Automatic notebook backups
==========================

While working with notebooks it is very common to...

In order to enable backup of notebooks copy the code below
into ``${HOME}/.jupyter/jupyter_notebook_config.py``.
You will need to restart the Jupyter server for this to take
effect.

.. code-block:: python

    from pathlib import Path
    import io
    import os

    _script_exporter = None

    def post_save(model, os_path, contents_manager, **kwargs):
        """post-save hook for converting notebooks to .py scripts"""
        from nbconvert.exporters.script import ScriptExporter

        if model['type'] != 'notebook':
            return   # only do this for notebooks
        if os_path.endswith('.py'):
            return
        if 'Untitled' in os_path:
            return  # do not convert Untitled notebooks

        global _script_exporter

        if _script_exporter is None:
            _script_exporter = ScriptExporter(parent=contents_manager)

        log = contents_manager.log

        p = Path(os_path)

        for j in range(9):
            try:
                f = p.parent / f'{p.stem}.py~{8-j}~'
                f.rename(p.parent / f'{p.stem}.py~{9-j}~')
            except:
                pass

        f = p.parent / f'{p.stem}.py'
        try:
            f.rename(p.parent / f'{p.stem}.py~{1}~')
        except:
            pass

        script, resources = _script_exporter.from_filename(os_path)
        with io.open(f"{f}", 'w', encoding='utf-8') as f:
            f.write(script)

    c.FileContentsManager.post_save_hook = post_save