base/pdf: Only call get_fonts() once per generation

src/pretix/base/pdf.py

@@ -52,7 +52,6 @@ import reportlab.rl_config
 from bidi.algorithm import get_display
 from django.conf import settings
 from django.contrib.staticfiles import finders
-from django.core.cache import cache
 from django.core.exceptions import ValidationError
 from django.db.models import Max, Min
 from django.db.models.fields.files import FieldFile
@@ -739,6 +738,7 @@ class Renderer:
         else:
             self.bg_bytes = None
             self.bg_pdf = None
+        self.event_fonts = list(get_fonts(event, pdf_support_required=True).keys()) + ['Open Sans']
 
     @classmethod
     def _register_fonts(cls, event: Event = None):
@@ -942,11 +942,7 @@ class Renderer:
 
         # Since pdfmetrics.registerFont is global, we want to make sure that no one tries to sneak in a font, they
         # should not have access to.
-        event_fonts = cache.get(f'event_fonts_pdf_support_required_{order.event.pk}')
-        if not event_fonts:
-            event_fonts = list(get_fonts(order.event, pdf_support_required=True).keys()) + ['Open Sans']
-            cache.set(f'event_fonts_pdf_support_required_{order.event.pk}', event_fonts, 30)
-        if font not in event_fonts:
+        if font not in self.event_fonts:
             logger.warning(f'Unauthorized use of font "{font}"')
             font = 'Open Sans'