Fix #312 -- Bulk-send vouchers via email (#1469)

* Allow to directly bulk-send vouchers via email

* Send mails

* Log messages

* Fix test failures

* Add new test cases

src/pretix/base/services/mail.py

@@ -121,7 +121,7 @@ def mail(email: str, subject: str, template: Union[str, LazyI18nString],
                 })
         renderer = ClassicMailRenderer(None)
         content_plain = body_plain = render_mail(template, context)
-        subject = str(subject).format_map(context)
+        subject = str(subject).format_map(TolerantDict(context))
         sender = sender or (event.settings.get('mail_from') if event else settings.MAIL_FROM)
         if event:
             sender_name = event.settings.mail_from_name or str(event.name)

src/pretix/base/services/vouchers.py

@@ -0,0 +1,46 @@
+from django.utils.translation import gettext
+from i18nfield.strings import LazyI18nString
+
+from pretix.base.email import get_email_context
+from pretix.base.i18n import language
+from pretix.base.models import Event, User, Voucher
+from pretix.base.services.mail import mail
+from pretix.base.services.tasks import ProfiledEventTask
+from pretix.celery_app import app
+
+
+@app.task(base=ProfiledEventTask)
+def vouchers_send(event: Event, vouchers: list, subject: str, message: str, recipients: list, user: int) -> None:
+    vouchers = list(Voucher.objects.filter(id__in=vouchers).order_by('id'))
+    user = User.objects.get(pk=user)
+    for r in recipients:
+        voucher_list = []
+        for i in range(r['number']):
+            voucher_list.append(vouchers.pop())
+        with language(event.settings.locale):
+            email_context = get_email_context(event=event, name=r.get('name') or '', voucher_list=[v.code for v in voucher_list])
+            mail(
+                r['email'],
+                subject,
+                LazyI18nString(message),
+                email_context,
+                event,
+                locale=event.settings.locale,
+            )
+            for v in voucher_list:
+                if r.get('tag') and r.get('tag') != v.tag:
+                    v.tag = r.get('tag')
+                if v.comment:
+                    v.comment += '\n\n'
+                v.comment = gettext('The voucher has been sent to {recipient}.').format(recipient=r['email'])
+                v.save(update_fields=['tag', 'comment'])
+                v.log_action(
+                    'pretix.voucher.sent',
+                    user=user,
+                    data={
+                        'recipient': r['email'],
+                        'name': r.get('name'),
+                        'subject': subject,
+                        'message': message,
+                    }
+                )