Make it possible/easier to render bokeh plots (#32)

Author: cpsievert

examples/outputs.py examples/outputs/app.pyexamples/outputs.py renamed to examples/outputs/app.py

@@ -5,7 +5,20 @@
 from ipyshiny import *
 import numpy as np
 
+
+# TODO: jupyter_bokeh assumes this additional JS has been loaded into the
+# (in a notebook, this comes in via bokeh.io.output_notebook()).
+# We could probably insert this on widget construction, just before the comm
+# gets initialized (it's not currently working due to run_coro_sync() not working
+# when session._send_message() wants to send a big payload).
+from htmltools import head_content, HTML
+from bokeh.resources import Resources
+
+bokeh_js = HTML(Resources(mode="inline").render())
+
+
 app_ui = ui.page_fluid(
+    head_content(bokeh_js),
     ui.layout_sidebar(
         ui.panel_sidebar(
             ui.input_radio_buttons(
@@ -17,14 +30,14 @@
                     "pydeck",
                     "altair",
                     "plotly",
-                    # TODO: fix me
-                    # "bokeh",
+                    "bokeh",
                     "bqplot",
                     "ipychart",
                     "ipywebrtc",
-                    "ipyvolume",
+                    # TODO: fix me
+                    # "ipyvolume",
                 ],
-                selected="qgrid",
+                selected="ipyleaflet",
             )
         ),
         ui.panel_main(
@@ -255,18 +268,12 @@ def _():
     @render_widget()
     def _():
         from bokeh.plotting import figure
-        from jupyter_bokeh import BokehModel
-
-        # TODO: figure out what this does and try to replicate it
-        import bokeh.io
-
-        bokeh.io.output_notebook()
 
         x = [1, 2, 3, 4, 5]
         y = [6, 7, 2, 4, 5]
         p = figure(title="Simple line example", x_axis_label="x", y_axis_label="y")
         p.line(x, y, legend_label="Temp.", line_width=2)
-        return BokehModel(p)
+        return p
 
 
 app = App(app_ui, server)

ipyshiny/_ipyshiny.py

@@ -185,28 +185,45 @@ def wrapper(fn: Union[IPyWidgetRenderFunc, IPyWidgetRenderFuncAsync]) -> IPyWidg
     return wrapper
 
 
-# altair objects aren't directly renderable as an ipywidget,
-# but we can still render them as an ipywidget via ipyvega
-# TODO: we should probably do this for bokeh, pydeck, and probably others as well
+# altair/pydeck/bokeh objects aren't directly renderable as an ipywidget,
+# but we can coerce them into one
 def _as_widget(x: object) -> Widget:
-    if widget_pkg(x) == "altair":
+    pkg = widget_pkg(x)
+    if pkg == "altair" and not isinstance(x, Widget):
         try:
             import altair
             from vega.widget import VegaWidget
 
             x = cast(altair.Chart, x)
             x = VegaWidget(x.to_dict())  # type: ignore
         except ImportError:
-            raise ImportError("ipyvega is required to render altair charts")
-    elif widget_pkg(x) == "pydeck":
-        import pydeck
+            raise ImportError(
+                "To render altair charts, the ipyvega package must be installed."
+            )
+        except Exception as e:
+            raise RuntimeError(f"Failed to coerce {x} into a VegaWidget: {e}")
 
-        if isinstance(x, pydeck.Deck):
+    elif pkg == "pydeck" and not isinstance(x, Widget):
+        try:
             from pydeck.widget import DeckGLWidget
 
-            x_ = x.to_json()
+            x_ = x.to_json()  # type: ignore
             x = DeckGLWidget()
             x.json_input = x_
+        except Exception as e:
+            raise RuntimeError(f"Failed to coerce {x} into a DeckGLWidget: {e}")
+
+    elif pkg == "bokeh" and not isinstance(x, Widget):
+        try:
+            from jupyter_bokeh import BokehModel
+
+            x = BokehModel(x)  # type: ignore
+        except ImportError:
+            raise ImportError(
+                "To render bokeh charts, the jupyter_bokeh package must be installed."
+            )
+        except Exception as e:
+            raise RuntimeError(f"Failed to coerce {x} into a BokehModel: {e}")
 
     if isinstance(x, Widget):
         return x