add websocket market

app/realtime/marketplace_hub.py

@@ -0,0 +1,47 @@
+# app/realtime/marketplace_hub.py
+from __future__ import annotations
+
+import asyncio
+from typing import Dict, Set, Any
+from fastapi import WebSocket
+
+class MarketplaceHub:
+    def __init__(self) -> None:
+        self._rooms: Dict[str, Set[WebSocket]] = {}
+        self._lock = asyncio.Lock()
+
+    async def connect(self, server_ip: str, ws: WebSocket) -> None:
+        await ws.accept()
+        async with self._lock:
+            self._rooms.setdefault(server_ip, set()).add(ws)
+
+    async def disconnect(self, server_ip: str, ws: WebSocket) -> None:
+        async with self._lock:
+            room = self._rooms.get(server_ip)
+            if not room:
+                return
+            room.discard(ws)
+            if not room:
+                self._rooms.pop(server_ip, None)
+
+    async def broadcast(self, server_ip: str, message: dict) -> None:
+        async with self._lock:
+            conns = list(self._rooms.get(server_ip, set()))
+
+        if not conns:
+            return
+
+        dead: list[WebSocket] = []
+        for ws in conns:
+            try:
+                await ws.send_json(message)
+            except Exception:
+                dead.append(ws)
+
+        if dead:
+            async with self._lock:
+                room = self._rooms.get(server_ip, set())
+                for ws in dead:
+                    room.discard(ws)
+
+marketplace_hub = MarketplaceHub()