pickle test 2 from intern

scanner.py

@@ -2,6 +2,8 @@ import asyncio
 import threading
 import time
 import redis
+import pickle
+import os
 from datetime import datetime, timezone
 from zoneinfo import ZoneInfo   # Python 3.9+
 from bleak import BleakScanner, BleakClient
@@ -16,9 +18,53 @@ _mac_cache: Set[str] = set()
 _lock = threading.Lock()
 _sensors_cache = []
 
-# other vars
-MI_SERVICE_UUID = "ebe0ccb0-7a0a-4b0c-8a1a-6ff2997da3a6"
-TEMP_CHAR_UUID = "ebe0ccc1-7a0a-4b0c-8a1a-6ff2997da3a6"
+# ----------------------------------------------------------------------
+# Pickle persistence helpers
+# ----------------------------------------------------------------------
+STATE_FILE = "scanner_state.pkl"
+
+def save_state() -> None:
+    """
+    Persist the MAC cache and sensor objects to disk.
+    Called automatically after each cache refresh and at program exit.
+    """
+    with _lock:
+        state = {
+            "mac_cache": _mac_cache,
+            "sensors": _sensors_cache,
+        }
+    try:
+        with open(STATE_FILE, "wb") as f:
+            pickle.dump(state, f, protocol=pickle.HIGHEST_PROTOCOL)
+        if debug_output:
+            print("[Scanner] State persisted to", STATE_FILE)
+    except Exception as exc:
+        # Don't crash the app – just log the error
+        print("[Scanner] Warning: could not persist state:", exc)
+
+def load_state() -> None:
+    """
+    Load the MAC cache and sensor objects from disk if the file exists.
+    Called automatically on import.
+    """
+    if not os.path.exists(STATE_FILE):
+        return
+    try:
+        with open(STATE_FILE, "rb") as f:
+            state = pickle.load(f)
+        with _lock:
+            # NOTE: we replace the lists/sets to avoid mutating old references
+            _mac_cache.clear()
+            _mac_cache.update(state.get("mac_cache", []))
+            global _sensors_cache
+            _sensors_cache = state.get("sensors", [])
+        if debug_output:
+            print("[Scanner] Loaded state from", STATE_FILE)
+    except Exception as exc:
+        print("[Scanner] Warning: could not load state:", exc)
+
+# Load any persisted state on module import
+load_state()
 
 # Redis Functions
 r = redis.Redis(host=bind_ip, port=redis_port)
@@ -72,6 +118,7 @@ def update_cache() -> None:
     # if redis is enabled, push full details to the redis server
     if enable_redis:
         update_redis(get_sensor_details())
+    save_state()
 
 # this helper function scans for MACs
 def scan_macs():