Fix Django ORM usage within components

Author: Archmonger

src/django_idom/layout.py

@@ -0,0 +1,18 @@
+import os
+
+from idom.core.layout import Layout, LayoutUpdate
+
+
+class DjangoLayout(Layout):
+    """Fixes Django ORM usage within components.
+    These issues are caused by async/sync mixed context limitations in the ORM.
+    Without this, `SynchronousOnlyOperation` exceptions occur when using the ORM in IDOM components.
+    This may be fixed in a future version, such as Django 5.0."""
+
+    def _create_layout_update(self, old_state) -> LayoutUpdate:
+        """Create a layout update, but set ALLOW ASYNC UNSAFE flags prior.
+        This allows the Django ORM to be used within components."""
+        os.environ["DJANGO_ALLOW_ASYNC_UNSAFE"] = "true"
+        layout_update = super()._create_layout_update(old_state)
+        os.environ.pop("DJANGO_ALLOW_ASYNC_UNSAFE")
+        return layout_update

src/django_idom/websocket/consumer.py

@@ -8,11 +8,12 @@
 from channels.auth import login
 from channels.db import database_sync_to_async as convert_to_async
 from channels.generic.websocket import AsyncJsonWebsocketConsumer
-from idom.core.layout import Layout, LayoutEvent
+from idom.core.layout import LayoutEvent
 from idom.core.serve import serve_json_patch
 
 from django_idom.config import IDOM_REGISTERED_COMPONENTS
 from django_idom.hooks import IdomWebsocket, WebsocketContext
+from django_idom.layout import DjangoLayout
 
 
 _logger = logging.getLogger(__name__)
@@ -73,7 +74,7 @@ async def _run_dispatch_loop(self):
         self._idom_recv_queue = recv_queue = asyncio.Queue()
         try:
             await serve_json_patch(
-                Layout(WebsocketContext(component_instance, value=socket)),
+                DjangoLayout(WebsocketContext(component_instance, value=socket)),
                 self.send_json,
                 recv_queue.get,
             )