feat(web): expose public ts property on ChatStream for fallback recovery

Author: srtaalej

slack_sdk/web/async_chat_stream.py

@@ -86,6 +86,15 @@ def __init__(
         self._stream_ts: Optional[str] = None
         self._buffer_size = buffer_size
 
+    @property
+    def ts(self) -> Optional[str]:
+        """The message timestamp of the stream.
+
+        Returns None until the first flush (when chat.startStream is called).
+        Can be used with chat.update as a fallback if the stream expires server-side.
+        """
+        return self._stream_ts
+
     async def append(
         self,
         *,

slack_sdk/web/chat_stream.py

@@ -76,6 +76,15 @@ def __init__(
         self._stream_ts: Optional[str] = None
         self._buffer_size = buffer_size
 
+    @property
+    def ts(self) -> Optional[str]:
+        """The message timestamp of the stream.
+
+        Returns None until the first flush (when chat.startStream is called).
+        Can be used with chat.update as a fallback if the stream expires server-side.
+        """
+        return self._stream_ts
+
     def append(
         self,
         *,

tests/slack_sdk/web/test_chat_stream.py

@@ -262,6 +262,22 @@ def test_streams_with_authorship_args(self):
             self.assertEqual(start_request.get("icon_emoji"), "abacus")
             self.assertNotIn("icon_url", start_request)
 
+    def test_ts_property_is_none_before_flush_and_set_after(self):
+        streamer = self.client.chat_stream(
+            buffer_size=5,
+            channel="C0123456789",
+            thread_ts="123.000",
+            recipient_team_id="T0123456789",
+            recipient_user_id="U0123456789",
+        )
+        self.assertIsNone(streamer.ts)
+
+        streamer.append(markdown_text="hello!")
+        self.assertEqual(streamer.ts, "123.123")
+
+        streamer.stop()
+        self.assertEqual(streamer.ts, "123.123")
+
     def test_streams_errors_when_appending_to_an_unstarted_stream(self):
         streamer = self.client.chat_stream(
             channel="C0123456789",