Sendmail plugin: Move to background process

src/pretix/plugins/sendmail/tasks.py

@@ -0,0 +1,63 @@
+import pytz
+from django.utils.formats import date_format
+from i18nfield.strings import LazyI18nString
+
+from pretix.base.i18n import language
+from pretix.base.models import Event, InvoiceAddress, Order, User
+from pretix.base.services.async import ProfiledTask
+from pretix.base.services.mail import SendMailException, mail
+from pretix.celery_app import app
+from pretix.multidomain.urlreverse import build_absolute_uri
+
+
+@app.task(base=ProfiledTask)
+def send_mails(event: int, user: int, subject: dict, message: dict, orders: list) -> None:
+    failures = []
+    event = Event.objects.get(pk=event)
+    user = User.objects.get(pk=user) if user else None
+    orders = Order.objects.filter(pk__in=orders)
+    subject = LazyI18nString(subject)
+    message = LazyI18nString(message)
+    tz = pytz.timezone(event.settings.timezone)
+
+    for o in orders:
+        try:
+            invoice_name = o.invoice_address.name
+            invoice_company = o.invoice_address.company
+        except InvoiceAddress.DoesNotExist:
+            invoice_name = ""
+            invoice_company = ""
+        try:
+            with language(o.locale):
+                email_context = {
+                    'event': o.event,
+                    'code': o.code,
+                    'date': date_format(o.datetime.astimezone(tz), 'SHORT_DATETIME_FORMAT'),
+                    'expire_date': date_format(o.expires, 'SHORT_DATE_FORMAT'),
+                    'url': build_absolute_uri(event, 'presale:event.order', kwargs={
+                        'order': o.code,
+                        'secret': o.secret
+                    }),
+                    'invoice_name': invoice_name,
+                    'invoice_company': invoice_company,
+                }
+                mail(
+                    o.email,
+                    subject,
+                    message,
+                    email_context,
+                    event,
+                    locale=o.locale,
+                    order=o
+                )
+                o.log_action(
+                    'pretix.plugins.sendmail.order.email.sent',
+                    user=user,
+                    data={
+                        'subject': subject.localize(o.locale),
+                        'message': message.localize(o.locale).format_map(email_context),
+                        'recipient': o.email
+                    }
+                )
+        except SendMailException:
+            failures.append(o.email)