Merge pull request #75 from thijskramer/initialize-loader-instance-di…

…fferently

Create singleton instance on app ready

django_vite/apps.py

@@ -0,0 +1,39 @@
+from django.apps import AppConfig
+from django.core.checks import Warning, register
+
+from .templatetags.django_vite import DjangoViteAssetLoader
+
+
+class DjangoViteAppConfig(AppConfig):
+    name = "django_vite"
+    verbose_name = "Django Vite"
+
+    def ready(self) -> None:
+        try:
+            # Create Loader instance at startup to prevent threading problems.
+            DjangoViteAssetLoader.instance()
+        except RuntimeError:
+            # Just continue, the system check below outputs a warning.
+            pass
+
+
+@register
+def check_loader_instance(**kwargs):
+    """Raise a warning during startup when instance retrieval fails."""
+
+    try:
+        # Make Loader instance at startup to prevent threading problems
+        DjangoViteAssetLoader.instance()
+        return []
+    except RuntimeError as exception:
+        return [
+            Warning(
+                exception,
+                id="DJANGO_VITE",
+                hint=(
+                    "Make sure you have generated a manifest file, "
+                    "and that the DJANGO_VITE_MANIFEST_PATH points "
+                    "to the correct location."
+                ),
+            )
+        ]

django_vite/templatetags/django_vite.py

@@ -466,10 +466,6 @@ def _generate_production_server_url(path: str) -> str:
             return urljoin(DJANGO_VITE_STATIC_URL_PREFIX, path)
 
 
-# Make Loader instance at startup to prevent threading problems
-DjangoViteAssetLoader.instance()
-
-
 @register.simple_tag
 @mark_safe
 def vite_hmr_client(**kwargs: Dict[str, str]) -> str: