Ignore new data coming from Adyen

When we migrated our Adyen account to the new 'systems communications'
interface, we started getting new data, which caused 500s. As all of it
comes in the 'additionalData.KEY = value' format and we don't need it,
we just blanket ignore it for now.

README.rst

@@ -76,6 +76,10 @@ See `adyen.settings_config.FromSettingsConfig` for an example.
 Changes
 =======
 
+0.4.1 - unreleased
+------------------
+- ignore additional data sent by Adyen's new-style system communications
+
 0.4.0 - released July 14th, 2015
 --------------------------------
 

adyen/gateway.py

@@ -60,6 +60,7 @@ class Constants:
     SESSION_VALIDITY = 'sessionValidity'
     SKIN_CODE = 'skinCode'
     SHIP_BEFORE_DATE = 'shipBeforeDate'
+    ADDITIONAL_DATA_PREFIX = 'additionalData.'
 
     SHOPPER_EMAIL = 'shopperEmail'
     SHOPPER_LOCALE = 'shopperLocale'
@@ -313,6 +314,16 @@ def process(self):
 
 
 class PaymentNotification(BaseResponse):
+    """
+    Class used to process payment notifications (HTTPS POST from Adyen to our servers).
+
+    Payment notifications can have multiple fields. They fall into four categories:
+    - required: Must be included.
+    - optional: Can be included.
+    - additional data: Can be included. Format is 'additionalData.VALUE' and we don't need the
+                       data at the moment, so it's ignored.
+    - unexpected: We loudly complain.
+    """
     REQUIRED_FIELDS = (
         Constants.CURRENCY,
         Constants.EVENT_CODE,
@@ -331,6 +342,25 @@ class PaymentNotification(BaseResponse):
         Constants.ORIGINAL_REFERENCE,
     )
 
+    def check_fields(self):
+        """
+        Delete unneeded additional data before validating.
+
+        Adyen's payment notification can come with additional data.
+        It can mostly be turned on and off in the notifications settings,
+        but some bits always seem to be delivered with the new
+        "System communication" setup (instead of the old "notifications" tab
+        in the settings).
+        We currently don't need any of that data, so we just drop it
+        before validating the response.
+        :return:
+        """
+        self.params = {
+            key: self.params[key]
+            for key in self.params if Constants.ADDITIONAL_DATA_PREFIX not in key
+        }
+        super().check_fields()
+
     def process(self):
         payment_result = self.params.get(Constants.SUCCESS, None)
         accepted = payment_result == Constants.TRUE

tests/test_adyen.py

@@ -9,7 +9,8 @@
 
 from freezegun import freeze_time
 
-from adyen.gateway import MissingFieldException, InvalidTransactionException
+from adyen.gateway import MissingFieldException, InvalidTransactionException, PaymentNotification, \
+    Constants, UnexpectedFieldException
 from adyen.models import AdyenTransaction
 from adyen.scaffold import Scaffold
 from adyen.facade import Facade
@@ -440,3 +441,47 @@ def test_assert_duplicate_notifications(self):
         # any more. But we still acknowledge it.
         assert (False, True) == self.scaffold.assess_notification_relevance(self.request)
 
+
+class MockClient:
+    secret_key = None
+
+
+class PaymentNotificationTestCase(TestCase):
+
+    def create_mock_notification(self, required=True, optional=False, additional=False):
+        keys_to_set = []
+        if required:
+            keys_to_set += PaymentNotification.REQUIRED_FIELDS
+        if optional:
+            keys_to_set += PaymentNotification.OPTIONAL_FIELDS
+        if additional:
+            keys_to_set += [Constants.ADDITIONAL_DATA_PREFIX + 'foo']
+        params = {key: 'FOO' for key in keys_to_set}
+
+        return PaymentNotification(MockClient(), params)
+
+    def test_required_fields_are_required(self):
+        notification = self.create_mock_notification(
+            required=False, optional=True, additional=True)
+        with self.assertRaises(MissingFieldException):
+            notification.check_fields()
+
+    def test_unknown_fields_cause_exception(self):
+        notification = self.create_mock_notification(
+            required=True, optional=False, additional=False)
+        notification.params['UNKNOWN_FIELD'] = 'foo'
+
+        with self.assertRaises(UnexpectedFieldException):
+            notification.check_fields()
+
+    def test_optional_fields_are_optional(self):
+        notification = self.create_mock_notification(
+            required=True, optional=False, additional=False)
+
+        notification.check_fields()
+
+    def test_additional_fields_are_ignored(self):
+        notification = self.create_mock_notification(
+            required=True, optional=False, additional=True)
+
+        notification.check_fields()