Cache sorting of countries

src/pretix/base/forms/questions.py

@@ -41,6 +41,7 @@ from pretix.base.settings import (
 )
 from pretix.base.templatetags.rich_text import rich_text
 from pretix.control.forms import SplitDateTimeField
+from pretix.helpers.countries import CachedCountries
 from pretix.helpers.escapejson import escapejson_attr
 from pretix.helpers.i18n import get_format_without_seconds
 from pretix.presale.signals import question_form_fields
@@ -297,7 +298,9 @@ class BaseQuestionsForm(forms.Form):
                 }),
             )
             country = (cartpos.country if cartpos else orderpos.country) or guess_country(event)
-            self.fields['country'] = CountryField().formfield(
+            self.fields['country'] = CountryField(
+                countries=CachedCountries
+            ).formfield(
                 required=event.settings.attendee_addresses_required and not self.all_optional,
                 label=_('Country'),
                 initial=country,
@@ -380,7 +383,9 @@ class BaseQuestionsForm(forms.Form):
                     initial=initial.answer if initial else None,
                 )
             elif q.type == Question.TYPE_COUNTRYCODE:
-                field = CountryField().formfield(
+                field = CountryField(
+                    countries=CachedCountries
+                ).formfield(
                     label=label, required=required,
                     help_text=help_text,
                     widget=forms.Select,
@@ -575,6 +580,8 @@ class BaseInvoiceAddressForm(forms.ModelForm):
         if not event.settings.invoice_address_vatid:
             del self.fields['vat_id']
 
+        self.fields['country'].choices = CachedCountries()
+
         c = [('', pgettext_lazy('address', 'Select state'))]
         fprefix = self.prefix + '-' if self.prefix else ''
         cc = None

src/pretix/base/models/orders.py

@@ -44,6 +44,7 @@ from pretix.base.services.locking import NoLockManager
 from pretix.base.settings import PERSON_NAME_SCHEMES
 from pretix.base.signals import order_gracefully_delete
 
+from ...helpers.countries import CachedCountries
 from .base import LockModel, LoggedModel
 from .event import Event, SubEvent
 from .items import Item, ItemVariation, Question, QuestionOption, Quota
@@ -2113,7 +2114,8 @@ class InvoiceAddress(models.Model):
     zipcode = models.CharField(max_length=30, verbose_name=_('ZIP code'), blank=False)
     city = models.CharField(max_length=255, verbose_name=_('City'), blank=False)
     country_old = models.CharField(max_length=255, verbose_name=_('Country'), blank=False)
-    country = CountryField(verbose_name=_('Country'), blank=False, blank_label=_('Select country'))
+    country = CountryField(verbose_name=_('Country'), blank=False, blank_label=_('Select country'),
+                           countries=CachedCountries)
     state = models.CharField(max_length=255, verbose_name=pgettext_lazy('address', 'State'), blank=True)
     vat_id = models.CharField(max_length=255, blank=True, verbose_name=_('VAT ID'),
                               help_text=_('Only for business customers within the EU.'))

src/pretix/helpers/countries.py

@@ -0,0 +1,29 @@
+from django.core.cache import cache
+from django.utils.translation import get_language
+from django_countries import Countries
+
+
+class CachedCountries(Countries):
+    _cached_lists = {}
+
+    def __iter__(self):
+        """
+        Iterate through countries, sorted by name, but cache the results based on the locale.
+        django-countries performs a unicode-aware sorting based on pyuca which is incredibly
+        slow.
+        """
+        cache_key = "countries:all:{}".format(get_language())
+        if cache_key in self._cached_lists:
+            yield from self._cached_lists[cache_key]
+            return
+
+        val = cache.get(cache_key)
+        if val:
+            self._cached_lists[cache_key] = val
+            yield from val
+            return
+
+        val = list(super().__iter__())
+        self._cached_lists[cache_key] = val
+        cache.set(cache_key, val, 3600 * 24 * 30)
+        yield from val