User Guide

Embedding Jupyter Widgets in Other Contexts than the Notebook

expand icon

Embedding Jupyter Widgets in Other Contexts than the Notebook

Jupyter interactive widgets can be serialized and embedded into

  • static web pages
  • sphinx documentation
  • html-converted notebooks on nbviewer

Here, we discuss embedding widgets using the custom widget manager in the @jupyter-widgets/html-manager npm package. Two embedders are provided:

  1. A basic embedder that only embeds standard controls, but can be used on any web page
  2. An embedder that uses RequireJS, and can embed standard and custom widgets

Embedding Widgets in HTML Web Pages

The classic notebook interface provides a Widgets menu for generating an HTML snippet that can be embedded into any static web page:

The menu provides three sets of actions

  • Save Notebook Widget State and Clear Notebook Widget State
  • Download Widget State
  • Embed Widgets

Save Notebook Widget State

A notebook file may be saved with the current widget state as metadata. This allows the notebook file to be rendered with rendered widgets (see the section about Sphinx below, for example). To save a notebook with the current widget state, use the Save Notebook Widget State menu item.

In order to delete old saved state and save new state to the notebook, do the following in order:

  1. Use the Clear Notebook Widget State menu and save the notebook. This clears the metadata from the notebook file.
  2. Restart the kernel and refresh the page. This clears the old widget state from the widget manager on the page.
  3. Create whatever widgets you'd like, and use Save Notebook Widget State and save the notebook. This saves the new widget state to the notebook file.

Embeddable HTML Snippet

The Embed widgets menu item provides a dialog containing an HTML page which embeds the current widgets. In order to support custom widgets, it uses the RequireJS embedder.

This HTML snippet is composed of multiple <script> tags embedded into an HTML document:

  • The first script tag loads RequireJS from a CDN. If you already have RequireJS on the page, you can delete this script tag.

  • The second script tag loads the RequireJS widget embedder. This defines appropriate modules and then sets up a function to render all of the widget views included on the page. If you are only embedding standard widgets and do not want to use RequireJS, you can replace these first two script tags with a script tag loading the standard embedder.

  • The next script tag is a script tag with mime type application/vnd.jupyter.widget-state+json that contains the state of all the widget models currently in use. The JSON schema for the content of this script tag is found in the @jupyter-widgets/schema npm package.

  • Then there are a number of script tags, each with mime type application/vnd.jupyter.widget-view+json, corresponding to the views which you want to display in the web page. These script tags must be in the body of the page, and are replaced with the rendered widgets. The JSON schema for the content of these script tags is found in the @jupyter-widgets/schema npm package.

    The Embed Widgets action currently creates one of these script tags for each view displayed in the notebook. If you'd like to lay out the views, or include only some of them, you can delete or include these script tags as you wish.

In order to clear widget state from the frontend so that it does not show up in the embedding, restart the kernel and then refresh the page, in that order.

Widget State JSON

The Download Widget State option triggers the downloading of a JSON file containing the serialized state of all the widget models currently in use, using the application/vnd.jupyter.widget-state+json format specified in the @jupyter-widgets/schema npm package.

Python interface

Embeddable code for the widgets can also be produced from Python. The ipywidgets.embed module provides several functions for embedding widgets into HTML documents programatically.

Use embed_minimal_html to create a simple, stand-alone HTML page:

from ipywidgets import IntSlider
from ipywidgets.embed import embed_minimal_html

slider = IntSlider(value=40)
embed_minimal_html('export.html', views=[slider], title='Widgets export')

This creates the stand-alone file export.html. To view the file, either start an HTTP server, such as the HTTP server in the Python standard library, or just open it in your web browser (by double-clicking on the file, or by writing file:///path/to/file in your browser search bar).

You will sometimes want greater granularity than that afforded by embed_minimal_html. Often, you want to control the structure of the HTML document in which the widgets are embedded. For this, use embed_data to get JSON exports of specific parts of the widget state. You can embed these in an HTML template:

import json

from ipywidgets import IntSlider
from ipywidgets.embed import embed_data

s1 = IntSlider(max=200, value=100)
s2 = IntSlider(value=40)
data = embed_data(views=[s1, s2])

html_template = """
<html>
  <head>

    <title>Widget export</title>

    <!-- Load RequireJS, used by the IPywidgets for dependency management -->
    <script 
      src="https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.4/require.min.js" 
      integrity="sha256-Ae2Vz/4ePdIu6ZyI/5ZGsYnb+m0JlOmKPjt6XZ9JJkA=" 
      crossorigin="anonymous">
    </script>

    <!-- Load IPywidgets bundle for embedding. -->
    <script 
      src="https://unpkg.com/@jupyter-widgets/html-manager@*/dist/embed-amd.js" 
      crossorigin="anonymous">
    </script>

    <!-- The state of all the widget models on the page -->
    <script type="application/vnd.jupyter.widget-state+json">
      {manager_state}
    </script>
  </head>

  <body>

    <h1>Widget export</h1>

    <div id="first-slider-widget">
      <!-- This script tag will be replaced by the view's DOM tree -->
      <script type="application/vnd.jupyter.widget-view+json">
        {widget_views[0]}
      </script>
    </div>

    <hrule />

    <div id="second-slider-widget">
      <!-- This script tag will be replaced by the view's DOM tree -->
      <script type="application/vnd.jupyter.widget-view+json">
        {widget_views[1]}
      </script>
    </div>

  </body>
</html>
"""

manager_state = json.dumps(data['manager_state'])
widget_views = [json.dumps(view) for view in data['widget_views']]
rendered_template = html_template.format(manager_state=manager_state, widget_views=widget_views)
with open('export.html', 'w') as fp:
    fp.write(rendered_template)

The web page needs to load RequireJS and the Jupyter widgets HTML manager. You then need to include the manager state in a <script> tag of type application/vnd.jupyter.widget-state+json, which can go in the head of the document. For each widget view, place a <script> tag of type application/vnd.jupyter.widget-view+json in the DOM element that should contain the view. The widget manager will replace each <script> tag with the DOM tree corresponding to the widget.

In this example, we used a Python string for the template, and used the format method to interpolate the state. For embedding in more complex documents, you may want to use a templating engine like Jinja2.

In all embedding functions in ipywidgets.embed, the state of all widgets known to the widget manager is included by default. You can alternatively pass a reduced state to use instead. This can be particularly relevant if you have many independent widgets with a large state, but only want to include the relevant ones in your export. To include only the state of specific views and their dependencies, use the function dependency_state:

from ipywidgets.embed import embed_snippet, dependency_state

s1 = IntSlider(max=200, value=100)
s2 = IntSlider(value=40)
embed_minimal_html(views=[s1, s2], state=dependency_state([s1, s2]))

Embedding Widgets in the Sphinx HTML Documentation

As of ipywidgets 6.0, Jupyter interactive widgets can be rendered in Sphinx html documentation. Two means of achieving this are provided:

Using the Jupyter Sphinx Extension

The jupyter_sphinx extension enables jupyter-specific features in sphinx. It can be install with pip and conda.

In the conf.py sphinx configuration file, add jupyter_sphinx.embed_widgets to the list of enabled extensions.

Two directives are provided: ipywidgets-setup and ipywidgets-display.

ipywidgets-setup code is used to run potential boilerplate and configuration code prior to running the display code. For example:

  • ipywidgets-setup:

    from ipywidgets import VBox, jsdlink, IntSlider, Button
    
  • ipywidgets-display:

    s1, s2 = IntSlider(max=200, value=100), IntSlider(value=40)
    b = Button(icon='legal')
    jsdlink((s1, 'value'), (s2, 'max'))
    VBox([s1, s2, b])
    

In the case of the ipywidgets-display code, the last statement of the code-block should contain the widget object you wish to be rendered.

Quoting the jupyter_sphinx readme,

Widgets rendered on the same page use the same widget manager. As a consequence, they can be linked with each other via JavaScript link widgets. However, no kernel is connected and therefore, interaction with the backend will not happen.

Using the nbsphinx Project

The nbsphinx sphinx extension provides a source parser for *.ipynb files. Custom Sphinx directives are used to show Jupyter Notebook code cells (and of course their results) in both HTML and LaTeX output.

In the case of the HTML output, Jupyter Interactive Widgets are also supported. However, it is a requirement that the notebook was correctly saved with the special "Save Notebook Widget State" action in the widgets menu.

Rendering Interactive Widgets on nbviewer

If your notebook was saved with the special "Save Notebook with Widgets" action in the Widgets menu, interactive widgets displayed in your notebook should also be rendered on nbviewer.

See e.g. the Widget List example from the documentation.

The Case of Custom Widget Libraries

Custom widgets can also be rendered on nbviewer, static HTML and RTD documentation. An illustration of this is the http://jupyter.org/widgets gallery.

The widget embedder attempts to fetch the model and view implementation of the custom widget from the npm CDN https://unpkg.com. The URL that is requested for, e.g. the bqplot module name, with the semver range ^2.0.0 is

https://unpkg.com/bqplot@^2.0.0/dist/index.js

which holds the webpack bundle for the bqplot library.

The widget-cookiecutter template project contains a template project for a custom widget library following the best practices for authoring widgets, which ensure that your custom widget library can render on nbviewer.

Using jupyter-widgets-controls in web contexts

The core jupyter-widgets-controls library, the JavaScript package of ipywidgets, is agnostic to the context in which it is used (Notebook, JupyterLab, static web page). For each context, we specialize the base widget manager implemented in @jupyter-widgets/base to provide the logic for

  • where widgets should be displayed,
  • how to retrieve information about their state.

Specifically:

  • The widgetsnbextension Python package provides the implementation of a specialized widget manager for the classic Jupyter notebook, and the packaging logic as a notebook extension.
  • The @jupyter-widgets/jupyterlab-manager npm package provides the implementation of a specialized widget manager for the context of JupyterLab, and the packaging logic as a lab extension.
  • The embed manager implemented in the @jupyter-widgets/html-manager npm package is a specialization of the base widget manager used for the static embedding of widgets used by the Sphinx extension, nbviewer, and the "Embed Widgets" command discussed above.

We provide additional examples of specializations of the base widget manager implementing other usages of Jupyter widgets in web contexts.

  1. The web1 example is a simplistic example showcasing the use of Jupyter widgets in a web context.
  2. The web2 example is a simple example making use of the application/vnd.jupyter.widget-state+json mime type.
  3. The web3 example showcases how communication with a Jupyter kernel can happen in a web context outside of the notebook or jupyterlab contexts.
  4. The web-tmpnb example makes use of the tmpnb service to spawn a Jupyter server, request a kernel from this server and implement the same feature as the web3 example.