Consistently set default background PDFs on server, not client (#2840)

Co-authored-by: Martin Gross <gross@rami.io>

src/pretix/plugins/ticketoutputpdf/api.py

@@ -24,6 +24,7 @@ from rest_framework import viewsets
 from pretix.api.serializers.i18n import I18nAwareModelSerializer
 from pretix.api.serializers.order import CompatibleJSONField
 
+from ...multidomain.utils import static_absolute
 from .models import TicketLayout, TicketLayoutItem
 
 
@@ -49,6 +50,12 @@ class TicketLayoutSerializer(I18nAwareModelSerializer):
         model = TicketLayout
         fields = ('id', 'name', 'default', 'layout', 'background', 'item_assignments')
 
+    def to_representation(self, instance):
+        d = super().to_representation(instance)
+        if not d['background']:
+            d['background'] = static_absolute(instance.event, "pretixpresale/pdf/ticket_default_a4.pdf")
+        return d
+
 
 class TicketLayoutViewSet(viewsets.ReadOnlyModelViewSet):
     serializer_class = TicketLayoutSerializer

src/pretix/plugins/ticketoutputpdf/apps.py

@@ -34,7 +34,7 @@
 
 from django.apps import AppConfig
 from django.utils.functional import cached_property
-from django.utils.translation import gettext_lazy as _
+from django.utils.translation import gettext, gettext_lazy as _
 
 from pretix import __version__ as version
 
@@ -63,3 +63,11 @@ class TicketOutputPdfApp(AppConfig):
         except ImportError:
             errs.append("Python package 'reportlab' is not installed.")
         return errs
+
+    def installed(self, event):
+        event.ticket_layouts.get_or_create(
+            default=True,
+            defaults={
+                'name': gettext('Default layout'),
+            }
+        )