Contributing to the Jupyter Notebook
====================================

If you're reading this section, you're probably interested in contributing to
Jupyter.  Welcome and thanks for your interest in contributing!

Please take a look at the Contributor documentation, familiarize yourself with
using the Jupyter Notebook, and introduce yourself on the mailing list and
share what area of the project you are interested in working on.

General Guidelines
------------------

For general documentation about contributing to Jupyter projects, see the
`Project Jupyter Contributor Documentation`__.

__ https://jupyter.readthedocs.io/en/latest/contributor/content-contributor.html


Setting Up a Development Environment
------------------------------------

Installing Node.js and npm
^^^^^^^^^^^^^^^^^^^^^^^^^^

Building the Notebook from its GitHub source code requires some tools to
create and minify JavaScript components and the CSS,
specifically Node.js and Node's package manager, ``npm``.
It should be node version ≥ 6.0.

If you use ``conda``, you can get them with::

    conda install -c conda-forge nodejs

If you use `Homebrew <https://brew.sh/>`_ on Mac OS X::

    brew install node

Installation on Linux may vary, but be aware that the `nodejs` or `npm` packages
included in the system package repository may be too old to work properly.

You can also use the installer from the `Node.js website <https://nodejs.org>`_.


Installing the Jupyter Notebook
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Once you have installed the dependencies mentioned above, use the following
steps::

    pip install --upgrade setuptools pip
    git clone https://github.com/jupyter/notebook
    cd notebook
    pip install -e .

If you are using a system-wide Python installation and you only want to install the notebook for you,
you can add ``--user`` to the install commands.

Once you have done this, you can launch the master branch of Jupyter notebook
from any directory in your system with::

    jupyter notebook

Verification
^^^^^^^^^^^^

While running the notebook, select one of your notebook files (the file will have the extension ``.ipynb``).
In the top tab you will click on "Help" and then click on "About". In the pop window you will see information about the version of Jupyter that you are running. You will see "The version of the notebook server is:".
If you are working in development mode, you will see that your version of Jupyter notebook will include the word "dev".

.. image:: ./docs/source/_static/images/jupyter-verification.png
   :width: 40pt

If it does not include the word "dev", you are currently not working in development mode and should follow the steps below to uninstall and reinstall Jupyter.

Troubleshooting the Installation
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

If you do not see that your Jupyter Notebook is not running on dev mode, it's possible that you are
running other instances of Jupyter Notebook. You can try the following steps:

1. Uninstall all instances of the notebook package. These include any installations you made using
   pip or conda
2. Run ``python3 -m pip install -e .`` in the notebook repository to install the notebook from there
3. Run ``npm run build`` to make sure the Javascript and CSS are updated and compiled
4. Launch with ``python3 -m notebook --port 8989``, and check that the browser is pointing to ``localhost:8989``
   (rather than the default 8888). You don't necessarily have to launch with port 8989, as long as you use
   a port that is neither the default nor in use, then it should be fine.
5. Verify the installation with the steps in the previous section.


Rebuilding JavaScript and CSS
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

There is a build step for the JavaScript and CSS in the notebook.
To make sure that you are working with up-to-date code, you will need to run
this command whenever there are changes to JavaScript or LESS sources::

    npm run build

**IMPORTANT:** Don't forget to run ``npm run build`` after switching branches. 
When switching between branches of different versions (e.g. ``4.x`` and 
``master``), run ``pip install -e .``. If you have tried the above and still 
find that the notebook is not reflecting the current source code, try cleaning
the repo with ``git clean -xfd`` and reinstalling with ``pip install -e .``.

Development Tip
"""""""""""""""

When doing development, you can use this command to automatically rebuild 
JavaScript and LESS sources as they are modified::

    npm run build:watch

Git Hooks
"""""""""

If you want to automatically update dependencies and recompile JavaScript and
CSS after checking out a new commit, you can install post-checkout and 
post-merge hooks which will do it for you::

    git-hooks/install-hooks.sh

See ``git-hooks/README.md`` for more details.


Running Tests
-------------

Python Tests
^^^^^^^^^^^^

Install dependencies::

    pip install -e .[test]

To run the Python tests, use::

    pytest

If you want coverage statistics as well, you can run::

    py.test --cov notebook -v --pyargs notebook

JavaScript Tests
^^^^^^^^^^^^^^^^

To run the JavaScript tests, you will need to have PhantomJS and CasperJS
installed::

    npm install -g casperjs phantomjs-prebuilt

Then, to run the JavaScript tests::

    python -m notebook.jstest [group]

where ``[group]`` is an optional argument that is a path relative to
``notebook/tests/``.
For example, to run all tests in ``notebook/tests/notebook``::

    python -m notebook.jstest notebook

or to run just ``notebook/tests/notebook/deletecell.js``::

    python -m notebook.jstest notebook/deletecell.js


Building the Documentation
--------------------------

To build the documentation you'll need `Sphinx <http://www.sphinx-doc.org/>`_,
`pandoc <http://pandoc.org/>`_ and a few other packages.

To install (and activate) a `conda environment`_ named ``notebook_docs``
containing all the necessary packages (except pandoc), use::

    conda env create -f docs/environment.yml
    source activate notebook_docs  # Linux and OS X
    activate notebook_docs         # Windows

.. _conda environment:
    https://conda.io/docs/user-guide/tasks/manage-environments.html#creating-an-environment-from-an-environment-yml-file

If you want to install the necessary packages with ``pip`` instead::

    pip install -r docs/doc-requirements.txt

Once you have installed the required packages, you can build the docs with::

    cd docs
    make html

After that, the generated HTML files will be available at
``build/html/index.html``. You may view the docs in your browser.

You can automatically check if all hyperlinks are still valid::

    make linkcheck

Windows users can find ``make.bat`` in the ``docs`` folder.

You should also have a look at the `Project Jupyter Documentation Guide`__.

__ https://jupyter.readthedocs.io/en/latest/contrib_docs/index.html
