Webhooks: default tracking event tags=[], metadata={}

If a tracking event doesn't contain tags or metadata, set the event
record fields to tags=[] or metadata={} to simplify checking values.

Closes #67

anymail/signals.py

@@ -32,11 +32,11 @@ class AnymailTrackingEvent(AnymailEvent):
         self.click_url = kwargs.pop('click_url', None)  # str
         self.description = kwargs.pop('description', None)  # str, usually human-readable, not normalized
         self.message_id = kwargs.pop('message_id', None)  # str, format may vary
-        self.metadata = kwargs.pop('metadata', None)  # dict
+        self.metadata = kwargs.pop('metadata', {})  # dict
         self.mta_response = kwargs.pop('mta_response', None)  # str, may include SMTP codes, not normalized
         self.recipient = kwargs.pop('recipient', None)  # str email address (just the email portion; no name)
         self.reject_reason = kwargs.pop('reject_reason', None)  # normalized to a RejectReason str
-        self.tags = kwargs.pop('tags', None)  # list of str
+        self.tags = kwargs.pop('tags', [])  # list of str
         self.user_agent = kwargs.pop('user_agent', None)  # str
 
 

anymail/webhooks/mailgun.py

@@ -113,7 +113,7 @@ class MailgunTrackingWebhookView(MailgunBaseWebhookView):
         try:
             headers = json.loads(esp_event['message-headers'])
         except (KeyError, ):
-            metadata = None
+            metadata = {}
         else:
             variables = [value for [field, value] in headers
                          if field == 'X-Mailgun-Variables']
@@ -121,10 +121,10 @@ class MailgunTrackingWebhookView(MailgunBaseWebhookView):
                 # Each X-Mailgun-Variables value is JSON. Parse and merge them all into single dict:
                 metadata = combine(*[json.loads(value) for value in variables])
             else:
-                metadata = None
+                metadata = {}
 
         # tags are sometimes delivered as X-Mailgun-Tag fields, sometimes as tag
-        tags = esp_event.getlist('tag', esp_event.getlist('X-Mailgun-Tag', None))
+        tags = esp_event.getlist('tag', esp_event.getlist('X-Mailgun-Tag', []))
 
         return AnymailTrackingEvent(
             event_type=event_type,

anymail/webhooks/mandrill.py

@@ -128,12 +128,12 @@ class MandrillTrackingWebhookView(MandrillBaseWebhookView):
         try:
             metadata = esp_event['msg']['metadata']
         except KeyError:
-            metadata = None
+            metadata = {}
 
         try:
             tags = esp_event['msg']['tags']
         except KeyError:
-            tags = None
+            tags = []
 
         return AnymailTrackingEvent(
             click_url=esp_event.get('url', None),

anymail/webhooks/postmark.py

@@ -89,7 +89,7 @@ class PostmarkTrackingWebhookView(PostmarkBaseWebhookView):
         try:
             tags = [esp_event['Tag']]
         except KeyError:
-            tags = None
+            tags = []
 
         return AnymailTrackingEvent(
             description=esp_event.get('Description', None),

anymail/webhooks/sendgrid.py

@@ -72,7 +72,7 @@ class SendGridTrackingWebhookView(SendGridBaseWebhookView):
         if len(metadata_keys) > 0:
             metadata = {key: esp_event[key] for key in metadata_keys}
         else:
-            metadata = None
+            metadata = {}
 
         return AnymailTrackingEvent(
             event_type=event_type,
@@ -82,7 +82,7 @@ class SendGridTrackingWebhookView(SendGridBaseWebhookView):
             recipient=esp_event.get('email', None),
             reject_reason=reject_reason,
             mta_response=mta_response,
-            tags=esp_event.get('category', None),
+            tags=esp_event.get('category', []),
             metadata=metadata,
             click_url=esp_event.get('url', None),
             user_agent=esp_event.get('useragent', None),

anymail/webhooks/sparkpost.py

@@ -108,7 +108,7 @@ class SparkPostTrackingWebhookView(SparkPostBaseWebhookView):
             tag = event['campaign_id']  # not 'rcpt_tags' -- those don't come from sending a message
             tags = [tag] if tag else None
         except KeyError:
-            tags = None
+            tags = []
 
         try:
             reject_reason = self.reject_reasons.get(event['bounce_class'], RejectReason.OTHER)
@@ -129,7 +129,7 @@ class SparkPostTrackingWebhookView(SparkPostBaseWebhookView):
             mta_response=event.get('raw_reason', None),
             # description=???,
             tags=tags,
-            metadata=event.get('rcpt_meta', None) or None,  # message + recipient metadata
+            metadata=event.get('rcpt_meta', None) or {},  # message + recipient metadata
             click_url=event.get('target_link_url', None),
             user_agent=event.get('user_agent', None),
             esp_event=raw_event,

docs/sending/tracking.rst

@@ -139,12 +139,14 @@ Normalized tracking event
 
     .. attribute:: metadata
 
-        A `dict` of unique data attached to the message, or `None`.
+        A `dict` of unique data attached to the message. Will be empty if the ESP
+        doesn't provide metadata with its tracking events.
         (See :attr:`AnymailMessage.metadata <anymail.message.AnymailMessage.metadata>`.)
 
     .. attribute:: tags
 
-        A `list` of `str` tags attached to the message, or `None`.
+        A `list` of `str` tags attached to the message. Will be empty if the ESP
+        doesn't provide tags with its tracking events.
         (See :attr:`AnymailMessage.tags <anymail.message.AnymailMessage.tags>`.)
 
     .. attribute:: reject_reason

tests/test_mailgun_webhooks.py

@@ -109,6 +109,8 @@ class MailgunDeliveryTestCase(WebhookTestCase):
         self.assertEqual(event.event_id, "06c96bafc3f42a66b9edd546347a2fe18dc23461fe80dc52f0")
         self.assertEqual(event.recipient, "recipient@example.com")
         self.assertEqual(querydict_to_postdict(event.esp_event), raw_event)
+        self.assertEqual(event.tags, [])
+        self.assertEqual(event.metadata, {})
 
     def test_dropped_bounce(self):
         raw_event = mailgun_sign({

tests/test_postmark_webhooks.py

@@ -78,6 +78,7 @@ class PostmarkDeliveryTestCase(WebhookTestCase):
         self.assertEqual(event.message_id, "883953f4-6105-42a2-a16a-77a8eac79483")
         self.assertEqual(event.recipient, "recipient@example.com")
         self.assertEqual(event.tags, ["welcome-email"])
+        self.assertEqual(event.metadata, {})
 
     def test_open_event(self):
         raw_event = {
@@ -106,3 +107,5 @@ class PostmarkDeliveryTestCase(WebhookTestCase):
         self.assertEqual(event.message_id, "f4830d10-9c35-4f0c-bca3-3d9b459821f8")
         self.assertEqual(event.recipient, "recipient@example.com")
         self.assertEqual(event.user_agent, "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0")
+        self.assertEqual(event.tags, [])
+        self.assertEqual(event.metadata, {})

tests/test_sendgrid_webhooks.py

@@ -73,8 +73,8 @@ class SendGridDeliveryTestCase(WebhookTestCase):
         self.assertEqual(event.event_id, "nOSv8m0eTQ-vxvwNwt3fZQ")
         self.assertEqual(event.recipient, "recipient@example.com")
         self.assertEqual(event.mta_response, "250 2.0.0 OK 1461095248 m143si2210036ioe.159 - gsmtp ")
-        self.assertEqual(event.tags, None)
+        self.assertEqual(event.tags, [])
-        self.assertEqual(event.metadata, None)
+        self.assertEqual(event.metadata, {})
 
     def test_dropped_invalid_event(self):
         raw_events = [{

tests/test_sparkpost_webhooks.py

@@ -97,8 +97,8 @@ class SparkPostDeliveryTestCase(WebhookTestCase):
         self.assertIsInstance(event, AnymailTrackingEvent)
         self.assertEqual(event.event_type, "delivered")
         self.assertEqual(event.recipient, "Recipient@example.com")
-        self.assertEqual(event.tags, None)
+        self.assertEqual(event.tags, [])
-        self.assertEqual(event.metadata, None)
+        self.assertEqual(event.metadata, {})
 
     def test_bounce_event(self):
         raw_events = [{