Merge pull request #96 from rstudio/cdn

Author: wch

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [UNRELEASED]
 
+* Closed #94: New `SHINYWIDGETS_CDN` and `SHINYWIDGETS_CDN_ONLY` environment variables were added to more easily specify the CDN provider. Also, the default provider has changed from <unpkg.com> to <cdn.jsdelivr.net/npm> (#95)
+* A warning is no longer issued (by default) when the path to a local widget extension is not found. This is because, if an internet connection is available, the widget assests are still loaded via CDN. To restore the previous behavior, set the `SHINYWIDGETS_EXTENSION_WARNING` environment variable to `"true"`. (#95)
 * Closed #14: Added a `bokeh_dependency()` function to simplify use of bokeh widgets. (#85)
 
 ## [0.1.6] - 2023-03-24

setup.cfg

@@ -34,7 +34,7 @@ setup_requires =
 install_requires =
     ipywidgets>=7.6.5
     jupyter_core
-    shiny>=0.2.10.9001
+    shiny>=0.3.0
     python-dateutil>=2.8.2
     # Needed because of https://github.com/python/importlib_metadata/issues/411
     importlib-metadata>=4.8.3,<5; python_version < "3.8"

shinywidgets/_dependencies.py

@@ -61,7 +61,9 @@ def output_binding_dependency() -> HTMLDependency:
 # possible for a Widget to have traits that are themselves Widgets
 # (which could have their own npm module), but in practice, I haven't seen any cases
 # where a 3rd party widget can contain a 3rd party widget.
-def require_dependency(w: Widget, session: Session) -> Optional[HTMLDependency]:
+def require_dependency(
+    w: Widget, session: Session, warn_if_missing: bool = True
+) -> Optional[HTMLDependency]:
     """
     Obtain an HTMLDependency for a 3rd party ipywidget that points
     require('widget-npm-package') requests in the browser to the correct local path.
@@ -86,11 +88,13 @@ def require_dependency(w: Widget, session: Session) -> Optional[HTMLDependency]:
     if module_dir is None:
         module_dir = jupyter_extension_path(jupyter_extension_destination(w))
         if module_dir is None:
-            warnings.warn(
-                f"Failed to discover JavaScript dependencies for {type(w)}."
-                + " Make sure it is installed as a jupyter notebook extension.",
-                stacklevel=2,
-            )
+            if warn_if_missing:
+                warnings.warn(
+                    f"Couldn't find local path to widget extension for {type(w)}."
+                    + " Since a CDN fallback is provided, the widget will still render if an internet connection is available."
+                    + " To avoid depending on a CDN, make sure the widget is installed as a jupyter extension.",
+                    stacklevel=2,
+                )
             return None
 
     version = parse_version_safely(getattr(w, "_model_module_version", "1.0"))
@@ -113,7 +117,7 @@ def require_dependency(w: Widget, session: Session) -> Optional[HTMLDependency]:
 
 
 def bokeh_dependency() -> HTMLDependency:
-    from bokeh.resources import Resources 
+    from bokeh.resources import Resources
 
     resources = Resources(mode="inline").render()
     return ui.head_content(ui.HTML(resources))

shinywidgets/_shinywidgets.py

@@ -13,7 +13,7 @@
 from uuid import uuid4
 from weakref import WeakSet
 
-from htmltools import Tag, TagList, css, tags
+from htmltools import Tag, TagList, css, head_content, tags
 from ipywidgets._version import (
     __protocol_version__,  # pyright: ignore[reportUnknownVariableType]
 )
@@ -36,6 +36,16 @@
     widget_pkg,
 )
 
+# Make it easier to customize the CDN fallback (and make it CDN-only)
+# https://ipywidgets.readthedocs.io/en/7.6.3/embedding.html#python-interface
+# https://github.com/jupyter-widgets/ipywidgets/blob/6f6156c7/packages/html-manager/src/libembed-amd.ts#L6-L14
+SHINYWIDGETS_CDN = os.getenv("SHINYWIDGETS_CDN", "https://cdn.jsdelivr.net/npm/")
+SHINYWIDGETS_CDN_ONLY = os.getenv("SHINYWIDGETS_CDN_ONLY", "false").lower() == "true"
+# Should shinywidgets warn if unable to find a local path to a widget extension?
+SHINYWIDGETS_EXTENSION_WARNING = (
+    os.getenv("SHINYWIDGETS_EXTENSION_WARNING", "false").lower() == "true"
+)
+
 
 def output_widget(
     id: str, *, width: Optional[str] = None, height: Optional[str] = None
@@ -44,6 +54,12 @@ def output_widget(
     return tags.div(
         *libembed_dependency(),
         output_binding_dependency(),
+        head_content(
+            tags.script(
+                data_jupyter_widgets_cdn=SHINYWIDGETS_CDN,
+                data_jupyter_widgets_cdn_only=SHINYWIDGETS_CDN_ONLY,
+            )
+        ),
         id=id,
         class_="shiny-ipywidget-output shiny-report-size shiny-report-theme",
         style=css(width=width, height=height),
@@ -83,7 +99,10 @@ def init_shiny_widget(w: Widget):
     # Make sure window.require() calls made by 3rd party widgets
     # (via handle_comm_open() -> new_model() -> loadClass() -> requireLoader())
     # actually point to directories served locally by shiny
-    widget_dep = require_dependency(w, session)
+    if SHINYWIDGETS_CDN_ONLY:
+        widget_dep = None
+    else:
+        widget_dep = require_dependency(w, session, SHINYWIDGETS_EXTENSION_WARNING)
 
     # By the time we get here, the user has already had an opportunity to specify a model_id,
     # so it isn't yet populated, generate a random one so we can assign the same id to the comm
@@ -108,11 +127,13 @@ def init_shiny_widget(w: Widget):
     # be doing on load in js/src/output.ts)
     # https://github.com/jupyter-widgets/widget-cookiecutter/blob/9694718/%7B%7Bcookiecutter.github_project_name%7D%7D/js/lib/extension.js#L8
     if widget_dep and widget_dep.source:
-        session.app._dependency_handler.mount(
-            f"/nbextensions/{widget_dep.name}",
-            StaticFiles(directory=widget_dep.source["subdir"]),
-            name=f"{widget_dep.name}-nbextension-static-resources",
-        )
+        src_dir = widget_dep.source.get("subdir", "")
+        if src_dir:
+            session.app._dependency_handler.mount(
+                f"/nbextensions/{widget_dep.name}",
+                StaticFiles(directory=src_dir),
+                name=f"{widget_dep.name}-nbextension-static-resources",
+            )
 
     # everything after this point should be done once per session
     if session in SESSIONS: