README.md

yaml-notebook-contents

A dirty hack to write .ipynb as YAML instead of JSON. A more thorough implementation would demand .ipynb.yml, but proxy the file naming out the manager.

There's really no reason to use this

• open notebook/lab
• make a notebook
• save it
• view it with Editor
  • Lab's default JSON viewer won't work

environment.yml

name: yamlcontents

channels:
- conda-forge

dependencies:
- jupyterlab >=2
- ruamel.yaml >=0.16
- ujson
- python >=3.7,<3.8.0a0

jupyter_notebook_config.py

import os
import ujson as json

from tornado.web import HTTPError

import traitlets
import nbformat

from ruamel.yaml import YAML

from notebook.services.contents.largefilemanager import LargeFileManager
from notebook.services.contents.fileio import path_to_intermediate, path_to_invalid, replace_file


class YamlContentsManager(LargeFileManager):
    yaml: YAML = traitlets.Instance(YAML)

    @traitlets.default("yaml")
    def _default_yaml(self):
        yaml = YAML(typ='safe')
        yaml.default_flow_style = False
        return yaml

    def _save_notebook(self, os_path, nb):
        """Save a notebook to an os_path."""
        nb_json = nbformat.writes(nb, version=nbformat.NO_CONVERT)
        yaml = self.yaml.load(nb_json)
        with self.atomic_writing(os_path, encoding='utf-8') as f:
            self.yaml.dump(yaml, f)

    def _read_notebook(self, os_path, as_version=4):
        """Read a notebook from an os path."""
        with self.open(os_path, 'r', encoding='utf-8') as f:
            try:
                nb_json = self.yaml.load(f.read() or "{}")
                return nbformat.from_dict(nb_json)
            except Exception as e:
                e_orig = e

            # If use_atomic_writing is enabled, we'll guess that it was also
            # enabled when this notebook was written and look for a valid
            # atomic intermediate.
            tmp_path = path_to_intermediate(os_path)

            if not self.use_atomic_writing or not os.path.exists(tmp_path):
                raise HTTPError(
                    400,
                    u"Unreadable Notebook: %s %r" % (os_path, e_orig),
                )

            # Move the bad file aside, restore the intermediate, and try again.
            invalid_file = path_to_invalid(os_path)
            replace_file(os_path, invalid_file)
            replace_file(tmp_path, os_path)
            return self._read_notebook(os_path, as_version)

c.NotebookApp.contents_manager_class = YamlContentsManager