Add edit functionality

examples/reference/chat/ChatFeed.ipynb

@@ -50,6 +50,7 @@
     "* **`header`** (Any): The header of the chat feed; commonly used for the title. Can be a string, pane, or widget.\n",
     "* **`callback_user`** (str): The default user name to use for the message provided by the callback.\n",
     "* **`callback_avatar`** (str, BytesIO, bytes, ImageBase): The default avatar to use for the entry provided by the callback. Takes precedence over `ChatMessage.default_avatars` if set; else, if None, defaults to the avatar set in `ChatMessage.default_avatars` if matching key exists. Otherwise defaults to the first character of the `callback_user`.\n",
+    "* **`edit_callback`** (callable): Callback to execute when a user edits a message. The signature must include the previous message value `contents`, the previous `user` name, and the component `instance`.\n",
     "* **`help_text`** (str): If provided, initializes a chat message in the chat log using the provided help text as the message object and `help` as the user. This is useful for providing instructions, and will not be included in the `serialize` method by default.\n",
     "* **`placeholder_text`** (str): The text to display next to the placeholder icon.\n",
     "* **`placeholder_params`** (dict) Defaults to `{\"user\": \" \", \"reaction_icons\": {}, \"show_copy_icon\": False, \"show_timestamp\": False}` Params to pass to the placeholder `ChatMessage`, like `reaction_icons`, `timestamp_format`, `show_avatar`, `show_user`, `show_timestamp`.\n",
@@ -651,6 +652,39 @@
     "message = chat_feed.send(\"Hello bots!\")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#### Edit Callbacks\n",
+    "\n",
+    "An `edit_callback` can be attached to the `ChatFeed` to handle message edits.\n",
+    "\n",
+    "The signature must include the latest available message value `contents`, the index of the edited message, and the chat `instance`.\n",
+    "\n",
+    "Here, when the user edits the first message, the downstream message is updated to match the edited message."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def echo_callback(content, index, instance):\n",
+    "    return content\n",
+    "\n",
+    "\n",
+    "def edit_callback(content, index, instance):\n",
+    "    instance.objects[index + 1].object = content\n",
+    "\n",
+    "\n",
+    "chat_feed = pn.chat.ChatFeed(\n",
+    "    edit_callback=edit_callback, callback=echo_callback, callback_user=\"Echo Guy\"\n",
+    ")\n",
+    "chat_feed.send(\"Edit this\")"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},

examples/reference/chat/ChatMessage.ipynb

@@ -45,6 +45,7 @@
     "* **`user`** (str): Name of the user who sent the message.\n",
     "* **`avatar`** (str | BinaryIO): The avatar to use for the user. Can be a single character text, an emoji, or anything supported by `pn.pane.Image`. If not set, uses the first character of the name.\n",
     "* **`default_avatars`** (Dict[str, str | BinaryIO]): A default mapping of user names to their corresponding avatars to use when the user is set but the avatar is not. You can modify, but not replace the dictionary. Note, the keys are *only* alphanumeric sensitive, meaning spaces, special characters, and case sensitivity is disregarded, e.g. `\"Chat-GPT3.5\"`, `\"chatgpt 3.5\"` and `\"Chat GPT 3.5\"` all map to the same value.\n",
+    "* **`edited`** (bool): An event that is triggered when the message is edited\n",
     "* **`footer_objects`** (List): A list of objects to display in the column of the footer of the message.\n",
     "* **`header_objects`** (List): A list of objects to display in the row of the header of the message.\n",
     "* **`avatar_lookup`** (Callable): A function that can lookup an `avatar` from a user name. The function signature should be `(user: str) -> Avatar`. If this is set, `default_avatars` is disregarded.\n",
@@ -61,6 +62,7 @@
     "* **`show_timestamp`** (bool): Whether to display the timestamp of the message.\n",
     "* **`show_reaction_icons`** (bool): Whether to display the reaction icons.\n",
     "* **`show_copy_icon`** (bool): Whether to show the copy icon.\n",
+    "* **`show_edit_icon`** (bool): Whether to display the edit icon.\n",
     "* **`show_activity_dot`** (bool): Whether to show the activity dot.\n",
     "* **`name`** (str): The title or name of the chat message widget, if any.\n",
     "\n",

panel/chat/feed.py

@@ -118,6 +118,11 @@ class ChatFeed(ListPanel):
         defaults to the avatar set in `ChatMessage.default_avatars` if matching key exists.
         Otherwise defaults to the first character of the `callback_user`.""")
 
+    edit_callback = param.Callable(allow_refs=False, doc="""
+        Callback to execute when a user edits a message.
+        The signature must include the new message value `contents`,
+        the `message_index`, and the `instance`.""")
+
     card_params = param.Dict(default={}, doc="""
         Params to pass to Card, like `header`, `header_background`, `header_color`, etc.""")
 
@@ -232,7 +237,16 @@ def __init__(self, *objects, **params):
         super().__init__(*objects, **params)
 
         if self.help_text:
-            self.objects = [ChatMessage(self.help_text, user="Help", **message_params), *self.objects]
+            self.objects = [
+                ChatMessage(
+                    self.help_text,
+                    user="Help",
+                    show_edit_icon=False,
+                    show_copy_icon=False,
+                    show_reaction_icons=False,
+                    **message_params
+                ), *self.objects
+            ]
 
         # instantiate the card's column
         linked_params = dict(
@@ -368,6 +382,17 @@ def _replace_placeholder(self, message: ChatMessage | None = None) -> None:
             except ValueError:
                 pass
 
+    async def _on_edit_message(self, event):
+        if self.edit_callback is None:
+            return
+        message = event.obj
+        contents = message.serialize()
+        index = self._chat_log.index(message)
+        if iscoroutinefunction(self.edit_callback):
+            await self.edit_callback(contents, index, self)
+        else:
+            self.edit_callback(contents, index, self)
+
     def _build_message(
         self,
         value: dict,
@@ -396,7 +421,15 @@ def _build_message(
             message_params["width"] = int(self.width - 80)
         message_params.update(input_message_params)
 
+        if "show_edit_icon" not in message_params:
+            user = message_params.get("user", "")
+            message_params["show_edit_icon"] = (
+                bool(self.edit_callback) and
+                user.lower() not in (self.callback_user.lower(), "help")
+            )
+
         message = ChatMessage(**message_params)
+        message.param.watch(self._on_edit_message, "edited")
         return message
 
     def _upsert_message(

panel/chat/input.py

@@ -71,10 +71,14 @@ class ChatAreaInput(_PnTextAreaInput):
         Can only be set during initialization.""",
     )
 
+    enter_pressed = param.Event(doc="""
+        Event when the enter key has been pressed.""")
+
     _widget_type: ClassVar[type[Model]] = _bkChatAreaInput
 
     _rename: ClassVar[Mapping[str, str | None]] = {
         "value": None,
+        "enter_pressed": None,
         **_PnTextAreaInput._rename,
     }
 
@@ -99,5 +103,6 @@ def _process_event(self, event: ChatMessageEvent) -> None:
         Clear value on shift enter key down.
         """
         self.value = event.value
+        self.enter_pressed = True
         with param.discard_events(self):
             self.value = ""

panel/chat/interface.py

@@ -693,6 +693,7 @@ def send(
                 user = self.user
             if avatar is None:
                 avatar = self.avatar
+        message_params["show_edit_icon"] = message_params.get("show_edit_icon", user == self.user)
         return super().send(value, user=user, avatar=avatar, respond=respond, **message_params)
 
     def stream(
@@ -739,4 +740,5 @@ def stream(
             # so only set to the default when not a ChatMessage
             user = user or self.user
             avatar = avatar or self.avatar
+        message_params["show_edit_icon"] = message_params.get("show_edit_icon", user == self.user)
         return super().stream(value, user=user, avatar=avatar, message=message, replace=replace, **message_params)

panel/chat/message.py

@@ -30,10 +30,13 @@
     HTML, DataFrame, HTMLBasePane, Markdown,
 )
 from ..pane.media import Audio, Video
+from ..pane.placeholder import Placeholder
 from ..param import ParamFunction
 from ..viewable import ServableMixin, Viewable
 from ..widgets.base import Widget
+from ..widgets.icon import ToggleIcon
 from .icon import ChatCopyIcon, ChatReactionIcons
+from .input import ChatAreaInput
 from .utils import (
     avatar_lookup, build_avatar_pane, serialize_recursively, stream_to,
 )
@@ -215,6 +218,9 @@ class ChatMessage(Pane):
     show_avatar = param.Boolean(default=True, doc="""
          Whether to display the avatar of the user.""")
 
+    show_edit_icon = param.Boolean(default=True, doc="""
+        Whether to display the edit icon.""")
+
     show_user = param.Boolean(default=True, doc="""
         Whether to display the name of the user.""")
 
@@ -241,16 +247,16 @@ class ChatMessage(Pane):
     user = param.Parameter(default="User", doc="""
         Name of the user who sent the message.""")
 
+    edited = param.Event(doc="""
+        An event that is triggered when the message is edited.""")
+
     _stylesheets: ClassVar[list[str]] = [f"{CDN_DIST}css/chat_message.css"]
 
     # Declares whether Pane supports updates to the Bokeh model
     _updates: ClassVar[bool] = True
 
     def __init__(self, object=None, **params):
         self._exit_stack = ExitStack()
-        self.chat_copy_icon = ChatCopyIcon(
-            visible=False, width=15, height=15, css_classes=["copy-icon"]
-        )
         if params.get("timestamp") is None:
             tz = params.get("timestamp_tz")
             if tz is not None:
@@ -264,8 +270,12 @@ def __init__(self, object=None, **params):
             params["reaction_icons"] = ChatReactionIcons(options=reaction_icons, default_layout=Row, sizing_mode=None)
         self._internal = True
         super().__init__(object=object, **params)
+        self.edit_icon = ToggleIcon(
+            icon="edit", active_icon="x", width=15, height=15,
+            stylesheets=self._stylesheets + self.param.stylesheets.rx(), css_classes=["edit-icon"],
+        )
         self.chat_copy_icon = ChatCopyIcon(
-            visible=False, width=15, height=15, css_classes=["copy-icon"],
+            visible=False, width=15, height=15, css_classes=["edit-icon"],
             stylesheets=self._stylesheets + self.param.stylesheets.rx(),
         )
         if not self.avatar:
@@ -285,15 +295,30 @@ def _build_layout(self):
         self.param.watch(self._update_avatar_pane, "avatar")
 
         self._object_panel = self._create_panel(self.object)
+        self._placeholder = Placeholder(
+            object=self._object_panel,
+            css_classes=["placeholder"],
+            stylesheets=self._stylesheets + self.param.stylesheets.rx(),
+            sizing_mode=None,
+        )
+        self._edit_area = ChatAreaInput(
+            value=self.object,
+            css_classes=["edit-area"],
+            stylesheets=self._stylesheets + self.param.stylesheets.rx()
+        )
+
         self._update_chat_copy_icon()
+        self._update_edit_widgets()
         self._center_row = Row(
-            self._object_panel,
+            self._placeholder,
             css_classes=["center"],
             stylesheets=self._stylesheets + self.param.stylesheets.rx(),
             sizing_mode=None
         )
         self.param.watch(self._update_object_pane, "object")
         self.param.watch(self._update_reaction_icons, "reaction_icons")
+        self.edit_icon.param.watch(self._toggle_edit, "value")
+        self._edit_area.param.watch(self._submit_edit, "enter_pressed")
 
         self._user_html = HTML(
             self.param.user, height=20,
@@ -338,6 +363,7 @@ def _build_layout(self):
         )
 
         self._icons_row = Row(
+            self.edit_icon,
             self.chat_copy_icon,
             self._render_reaction_icons(),
             css_classes=["icons"],
@@ -574,6 +600,7 @@ def _update_object_pane(self, event=None):
         if old is not new:
             self._center_row[0] = new
         self._update_chat_copy_icon()
+        self._update_edit_widgets()
 
     @param.depends("avatar_lookup", "user", watch=True)
     def _update_avatar(self):
@@ -608,6 +635,39 @@ def _update_chat_copy_icon(self):
             self.chat_copy_icon.value = ""
             self.chat_copy_icon.visible = False
 
+    def _update_edit_widgets(self):
+        object_panel = self._object_panel
+        if isinstance(object_panel, HTMLBasePane):
+            object_panel = object_panel.object
+        elif isinstance(object_panel, Widget):
+            object_panel = object_panel.value
+        if isinstance(object_panel, str) and self.show_edit_icon:
+            self.edit_icon.visible = True
+        else:
+            self.edit_icon.visible = False
+
+    def _toggle_edit(self, event):
+        if event.new:
+            with param.discard_events(self):
+                if isinstance(self._object_panel, HTMLBasePane):
+                    self._edit_area.value = self._object_panel.object
+                elif isinstance(self._object_panel, Widget):
+                    self._edit_area.value = self._object_panel.value
+            self._placeholder.update(object=self._edit_area)
+        else:
+            self._placeholder.update(object=self._object_panel)
+
+    def _submit_edit(self, event):
+        if isinstance(self.object, HTMLBasePane):
+            self.object.object = self._edit_area.value
+        elif isinstance(self.object, Widget):
+            self.object.value = self._edit_area.value
+        else:
+            self.object = self._edit_area.value
+        self.param.trigger("object")
+        self.edit_icon.value = False
+        self.edited = True
+
     def _cleanup(self, root=None) -> None:
         """
         Cleanup the exit stack.

panel/dist/css/chat_message.css

@@ -147,3 +147,18 @@
   font-size: 1.25em;
   line-height: 0.9em;
 }
+
+.edit-icon {
+  margin-top: 4px;
+  margin-inline: 3px;
+}
+
+.placeholder {
+  margin: 0;
+  width: calc(100% - 15px);
+}
+
+.edit-area {
+  /* for that smooth transition on a one line message */
+  height: 51.5px;
+}

panel/tests/chat/test_feed.py

@@ -1598,3 +1598,22 @@ def append_callback(message, instance):
         chat_feed.send("AB")
         wait_until(lambda: chat_feed.objects[-1].object == "Echo: AB")
         assert logs == ["AB", "Echo: ", "Echo: AB"]
+
+
+@pytest.mark.xdist_group("chat")
+class TestChatFeedEditCallback:
+
+    @pytest.mark.parametrize("edit_callback", [None, lambda content, index, instance: ""])
+    def test_show_edit_icon_callback(self, chat_feed, edit_callback):
+        chat_feed.edit_callback = edit_callback
+        chat_feed.send("Hello")
+        assert chat_feed[0].show_edit_icon is bool(edit_callback)
+
+    @pytest.mark.parametrize("user", ["User", "Assistant", "Help"])
+    def test_show_edit_icon_user(self, chat_feed, user):
+        chat_feed.edit_callback = lambda content, index, instance: ""
+        chat_feed.send("Hello", user=user)
+        if user == "User":
+            assert chat_feed[0].show_edit_icon
+        else:
+            assert not chat_feed[0].show_edit_icon

panel/tests/chat/test_interface.py

@@ -521,3 +521,22 @@ def test_scale_height(self):
         assert chat_interface._chat_log.sizing_mode == "scale_height"
         assert chat_interface._input_layout.sizing_mode == "stretch_width"
         assert chat_interface._input_layout[0].sizing_mode == "stretch_width"
+
+
+@pytest.mark.xdist_group("chat")
+class TestChatInterfaceEditCallback:
+
+    @pytest.fixture
+    def chat_interface(self):
+        return ChatInterface()
+
+    def test_show_edit_icon_user(self, chat_interface):
+        chat_interface.edit_callback = lambda content, index, instance: ""
+        chat_interface.send("Hello")
+        assert chat_interface[0].show_edit_icon
+
+    @pytest.mark.parametrize("user", ["admin", "Assistant", "Help"])
+    def test_not_show_edit_icon_user(self, chat_interface, user):
+        chat_interface.edit_callback = lambda content, index, instance: ""
+        chat_interface.send("Hello", user=user)
+        assert not chat_interface[0].show_edit_icon