Allow django_backend to take advantage of message_streams

CONTRIBUTORS.md

@@ -28,5 +28,6 @@ Everyone that made python-postmark awesome
 - Nikolay Fominykh (https://github.com/tigrus)
 - Gabe Limon (https://github.com/gabelimon)
 - Olle Hellgren (https://github.com/anulaibar)
+- Harry Khanna (https://www.khanna.law/)
 
 (Did I miss anyone?)

README.md

@@ -68,6 +68,17 @@ mail = EmailMultiAlternatives(subject, msg_plain, from_email, recipients, connec
 mail.tag = tag
 mail.send()
 ```
+
+#### Setting the `message_stream`
+```python
+from django.core.mail import get_connection, EmailMultiAlternatives
+
+mail = EmailMultiAlternatives(subject, msg_plain, from_email, recipients, connection=connection, headers=headers)
+
+mail.message_stream = "broadcast"
+mail.send()
+```
+
 
 Tornado
 -------

postmark/django_backend.py

@@ -21,6 +21,12 @@ def __init__(self, *args, **kwargs):
         else:
             self.track_opens = getattr(settings, 'POSTMARK_TRACK_OPENS', False)
 
+        if 'message_stream' in kwargs:
+            self.message_stream = kwargs['message_stream']
+            del kwargs['message_stream']
+        else:
+            self.message_stream = None
+
         super(PMEmailMessage, self).__init__(*args, **kwargs)
 
 
@@ -38,6 +44,13 @@ def __init__(self, *args, **kwargs):
         else:
             self.track_opens = getattr(settings, 'POSTMARK_TRACK_OPENS', False)
 
+        if 'message_stream' in kwargs:
+            self.message_stream = kwargs['message_stream']
+            del kwargs['message_stream']
+        else:
+            self.message_stream = None
+
+
         super(PMEmailMultiAlternatives, self).__init__(*args, **kwargs)
 
 
@@ -117,6 +130,7 @@ def _build_message(self, message):
                     else:
                         attachments.append(item)
 
+        message_stream = getattr(message, 'message_stream', None)
         postmark_message = PMMail(api_key=self.api_key,
                                   subject=message.subject,
                                   sender=message.from_email,
@@ -127,7 +141,8 @@ def _build_message(self, message):
                                   html_body=html_body,
                                   reply_to=reply_to,
                                   custom_headers=custom_headers,
-                                  attachments=attachments)
+                                  attachments=attachments,
+                                  message_stream=message_stream)
 
         postmark_message.tag = getattr(message, 'tag', None)
         postmark_message.track_opens = getattr(message, 'track_opens', False)

tests.py

@@ -416,6 +416,21 @@ def test_send_attachment_bytes(self):
         with mock.patch('postmark.core.urlopen', side_effect=HTTPError('', 200, '', {}, None)):
             message.send()
 
+    def test_message_stream(self):
+        message = EmailMultiAlternatives(
+            connection=EmailBackend(api_key='dummy'),
+            from_email='from@test.com', to=['recipient@test.com'], subject='html test', body='hello there'
+        )
+        message.attach_alternative('<b>hello</b> there', 'text/html')
+        message.message_stream = 'broadcast'
+
+        with mock.patch('postmark.core.urlopen', side_effect=HTTPError('', 200, '', {}, None)) as transport:
+            message.send()
+            data = json.loads(transport.call_args[0][0].data.decode('utf-8'))
+            self.assertEqual('broadcast', data['MessageStream'])
+            self.assertEqual('hello there', data['TextBody'])
+            self.assertEqual('<b>hello</b> there', data['HtmlBody'])
+
 
 
 if __name__ == '__main__':