feat(Chat): The .append_message() method now automatically streams in generators

CHANGELOG.md

@@ -15,6 +15,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * `shiny create` includes new and improved `ui.Chat()` template options. Most of these templates leverage the new [`{chatlas}` package](https://posit-dev.github.io/chatlas/), our opinionated approach to interfacing with various LLM. (#1806)
 
+* `ui.Chat`'s `.append_message()` method now automatically streams generators and async generators. (#1800)
+
 ### Bug fixes
 
 * `ui.Chat()` now correctly handles new `ollama.chat()` return value introduced in `ollama` v0.4. (#1787)

shiny/ui/_chat.py

@@ -541,13 +541,21 @@ async def append_message(self, message: Any) -> None:
             The message to append. A variety of message formats are supported including
             a string, a dictionary with `content` and `role` keys, or a relevant chat
             completion object from platforms like OpenAI, Anthropic, Ollama, and others.
+            When the message is a generator or async generator, it is automatically
+            treated as a stream of message chunks (i.e., uses
+            `.append_message_stream()`)
 
         Note
         ----
-        Use `.append_message_stream()` instead of this method when `stream=True` (or
-        similar) is specified in model's completion method.
+        Although this method tries its best to handle various message formats, it's
+        not always possible to handle every message format. If you encounter an error
+        or no response when appending a message, try extracting the message content
+        as a string and passing it to this method.
         """
-        await self._append_message(message)
+        if inspect.isasyncgen(message) or inspect.isgenerator(message):
+            await self.append_message_stream(message)
+        else:
+            await self._append_message(message)
 
     async def _append_message(
         self, message: Any, *, chunk: ChunkOption = False, stream_id: str | None = None