send_email: Add support for multiple recipients.

This adds a function that sends provided email to all administrators
of a realm, but in a single email. As a result, send_email now takes
arguments to_user_ids and to_emails instead of to_user_id and
to_email.

We adjust other APIs to match, but note that send_future_email does
not yet support the multiple recipients model for good reasons.

Tweaked by tabbott to modify `manage.py deliver_email` to handle
backwards-compatibily for any ScheduledEmail objects already in the
database.

Fixes #10896.

zerver/forms.py

@@ -250,7 +250,7 @@ class ZulipPasswordResetForm(PasswordResetForm):
         if user is not None:
             context['active_account_in_realm'] = True
             context['reset_url'] = generate_password_reset_url(user, token_generator)
-            send_email('zerver/emails/password_reset', to_user_id=user.id,
+            send_email('zerver/emails/password_reset', to_user_ids=[user.id],
                        from_name="Zulip Account Security",
                        from_address=FromAddress.tokenized_no_reply_address(),
                        context=context)
@@ -259,7 +259,7 @@ class ZulipPasswordResetForm(PasswordResetForm):
             active_accounts_in_other_realms = UserProfile.objects.filter(email__iexact=email, is_active=True)
             if active_accounts_in_other_realms:
                 context['active_accounts_in_other_realms'] = active_accounts_in_other_realms
-            send_email('zerver/emails/password_reset', to_email=email,
+            send_email('zerver/emails/password_reset', to_emails=[email],
                        from_name="Zulip Account Security",
                        from_address=FromAddress.tokenized_no_reply_address(),
                        context=context)

zerver/lib/actions.py

@@ -43,7 +43,7 @@ from zerver.lib.message import (
 )
 from zerver.lib.realm_icon import realm_icon_url
 from zerver.lib.retention import move_messages_to_archive
-from zerver.lib.send_email import send_email, FromAddress
+from zerver.lib.send_email import send_email, FromAddress, send_email_to_admins
 from zerver.lib.stream_subscription import (
     get_active_subscriptions_for_stream_id,
     get_active_subscriptions_for_stream_ids,
@@ -795,7 +795,7 @@ def do_start_email_change_process(user_profile: UserProfile, new_email: str) ->
         'new_email': new_email,
         'activate_url': activation_url
     })
-    send_email('zerver/emails/confirm_new_email', to_email=new_email,
+    send_email('zerver/emails/confirm_new_email', to_emails=[new_email],
                from_name='Zulip Account Security', from_address=FromAddress.tokenized_no_reply_address(),
                context=context)
 
@@ -4429,7 +4429,7 @@ def do_send_confirmation_email(invitee: PreregistrationUser,
     context = {'referrer_full_name': referrer.full_name, 'referrer_email': referrer.email,
                'activate_url': activation_url, 'referrer_realm_name': referrer.realm.name}
     from_name = "%s (via Zulip)" % (referrer.full_name,)
-    send_email('zerver/emails/invitation', to_email=invitee.email, from_name=from_name,
+    send_email('zerver/emails/invitation', to_emails=[invitee.email], from_name=from_name,
                from_address=FromAddress.tokenized_no_reply_address(), context=context)
 
 def email_not_system_bot(email: str) -> None:
@@ -5185,12 +5185,10 @@ def missing_any_realm_internal_bots() -> bool:
 
 def do_send_realm_reactivation_email(realm: Realm) -> None:
     confirmation_url = create_confirmation_link(realm, realm.host, Confirmation.REALM_REACTIVATION)
-    admins = realm.get_admin_users()
     context = {'confirmation_url': confirmation_url,
                'realm_uri': realm.uri,
                'realm_name': realm.name}
-    for admin in admins:
+    send_email_to_admins(
-        send_email(
+        'zerver/emails/realm_reactivation', realm,
-            'zerver/emails/realm_reactivation', to_email=admin.email,
         from_address=FromAddress.tokenized_no_reply_address(),
         from_name="Zulip Account Security", context=context)

zerver/lib/digest.py

@@ -262,6 +262,6 @@ def handle_digest_email(user_profile_id: int, cutoff: float) -> None:
                       new_streams_count, new_users_count):
         logger.info("Sending digest email for %s" % (user_profile.email,))
         # Send now, as a ScheduledEmail
-        send_future_email('zerver/emails/digest', user_profile.realm, to_user_id=user_profile.id,
+        send_future_email('zerver/emails/digest', user_profile.realm, to_user_ids=[user_profile.id],
                           from_name="Zulip Digest", from_address=FromAddress.NOREPLY,
                           context=context)

zerver/lib/notifications.py

@@ -382,7 +382,7 @@ def do_send_missedmessage_events_reply_in_zulip(user_profile: UserProfile,
 
     email_dict = {
         'template_prefix': 'zerver/emails/missed_message',
-        'to_user_id': user_profile.id,
+        'to_user_ids': [user_profile.id],
         'from_name': from_name,
         'from_address': from_address,
         'reply_to_email': formataddr((reply_to_name, reply_to_address)),
@@ -534,12 +534,12 @@ def enqueue_welcome_emails(user: UserProfile, realm_creation: bool=False) -> Non
             context["ldap_username"] = user.email
 
     send_future_email(
-        "zerver/emails/followup_day1", user.realm, to_user_id=user.id, from_name=from_name,
+        "zerver/emails/followup_day1", user.realm, to_user_ids=[user.id], from_name=from_name,
         from_address=from_address, context=context)
 
     if other_account_count == 0:
         send_future_email(
-            "zerver/emails/followup_day2", user.realm, to_user_id=user.id, from_name=from_name,
+            "zerver/emails/followup_day2", user.realm, to_user_ids=[user.id], from_name=from_name,
             from_address=from_address, context=context, delay=followup_day2_email_delay(user))
 
 def convert_html_to_markdown(html: str) -> str:

zerver/lib/send_email.py

@@ -33,17 +33,17 @@ class FromAddress:
             return parseaddr(settings.TOKENIZED_NOREPLY_EMAIL_ADDRESS)[1].format(token=generate_key())
         return FromAddress.NOREPLY
 
-def build_email(template_prefix: str, to_user_id: Optional[int]=None,
+def build_email(template_prefix: str, to_user_ids: Optional[List[int]]=None,
-                to_email: Optional[str]=None, from_name: Optional[str]=None,
+                to_emails: Optional[List[str]]=None, from_name: Optional[str]=None,
                 from_address: Optional[str]=None, reply_to_email: Optional[str]=None,
                 context: Optional[Dict[str, Any]]=None) -> EmailMultiAlternatives:
     # Callers should pass exactly one of to_user_id and to_email.
-    assert (to_user_id is None) ^ (to_email is None)
+    assert (to_user_ids is None) ^ (to_emails is None)
-    if to_user_id is not None:
+    if to_user_ids is not None:
-        to_user = get_user_profile_by_id(to_user_id)
+        to_users = [get_user_profile_by_id(to_user_id) for to_user_id in to_user_ids]
         # Change to formataddr((to_user.full_name, to_user.email)) once
         # https://github.com/zulip/zulip/issues/4676 is resolved
-        to_email = to_user.delivery_email
+        to_emails = [to_user.delivery_email for to_user in to_users]
 
     if context is None:
         context = {}
@@ -81,7 +81,7 @@ def build_email(template_prefix: str, to_user_id: Optional[int]=None,
     elif from_address == FromAddress.NOREPLY:
         reply_to = [FromAddress.NOREPLY]
 
-    mail = EmailMultiAlternatives(subject, message, from_email, [to_email], reply_to=reply_to)
+    mail = EmailMultiAlternatives(subject, message, from_email, to_emails, reply_to=reply_to)
     if html_message is not None:
         mail.attach_alternative(html_message, 'text/html')
     return mail
@@ -91,10 +91,11 @@ class EmailNotDeliveredException(Exception):
 
 # When changing the arguments to this function, you may need to write a
 # migration to change or remove any emails in ScheduledEmail.
-def send_email(template_prefix: str, to_user_id: Optional[int]=None, to_email: Optional[str]=None,
+def send_email(template_prefix: str, to_user_ids: Optional[List[int]]=None,
-               from_name: Optional[str]=None, from_address: Optional[str]=None,
+               to_emails: Optional[List[str]]=None, from_name: Optional[str]=None,
-               reply_to_email: Optional[str]=None, context: Dict[str, Any]={}) -> None:
+               from_address: Optional[str]=None, reply_to_email: Optional[str]=None,
-    mail = build_email(template_prefix, to_user_id=to_user_id, to_email=to_email, from_name=from_name,
+               context: Dict[str, Any]={}) -> None:
+    mail = build_email(template_prefix, to_user_ids=to_user_ids, to_emails=to_emails, from_name=from_name,
                        from_address=from_address, reply_to_email=reply_to_email, context=context)
     template = template_prefix.split("/")[-1]
     logger.info("Sending %s email to %s" % (template, mail.to))
@@ -106,27 +107,39 @@ def send_email(template_prefix: str, to_user_id: Optional[int]=None, to_email: O
 def send_email_from_dict(email_dict: Mapping[str, Any]) -> None:
     send_email(**dict(email_dict))
 
-def send_future_email(template_prefix: str, realm: Realm, to_user_id: Optional[int]=None,
+def send_future_email(template_prefix: str, realm: Realm, to_user_ids: Optional[List[int]]=None,
-                      to_email: Optional[str]=None, from_name: Optional[str]=None,
+                      to_emails: Optional[List[str]]=None, from_name: Optional[str]=None,
                       from_address: Optional[str]=None, context: Dict[str, Any]={},
                       delay: datetime.timedelta=datetime.timedelta(0)) -> None:
+    # WARNING: Be careful when using this with multiple recipients;
+    # because the current ScheduledEmail model (used primarily for
+    # cancelling planned emails) does not support multiple recipients,
+    # this is only valid to use for such emails where we don't expect
+    # the cancellation feature to be relevant.
+    #
+    # For that reason, we currently assert that the list of
+    # to_user_ids/to_emails is 1 below, but in theory that could be
+    # changed as long as the callers are in a situation where the
+    # above problem is not relevant.
     template_name = template_prefix.split('/')[-1]
-    email_fields = {'template_prefix': template_prefix, 'to_user_id': to_user_id, 'to_email': to_email,
+    email_fields = {'template_prefix': template_prefix, 'to_user_ids': to_user_ids, 'to_emails': to_emails,
                     'from_name': from_name, 'from_address': from_address, 'context': context}
 
     if settings.DEVELOPMENT and not settings.TEST_SUITE:
-        send_email(template_prefix, to_user_id=to_user_id, to_email=to_email, from_name=from_name,
+        send_email(template_prefix, to_user_ids=to_user_ids, to_emails=to_emails, from_name=from_name,
                    from_address=from_address, context=context)
         # For logging the email
 
-    assert (to_user_id is None) ^ (to_email is None)
+    assert (to_user_ids is None) ^ (to_emails is None)
-    if to_user_id is not None:
+    if to_user_ids is not None:
         # The realm is redundant if we have a to_user_id; this assert just
         # expresses that fact
-        assert(UserProfile.objects.filter(id=to_user_id, realm=realm).exists())
+        assert(len(to_user_ids) == 1)
-        to_field = {'user_id': to_user_id}  # type: Dict[str, Any]
+        assert(UserProfile.objects.filter(id__in=to_user_ids, realm=realm).exists())
+        to_field = {'user_id': to_user_ids[0]}  # type: Dict[str, Any]
     else:
-        to_field = {'address': parseaddr(to_email)[1]}
+        assert(len(to_emails) == 1)
+        to_field = {'address': parseaddr(to_emails[0])[1]}
 
     ScheduledEmail.objects.create(
         type=EMAIL_TYPES[template_name],
@@ -134,3 +147,10 @@ def send_future_email(template_prefix: str, realm: Realm, to_user_id: Optional[i
         realm=realm,
         data=ujson.dumps(email_fields),
         **to_field)
+
+def send_email_to_admins(template_prefix: str, realm: Realm, from_name: Optional[str]=None,
+                         from_address: Optional[str]=None, context: Dict[str, Any]={}) -> None:
+    admins = realm.get_admin_users()
+    admin_user_ids = [admin.id for admin in admins]
+    send_email(template_prefix, to_user_ids=admin_user_ids, from_name=from_name,
+               from_address=from_address, context=context)

zerver/management/commands/deliver_email.py

@@ -48,6 +48,14 @@ Usage: ./manage.py deliver_email
                     scheduled_timestamp__lte=timezone_now())
                 if email_jobs_to_deliver:
                     for job in email_jobs_to_deliver:
+                        # Reformat any jobs that used the old to_email
+                        # and to_user_ids argument formats.
+                        if 'to_email' in job:
+                            job['to_emails'] = [job['to_email']]
+                            del job['to_email']
+                        if 'to_user_ids' in job:
+                            job['to_user_ids'] = [job['to_user_id']]
+                            del job['to_user_ids']
                         try:
                             send_email(**loads(job.data))
                             job.delete()

zerver/management/commands/send_password_reset_email.py

@@ -47,6 +47,6 @@ class Command(ZulipBaseCommand):
                 'realm_uri': user_profile.realm.uri,
                 'active_account_in_realm': True,
             }
-            send_email('zerver/emails/password_reset', to_user_id=user_profile.id,
+            send_email('zerver/emails/password_reset', to_user_ids=[user_profile.id],
                        from_address=FromAddress.tokenized_no_reply_address(),
                        from_name="Zulip Account Security", context=context)

zerver/signals.py

@@ -96,7 +96,7 @@ def email_on_new_login(sender: Any, user: UserProfile, request: Any, **kwargs: A
 
         email_dict = {
             'template_prefix': 'zerver/emails/notify_new_login',
-            'to_user_id': user.id,
+            'to_user_ids': [user.id],
             'from_name': 'Zulip Account Security',
             'from_address': FromAddress.NOREPLY,
             'context': context}

zerver/tests/test_digest.py

@@ -40,7 +40,7 @@ class TestDigestEmailMessages(ZulipTestCase):
         self.assertEqual(mock_send_future_email.call_count, 1)
 
         kwargs = mock_send_future_email.call_args[1]
-        self.assertEqual(kwargs['to_user_id'], user_profile.id)
+        self.assertEqual(kwargs['to_user_ids'], [user_profile.id])
         html = kwargs['context']['unread_pms'][0]['header']['html']
         expected_url = "'http://zulip.testserver/#narrow/pm-with/{id}-hamlet'".format(id=hamlet.id)
         self.assertIn(expected_url, html)
@@ -74,7 +74,7 @@ class TestDigestEmailMessages(ZulipTestCase):
         self.assertEqual(mock_send_future_email.call_count, 1)
 
         kwargs = mock_send_future_email.call_args[1]
-        self.assertEqual(kwargs['to_user_id'], user_profile.id)
+        self.assertEqual(kwargs['to_user_ids'], [user_profile.id])
         html = kwargs['context']['unread_pms'][0]['header']['html']
 
         other_user_ids = sorted([
@@ -125,7 +125,7 @@ class TestDigestEmailMessages(ZulipTestCase):
 
         self.assertEqual(mock_send_future_email.call_count, 1)
         kwargs = mock_send_future_email.call_args[1]
-        self.assertEqual(kwargs['to_user_id'], othello.id)
+        self.assertEqual(kwargs['to_user_ids'], [othello.id])
 
         hot_convo = kwargs['context']['hot_conversations'][0]
 

zerver/tests/test_queue_worker.py

@@ -248,7 +248,7 @@ class WorkerTest(ZulipTestCase):
 
         data = {
             'template_prefix': 'zerver/emails/confirm_new_email',
-            'to_email': self.example_email("hamlet"),
+            'to_emails': [self.example_email("hamlet")],
             'from_name': 'Zulip Account Security',
             'from_address': FromAddress.NOREPLY,
             'context': {}

zerver/tests/test_realm.py

@@ -182,7 +182,7 @@ class RealmTest(ZulipTestCase):
     def test_do_deactivate_realm_clears_scheduled_jobs(self) -> None:
         user = self.example_user('hamlet')
         send_future_email('zerver/emails/followup_day1', user.realm,
-                          to_user_id=user.id, delay=datetime.timedelta(hours=1))
+                          to_user_ids=[user.id], delay=datetime.timedelta(hours=1))
         self.assertEqual(ScheduledEmail.objects.count(), 1)
         do_deactivate_realm(user.realm)
         self.assertEqual(ScheduledEmail.objects.count(), 0)

zerver/tests/test_signup.py

@@ -1159,8 +1159,9 @@ so we didn't send them an invitation. We did send invitations to everyone else!"
             'referrer_realm_name': referrer.realm.name,
         })
         with self.settings(EMAIL_BACKEND='django.core.mail.backends.console.EmailBackend'):
+            email = data["email"]
             send_future_email(
-                "zerver/emails/invitation_reminder", referrer.realm, to_email=data["email"],
+                "zerver/emails/invitation_reminder", referrer.realm, to_emails=[email],
                 from_address=FromAddress.NOREPLY, context=context)
         email_jobs_to_deliver = ScheduledEmail.objects.filter(
             scheduled_timestamp__lte=timezone_now())
@@ -1553,7 +1554,7 @@ class EmailUnsubscribeTests(ZulipTestCase):
         context = {'name': '', 'realm_uri': '', 'unread_pms': [], 'hot_conversations': [],
                    'new_users': [], 'new_streams': {'plain': []}, 'unsubscribe_link': ''}
         send_future_email('zerver/emails/digest', user_profile.realm,
-                          to_user_id=user_profile.id, context=context)
+                          to_user_ids=[user_profile.id], context=context)
 
         self.assertEqual(1, ScheduledEmail.objects.filter(user=user_profile).count())
 

zerver/tests/test_users.py

@@ -810,7 +810,7 @@ class ActivateTest(ZulipTestCase):
     def test_clear_scheduled_jobs(self) -> None:
         user = self.example_user('hamlet')
         send_future_email('zerver/emails/followup_day1', user.realm,
-                          to_user_id=user.id, delay=datetime.timedelta(hours=1))
+                          to_user_ids=[user.id], delay=datetime.timedelta(hours=1))
         self.assertEqual(ScheduledEmail.objects.count(), 1)
         do_deactivate_user(user)
         self.assertEqual(ScheduledEmail.objects.count(), 0)

zerver/views/registration.py

@@ -360,7 +360,7 @@ def prepare_activation_url(email: str, request: HttpRequest,
     return activation_url
 
 def send_confirm_registration_email(email: str, activation_url: str) -> None:
-    send_email('zerver/emails/confirm_registration', to_email=email,
+    send_email('zerver/emails/confirm_registration', to_emails=[email],
                from_address=FromAddress.tokenized_no_reply_address(),
                context={'activate_url': activation_url})
 
@@ -490,7 +490,7 @@ def find_account(request: HttpRequest) -> HttpResponse:
                     'realm_uri': user_profile.realm.uri,
                     'realm_name': user_profile.realm.name,
                 }
-                send_email('zerver/emails/find_team', to_user_id=user_profile.id, context=ctx)
+                send_email('zerver/emails/find_team', to_user_ids=[user_profile.id], context=ctx)
 
             # Note: Show all the emails in the result otherwise this
             # feature can be used to ascertain which email addresses

zerver/views/user_settings.py

@@ -42,7 +42,7 @@ def confirm_email_change(request: HttpRequest, confirmation_key: str) -> HttpRes
     do_change_user_email(user_profile, new_email)
 
     context = {'realm_name': user_profile.realm.name, 'new_email': new_email}
-    send_email('zerver/emails/notify_change_in_email', to_email=old_email,
+    send_email('zerver/emails/notify_change_in_email', to_emails=[old_email],
                from_name="Zulip Account Security", from_address=FromAddress.SUPPORT,
                context=context)
 

zerver/worker/queue_processors.py

@@ -232,7 +232,7 @@ class ConfirmationEmailWorker(QueueProcessingWorker):
         send_future_email(
             "zerver/emails/invitation_reminder",
             referrer.realm,
-            to_email=invitee.email,
+            to_emails=[invitee.email],
             from_address=FromAddress.tokenized_no_reply_address(),
             context=context,
             delay=datetime.timedelta(days=2))