How to cause Jupyter Lab to save notebook (programmatically)

Question

I have a notebook that runs overnight, and prints out a bunch of stuff, including images and such. I want to cause this output to be saved programatically (perhaps at certain intervals). I also want to save the code that was run. In a Jupyter notebook, you could do:

from IPython.display import display, Javascript
display(Javascript('IPython.notebook.save_checkpoint();'))
# causes the current .ipynb file to save itself (same as hitting CTRL+s)

(from Save an IPython notebook programmatically from within itself?)

Although, I found that this javascript injection did not work in Jupyter lab(Jupyter not found). My question is how to do the equivalent of the above code in Jupyter lab. Upon inspecting the HTML of the jupyter lab, I could not find the Jupyter object.

Cross-referencing relevant discussion on GitHub: https://github.com/jupyterlab/jupyterlab/issues/6161 — krassowski, Sep 17 '21 at 19:46

score 8 · Accepted Answer · answered Sep 01 '21 at 09:29

8

You can use ipylab to access JupyterLab API from Python. To save the notebook just invoke the docmanager:save command:

from ipylab import JupyterFrontEnd

app = JupyterFrontEnd()
app.commands.execute('docmanager:save')

You can get the full list of commands with app.commands.list_commands().

answered Sep 01 '21 at 09:29

krassowski

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I get an empty list in Jupyterlab 3.2.3 and ipylab 0.5.2 – Stefan Dec 16 '21 at 16:25
Did you restart JupyterLab after installing `ipylab`? – krassowski Dec 16 '21 at 16:27
yes ---------------- – Stefan Dec 16 '21 at 16:28
Hmm. I saw something like that once and never again. Would you mind reporting it on https://github.com/jtpio/ipylab/issues with any logs in the browser console and terminal? – krassowski Dec 16 '21 at 16:30
https://github.com/jtpio/ipylab/issues/82 "Module ipylab, semver range ^0.5.2 is not registered as a widget module" – Stefan Dec 20 '21 at 13:35

score 2 · Answer 2 · answered Apr 01 '21 at 20:46

JupyterLab has a bulit-in auto-save function. You can configure the time interval using the Advanced Settings Editor, the Document Manager section (see screenshot below).

However, if you really want a JavaScript solution you could just invoke the keyboard shortcut Ctrl + s with:

from IPython.display import display, Javascript

display(Javascript(
    "document.body.dispatchEvent("
    "new KeyboardEvent('keydown', {key:'s', keyCode: 83, ctrlKey: true}"
    "))"
))

this will only work as long as you do not change focus to a different notebook. However, you can always use an invisible HTML node such as input to reclaim the focus first:

from IPython.display import display, HTML

script = """
this.nextElementSibling.focus();
this.dispatchEvent(new KeyboardEvent('keydown', {key:'s', keyCode: 83, ctrlKey: true}));
"""
display(HTML((
    '<img src onerror="{}" style="display:none">'
    '<input style="width:0;height:0;border:0">'
).format(script)))

And you can always wrap the script in window.setTimout or window.setInterval - but it should not be needed thanks to the built in auto-save function of JupyterLab.

Note: this will need adjustment on Mac OS which uses different default keys for save. — krassowski, Apr 01 '21 at 20:47
Thanks, this is a great solution. I wonder if there is a way to make jupyter save even when my screen is black, and my browser might not be active, so a server-side method that does not require an active client? — charles strauss, Apr 05 '21 at 23:12

score 2 · Answer 3 · answered Sep 06 '21 at 17:59

I just wanted to share a really small tweak of the other solution by krassowski that works for JupyterLab on MacOS:

from IPython.display import display, HTML

script = """
this.nextElementSibling.focus();
this.dispatchEvent(new KeyboardEvent('keydown', {key:'s', keyCode: 83, metaKey: true}));
"""
display(HTML((
    '<img src onerror="{}" style="display:none">'
    '<input style="width:0;height:0;border:0">'
).format(script)))

How to cause Jupyter Lab to save notebook (programmatically)

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