fix(pubsub): accept messages without data

src/firebase_functions/pubsub_fn.py

@@ -41,30 +41,32 @@ class Message(_typing.Generic[T]):
     Autogenerated ID that uniquely identifies this message.
     """
 
-    publish_time: str
+    publish_time: _dt.datetime
     """
-    Time the message was published.
+    Time the message was published, as a timezone-aware datetime.
     """
 
     attributes: dict[str, str]
     """
     User-defined attributes published with the message, if any.
     """
 
-    data: str
+    data: str | None = None
     """
-    The data payload of this message object as a base64-encoded string.
+    The data payload of this message object as a base64-encoded string,
+    or `None` if the message was published without a payload.
     """
 
-    ordering_key: str
+    ordering_key: str | None = None
     """
-    User-defined key used to ensure ordering amongst messages with the same key.
+    User-defined key used to ensure ordering amongst messages with the same key,
+    or `None` if the message was published without one.
     """
 
     @property
     def json(self) -> T | None:
         try:
-            if self.data is not None:
+            if self.data:
                 return _json.loads(_base64.b64decode(self.data).decode("utf-8"))
             else:
                 return None

tests/test_pubsub_fn.py

@@ -29,6 +29,33 @@
 )
 
 
+def _raw_event(message: dict, time: str = "2023-03-11T13:25:37.403Z") -> _CloudEvent:
+    return _CloudEvent(
+        attributes={
+            "id": "test-message",
+            "source": "https://example.com/pubsub",
+            "specversion": "1.0",
+            "time": time,
+            "type": "com.example.pubsub.message",
+        },
+        data={
+            "message": {
+                "message_id": "message-id-123",
+                "publish_time": time,
+                **message,
+            },
+            "subscription": "my-subscription",
+        },
+    )
+
+
+def _handled_message(message: dict) -> Message:
+    func = MagicMock()
+    _message_handler(func, _raw_event(message))
+    func.assert_called_once()
+    return func.call_args.args[0].data.message
+
+
 class TestPubSub(unittest.TestCase):
     """
     PubSub function tests.
@@ -55,24 +82,12 @@ def test_message_handler(self):
         formatted CloudEvent instance.
         """
         func = MagicMock()
-        raw_event = _CloudEvent(
-            attributes={
-                "id": "test-message",
-                "source": "https://example.com/pubsub",
-                "specversion": "1.0",
-                "time": "2023-03-11T13:25:37.403Z",
-                "type": "com.example.pubsub.message",
-            },
-            data={
-                "message": {
-                    "attributes": {"key": "value"},
-                    # {"test": "value"}
-                    "data": "eyJ0ZXN0IjogInZhbHVlIn0=",
-                    "message_id": "message-id-123",
-                    "publish_time": "2023-03-11T13:25:37.403Z",
-                },
-                "subscription": "my-subscription",
-            },
+        raw_event = _raw_event(
+            {
+                "attributes": {"key": "value"},
+                # {"test": "value"}
+                "data": "eyJ0ZXN0IjogInZhbHVlIn0=",
+            }
         )
 
         _message_handler(func, raw_event)
@@ -103,51 +118,67 @@ def init():
             hello = "world"
 
         func = MagicMock()
-        raw_event = _CloudEvent(
-            attributes={
-                "id": "test-message",
-                "source": "https://example.com/pubsub",
-                "specversion": "1.0",
-                "time": "2023-03-11T13:25:37.403Z",
-                "type": "com.example.pubsub.message",
-            },
-            data={
-                "message": {
-                    "attributes": {"key": "value"},
-                    "data": "eyJ0ZXN0IjogInZhbHVlIn0=",
-                    "message_id": "message-id-123",
-                    "publish_time": "2023-03-11T13:25:37.403Z",
-                },
-                "subscription": "my-subscription",
-            },
-        )
+        raw_event = _raw_event({"data": "eyJ0ZXN0IjogInZhbHVlIn0="})
 
         _message_handler(func, raw_event)
 
         self.assertEqual("world", hello)
 
     def test_datetime_without_mircroseconds_doesnt_throw(self):
         time = "2023-03-11T13:25:37Z"
-        raw_event = _CloudEvent(
-            attributes={
-                "id": "test-message",
-                "source": "https://example.com/pubsub",
-                "specversion": "1.0",
-                "time": time,
-                "type": "com.example.pubsub.message",
-            },
-            data={
-                "message": {
-                    "attributes": {"key": "value"},
-                    "data": "eyJ0ZXN0IjogInZhbHVlIn0=",
-                    "message_id": "message-id-123",
-                    "publish_time": time,
-                },
-                "subscription": "my-subscription",
-            },
-        )
+        raw_event = _raw_event({"data": "eyJ0ZXN0IjogInZhbHVlIn0="}, time=time)
         try:
             _message_handler(lambda _: None, raw_event)
         # pylint: disable=broad-except
         except Exception:
             self.fail("Datetime without microseconds should not throw an exception")
+
+
+class TestPubSubMessageData(unittest.TestCase):
+    def test_message_without_data_reaches_handler_with_none(self):
+        message = _handled_message({"attributes": {"key": "value"}})
+        self.assertIsNone(message.data)
+        self.assertIsNone(message.json)
+        self.assertEqual(message.attributes, {"key": "value"})
+        self.assertEqual(message.message_id, "message-id-123")
+
+    def test_message_with_data_decodes_json(self):
+        # base64 of '{"test": "value"}'
+        message = _handled_message({"data": "eyJ0ZXN0IjogInZhbHVlIn0="})
+        self.assertEqual(message.data, "eyJ0ZXN0IjogInZhbHVlIn0=")
+        self.assertEqual(message.json, {"test": "value"})
+        self.assertEqual(message.attributes, {})
+
+    def test_message_with_empty_string_data_returns_none_json(self):
+        message = _handled_message({"data": ""})
+        self.assertEqual(message.data, "")
+        self.assertIsNone(message.json)
+
+    def test_message_with_invalid_data_json_raises(self):
+        # base64 of "not json"
+        message = _handled_message({"data": "bm90IGpzb24="})
+        with self.assertRaisesRegex(ValueError, "^Unable to parse Pub/Sub message data as JSON: "):
+            _ = message.json
+
+    def test_message_with_ordering_key_keeps_it(self):
+        message = _handled_message({"data": "eyJ0ZXN0IjogInZhbHVlIn0=", "orderingKey": "abc"})
+        self.assertEqual(message.ordering_key, "abc")
+
+    def test_message_built_directly_defaults_data_and_ordering_key_to_none(self):
+        message = Message(
+            message_id="message-id-123",
+            publish_time=_dt.datetime(2023, 3, 11, tzinfo=_dt.timezone.utc),
+            attributes={},
+        )
+        self.assertIsNone(message.data)
+        self.assertIsNone(message.ordering_key)
+        self.assertIsNone(message.json)
+
+    def test_publish_time_is_timezone_aware_datetime(self):
+        message = _handled_message({"data": "eyJ0ZXN0IjogInZhbHVlIn0="})
+        self.assertIsInstance(message.publish_time, _dt.datetime)
+        self.assertEqual(
+            message.publish_time,
+            _dt.datetime(2023, 3, 11, 13, 25, 37, 403000, tzinfo=_dt.timezone.utc),
+        )
+        self.assertEqual(message.publish_time.utcoffset(), _dt.timedelta(0))