Sendmail plugin: Allow to attach a file to emails (#1814)

* sendmail: allow to attach files to emails

* Fix mixup of model objects and model IDs

* Attach to order-level emails, not only position-level emails

* Give attachments a proper file type

* Add a warning note about higher spam chances

Co-authored-by: Raphael Michel <mail@raphaelmichel.de>

src/pretix/plugins/sendmail/forms.py

@@ -7,6 +7,7 @@ from i18nfield.forms import I18nFormField, I18nTextarea, I18nTextInput
 from pretix.base.email import get_available_placeholders
 from pretix.base.forms import PlaceholderValidator
 from pretix.base.models import CheckinList, Item, Order, SubEvent
+from pretix.control.forms import ExtFileField
 from pretix.control.forms.widgets import Select2, Select2Multiple
 
 
@@ -20,6 +21,18 @@ class MailForm(forms.Form):
     sendto = forms.MultipleChoiceField()  # overridden later
     subject = forms.CharField(label=_("Subject"))
     message = forms.CharField(label=_("Message"))
+    attachment = ExtFileField(
+        label=_("Attachment"),
+        required=False,
+        ext_whitelist=(
+            ".png", ".jpg", ".gif", ".jpeg", ".pdf", ".txt", ".docx", ".gif", ".svg",
+            ".pptx", ".ppt", ".doc", ".xlsx", ".xls", ".jfif", ".heic", ".heif", ".pages",
+            ".bmp", ".tif", ".tiff"
+        ),
+        help_text=_('Sending an attachment increases the chance of your email not arriving or being sorted into spam folders. We recommend only using PDFs '
+                    'of no more than 2 MB in size.'),
+        max_size=10 * 1024 * 1024
+    )  # TODO i18n
     items = forms.ModelMultipleChoiceField(
         widget=forms.CheckboxSelectMultiple(
             attrs={'class': 'scrolling-multiple-choice'}

src/pretix/plugins/sendmail/tasks.py

@@ -10,7 +10,8 @@ from pretix.celery_app import app
 
 @app.task(base=ProfiledEventTask, acks_late=True)
 def send_mails(event: Event, user: int, subject: dict, message: dict, orders: list, items: list,
-               recipients: str, filter_checkins: bool, not_checked_in: bool, checkin_lists: list) -> None:
+               recipients: str, filter_checkins: bool, not_checked_in: bool, checkin_lists: list,
+               attachments: list = None) -> None:
     failures = []
     user = User.objects.get(pk=user) if user else None
     orders = Order.objects.filter(pk__in=orders, event=event)
@@ -61,7 +62,8 @@ def send_mails(event: Event, user: int, subject: dict, message: dict, orders: li
                             event,
                             locale=o.locale,
                             order=o,
-                            position=p
+                            position=p,
+                            attach_cached_files=attachments
                         )
                         o.log_action(
                             'pretix.plugins.sendmail.order.email.sent.attendee',
@@ -87,7 +89,8 @@ def send_mails(event: Event, user: int, subject: dict, message: dict, orders: li
                         email_context,
                         event,
                         locale=o.locale,
-                        order=o
+                        order=o,
+                        attach_cached_files=attachments
                     )
                     o.log_action(
                         'pretix.plugins.sendmail.order.email.sent',

src/pretix/plugins/sendmail/templates/pretixplugins/sendmail/send_form.html

@@ -5,7 +5,7 @@
 {% block content %}
     <h1>{% trans "Send out emails" %}</h1>
     {% block inner %}
-        <form class="form-horizontal" method="post" action="">
+        <form class="form-horizontal" method="post" action="" enctype="multipart/form-data">
             {% csrf_token %}
             {% bootstrap_field form.recipients layout='horizontal' %}
             {% bootstrap_field form.sendto layout='horizontal' %}
@@ -32,6 +32,7 @@
             </div>
             {% bootstrap_field form.subject layout='horizontal' %}
             {% bootstrap_field form.message layout='horizontal' %}
+            {% bootstrap_field form.attachment layout='horizontal' %}
             {% if request.method == "POST" %}
             <fieldset>
             <legend>{% trans "E-mail preview" %}</legend>

src/pretix/plugins/sendmail/views.py

@@ -1,4 +1,5 @@
 import logging
+from datetime import timedelta
 
 import bleach
 from django.contrib import messages
@@ -11,7 +12,7 @@ from django.views.generic import FormView, ListView
 
 from pretix.base.email import get_available_placeholders
 from pretix.base.i18n import LazyI18nString, language
-from pretix.base.models import LogEntry, Order, OrderPosition
+from pretix.base.models import CachedFile, LogEntry, Order, OrderPosition
 from pretix.base.models.event import SubEvent
 from pretix.base.services.mail import TolerantDict
 from pretix.base.templatetags.rich_text import markdown_compile_email
@@ -136,19 +137,34 @@ class SenderView(EventPermissionRequiredMixin, FormView):
 
             return self.get(self.request, *self.args, **self.kwargs)
 
+        attachment = None
+        if 'attachment' in self.request.FILES:
+            attachment = self.request.FILES['attachment']
+            cf = CachedFile.objects.create(
+                expires=now() + timedelta(days=1),
+                date=now(),
+                filename=attachment.name,
+                type=attachment.content_type,
+            )
+            cf.file.save(attachment.name, attachment.file)
+            cf.save()
+        kwargs = {
+            'recipients': form.cleaned_data['recipients'],
+            'event': self.request.event.pk,
+            'user': self.request.user.pk,
+            'subject': form.cleaned_data['subject'].data,
+            'message': form.cleaned_data['message'].data,
+            'orders': [o.pk for o in orders],
+            'items': [i.pk for i in form.cleaned_data.get('items')],
+            'not_checked_in': form.cleaned_data.get('not_checked_in'),
+            'checkin_lists': [i.pk for i in form.cleaned_data.get('checkin_lists')],
+            'filter_checkins': form.cleaned_data.get('filter_checkins'),
+        }
+        if attachment is not None:
+            kwargs['attachments'] = [cf.id]
+
         send_mails.apply_async(
-            kwargs={
-                'recipients': form.cleaned_data['recipients'],
-                'event': self.request.event.pk,
-                'user': self.request.user.pk,
-                'subject': form.cleaned_data['subject'].data,
-                'message': form.cleaned_data['message'].data,
-                'orders': [o.pk for o in orders],
-                'items': [i.pk for i in form.cleaned_data.get('items')],
-                'not_checked_in': form.cleaned_data.get('not_checked_in'),
-                'checkin_lists': [i.pk for i in form.cleaned_data.get('checkin_lists')],
-                'filter_checkins': form.cleaned_data.get('filter_checkins'),
-            }
+            kwargs=kwargs
         )
         self.request.event.log_action('pretix.plugins.sendmail.sent',
                                       user=self.request.user,