Support all Jupyter Paths when loading static resources

[DonJayamanne]

We recently updated IPyWidgets to load static resources from a couple of different places,
however Jupyter has a pre-defined & documented list

Today we load static resources from just 2 places, however jupyter has more than that.
E.g. if you look at the isntallation of pythreejs, if user installs widgets into --system, then they will not work in VS Code.
We don't load widgets from the --system location.

Todo:

• Load static resources from all directories that Jupyter loads from
• Use the same priority that Jupyter uses

Ref

• Documentation of the paths can be found here https://docs.jupyter.org/en/latest/use/jupyter-directories.html#data-files
• Source for priority & paths can be found in jupyter_path function in site-packages/jupyter_core/paths.py

[DonJayamanne]

Order of priority:

• ~/Library/Jupyter -> /Users/donjayamanne/Library/Jupyter/nbextensions
• <sys-prefix>/share/jupyter -> /Users/donjayamanne/crap/.venvPythreeJs/share/jupyter/nbextensions
• /usr/local/share/jupyter/nbextensions
• /usr/share/jupyter/nbextensions

Basically its exactly as defined in JUPYTER_PATH section

[connor4312]

Are there repro steps for this?

[DonJayamanne]

• Create python virtual env
• Install pythreejs into virtual env python -m pip install pythreejs
• Then run python -m jupyter nbextension uninstall --sys-prefix --py pythreejs // uninstall js scripts for virtual env
• Then run python -m jupyter nbextension install --user --py pythreejs // install js scripts into global location
• Ensure the temp/tmp file directories in Jupyter extension folder have been deleted
• Create a notebook and run the following cell (ensuring you have selected the virtual env) & verify the widget is displayed

from pythreejs import *
from IPython.display import display
from math import pi

# Reduce repo churn for examples with embedded state:
from pythreejs._example_helper import use_example_model_ids
use_example_model_ids()

BoxGeometry(
    width=5,
    height=10,
    depth=15,
    widthSegments=5,
    heightSegments=10,
    depthSegments=15)