owner from full name
 - `repo`: Repository name from full name
 
+### System Checks
+
+The library includes Django system checks to validate your webhook configuration:
+
+#### `django_github_app.E001`
+
+Error raised when both `AsyncWebhookView` and `SyncWebhookView` are detected in your URL configuration. You must use either async or sync webhooks consistently throughout your project, not both.
+
+To fix this error, ensure all your webhook views are of the same type:
+
+- Use `AsyncWebhookView` for all webhook endpoints in ASGI projects
+- Use `SyncWebhookView` for all webhook endpoints in WSGI projects
+
 ## Configuration
 
 Configuration of django-github-app is done through a `GITHUB_APP` dictionary in your Django project's `DJANGO_SETTINGS_MODULE`.

src/django_github_app/apps.py

@@ -12,4 +12,5 @@ class GitHubAppConfig(AppConfig):
 
     @override
     def ready(self):
+        from . import checks  # noqa: F401
         from .events import ahandlers  # noqa: F401

src/django_github_app/checks.py

@@ -0,0 +1,30 @@
+from __future__ import annotations
+
+from django.core.checks import Error
+from django.core.checks import Tags
+from django.core.checks import register
+
+from django_github_app.views import AsyncWebhookView
+from django_github_app.views import get_webhook_views
+
+
+@register(Tags.urls)
+def check_webhook_views(app_configs, **kwargs):
+    errors = []
+    views = get_webhook_views()
+
+    if views:
+        view_types = {
+            "async" if issubclass(v, AsyncWebhookView) else "sync" for v in views
+        }
+        if len(view_types) > 1:
+            errors.append(
+                Error(
+                    "Multiple webhook view types detected.",
+                    hint="Use either AsyncWebhookView or SyncWebhookView, not both.",
+                    obj="django_github_app.views",
+                    id="django_github_app.E001",
+                )
+            )
+
+    return errors

src/django_github_app/views.py

@@ -12,6 +12,7 @@
 from django.core.exceptions import BadRequest
 from django.http import HttpRequest
 from django.http import JsonResponse
+from django.urls import get_resolver
 from django.utils.decorators import method_decorator
 from django.views.decorators.csrf import csrf_exempt
 from django.views.generic import View
@@ -106,3 +107,18 @@ def post(self, request: HttpRequest) -> JsonResponse:  # pragma: no cover
             self.router.dispatch(event, gh)
 
         return self.get_response(event_log)
+
+
+def get_webhook_views():
+    resolver = get_resolver()
+    found_views = []
+
+    for pattern in resolver.url_patterns:
+        if hasattr(pattern, "callback"):
+            callback = pattern.callback
+            view_class = getattr(callback, "view_class", None)
+            if view_class:
+                if issubclass(view_class, (AsyncWebhookView, SyncWebhookView)):
+                    found_views.append(view_class)
+
+    return found_views

tests/conftest.py

@@ -9,6 +9,8 @@
 from asgiref.sync import sync_to_async
 from django.conf import settings
 from django.test import override_settings
+from django.urls import clear_url_caches
+from django.urls import path
 from model_bakery import baker
 
 from django_github_app.conf import GITHUB_APP_SETTINGS_NAME
@@ -71,6 +73,28 @@ def _override_app_settings(**kwargs):
     return _override_app_settings
 
 
+@pytest.fixture
+def urlpatterns():
+    @contextlib.contextmanager
+    def _urlpatterns(views):
+        urlpatterns = [path(f"{i}/", view.as_view()) for i, view in enumerate(views)]
+
+        clear_url_caches()
+
+        with override_settings(
+            ROOT_URLCONF=type(
+                "urls",
+                (),
+                {"urlpatterns": urlpatterns},
+            ),
+        ):
+            yield
+
+        clear_url_caches()
+
+    return _urlpatterns
+
+
 @pytest.fixture(scope="session", autouse=True)
 def register_modeladmins(test_admin_site):
     from django_github_app.admin import EventLogModelAdmin

tests/test_checks.py

@@ -0,0 +1,59 @@
+from __future__ import annotations
+
+from django.core.checks import Error
+from django.views.generic import View
+
+from django_github_app.checks import check_webhook_views
+from django_github_app.views import AsyncWebhookView
+from django_github_app.views import SyncWebhookView
+
+
+class TestCheckWebhookViews:
+    def test_async(self, urlpatterns):
+        with urlpatterns([AsyncWebhookView]):
+            errors = check_webhook_views(None)
+
+        assert not errors
+
+    def test_sync(self, urlpatterns):
+        with urlpatterns([SyncWebhookView]):
+            errors = check_webhook_views(None)
+
+        assert not errors
+
+    def test_async_multiple(self, urlpatterns):
+        with urlpatterns([AsyncWebhookView, AsyncWebhookView]):
+            errors = check_webhook_views(None)
+
+        assert not errors
+
+    def test_sync_multiple(self, urlpatterns):
+        with urlpatterns([SyncWebhookView, SyncWebhookView]):
+            errors = check_webhook_views(None)
+
+        assert not errors
+
+    def test_mixed_error(self, urlpatterns):
+        with urlpatterns([AsyncWebhookView, SyncWebhookView]):
+            errors = check_webhook_views(None)
+
+        assert len(errors) == 1
+
+        error = errors[0]
+
+        assert isinstance(error, Error)
+        assert error.id == "django_github_app.E001"
+        assert "Multiple webhook view types detected" in error.msg
+        assert "Use either AsyncWebhookView or SyncWebhookView" in error.hint
+
+    def test_normal_view(self, urlpatterns):
+        with urlpatterns([View]):
+            errors = check_webhook_views(None)
+
+        assert not errors
+
+    def test_none(self, urlpatterns):
+        with urlpatterns([]):
+            errors = check_webhook_views(None)
+
+        assert not errors

tests/test_views.py

@@ -10,6 +10,7 @@
 from django.core.exceptions import BadRequest
 from django.http import JsonResponse
 from django.utils import timezone
+from django.views.generic import View
 from gidgethub import sansio
 from gidgethub.abc import GitHubAPI
 from model_bakery import baker
@@ -21,6 +22,7 @@
 from django_github_app.views import AsyncWebhookView
 from django_github_app.views import BaseWebhookView
 from django_github_app.views import SyncWebhookView
+from django_github_app.views import get_webhook_views
 
 pytestmark = pytest.mark.django_db
 
@@ -303,3 +305,39 @@ def test_router_dispatch_unhandled_event(
         response = view.post(request)
 
         assert response.status_code == HTTPStatus.OK
+
+
+class TestProjectWebhookViews:
+    def test_get_async(self, urlpatterns):
+        with urlpatterns([AsyncWebhookView]):
+            views = get_webhook_views()
+
+        assert len(views) == 1
+        assert views[0] == AsyncWebhookView
+
+    def test_get_sync(self, urlpatterns):
+        with urlpatterns([SyncWebhookView]):
+            views = get_webhook_views()
+
+        assert len(views) == 1
+        assert views[0] == SyncWebhookView
+
+    def test_get_both(self, urlpatterns):
+        with urlpatterns([AsyncWebhookView, SyncWebhookView]):
+            views = get_webhook_views()
+
+        assert len(views) == 2
+        assert AsyncWebhookView in views
+        assert SyncWebhookView in views
+
+    def test_get_normal_view(self, urlpatterns):
+        with urlpatterns([View]):
+            views = get_webhook_views()
+
+        assert len(views) == 0
+
+    def test_get_none(self, urlpatterns):
+        with urlpatterns([]):
+            views = get_webhook_views()
+
+        assert len(views) == 0