Adds universal websocket manager any extension can use

Connect to the `ws://<your-lnbits>/api/v1/ws/{item_id}` endpoint

POST data to the websocket with `https://<your-lnbits>/api/v1/ws/{item_id}`

lnbits/core/views/api.py

@@ -12,7 +12,7 @@ from urllib.parse import ParseResult, parse_qs, urlencode, urlparse, urlunparse
 import async_timeout
 import httpx
 import pyqrcode
-from fastapi import Depends, Header, Query, Request
+from fastapi import Depends, Header, Query, Request, WebSocket, WebSocketDisconnect
 from fastapi.exceptions import HTTPException
 from fastapi.params import Body
 from loguru import logger
@@ -697,3 +697,47 @@ async def api_auditor(wallet: WalletTypeInfo = Depends(get_key_type)):
         "delta_msats": delta,
         "timestamp": int(time.time()),
     }
+
+
+##################UNIVERSAL WEBSOCKET MANAGER########################
+
+class websocketConnectionManager:
+    def __init__(self):
+        self.active_connections: List[WebSocket] = []
+
+    async def connect(self, websocket: WebSocket, item_id: str):
+        await websocket.accept()
+        websocket.id = item_id
+        self.active_connections.append(websocket)
+
+    def disconnect(self, websocket: WebSocket):
+        self.active_connections.remove(websocket)
+
+    async def send_personal_message(self, message: str, item_id: str):
+        for connection in self.active_connections:
+            if connection.id == item_id:
+                await connection.send_text(message)
+
+    async def broadcast(self, message: str):
+        for connection in self.active_connections:
+            await connection.send_text(message)
+
+manager = websocketConnectionManager()
+
+@core_app.websocket("/api/v1/ws/{item_id}")
+async def websocket_endpoint(websocket: WebSocket, item_id: str):
+    await manager.connect(websocket, item_id)
+    try:
+        while True:
+            data = await websocket.receive_text()
+    except WebSocketDisconnect:
+        manager.disconnect(websocket)
+
+@core_app.post("/api/v1/ws/{item_id}")
+async def websocket_endpoint(item_id: str, data: str):
+    await updater(item_id, data)
+
+async def updater(item_id, data):
+    return await manager.send_personal_message(
+        f"{data}", item_id
+    )