jupyter笔记本 - 检查魔法是否可用

Question

I am trying to call a python command from within javascript using the ipykernel.comm. The problem is that I want to use the same code regardless if I run python3 kernel or pyspark3 kernel. For the latter I need to run code with %%local cell magic, which does not work for the pure python 3 kernel.

How do I programmatically check if a given (frontend) magic is available?

I tried looking into get_ipython().magics_manager.registry but I feel that is not the way. I tried to look on the frontend (javascript) side but I also could not find it.

I thought maybe the source for sparkmagic will help me, but no luck. I do not know how to access IPython.CodeCell.config_defaults

sparkmagic's kernel.js

Answer 1

Instead of checking if the command is available you just use it and catch the exception if it is not supported.

Example:

from IPython.core.error import UsageError
try:
    %%local
except UsageError:
    print("Magic %%local not support in this kernel")

Answer 2

You can get the available magics via:

from IPython import get_ipython

line_magics = list(get_ipython().magics_manager.magics.get('line'))
cell_magics = list(get_ipython().magics_manager.magics.get('cell'))