Add List-Unsubscribe-Post email header

hc/accounts/models.py

@@ -174,7 +174,11 @@ class Profile(models.Model):
 
         unsub_url = self.reports_unsub_url()
 
-        headers = {"List-Unsubscribe": "<%s>" % unsub_url, "X-Bounce-Url": unsub_url}
+        headers = {
+            "List-Unsubscribe": "<%s>" % unsub_url,
+            "X-Bounce-Url": unsub_url,
+            "List-Unsubscribe-Post": "List-Unsubscribe=One-Click",
+        }
 
         ctx = {
             "checks": checks,

hc/api/tests/test_notify.py

@@ -274,6 +274,7 @@ class NotifyTestCase(BaseTestCase):
         self.assertEqual(email.to[0], "alice@example.org")
         self.assertTrue("X-Bounce-Url" in email.extra_headers)
         self.assertTrue("List-Unsubscribe" in email.extra_headers)
+        self.assertTrue("List-Unsubscribe-Post" in email.extra_headers)
 
     def test_email_transport_handles_json_value(self):
         payload = {"value": "alice@example.org", "up": True, "down": True}

hc/api/tests/test_sendreports.py

@@ -46,6 +46,7 @@ class SendReportsTestCase(BaseTestCase):
 
         email = mail.outbox[0]
         self.assertTrue("List-Unsubscribe" in email.extra_headers)
+        self.assertTrue("List-Unsubscribe-Post" in email.extra_headers)
 
     def test_it_obeys_next_report_date(self):
         self.profile.next_report_date = now() + td(days=1)

hc/api/transports.py

@@ -61,7 +61,11 @@ class Email(Transport):
 
         unsub_link = self.channel.get_unsub_link()
 
-        headers = {"X-Bounce-Url": bounce_url, "List-Unsubscribe": "<%s>" % unsub_link}
+        headers = {
+            "X-Bounce-Url": bounce_url,
+            "List-Unsubscribe": "<%s>" % unsub_link,
+            "List-Unsubscribe-Post": "List-Unsubscribe=One-Click",
+        }
 
         try:
             # Look up the sorting preference for this email address