Add unsubscribe links to digest e-mails.

(imported from commit 4e2a324decf4bc694752cc24b9085361338a08a5)

templates/zerver/emails/digest/digest_email.txt

@@ -52,4 +52,11 @@ Click here to log in to Zulip and catch up: https://{{ external_host }}.
 Cheers,
 The Zulip Team
 
-To disable future email notifications, please visit https://{{ external_host }}/#settings.
+--
+Manage email preferences:
+
+https://{{ external_host }}/#settings
+
+Unsubscribe from digest emails:
+
+{{ unsubscribe_link }}

templates/zerver/emails/digest/digest_email_html.txt

@@ -95,5 +95,7 @@ Here are some of the hot conversations that have happened while you've been gone
 <br>
 The Zulip Team</p>
 
-<p>To disable future email notifications, please visit your <a
-href="https://{{ external_host }}/#settings">Zulip Settings page</a>.</p>
+<p>
+  <a href="https://{{ external_host }}/#settings">Manage email preferences</a> |
+  <a href="{{ unsubscribe_link }}">Unsubscribe from digest emails</a>
+</p>

zerver/lib/actions.py

@@ -1223,6 +1223,19 @@ def do_change_enable_offline_push_notifications(user_profile, offline_push_notif
                    'user': user_profile.email,
                    'enable_offline_push_notifications': offline_push_notifications})
 
+def do_change_enable_digest_emails(user_profile, enable_digest_emails, log=True):
+    user_profile.enable_digest_emails = enable_digest_emails
+    user_profile.save(update_fields=["enable_digest_emails"])
+
+    if not enable_digest_emails:
+        # Remove any digest emails that have been enqueued.
+        clear_followup_emails_queue(user_profile.email)
+
+    if log:
+        log_event({'type': 'enable_digest_emails',
+                   'user': user_profile.email,
+                   'enable_digest_emails': enable_digest_emails})
+
 def do_change_enter_sends(user_profile, enter_sends):
     user_profile.enter_sends = enter_sends
     user_profile.save(update_fields=["enter_sends"])

zerver/lib/digest.py

@@ -8,7 +8,7 @@ from django.template import loader
 from django.conf import settings
 
 from zerver.lib.actions import build_message_list, hashchange_encode, \
-    send_future_email
+    send_future_email, one_click_unsubscribe_link
 from zerver.models import UserProfile, UserMessage, Recipient, Stream, \
     Subscription
 
@@ -118,7 +118,11 @@ def handle_digest_email(user_profile_id, cutoff):
         message__pub_date__gt=cutoff).order_by("message__pub_date")
 
     # Start building email template data.
-    template_payload = {'name': user_profile.full_name, 'external_host': settings.EXTERNAL_HOST}
+    template_payload = {
+        'name': user_profile.full_name,
+        'external_host': settings.EXTERNAL_HOST,
+        'unsubscribe_link': one_click_unsubscribe_link(user_profile, "digest")
+        }
 
     # Gather recent missed PMs, re-using the missed PM email logic.
     pms = all_messages.filter(~Q(message__recipient__type=Recipient.STREAM))

zerver/views/__init__.py

@@ -34,7 +34,7 @@ from zerver.lib.actions import bulk_remove_subscriptions, \
     update_user_presence, bulk_add_subscriptions, do_update_message_flags, \
     recipient_for_emails, extract_recipients, do_events_register, \
     get_status_dict, do_change_enable_offline_email_notifications, \
-    do_update_message, internal_prep_message, \
+    do_change_enable_digest_emails, do_update_message, internal_prep_message, \
     do_send_messages, get_default_subs, do_deactivate_user, do_reactivate_user, \
     user_email_is_unique, do_invite_users, do_refer_friend, compute_mit_user_fullname, \
     do_add_alert_words, do_remove_alert_words, do_set_alert_words, get_subscriber_emails, \
@@ -2352,13 +2352,17 @@ def do_missedmessage_unsubscribe(user_profile):
 def do_welcome_unsubscribe(user_profile):
     clear_followup_emails_queue(user_profile.email)
 
+def do_digest_unsubscribe(user_profile):
+    do_change_enable_digest_emails(user_profile, False)
+
 # The keys are part of the URL for the unsubscribe link and must be valid
 # without encoding.
 # The values are a tuple of (display name, unsubscribe function), where the
 # display name is what we call this class of email in user-visible text.
 email_unsubscribers = {
     "missed_messages": ("missed messages", do_missedmessage_unsubscribe),
-    "welcome": ("welcome", do_welcome_unsubscribe)
+    "welcome": ("welcome", do_welcome_unsubscribe),
+    "digest": ("digest", do_digest_unsubscribe)
     }
 
 # Login NOT required. These are for one-click unsubscribes.