Jupyter NbClassic

Common errors

• ModuleNotFoundError: No module named 'nbclassic'

  cause The `nbclassic` package is either not installed in the active Python environment or its installation path is not correctly configured in your system's PATH, preventing Jupyter from finding it.
  fix Ensure `nbclassic` is installed in your active environment: `pip install nbclassic` or `conda install nbclassic`. If already installed, check your PATH environment variable or try launching with `python -m nbclassic`.

• ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behavior is the source of the following dependency conflicts. notebook 6.5.1 requires nbclassic==0.4.5, but you have nbclassic 0.4.6 which is incompatible.

  cause There is a version mismatch between the `notebook` package and `nbclassic`, where a specific version of `notebook` explicitly requires an incompatible version of `nbclassic`.
  fix Downgrade or upgrade `nbclassic` to match the version required by `notebook`, or upgrade both to compatible recent versions. For example, `pip install notebook==6.5.1 nbclassic==0.4.5` or `pip install --upgrade notebook nbclassic` to get the latest compatible versions.

• ImportError: cannot import name '_i18n' from 'jupyter_server.transutils'

  cause This error typically occurs when `nbclassic` is attempting to import a utility from `jupyter_server` that has been moved or removed in a different version of `jupyter_server`, indicating an incompatibility between the two packages.
  fix Upgrade both `jupyter_server` and `nbclassic` to their latest compatible versions: `pip install --upgrade jupyter_server nbclassic` or `conda update jupyter_server nbclassic`.

• 500: Internal Server Error (KeyError: 'terminals_available')

  cause This server-side error, often appearing when launching `jupyter nbclassic` or attempting to open notebooks, is frequently due to an incompatibility or missing configuration related to terminal handling between `nbclassic` and `jupyter_server` versions.
  fix Ensure both `jupyter_server` and `nbclassic` are updated to their latest compatible versions: `pip install --upgrade jupyter_server nbclassic`. Additionally, ensure that the `jupyter-server-terminals` package is installed: `pip install jupyter-server-terminals`.

Warnings

• breaking Static asset paths for the classic Notebook were changed in nbclassic v1.3.2, breaking the ability to serve them from original endpoints. This was fixed in v1.3.3 by copying assets to legacy paths. Users on v1.3.2 may experience UI issues. [1]
  Fix: Upgrade to nbclassic v1.3.3 or newer.
• gotcha When nbclassic is installed alongside Jupyter Notebook 7 (or JupyterLab), its UI will be served under the `/nbclassic/tree` base path, rather than the default `/tree` path. This is to avoid conflicts with Notebook 7, which uses `/tree`. [10, 11]
  Fix: Access nbclassic at the `/nbclassic/tree` URL endpoint in your browser. Notebook 7 may provide a dropdown to switch interfaces. [10, 11]
• breaking Support for Python 3.8 was dropped in nbclassic v1.3.0. Attempts to install or run nbclassic on Python 3.8 or older will fail. [15]
  Fix: Ensure your Python environment is 3.9 or newer.
• gotcha Older `notebook` package versions (e.g., `notebook==6.5.1`) might have strict dependency requirements on specific `nbclassic` versions (e.g., `nbclassic==0.4.5`). Installing a newer `nbclassic` (e.g., `0.4.6` or `1.x.x`) can lead to dependency conflicts during `pip install`. [16]
  Fix: Carefully manage dependencies, potentially using a virtual environment and checking `notebook`'s explicit `nbclassic` requirements. Consider upgrading to `notebook` v7+ if possible, which uses `jupyter-server` and `nbclassic` more smoothly. [16]
• breaking Entrypoints for extensions were renamed in NbClassic (e.g., `jupyter-nbclassic-extension`, `jupyter nbclassic-serverextension`, `jupyter-nbclassic-bundlerextension`). Older commands or configurations using `jupyter nbextension` for nbclassic might fail or target the wrong server. [7, 8]
  Fix: Update scripts and configurations to use the new `jupyter-nbclassic-extension` (or other relevant `jupyter-nbclassic-*` commands) for managing nbclassic extensions. [8]
• gotcha When configuring the startup directory for nbclassic (especially alongside JupyterLab >= 3), use `c.ServerApp.root_dir` in `jupyter_server_config.py` instead of the older `c.NotebookApp.notebook_dir` in `jupyter_notebook_config.py`. [18]
  Fix: Use `jupyter server --generate-config` to create the correct configuration file and set `c.ServerApp.root_dir` for the desired startup path. [18]

Install

• pip install nbclassic Install from PyPI

Imports

• NBClassicApp

  from nbclassic.nbclassicapp import NBClassicApp

  While nbclassic is primarily used via the command line, this is the main application class for programmatic configuration or advanced extension development. Most users will interact via 'jupyter nbclassic'.
• NBClassicConfigShimMixin

  from nbclassic.nbclassicapp import NBClassicConfigShimMixin

  Relevant for applications that previously subclassed `NotebookApp` and need to leverage the Jupyter Server backend while handling moved traits. [4]

Quickstart

To launch the classic Jupyter Notebook interface, simply run `jupyter nbclassic` in your terminal. This will start a Jupyter Server and open the notebook interface in your web browser, typically at `http://127.0.0.1:8888`. [1, 2]

jupyter nbclassic