Added WebSocket notify API for spools

spoolman/api/v1/spool.py

@@ -1,10 +1,11 @@
 """Spool related endpoints."""
 
+import asyncio
 import logging
 from datetime import datetime
 from typing import Annotated, Optional
 
-from fastapi import APIRouter, Depends, Query
+from fastapi import APIRouter, Depends, Query, WebSocket, WebSocketDisconnect
 from fastapi.encoders import jsonable_encoder
 from fastapi.exceptions import RequestValidationError
 from fastapi.responses import JSONResponse
@@ -17,6 +18,7 @@ from spoolman.database import spool
 from spoolman.database.database import get_db_session
 from spoolman.database.utils import SortOrder
 from spoolman.exceptions import ItemCreateError
+from spoolman.ws import websocket_manager
 
 logger = logging.getLogger(__name__)
 
@@ -242,7 +244,10 @@ async def find(
 @router.get(
     "/{spool_id}",
     name="Get spool",
-    description="Get a specific spool.",
+    description=(
+        "Get a specific spool. A websocket is served on the same path to listen for changes to the spool. "
+        "The response model is the same for the websocket messages as for this endpoint."
+    ),
     response_model_exclude_none=True,
     responses={404: {"model": Message}},
 )
@@ -254,6 +259,25 @@ async def get(
     return Spool.from_db(db_item)
 
 
+@router.websocket(
+    "/{spool_id}",
+    name="Listen to spool changes",
+)
+async def notify(
+    websocket: WebSocket,
+    spool_id: int,
+) -> None:
+    await websocket.accept()
+    websocket_manager.connect(("spool", str(spool_id)), websocket)
+    try:
+        while True:
+            await asyncio.sleep(0.5)
+            if await websocket.receive_text():
+                await websocket.send_json({"status": "healthy"})
+    except WebSocketDisconnect:
+        websocket_manager.disconnect(("spool", str(spool_id)), websocket)
+
+
 @router.post(
     "",
     name="Add spool",