Jupyter notebook post hook save to rename untitled notebooks to `YYYY-MM-DD_untitled-N.ipynb`

jupyter_notebook_config.py

# This file should be put in ~/.jupyter/
# New notebooks will be renamed to YYYY-MM-DD_untitled-N.ipynb instead of Untitled.ipynb
# Please be aware that this code has **NOT** been tested extensively, I wrote it rather quickly, 
# and thus your notebook might be deleted by accident. 
#
# USE THIS CODE AT YOUR OWN RISK
#

import os
import re
import time
import shutil

time_template = '%Y-%m-%d'
date_re = re.compile(r"\d{4}-\d{2}-\d{2}")

def harmonize_filename(model, os_path, contents_manager, **kwargs):
    # First check this is a notebook and it already starts with a date
    if model['type'] != 'notebook' or date_re.search(os_path) is not None:
        return
    # make this work only for Untitled notebooks
    # get notebook name
    notebook_fn = os.path.basename(os_path)
    if not notebook_fn.startswith('Untitled'):
        return

    # if not rename it as YYYY-MM-DD_current-notebook-name.ipynb
    notebook_fn = notebook_fn.lower().replace(' ', '-')
    today = time.strftime(time_template)
    notebook_fn = f"{today}_{notebook_fn}"
    # Now check if it already exist, as when we create new untitled notebooks
    # if so, append a number
    new_notebook = os.path.join(contents_manager.root_dir, notebook_fn)
    while os.path.exists(new_notebook):
        base, ext = os.path.splitext(notebook_fn)
        # assumption: it will be titled YYYY-MM-DD_untitled-N.ipynb
        try:
            base_split = base.split('-')
            number = int(base_split[-1])
        except ValueError:
            number = 0
        number += 1
        if number == 1:
            base_split.append(str(number))
        else:
            base_split[-1] = str(number)
        base = '-'.join(base_split)
        notebook_fn = base + ext
        new_notebook = os.path.join(contents_manager.root_dir, notebook_fn)
    # change name in model too
    model['name'] = notebook_fn
    model['path'] = notebook_fn
    # rename
    old_notebook = os.path.join(contents_manager.root_dir, os_path)
    shutil.move(old_notebook, new_notebook)

c.FileContentsManager.post_save_hook = harmonize_filename