Implement background scanner

for now just outputs uid as configured by test.py

app/main.py

@@ -4,8 +4,9 @@ from contextlib import asynccontextmanager
 from dotenv import load_dotenv
 
 from .controllers import userManager, cardManager, groupManager, aaManager, doorManager
-from .services.database import create_db_and_tables
+from .services.database import create_db_and_tables, get_session
 from .services.auth import token_router, create_first_user
+from app.services.scanner import BackgroundScanner
 
 oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
 
@@ -15,7 +16,10 @@ async def lifespan(app: FastAPI):
     create_db_and_tables()
     create_first_user()
     print("Database created and tables initialized.")
+    scanner = BackgroundScanner(db=get_session())
+    scanner.start()
     yield
+    scanner.stop()
 
 app = FastAPI(lifespan=lifespan)
 

app/services/scanner.py

@@ -0,0 +1,107 @@
+import logging
+import threading
+import time
+import os
+
+from typing import Optional
+from sqlmodel import Session
+from dotenv import load_dotenv
+
+from smartcard.CardRequest import CardRequest
+from smartcard.CardType import AnyCardType
+from smartcard.Exceptions import CardRequestTimeoutException
+
+from desfire import DESFire, DESFireKey, PCSCDevice, diversify_key, get_list, to_hex_string
+from desfire.enums import DESFireCommunicationMode, DESFireFileType, DESFireKeySettings, DESFireKeyType
+from desfire.schemas import FilePermissions, FileSettings, KeySettings
+
+#ENV vars
+load_dotenv()
+MIFARE_APP_MASTER_KEY = os.getenv('MIFARE_APP_MASTER_KEY')
+MIFARE_ACL_READ_BASE_KEY = os.getenv('MIFARE_ACL_READ_BASE_KEY')
+MIFARE_ACL_WRITE_BASE_KEY = os.getenv('MIFARE_ACL_WRITE_BASE_KEY')
+
+# Constants
+MIFARE_APP_ID = "DEAFFE"  # 7 bytes
+MIFARE_ACL_READ_BASE_KEY_ID = 0x1
+MIFARE_ACL_WRITE_BASE_KEY_ID = 0x2
+MIFARE_SYS_ID = "FF0000"  # 3 bytes, can essentially be anything
+MIFARE_ENCRYPTED_FILE_ID = 0x1
+
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+if MIFARE_APP_MASTER_KEY == None:
+    logger.critical("NO MASTER KEY LOADED")
+    exit(1)
+
+class BackgroundScanner:
+    def __init__(self, db):
+        self.db = db
+        self.is_running = False
+        self.thread: Optional[threading.Thread] = None
+
+    def start(self):
+        if self.is_running:
+            logger.info("Scanner already running")
+            return
+        self.is_running = True
+        self.thread = threading.Thread(target=self._scan_loop, daemon=True)
+        self.thread.start()
+        logger.info("Scanner started")
+
+    def stop(self):
+        self.is_running = False
+        if self.thread:
+            self.thread.join()
+        logger.info("Scanner stopped")
+
+    def _scan_loop(self):
+        while self.is_running:
+            try:
+                card_content = self._read_card()
+                if card_content:
+                    logger.info(to_hex_string(card_content))
+                    time.sleep(5)
+                    logger.debug("READY after success")
+                    #self._check_db(card_content)
+                else:
+                    time.sleep(0.5)
+                    logger.debug("READY after timout")
+
+            except Exception as e:
+                logger.error(f"Error in scan function: {e}", exc_info=True)
+                time.sleep(6)
+
+    def _read_card(self):
+        cardtype = AnyCardType()
+        cardrequest = CardRequest(timeout=5, cardType=cardtype)
+        try:
+            cardservice = cardrequest.waitforcard()
+        except CardRequestTimeoutException:
+            logger.debug("No tag detected within the timeout.")
+            return
+        
+        cardservice.connection.connect()
+        # Create Desfire object
+        desfire = DESFire(PCSCDevice(cardservice.connection.component))
+        aes_keysettings = KeySettings(
+            key_type=DESFireKeyType.DF_KEY_AES,
+        )
+
+        #Auth
+        logger.info("Start auth")
+        aes_app_mk = DESFireKey(aes_keysettings, MIFARE_APP_MASTER_KEY)
+
+        apps = desfire.get_application_ids()
+        logger.info(f"app id's are: {apps}")
+        desfire.select_application(MIFARE_APP_ID)
+
+        desfire.authenticate(0x0, aes_app_mk)
+        
+        logger.info("Read data")
+        file_data = desfire.get_file_settings(MIFARE_ENCRYPTED_FILE_ID)
+        logger.info(f"File settings: {file_data}")
+        rdata = desfire.read_file_data(MIFARE_ENCRYPTED_FILE_ID, file_data)
+        return rdata