v0.2 Preview: Construction Plan.

backend/contest/consumers.py

@@ -0,0 +1,54 @@
+from channels.db import database_sync_to_async
+from channels.generic.websocket import AsyncJsonWebsocketConsumer
+
+from .models import RealtimeMatch
+
+
+class MatchConsumer(AsyncJsonWebsocketConsumer):
+    async def connect(self):
+        self.match_id = self.scope["url_route"]["kwargs"]["match_id"]
+        self.group_name = f"match_{self.match_id}"
+        user = self.scope["user"]
+        if not user.is_authenticated or not await self._is_participant(user.id):
+            await self.close(code=4403)
+            return
+        await self.channel_layer.group_add(self.group_name, self.channel_name)
+        await self.accept()
+        await self.send_json({"type": "connected", "match_id": str(self.match_id)})
+
+    async def disconnect(self, close_code):
+        if hasattr(self, "group_name"):
+            await self.channel_layer.group_discard(self.group_name, self.channel_name)
+
+    async def receive_json(self, content, **kwargs):
+        event_type = content.get("type")
+        if event_type == "ping":
+            await self.send_json({"type": "pong"})
+            return
+        if event_type == "progress":
+            answered_count = max(0, min(int(content.get("answered_count", 0)), 100))
+            await self.channel_layer.group_send(
+                self.group_name,
+                {
+                    "type": "match.progress",
+                    "user_id": str(self.scope["user"].id),
+                    "answered_count": answered_count,
+                },
+            )
+
+    async def match_progress(self, event):
+        await self.send_json(
+            {
+                "type": "progress",
+                "user_id": event["user_id"],
+                "answered_count": event["answered_count"],
+            }
+        )
+
+    @database_sync_to_async
+    def _is_participant(self, user_id):
+        return RealtimeMatch.objects.filter(id=self.match_id).filter(
+            player_one_id=user_id
+        ).exists() or RealtimeMatch.objects.filter(
+            id=self.match_id, player_two_id=user_id
+        ).exists()