emails: add backend to add headers (#50753)

hobo/emails/backend.py

@@ -0,0 +1,35 @@
+# hobo - portal to configure and deploy applications
+# Copyright (C) 2015-2021 Entr'ouvert
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from django.conf import settings
+import django.core.mail.backends.smtp
+
+
+class EmailBackend(django.core.mail.backends.smtp.EmailBackend):
+    def _send(self, email_message):
+        try:
+            url = settings.TEMPLATE_VARS['email_unsubscribe_info_url']
+            if url:
+                email_message.extra_headers['List-Unsubscribe'] = '<%s>' % url
+        except (KeyError, TypeError):
+            pass
+        try:
+            url = settings.TEMPLATE_VARS['email_abuse_report_url']
+            if url:
+                email_message.extra_headers['X-Report-Abuse'] = 'Please report abuse for this email here: %s' % url
+        except (KeyError, TypeError):
+            pass
+        return super()._send(email_message)

hobo/emails/forms.py

@@ -36,6 +36,11 @@ class EmailsForm(forms.Form):
             help_text=_('Custom prefix for emails subject (defaults to global title)'))
     email_signature = forms.CharField(label=_('Signature'), required=False,
             widget=forms.Textarea)
+    email_unsubscribe_info_url = forms.CharField(
+            label=_('URL with informations about emails sent by the platform'), required=False,
+            help_text=_('It should contain details such as what emails are sent and how not to receive them.'))
+    email_abuse_report_url = forms.CharField(label=_('URL for email abuse reports'), required=False,
+            help_text=_('It should contain a form to submit email abuse reports'))
 
     def __init__(self, *args, **kwargs):
         super(EmailsForm, self).__init__(*args, **kwargs)

hobo/emails/views.py

@@ -24,7 +24,10 @@ from .forms import EmailsForm
 
 class HomeView(VariablesFormMixin, TemplateView):
     template_name = 'hobo/emails_home.html'
-    variables = ['default_from_email', 'email_sender_name', 'global_email_prefix', 'email_signature']
+    variables = ['default_from_email', 'email_sender_name',
+            'global_email_prefix', 'email_signature',
+            'email_unsubscribe_info_url',
+            'email_abuse_report_url']
     form_class = EmailsForm
     success_message = _('Emails settings have been updated. '
                         'It will take a few seconds to be effective.')