first commit

backend/app/services/streaming/hub.py

@@ -0,0 +1,25 @@
+import asyncio
+from typing import Dict, Set, Any
+
+class Hub:
+    def __init__(self):
+        self._lock = asyncio.Lock()
+        self._subs: Dict[int, Set[Any]] = {}  # panel_id -> set[WebSocket]
+
+    async def subscribe(self, panel_id: int, ws):
+        async with self._lock:
+            self._subs.setdefault(panel_id, set()).add(ws)
+
+    async def unsubscribe(self, panel_id: int, ws):
+        async with self._lock:
+            s = self._subs.get(panel_id)
+            if s and ws in s:
+                s.remove(ws)
+            if s and len(s) == 0:
+                self._subs.pop(panel_id, None)
+
+    async def connections(self, panel_id: int):
+        async with self._lock:
+            return list(self._subs.get(panel_id, set()))
+
+hub = Hub()