feat: add boilerplate

app/realtime.py

@@ -0,0 +1,31 @@
+import json
+from collections import defaultdict
+
+from fastapi import WebSocket
+
+
+class Hub:
+    def __init__(self) -> None:
+        self.rooms: dict[str, list[WebSocket]] = defaultdict(list)
+
+    async def join(self, session_id: str, ws: WebSocket) -> None:
+        await ws.accept()
+        self.rooms[session_id].append(ws)
+
+    def leave(self, session_id: str, ws: WebSocket) -> None:
+        conns = self.rooms.get(session_id, [])
+        if ws in conns:
+            conns.remove(ws)
+
+    async def broadcast(self, session_id: str, payload: dict) -> None:
+        dead = []
+        for ws in list(self.rooms.get(session_id, [])):
+            try:
+                await ws.send_text(json.dumps(payload))
+            except Exception:
+                dead.append(ws)
+        for ws in dead:
+            self.leave(session_id, ws)
+
+
+hub = Hub()