Working with templates and UI

The pages of the JupyterHub application are generated from Jinja templates. These allow the header, for example, to be defined once and incorporated into all pages. By providing your own templates, you can have complete control over JupyterHub’s appearance.

Custom Templates

JupyterHub will look for custom templates in all of the paths in the JupyterHub.template_paths configuration option, falling back on the default templates if no custom template with that name is found. This fallback behavior is new in version 0.9; previous versions searched only those paths explicitly included in template_paths. You may override as many or as few templates as you desire.

Extending Templates

Jinja provides a mechanism to extend templates. A base template can define a block, and child templates can replace or supplement the material in the block. The JupyterHub templates make extensive use of blocks, which allows you to customize parts of the interface easily.

In general, a child template can extend a base template, page.html, by beginning with:

{% extends "page.html" %}

This works, unless you are trying to extend the default template for the same file name. Starting in version 0.9, you may refer to the base file with a templates/ prefix. Thus, if you are writing a custom page.html, start the file with this block:

{% extends "templates/page.html" %}

By defining blocks with same name as in the base template, child templates can replace those sections with custom content. The content from the base template can be included with the {{ super() }} directive.

Example

To add an additional message to the spawn-pending page, below the existing text about the server starting up, place this content in a file named spawn_pending.html in a directory included in the JupyterHub.template_paths configuration option.

{% extends "templates/spawn_pending.html" %} {% block message %} {{ super() }}
<p>Patience is a virtue.</p>
{% endblock %}

Page Announcements

To add announcements to be displayed on a page, you have two options:

• Extend the page templates as described above

• Use configuration variables

Announcement Configuration Variables

If you set the configuration variable JupyterHub.template_vars = {'announcement': 'some_text'}, the given some_text will be placed on the top of all pages. The more specific variables announcement_login, announcement_spawn, announcement_home, and announcement_logout are more specific and only show on their respective pages (overriding the global announcement variable). Note that changing these variables require a restart, unlike direct template extension.

You can get the same effect by extending templates, which allows you to update the messages without restarting. Set c.JupyterHub.template_paths as mentioned above, and then create a template (for example, login.html) with:

{% extends "templates/login.html" %} {% set announcement = 'some message' %}

Extending page.html puts the message on all pages, but note that extending page.html take precedence over an extension of a specific page (unlike the variable-based approach above).