Fix of the encryption processing with the Student class

Web/app.py

@@ -4108,28 +4108,20 @@ def student_cards_admin():
                         app.logger.error(f"Error adding student card: {e}")
                         flash('Fehler beim Hinzufügen des Ausweises.', 'error')
 
-    # Get all student cards
+    # Get all student cards and decrypt them
     all_cards = list(student_cards.find().sort('AusweisId', 1))
     all_cards = [_decrypt_student_card_doc(card) for card in all_cards]
     client.close()
 
-    # Alle eindeutigen Klassen für das Dropdown ermitteln
-    client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
-    db = client[cfg.MONGODB_DB]
-    student_cards_collection = db['student_cards']
-
-    # Extrahiere alle vorhandenen Klassen, entferne leere/None Werte und sortiere sie
-    raw_classes = student_cards_collection.distinct('Klasse')
-    available_classes = sorted([c for c in raw_classes if c])
-
-    client.close()
+    raw_classes = set(card.get('Klasse', '').strip() for card in all_cards if card.get('Klasse'))
+    available_classes = sorted(list(raw_classes))
 
     return render_template(
         'student_cards_admin.html',
-        student_cards=all_cards,
+        student_cards=all_cards,  # Hier all_cards übergeben
         edit_mode=edit_mode,
         form_data=form_data,
-        available_classes=available_classes,
+        available_classes=available_classes, # Enthält nun die lesbaren Klassen
         config=cfg.get_school_info()
     )
 
@@ -4439,10 +4431,19 @@ def student_card_class_barcode_download():
         db = client[cfg.MONGODB_DB]
         student_cards = db['student_cards']
 
-        class_cards = list(student_cards.find({'Klasse': class_name}).sort('AusweisId', 1))
-        class_cards = [_decrypt_student_card_doc(card) for card in class_cards]
+        # 1. Alle Ausweise laden
+        all_cards = list(student_cards.find().sort('AusweisId', 1))
         client.close()
 
+        # 2. Alle entschlüsseln
+        decrypted_cards = [_decrypt_student_card_doc(card) for card in all_cards]
+        
+        # 3. Im Speicher nach der Klartext-Klasse filtern
+        class_cards = [
+            card for card in decrypted_cards 
+            if card.get('Klasse', '').strip() == class_name
+        ]
+
         if not class_cards:
             flash(f'Keine Ausweise für die Klasse "{class_name}" gefunden.', 'error')
             return redirect(url_for('student_cards_admin'))