Support multi args

panel/chat/feed.py

@@ -10,8 +10,8 @@
 
 from enum import Enum
 from inspect import (
-    isasyncgen, isasyncgenfunction, isawaitable, iscoroutinefunction,
-    isgenerator, isgeneratorfunction,
+    getfullargspec, isasyncgen, isasyncgenfunction, isawaitable,
+    iscoroutinefunction, isgenerator, isgeneratorfunction,
 )
 from io import BytesIO
 from typing import (
@@ -430,7 +430,15 @@ def _gather_callback_args(self, message: ChatMessage) -> Any:
             contents = value.value
         else:
             contents = value
-        return contents, message.user, self
+
+        callback_args = getfullargspec(self.callback).args
+        if len(callback_args) > 3:
+            raise ValueError('Function should have at most 3 arguments')
+        elif len(callback_args) == 0:
+            raise ValueError('Function should have at least one argument')
+
+        input_args = (contents, message.user, self)
+        return input_args[:len(callback_args)]
 
     async def _serialize_response(self, response: Any) -> ChatMessage | None:
         """

panel/tests/chat/test_feed.py

@@ -888,6 +888,59 @@ def callback(contents, user, instance):
         assert feed.objects[-1].object == "helloooo"
         assert chat_feed._placeholder not in chat_feed._chat_log
 
+    def test_callback_one_argument(self, chat_feed):
+        def callback(contents):
+            return contents
+
+        chat_feed.callback = callback
+        chat_feed.send("Message", respond=True)
+        wait_until(lambda: len(chat_feed.objects) == 2)
+        assert chat_feed.objects[1].object == "Message"
+
+    def test_callback_two_arguments(self, chat_feed):
+        def callback(contents, user):
+            return f"{user}: {contents}"
+
+        chat_feed.callback = callback
+        chat_feed.send("Message", respond=True)
+        wait_until(lambda: len(chat_feed.objects) == 2)
+        assert chat_feed.objects[1].object == "User: Message"
+
+    def test_callback_two_arguments_with_keyword(self, chat_feed):
+        def callback(contents, user=None):
+            return f"{user}: {contents}"
+
+        chat_feed.callback = callback
+        chat_feed.send("Message", respond=True)
+        wait_until(lambda: len(chat_feed.objects) == 2)
+        assert chat_feed.objects[1].object == "User: Message"
+
+    def test_callback_three_arguments_with_keyword(self, chat_feed):
+        def callback(contents, user=None, instance=None):
+            return f"{user}: {contents}"
+
+        chat_feed.callback = callback
+        chat_feed.send("Message", respond=True)
+        wait_until(lambda: len(chat_feed.objects) == 2)
+        assert chat_feed.objects[1].object == "User: Message"
+
+    def test_callback_two_arguments_yield(self, chat_feed):
+        def callback(contents, user):
+            yield f"{user}: {contents}"
+
+        chat_feed.callback = callback
+        chat_feed.send("Message", respond=True)
+        wait_until(lambda: len(chat_feed.objects) == 2)
+        assert chat_feed.objects[1].object == "User: Message"
+
+    def test_callback_two_arguments_async_yield(self, chat_feed):
+        async def callback(contents, user):
+            yield f"{user}: {contents}"
+
+        chat_feed.callback = callback
+        chat_feed.send("Message", respond=True)
+        wait_until(lambda: len(chat_feed.objects) == 2)
+        assert chat_feed.objects[1].object == "User: Message"
 
 @pytest.mark.xdist_group("chat")
 class TestChatFeedSerializeForTransformers: