Improve Performance

NfcReaderService.py

@@ -10,69 +10,98 @@ from pynput.keyboard import Controller
 
 from card_reader import read_card
 
+GET_UID = [0xFF, 0xCA, 0x00, 0x00, 0x00]
 
 class NfcReaderService:
     def __init__(self) -> None:
         self._is_running = True
         self._last_uid = None
         self._keyboard = Controller()
-        self._last_write = datetime(1900, 1, 1)
+        self._last_write = datetime.min
 
     def run(self) -> None:
         print("Reader ready.")
 
         while self._is_running:
             try:
-                time.sleep(0.1)
-                card_request = CardRequest(timeout=None)
-                print("Waiting for card...")
-                card_service = card_request.waitforcard()
-                connection = card_service.connection
-                print("Connected to card!")
-
-                try:
-                    connection.connect(CardConnection.T1_protocol)
-
-                    GET_UID = [0xFF, 0xCA, 0x00, 0x00, 0x00]
-                    uid, sw1, sw2 = connection.transmit(GET_UID)
-
-                    if sw1 != 0x90:
-                        raise CardConnectionException("UID read failed")
-
-                    uid_hex = toHexString(uid)
-
-                    if uid_hex == self._last_uid:
-                        connection.disconnect()
-                        time.sleep(0.5)
-                        self._last_uid = None
-                        continue
-
-                    self._last_uid = uid_hex
-
-                    user_id = read_card(connection)
-                    if user_id is not None:
-                        now = datetime.now()
-                        if now - self._last_write > timedelta(seconds=2):
-                            self._keyboard.type(str(user_id))
-                            self._last_write = now
-
-                except (CardConnectionException, NoCardException):
-                    pass
-
-                finally:
-                    try:
-                        connection.disconnect()
-                    except:
-                        pass
-
-                time.sleep(0.5)
+                self._poll_card()
 
             except (KeyboardInterrupt, SystemExit):
                 self.stop()
 
+            except Exception as e:
+                print(f"[ERROR] Unexpected failure: {e}")
+                time.sleep(1)
+
+    def _poll_card(self) -> None:
+        card_request = CardRequest(timeout=1)
+
+        try:
+            card_service = card_request.waitforcard()
+        except NoCardException:
+            self._last_uid = None
+            return
+
+        connection = card_service.connection
+
+        try:
+            connection.connect(CardConnection.T1_protocol)
+
+            uid_hex = self._read_uid(connection)
+            if uid_hex is None:
+                return
+
+            # Card still present and unchanged -> ignore
+            if uid_hex == self._last_uid:
+                return
+
+            self._last_uid = uid_hex
+
+            self._handle_card(connection)
+
+        except (CardConnectionException, NoCardException) as e:
+            print(f"[CARD ERROR] {e}")
+
+        finally:
+            try:
+                connection.disconnect()
+            except Exception:
+                pass
+
+    def _read_uid(self, connection) -> Optional[str]:
+        uid, sw1, sw2 = connection.transmit(GET_UID)
+
+        if sw1 != 0x90:
+            raise CardConnectionException("UID read failed")
+
+        return toHexString(uid)
+
+    def _handle_card(self, connection) -> None:
+        user_id = read_card(connection)
+
+        if user_id is None:
+            return
+
+        now = datetime.now()
+
+        # debounce keyboard output
+        if now - self._last_write < timedelta(seconds=2):
+            return
+
+        self._send_to_keyboard(user_id)
+        self._last_write = now
+
+    def _send_to_keyboard(self, user_id: str) -> None:
+        try:
+            self._keyboard.type(f"{user_id}\n")
+        except Exception as e:
+            print(f"[KEYBOARD ERROR] {e}")
+
     def stop(self) -> None:
+        print("Stopping NFC service.")
         self._is_running = False
 
+
 if __name__ == "__main__":
     service = NfcReaderService()
     service.run()