feat(anywidget): Drop ipywidgets dependency

anywidget/_descriptor.py

@@ -300,6 +300,7 @@ def __init__(
         self._extra_state = (extra_state or {}).copy()
         self._extra_state.setdefault(_ANYWIDGET_ID_KEY, _anywidget_id(obj))
         self._no_view = no_view
+        self._callbacks = []
 
         try:
             self._obj: Callable[[], Any] = weakref.ref(obj, self._on_obj_deleted)
@@ -388,21 +389,25 @@ def _handle_msg(self, msg: CommMessage) -> None:
 
         elif data["method"] == "request_state":
             self.send_state()
-
-        # elif method == "custom":
-        # Handle a custom msg from the front-end.
-        # if "content" in data:
-        #     self._handle_custom_msg(data["content"], msg["buffers"])
+        elif data["method"] == "custom":
+            if "content" in data:
+                self._handle_custom_msg(data["content"], msg["buffers"])
         else:  # pragma: no cover
             raise ValueError(
                 f"Unrecognized method: {data['method']}.  Please report this at "
                 "https://github.com/manzt/anywidget/issues"
             )
 
-    # def _handle_custom_msg(self, content: Any, buffers: list[memoryview]):
-    #     # TODO: handle custom callbacks
-    #     # https://github.com/jupyter-widgets/ipywidgets/blob/6547f840edc1884c75e60386ec7fb873ba13f21c/python/ipywidgets/ipywidgets/widgets/widget.py#L662
-    #     ...
+    def _handle_custom_msg(self, content: Any, buffers: list[memoryview]):
+        # https://github.com/jupyter-widgets/ipywidgets/blob/b78de43e12ff26e4aa16e6e4c6844a7c82a8ee1c/python/ipywidgets/ipywidgets/widgets/widget.py#L186
+        for callback in self._callbacks:
+            try:
+                callback(content, buffers)
+            except Exception:
+                warnings.warn(
+                    "Error in custom message callback",
+                    stacklevel=2,
+                )
 
     def __call__(self, **kwargs: Sequence[str]) -> tuple[dict, dict] | None:
         """Called when _repr_mimebundle_ is called on the python object."""
@@ -468,6 +473,18 @@ def unsync_object_with_view(self) -> None:
             with contextlib.suppress(Exception):
                 self._disconnectors.pop()()
 
+    def register_callback(
+        self, callback: Callable[[Any, Any, list[bytes]], None]
+    ) -> None:
+        self._callbacks.append(callback)
+
+    def send(
+        self, content: str | list | dict, buffers: list[memoryview] | None = None
+    ) -> None:
+        """Send a custom message to the front-end view."""
+        data = {"method": "custom", "content": content}
+        self._comm.send(data=data, buffers=buffers)  # type: ignore[arg-type]
+
 
 # ------------- Helper function --------------
 

anywidget/_protocols.py

@@ -64,8 +64,8 @@ class AnywidgetProtocol(Protocol):
 class WidgetBase(Protocol):
     """Widget subclasses with a custom message reducer."""
 
-    def send(self, msg: str | dict | list, buffers: list[bytes]) -> None: ...
+    def send(self, msg: Any, buffers: list[memoryview] | None) -> None: ...
 
     def on_msg(
-        self, callback: Callable[[Any, str | list | dict, list[bytes]], None]
+        self, callback: Callable[[str | list | dict, list[bytes]], None]
     ) -> None: ...

anywidget/experimental.py

@@ -149,13 +149,14 @@ def _register_anywidget_commands(widget: WidgetBase) -> None:
         return None
 
     def handle_anywidget_command(
-        self: WidgetBase, msg: str | list | dict, buffers: list[bytes]
+        msg: typing.Any,
+        buffers: list[bytes | memoryview] | None = None,
     ) -> None:
         if not isinstance(msg, dict) or msg.get("kind") != "anywidget-command":
             return
         cmd = cmds[msg["name"]]
-        response, buffers = cmd(widget, msg["msg"], buffers)
-        self.send(
+        response, buffers = cmd(widget, msg["msg"], buffers or [])
+        widget.send(
             {
                 "id": msg["id"],
                 "kind": "anywidget-command-response",

anywidget/widget.py

@@ -2,80 +2,42 @@
 
 from __future__ import annotations
 
-from typing import Any
+from typing import Any, Callable
 
-import ipywidgets
-import traitlets.traitlets as t
+import traitlets
 
-from ._file_contents import FileContents, VirtualFileContents
-from ._util import (
-    _ANYWIDGET_ID_KEY,
-    _CSS_KEY,
-    _DEFAULT_ESM,
-    _ESM_KEY,
-    enable_custom_widget_manager_once,
-    in_colab,
-    repr_mimebundle,
-    try_file_contents,
-)
-from ._version import _ANYWIDGET_SEMVER_VERSION
+from ._descriptor import MimeBundleDescriptor
+from ._util import _CSS_KEY, _ESM_KEY
 from .experimental import _collect_anywidget_commands, _register_anywidget_commands
 
 
-class AnyWidget(ipywidgets.DOMWidget):  # type: ignore [misc]
+class AnyWidget(traitlets.HasTraits):  # type: ignore [misc]
     """Main AnyWidget base class."""
 
-    _model_name = t.Unicode("AnyModel").tag(sync=True)
-    _model_module = t.Unicode("anywidget").tag(sync=True)
-    _model_module_version = t.Unicode(_ANYWIDGET_SEMVER_VERSION).tag(sync=True)
-
-    _view_name = t.Unicode("AnyView").tag(sync=True)
-    _view_module = t.Unicode("anywidget").tag(sync=True)
-    _view_module_version = t.Unicode(_ANYWIDGET_SEMVER_VERSION).tag(sync=True)
+    _repr_mimebundle_: MimeBundleDescriptor
 
     def __init__(self, *args: Any, **kwargs: Any) -> None:
-        if in_colab():
-            enable_custom_widget_manager_once()
-
-        anywidget_traits = {}
-        for key in (_ESM_KEY, _CSS_KEY):
-            if hasattr(self, key) and not self.has_trait(key):
-                value = getattr(self, key)
-                anywidget_traits[key] = t.Unicode(str(value)).tag(sync=True)
-                if isinstance(value, (VirtualFileContents, FileContents)):
-                    value.changed.connect(
-                        lambda new_contents, key=key: setattr(self, key, new_contents)
-                    )
-
-        # show default _esm if not defined
-        if not hasattr(self, _ESM_KEY):
-            anywidget_traits[_ESM_KEY] = t.Unicode(_DEFAULT_ESM).tag(sync=True)
-
-        # TODO: a better way to uniquely identify this subclasses?
-        # We use the fully-qualified name to get an id which we
-        # can use to update CSS if necessary.
-        anywidget_traits[_ANYWIDGET_ID_KEY] = t.Unicode(
-            f"{self.__class__.__module__}.{self.__class__.__name__}"
-        ).tag(sync=True)
-
-        self.add_traits(**anywidget_traits)
         super().__init__(*args, **kwargs)
         _register_anywidget_commands(self)
+        # Access _repr_mimebundle_ descriptor to trigger comm initialization
+        self._repr_mimebundle_  # noqa: B018
 
     def __init_subclass__(cls, **kwargs: dict) -> None:
-        """Coerces _esm and _css to FileContents if they are files."""
+        """Create the _repr_mimebundle_ descriptor and register anywidget commands."""
         super().__init_subclass__(**kwargs)
-        for key in (_ESM_KEY, _CSS_KEY) & cls.__dict__.keys():
-            # TODO: Upgrate to := when we drop Python 3.7
-            file_contents = try_file_contents(getattr(cls, key))
-            if file_contents:
-                setattr(cls, key, file_contents)
+        extra_state = {
+            key: getattr(cls, key) for key in (_ESM_KEY, _CSS_KEY) & cls.__dict__.keys()
+        }
+        cls._repr_mimebundle_ = MimeBundleDescriptor(**extra_state)
         _collect_anywidget_commands(cls)
 
-    def _repr_mimebundle_(self, **kwargs: dict) -> tuple[dict, dict] | None:
-        plaintext = repr(self)
-        if len(plaintext) > 110:
-            plaintext = plaintext[:110] + "…"
-        if self._view_name is None:
-            return None  # type: ignore[unreachable]
-        return repr_mimebundle(model_id=self.model_id, repr_text=plaintext)
+    def send(self, msg: Any, buffers: list[memoryview] | None = None) -> None:
+        """Send a message to the frontend."""
+        self._repr_mimebundle_.send(content=msg, buffers=buffers)
+
+    def on_msg(
+        self, callback: Callable[[Any, str | list | dict, list[bytes]], None]
+    ) -> None:
+        """Register a message handler."""
+        self._repr_mimebundle_.register_callback(callback)
+

pyproject.toml

@@ -30,7 +30,6 @@ test = [
     "ipython<8.13; python_version < '3.9'",
 ]
 dev = [
-    "comm>=0.1.0",
     "watchfiles>=0.18.0",
 ]