pickle test 2 from intern

README.md

@@ -2,7 +2,7 @@
 
 ## Summary
 
-This is an API for monitoring Temperature and Humidity data for Xiaomii LYWSD03MMC BLE sensors. The app will scan for any of these devices by looking for the Bluetooth MAC octet and then filtering by model. Once it has a list of MACs, it will then attempt to read the Temp/Humidity data for each MAC and record it. This data can be interacted with through an API.
+This is an API for monitoring Temperature and Humidity data for Xiaomii LYWSD03MMC BLE sensors. The app will scan for any of these devices by looking for the Bluetooth MAC octet and then filtering by model. Once it has a list of MACs, it will then attempt to read the Temp/Humidity data for each MAC and record it. This data can be interacted with through an API. The app has a Redis publishing function for use with websockets. The comment field for sensors can be configured using the appropriate variable in the `config.py` as well. 
 
 Some product info can be found here at my Knowledgebase:
 
@@ -12,10 +12,6 @@ https://kb.matt-cloud.com/books/07-saved-articles/page/xiaomii-temperaturehumidi
 
 Aside from a REST API, there are a few more features which need to be added to this app. 
 
-* Friendly Names for Sensors
-    * There will be a variable added to the `config.py` file to pre-configure friendly names for specific MAC addresses.
-    * For example, *Living Room* or *Main Bedroom*
-    * This data will also be integrated into the API to replace the **comment** field
 * Data persistence across app launches
     * I will do this with the **Pickle** package
 

app.py

@@ -1,13 +1,15 @@
 import redis
+import atexit
 from flask import Flask, jsonify
 from flask_apscheduler import APScheduler
 from datetime import datetime, timedelta
-from scanner import update_cache, get_cache_snapshot, get_sensor_summary, get_sensor_details, scan_macs
+from scanner import *
 from config import *
 from ble_redis import *
 import logging
 logging.getLogger('apscheduler').setLevel(logging.ERROR)  
 
+
 app = Flask(__name__)
 scheduler = APScheduler()
 scheduler.init_app(app)
@@ -54,4 +56,6 @@ def hello():
 # --- Run --------------------------------------------------------------
 if __name__ == '__main__':
     # The scheduler runs in its own thread; the main thread serves Flask.
-    app.run(host=bind_ip, port=api_port, debug=False)
+    app.run(host=bind_ip, port=api_port, debug=False)
+    # Register a graceful shutdown hook so the scanner state is persisted
+    atexit.register(save_state)

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():

sensors.py

@@ -71,7 +71,7 @@ class Sensor:
         return is_valid
 
     # ----------------------------------------------------------------------- #
-    #  Life‑cycle hooks
+    #  Life-cycle hooks
     # ----------------------------------------------------------------------- #
 
     def __post_init__(self) -> None: