Fix: Postmark tracking webhook handle SubscriptionChange events

Handle Postmark SubscriptionChange events as Anymail 
unsubscribe, subscribe, or bounce Anymail tracking events.

CHANGELOG.rst

@@ -25,6 +25,19 @@ Release history
 ^^^^^^^^^^^^^^^
     ..  This extra heading level keeps the ToC from becoming unmanageably long
 
+vNext
+-----
+
+*Unreleased changes*
+
+Fixes
+~~~~~
+
+* **Postmark:** Handle Postmark's SubscriptionChange events as Anymail
+  unsubscribe, subscribe, or bounce tracking events, rather than "unknown".
+  (Thanks to `@puru02`_ for the fix.)
+
+
 v8.6 LTS
 --------
 
@@ -1344,6 +1357,7 @@ Features
 .. _@mbk-ok: https://github.com/mbk-ok
 .. _@mwheels: https://github.com/mwheels
 .. _@nuschk: https://github.com/nuschk
+.. _@puru02: https://github.com/puru02
 .. _@RignonNoel: https://github.com/RignonNoel
 .. _@sebashwa: https://github.com/sebashwa
 .. _@sebbacon: https://github.com/sebbacon

anymail/webhooks/postmark.py

@@ -34,6 +34,7 @@ class PostmarkTrackingWebhookView(PostmarkBaseWebhookView):
         'Delivery': EventType.DELIVERED,
         'Open': EventType.OPENED,
         'SpamComplaint': EventType.COMPLAINED,
+        'SubscriptionChange': EventType.UNSUBSCRIBED,
         'Inbound': EventType.INBOUND,  # future, probably
     }
 
@@ -61,6 +62,7 @@ class PostmarkTrackingWebhookView(PostmarkBaseWebhookView):
         'InboundError': (EventType.INBOUND_FAILED, None),
         'DMARCPolicy': (EventType.REJECTED, RejectReason.BLOCKED),
         'TemplateRenderingFailed': (EventType.FAILED, None),
+        'ManualSuppression': (EventType.UNSUBSCRIBED, RejectReason.UNSUBSCRIBED),
     }
 
     def esp_to_anymail_event(self, esp_event):
@@ -87,11 +89,21 @@ class PostmarkTrackingWebhookView(PostmarkBaseWebhookView):
                 event_type, reject_reason = self.event_types[esp_event['Type']]
             except KeyError:
                 pass
+        if event_type == EventType.UNSUBSCRIBED:
+            if esp_event['SuppressSending']:
+                # Postmark doesn't provide a way to distinguish between
+                # explicit unsubscribes and bounces
+                try:
+                    event_type, reject_reason = self.event_types[esp_event['SuppressionReason']]
+                except KeyError:
+                    pass
+            else:
+                event_type, reject_reason = self.event_types['Subscribe']
 
         recipient = getfirst(esp_event, ['Email', 'Recipient'], None)  # Email for bounce; Recipient for open
 
         try:
-            timestr = getfirst(esp_event, ['DeliveredAt', 'BouncedAt', 'ReceivedAt'])
+            timestr = getfirst(esp_event, ['DeliveredAt', 'BouncedAt', 'ReceivedAt', 'ChangedAt'])
         except KeyError:
             timestamp = None
         else:

tests/test_postmark_webhooks.py

@@ -220,3 +220,96 @@ class PostmarkDeliveryTestCase(WebhookTestCase):
         with self.assertRaisesMessage(AnymailConfigurationError, errmsg):
             self.client.post('/anymail/postmark/tracking/', content_type='application/json',
                              data=json.dumps({"RecordType": "Inbound"}))
+
+    def test_unsubscribe(self):
+        raw_event = {
+            "RecordType": "SubscriptionChange",
+            "MessageID": "a4909a96-73d7-4c49-b148-a54522d3f7ac",
+            "ServerID": 23,
+            "MessageStream": "outbound",
+            "ChangedAt": "2022-06-05T17:17:32Z",
+            "Recipient": "john@example.com",
+            "Origin": "Recipient",
+            "SuppressSending": True,
+            "SuppressionReason": "ManualSuppression",
+            "Tag": "welcome-email",
+            "Metadata": {
+                "example": "value",
+                "example_2": "value"
+            }
+        }
+        response = self.client.post('/anymail/postmark/tracking/',
+                                    content_type='application/json', data=json.dumps(raw_event))
+        self.assertEqual(response.status_code, 200)
+        kwargs = self.assert_handler_called_once_with(self.tracking_handler, sender=PostmarkTrackingWebhookView,
+                                                      event=ANY, esp_name='Postmark')
+        event = kwargs['event']
+        self.assertIsInstance(event, AnymailTrackingEvent)
+        self.assertEqual(event.event_type, "unsubscribed")
+        self.assertEqual(event.esp_event, raw_event)
+        self.assertEqual(event.timestamp, datetime(2022, 6, 5, 17, 17, 32, tzinfo=utc))
+        self.assertEqual(event.message_id, "a4909a96-73d7-4c49-b148-a54522d3f7ac")
+        self.assertEqual(event.recipient, "john@example.com",)
+        self.assertEqual(event.reject_reason, "unsubscribed")
+
+    def test_resubscribe(self):
+        raw_event = {
+            "RecordType": "SubscriptionChange",
+            "MessageID": "a4909a96-73d7-4c49-b148-a54522d3f7ac",
+            "ServerID": 23,
+            "MessageStream": "outbound",
+            "ChangedAt": "2022-06-05T17:17:32Z",
+            "Recipient": "john@example.com",
+            "Origin": "Recipient",
+            "SuppressSending": False,
+            "SuppressionReason": None,
+            "Tag": "welcome-email",
+            "Metadata": {
+                "example": "value",
+                "example_2": "value"
+            }
+        }
+        response = self.client.post('/anymail/postmark/tracking/',
+                                    content_type='application/json', data=json.dumps(raw_event))
+        self.assertEqual(response.status_code, 200)
+        kwargs = self.assert_handler_called_once_with(self.tracking_handler, sender=PostmarkTrackingWebhookView,
+                                                      event=ANY, esp_name='Postmark')
+        event = kwargs['event']
+        self.assertIsInstance(event, AnymailTrackingEvent)
+        self.assertEqual(event.event_type, "subscribed")
+        self.assertEqual(event.esp_event, raw_event)
+        self.assertEqual(event.timestamp, datetime(2022, 6, 5, 17, 17, 32, tzinfo=utc))
+        self.assertEqual(event.message_id, "a4909a96-73d7-4c49-b148-a54522d3f7ac")
+        self.assertEqual(event.recipient, "john@example.com",)
+        self.assertEqual(event.reject_reason, None)
+
+    def test_subscription_change_bounce(self):
+        raw_event = {
+            "RecordType": "SubscriptionChange",
+            "MessageID": "b4cb783d-78ed-43f2-983b-63f55c712dc8",
+            "ServerID": 23,
+            "MessageStream": "outbound",
+            "ChangedAt": "2022-06-05T17:17:32Z",
+            "Recipient": "john@example.com",
+            "Origin": "Recipient",
+            "SuppressSending": True,
+            "SuppressionReason": "HardBounce",
+            "Tag": "my-tag",
+            "Metadata": {
+                "example": "value",
+                "example_2": "value"
+            }
+        }
+        response = self.client.post('/anymail/postmark/tracking/',
+                                    content_type='application/json', data=json.dumps(raw_event))
+        self.assertEqual(response.status_code, 200)
+        kwargs = self.assert_handler_called_once_with(self.tracking_handler, sender=PostmarkTrackingWebhookView,
+                                                      event=ANY, esp_name='Postmark')
+        event = kwargs['event']
+        self.assertIsInstance(event, AnymailTrackingEvent)
+        self.assertEqual(event.event_type, "bounced")
+        self.assertEqual(event.esp_event, raw_event)
+        self.assertEqual(event.timestamp, datetime(2022, 6, 5, 17, 17, 32,  tzinfo=utc))
+        self.assertEqual(event.message_id, "b4cb783d-78ed-43f2-983b-63f55c712dc8")
+        self.assertEqual(event.recipient, "john@example.com",)
+        self.assertEqual(event.reject_reason, "bounced")