Allow to configure length of ticket secret

src/pretix/base/secrets.py

@@ -29,7 +29,6 @@ from cryptography.hazmat.primitives.serialization import (
     Encoding, NoEncryption, PrivateFormat, PublicFormat, load_pem_private_key,
     load_pem_public_key,
 )
-from django.conf import settings
 from django.dispatch import receiver
 from django.utils.crypto import get_random_string
 from django.utils.translation import gettext_lazy as _
@@ -111,7 +110,7 @@ class RandomTicketSecretGenerator(BaseTicketSecretGenerator):
         if current_secret and not force_invalidate:
             return current_secret
         return get_random_string(
-            length=settings.ENTROPY['ticket_secret'],
+            length=self.event.settings.ticket_secret_length,
             # Exclude o,0,1,i,l to avoid confusion with bad fonts/printers
             allowed_chars='abcdefghjkmnpqrstuvwxyz23456789'
         )

src/pretix/base/settings.py

@@ -461,6 +461,32 @@ DEFAULTS = {
         'default': 'random',
         'type': str,
     },
+    'ticket_secret_length': {
+        'default': settings.ENTROPY['ticket_secret'],
+        'type': int,
+        'form_class': forms.IntegerField,
+        'serializer_class': serializers.IntegerField,
+        'serializer_kwargs': dict(
+            validators=[
+                MinValueValidator(12),
+                MaxValueValidator(64),
+            ]
+        ),
+        'form_kwargs': dict(
+            label=_('Length of ticket codes'),
+            validators=[
+                MinValueValidator(12),
+                MaxValueValidator(64),
+            ],
+            widget=forms.NumberInput(
+                attrs={
+                    'min': '12',
+                    'max': '64',
+                    'data-display-dependency': 'input[name=ticket_secret_generator][value=random]',
+                },
+            ),
+        )
+    },
     'reservation_time': {
         'default': '30',
         'type': int,