feat: Enhance permission handling in fallback endpoints for improved user experience

Web/app.py

@@ -206,6 +206,7 @@ PERMISSION_ACTION_ENDPOINTS = {
     'register': 'can_manage_users',
     'admin_reset_user_password': 'can_manage_users',
     'admin_update_user_permissions': 'can_manage_users',
+    'admin_anonymize_names': 'can_manage_users',
     'home_admin': 'can_manage_settings',
     'upload_admin': 'can_manage_settings',
     'library_admin': 'can_manage_settings',
@@ -297,7 +298,7 @@ def _enforce_user_permissions():
             return jsonify({'ok': False, 'message': message}), 403
 
         flash(message, 'error')
-        fallback_endpoint = _permission_denied_fallback_endpoint(permissions)
+        fallback_endpoint = _permission_denied_fallback_endpoint(permissions, current_endpoint=endpoint)
         return redirect(url_for(fallback_endpoint))
 
     action_key = PERMISSION_ACTION_ENDPOINTS.get(endpoint)
@@ -307,7 +308,7 @@ def _enforce_user_permissions():
             return jsonify({'ok': False, 'message': message}), 403
 
         flash(message, 'error')
-        fallback_endpoint = _permission_denied_fallback_endpoint(permissions)
+        fallback_endpoint = _permission_denied_fallback_endpoint(permissions, current_endpoint=endpoint)
         return redirect(url_for(fallback_endpoint))
 
     return None
@@ -375,8 +376,16 @@ def _action_access_allowed(permissions, action_key):
     return bool(action_permissions.get(action_key, True))
 
 
-def _permission_denied_fallback_endpoint(permissions):
-    for candidate in ('home', 'my_borrowed_items', 'tutorial_page', 'notifications_view', 'impressum'):
+def _permission_denied_fallback_endpoint(permissions, current_endpoint=None):
+    username = session.get('username')
+    is_admin_user = bool(username and us.check_admin(username))
+    admin_home_allowed = _page_access_allowed(permissions, 'home_admin') and _action_access_allowed(permissions, 'can_manage_settings')
+
+    for candidate in ('my_borrowed_items', 'tutorial_page', 'notifications_view', 'impressum', 'home'):
+        if current_endpoint and candidate == current_endpoint:
+            continue
+        if candidate == 'home' and is_admin_user and not admin_home_allowed:
+            continue
         if _page_access_allowed(permissions, candidate):
             return candidate
     return 'logout'
@@ -1588,14 +1597,25 @@ def _student_card_id_slug(value):
     return re.sub(r'[^a-z0-9]+', '', normalized).upper()
 
 
+def _name_to_alias(full_name):
+    """Convert clear names to deterministic aliases, e.g. Simon Frings -> SimFri."""
+    text = sanitize_form_value(full_name)
+    if not text:
+        return 'User'
+
+    parts = [p for p in re.split(r'\s+', text) if p]
+    if len(parts) >= 2:
+        return us.build_name_synonym(parts[0], parts[-1])
+    return us.build_name_synonym(parts[0], '')
+
+
 def _build_student_card_excel_id(student_name, class_name, row_number, used_ids):
-    """Create a stable student-card ID when the spreadsheet does not provide one."""
-    name_slug = _student_card_id_slug(student_name)
+    """Create a stable student-card ID without embedding personal names."""
     class_slug = _student_card_id_slug(class_name)
 
-    base_parts = [part for part in (class_slug, name_slug) if part]
+    base_parts = [part for part in (class_slug,) if part]
     if base_parts:
-        base_id = f"SC-{'-'.join(base_parts[:2])}"
+        base_id = f"SC-{'-'.join(base_parts[:1])}-ROW-{row_number}"
     else:
         base_id = f"SC-ROW-{row_number}"
 
@@ -1715,6 +1735,8 @@ def _upload_student_cards_excel():
                 student_name = f'{first_name} {last_name}'.strip()
                 validation_warnings.append((row_number, 'Schülername wurde aus Vorname und Nachname zusammengesetzt'))
 
+            student_name_alias = _name_to_alias(student_name)
+
             if not ausweis_id and not student_name and not class_name:
                 continue
 
@@ -1739,7 +1761,7 @@ def _upload_student_cards_excel():
             planned_rows.append({
                 'row_number': row_number,
                 'ausweis_id': ausweis_id,
-                'student_name': student_name,
+                'student_name': student_name_alias,
                 'class_name': class_name,
                 'notes': notes,
                 'default_borrow_days': default_borrow_days,
@@ -2393,7 +2415,14 @@ def home():
             student_max_borrow_days=cfg.STUDENT_MAX_BORROW_DAYS
         )
     else:
-        return redirect(url_for('home_admin'))
+        permissions = _get_current_user_permissions() or us.build_default_permission_payload('standard_user')
+        if _page_access_allowed(permissions, 'home_admin') and _action_access_allowed(permissions, 'can_manage_settings'):
+            return redirect(url_for('home_admin'))
+
+        fallback_endpoint = _permission_denied_fallback_endpoint(permissions, current_endpoint='home')
+        if fallback_endpoint == 'logout':
+            flash('Für diesen Benutzer sind aktuell keine Seiten freigegeben.', 'error')
+        return redirect(url_for(fallback_endpoint))
 
 
 @app.route('/home_admin')
@@ -3172,6 +3201,7 @@ def student_cards_admin():
         action = request.form.get('action', 'add')
         ausweis_id = request.form.get('ausweis_id', '').strip().upper()
         student_name = request.form.get('student_name', '').strip()
+        student_name_alias = _name_to_alias(student_name)
         default_borrow_days = request.form.get('default_borrow_days', 14)
         class_name = request.form.get('class_name', '').strip()
         notes = request.form.get('notes', '').strip()
@@ -3198,7 +3228,7 @@ def student_cards_admin():
                     else:
                         encrypted_payload = encrypt_document_fields(
                             {
-                                'SchülerName': student_name,
+                                'SchülerName': student_name_alias,
                                 'Klasse': class_name,
                                 'Notizen': notes,
                             },
@@ -3231,7 +3261,7 @@ def student_cards_admin():
                     try:
                         encrypted_payload = encrypt_document_fields(
                             {
-                                'SchülerName': student_name,
+                                'SchülerName': student_name_alias,
                                 'Klasse': class_name,
                                 'Notizen': notes,
                             },
@@ -3701,7 +3731,11 @@ def login():
             session['admin'] = is_admin_user
             session['is_admin'] = is_admin_user
             if is_admin_user:
-                return redirect(url_for('home_admin'))
+                permissions = us.get_effective_permissions(username)
+                if _page_access_allowed(permissions, 'home_admin') and _action_access_allowed(permissions, 'can_manage_settings'):
+                    return redirect(url_for('home_admin'))
+                fallback_endpoint = _permission_denied_fallback_endpoint(permissions, current_endpoint='login')
+                return redirect(url_for(fallback_endpoint))
             else:
                 return redirect(url_for('home'))
         else:
@@ -7811,6 +7845,72 @@ def admin_update_user_permissions():
     return redirect(url_for('user_del'))
 
 
+@app.route('/admin_anonymize_names', methods=['POST'])
+def admin_anonymize_names():
+    """Anonymize already stored personal names into short aliases."""
+    if 'username' not in session or not us.check_admin(session['username']):
+        flash('Nicht autorisierter Zugriff', 'error')
+        return redirect(url_for('login'))
+
+    client = None
+    try:
+        client = MongoClient(MONGODB_HOST, MONGODB_PORT)
+        db = client[MONGODB_DB]
+        users_col = db['users']
+        student_cards_col = db['student_cards']
+
+        users_updated = 0
+        cards_updated = 0
+
+        for user_doc in users_col.find({}, {'name': 1, 'last_name': 1, 'Username': 1, 'username': 1}):
+            first = str(user_doc.get('name') or '').strip()
+            last = str(user_doc.get('last_name') or '').strip()
+            fallback = str(user_doc.get('Username') or user_doc.get('username') or '').strip()
+
+            alias = us.build_name_synonym(first or fallback, last)
+            result = users_col.update_one(
+                {'_id': user_doc['_id']},
+                {'$set': {'name': alias, 'last_name': ''}}
+            )
+            if result.modified_count > 0:
+                users_updated += 1
+
+        for card_doc in student_cards_col.find({}, {'SchülerName': 1, 'Klasse': 1, 'Notizen': 1}):
+            decrypted = _decrypt_student_card_doc(card_doc)
+            alias = _name_to_alias(decrypted.get('SchülerName', ''))
+            class_name = sanitize_form_value(decrypted.get('Klasse', ''))
+            notes = sanitize_form_value(decrypted.get('Notizen', ''))
+
+            encrypted_payload = encrypt_document_fields(
+                {
+                    'SchülerName': alias,
+                    'Klasse': class_name,
+                    'Notizen': notes,
+                },
+                STUDENT_CARD_ENCRYPTED_FIELDS,
+            )
+
+            result = student_cards_col.update_one(
+                {'_id': card_doc['_id']},
+                {'$set': {'Aktualisiert': datetime.datetime.now(), **encrypted_payload}}
+            )
+            if result.modified_count > 0:
+                cards_updated += 1
+
+        flash(
+            f'Anonymisierung abgeschlossen: {users_updated} Benutzer und {cards_updated} Ausweise aktualisiert.',
+            'success'
+        )
+    except Exception as exc:
+        app.logger.error(f'Error anonymizing names: {exc}')
+        flash('Fehler bei der Anonymisierung der Namen.', 'error')
+    finally:
+        if client:
+            client.close()
+
+    return redirect(url_for('user_del'))
+
+
 @app.route('/logs')
 def logs():
     """

Web/templates/user_del.html

@@ -17,6 +17,16 @@
     <div class="user-management-container">
         <h2>Benutzer</h2>
 
+        <form method="POST" action="{{ url_for('admin_anonymize_names') }}" class="mb-3">
+            <button
+                type="submit"
+                class="btn btn-outline-danger"
+                onclick="return confirm('Sollen alle gespeicherten Klarnamen dauerhaft in Synonym-Kuerzel umgewandelt werden?')"
+            >
+                Gespeicherte Namen anonymisieren
+            </button>
+        </form>
+
         <div class="filter-bar mb-3">
             <div class="row g-2 align-items-end">
                 <div class="col-md-3">

Web/user.py

@@ -12,6 +12,7 @@ Provides methods for creating, validating, and retrieving user information.
 '''
 import hashlib
 import copy
+import re
 from bson.objectid import ObjectId
 import settings as cfg
 from settings import MongoClient
@@ -24,6 +25,38 @@ def normalize_student_card_id(card_id):
     return str(card_id).strip().upper()
 
 
+def _clean_name_fragment(value):
+    cleaned = re.sub(r'[^A-Za-zÄÖÜäöüß]', '', str(value or '').strip())
+    if not cleaned:
+        return ''
+    replacements = {
+        'ä': 'ae',
+        'ö': 'oe',
+        'ü': 'ue',
+        'ß': 'ss',
+        'Ä': 'Ae',
+        'Ö': 'Oe',
+        'Ü': 'Ue',
+    }
+    for old_char, new_char in replacements.items():
+        cleaned = cleaned.replace(old_char, new_char)
+    return cleaned
+
+
+def build_name_synonym(first_name, last_name=''):
+    """Build a deterministic, non-personalized short alias like 'SimFri'."""
+    first = _clean_name_fragment(first_name)
+    last = _clean_name_fragment(last_name)
+
+    if first and last:
+        return (first[:3] + last[:3]).title()
+
+    combined = (first + last)
+    if not combined:
+        return 'User'
+    return combined[:6].title()
+
+
 ACTION_PERMISSION_KEYS = (
     'can_borrow',
     'can_insert',
@@ -361,13 +394,15 @@ def add_user(username, password, name, last_name, is_student=False, student_card
         return False
     permission_defaults = build_default_permission_payload('standard_user')
 
+    name_alias = build_name_synonym(name, last_name)
+
     user_doc = {
         'Username': username,
         'Password': hashing(password),
         'Admin': False,
         'active_ausleihung': None,
-        'name': name,
-        'last_name': last_name,
+        'name': name_alias,
+        'last_name': '',
         'IsStudent': bool(is_student),
         'PermissionPreset': permission_defaults['preset'],
         'ActionPermissions': permission_defaults['actions'],
@@ -714,13 +749,14 @@ def update_user_name(username, name, last_name):
         bool: True if updated successfully, False otherwise
     """
     try:
+        name_alias = build_name_synonym(name, last_name)
         client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
         db = client[cfg.MONGODB_DB]
         users = db['users']
         
         result = users.update_one(
             {'Username': username}, 
-            {'$set': {'name': name, 'last_name': last_name}}
+            {'$set': {'name': name_alias, 'last_name': ''}}
         )
         
         client.close()