Jingo

Jingo is an adapter for using Jinja2 templates within Django.

Note

Coffin or Jingo?

Jingo differs from Coffin in two major ways:

  • Jingo serves purely as a minimalistic bridge between Django and Jinja2. Coffin attempts to reduce the differences between Jinja2 templates and Django’s native templates.
  • Jingo has a far superior name, as it is a portmanteau of ‘Jinja’ and Django.

Usage

When configured properly (see Settings below) you can render Jinja2 templates in your view the same way you’d render Django templates:

from django.shortcuts import render


def my_view(request):
    context = dict(user_ids=(1, 2, 3, 4))
    return render(request, 'users/search.html', context)

Note

Not only does django.shortcuts.render work, but so does any method that Django provides to render templates from files.

If you’re using Django’s low-level Template class with a literal string, e.g.:

from django.templates import Template

t = Template('template string')

then you’ll need to change that code slightly, to:

from jingo import env

t = env.from_string('template_string')

and then the template will be rendered with all the same features that Jingo provides when rendering template files.

Settings

You’ll want to use Django to use jingo’s template loader. In settings.py:

TEMPLATE_LOADERS = (
    'jingo.Loader',
    'django.template.loaders.filesystem.Loader',
    'django.template.loaders.app_directories.Loader',
)

This will let you use django.shortcuts.render or django.shortcuts.render_to_response.

You can optionally specify which filename patterns to consider Jinja2 templates:

JINGO_INCLUDE_PATTERN = r'\.jinja2'  # use any regular expression here

This will consider every template file that contains the substring .jinja2 to be a Jinja2 file (unless it’s in a module explicitly excluded, see below).

And finally you may have apps that do not use Jinja2, these must be excluded from the loader:

JINGO_EXCLUDE_APPS = ('debug_toolbar',)

If a template path begins with debug_toolbar, the Jinja loader will raise a TemplateDoesNotExist exception. This causes Django to move onto the next loader in TEMPLATE_LOADERS to find a template - in this case, django.template.loaders.filesystem.Loader.

Note

Technically, we’re looking at the template path, not the app. Often these are the same, but in some cases, like ‘registration’ in the default setting–which is an admin template–they are not.

The default is in jingo.EXCLUDE_APPS:

EXCLUDE_APPS = (
    'admin',
    'admindocs',
    'registration',
    'context_processors',
)

Changed in version 0.6.2: Added context_processors application.

If you want to configure the Jinja environment, use JINJA_CONFIG in settings.py. It can be a dict or a function that returns a dict.

JINJA_CONFIG = {'autoescape': False}

or

def JINJA_CONFIG():
    return {'the_answer': 41 + 1}

Template Helpers

Instead of template tags, Jinja encourages you to add functions and filters to the templating environment. In jingo, we call these helpers. When the Jinja environment is initialized, jingo will try to open a helpers.py file from every app in INSTALLED_APPS. Two decorators are provided to ease the environment extension:

jingo.register.filter()

Adds the decorated function to Jinja’s filter library.

jingo.register.function()

Adds the decorated function to Jinja’s global namespace.

Default Helpers

Helpers are available in all templates automatically, without any extra loading.

jingo.helpers.class_selected(a, b)

Return 'class="selected"' if a == b.

jingo.helpers.csrf(context)

Equivalent of Django’s {% crsf_token %}.

jingo.helpers.datetime(t, fmt=None)

Call datetime.strftime with the given format string.

jingo.helpers.f(string, *args, **kwargs)

Uses str.format for string interpolation.

>>> {{ "{0} arguments and {x} arguments"|f('positional', x='keyword') }}
"positional arguments and keyword arguments"
jingo.helpers.fe(string, *args, **kwargs)

Format a safe string with potentially unsafe arguments, then return a safe string.

jingo.helpers.field_attrs(field_inst, **kwargs)

Adds html attributes to django form fields

jingo.helpers.ifeq(a, b, text)

Return text if a == b.

jingo.helpers.nl2br(string)

Turn newlines into <br>.

jingo.helpers.url(*args, **kw)

Return URL using django’s reverse() function.

Template Environment

A single Jinja Environment is created for use in all templates. This is available as jingo.env if you need to work with the Environment.

Localization

Since we all love L10n, let’s see what it looks like in Jinja templates:

<h2>{{ _('Reviews for {0}')|f(addon.name) }}</h2>

The simple way is to use the familiar underscore and string within a {{ }} moustache block. f is an interpolation filter documented below. Sphinx could create a link if I knew how to do that.

The other method uses Jinja’s trans tag:

{% trans user=review.user|user_link, date=review.created|datetime %}
  by {{ user }} on {{ date }}
{% endtrans %}

trans is nice when you have a lot of text or want to inject some variables directly. Both methods are useful, pick the one that makes you happy.

Forms

Django marks its form HTML “safe” according to its own rules, which Jinja2 does not recognize.

Django marks its form HTML “safe” according to its own rules, which Jinja2 does not recognize.

This monkeypatches Django to support the __html__ protocol used in Jinja2 templates. Form, BoundField, ErrorList, and other form objects that render HTML through their __unicode__ method are extended with __html__ so they can be rendered in Jinja2 templates without adding |safe.

Call the patch() function to execute the patch. It must be called before django.forms is imported for the conditional_escape patch to work properly. The root URLconf is the recommended location for calling patch().

Usage:

import jingo.monkey
jingo.monkey.patch()

This patch was originally developed by Jeff Balogh and this version is taken from the nuggets project at https://github.com/mozilla/nuggets/blob/master/safe_django_forms.py

Testing

To run the test suite, you need to define DJANGO_SETTINGS_MODULE first:

$ export DJANGO_SETTINGS_MODULE="fake_settings"
$ nosetests

or simply run:

$ python run_tests.py

To test on all supported versions of Python and Django:

$ pip install tox
$ tox
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