Upgrading templates to Django 1.8

Django’s template system was overhauled in Django 1.8 when it gained support for multiple template engines. This document complements the release notes with detailed upgrade instructions on some topics.

The TEMPLATES settings

A new setting was introduced in Django 1.8: TEMPLATES. All existing template-related settings were deprecated.

During the deprecation period, Django will create a backwards-compatible TEMPLATES based on the TEMPLATE_* settings if you don’t define it yourself.

Here’s how to define TEMPLATES in your settings module.

If you’re using the default value of TEMPLATE_LOADERS, that is, if it isn’t defined in your settings file or if it’s set to:

['django.template.loaders.filesystem.Loader',
 'django.template.loaders.app_directories.Loader']

then you should define TEMPLATES as follows:

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [
            # insert your TEMPLATE_DIRS here
        ],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                # Insert your TEMPLATE_CONTEXT_PROCESSORS here or use this
                # list if you haven't customized them:
                'django.contrib.auth.context_processors.auth',
                'django.template.context_processors.debug',
                'django.template.context_processors.i18n',
                'django.template.context_processors.media',
                'django.template.context_processors.static',
                'django.template.context_processors.tz',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

If you aren’t using the default value of TEMPLATE_LOADERS, then you should define TEMPLATES as follows:

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [
            # insert your TEMPLATE_DIRS here
        ],
        'OPTIONS': {
            'context_processors': [
                # Insert your TEMPLATE_CONTEXT_PROCESSORS here or use this
                # list if you haven't customized them:
                'django.contrib.auth.context_processors.auth',
                'django.template.context_processors.debug',
                'django.template.context_processors.i18n',
                'django.template.context_processors.media',
                'django.template.context_processors.static',
                'django.template.context_processors.tz',
                'django.contrib.messages.context_processors.messages',
            ],
            'loaders': [
                # insert your TEMPLATE_LOADERS here
            ]
        },
    },
]

Furthermore you should replace django.core.context_processors with django.template.context_processors in the names of context processors.

If your settings module defines ALLOWED_INCLUDE_ROOTS or TEMPLATE_STRING_IF_INVALID, include their values under the 'allowed_include_roots' and 'string_if_invalid' keys in the 'OPTIONS' dictionary.

If it sets TEMPLATE_DEBUG to a value that differs from DEBUG, include that value under the 'debug' key in 'OPTIONS'.

Once you have defined TEMPLATES, you can safely remove ALLOWED_INCLUDE_ROOTS, TEMPLATE_CONTEXT_PROCESSORS, TEMPLATE_DEBUG, TEMPLATE_DIRS, TEMPLATE_LOADERS, and TEMPLATE_STRING_IF_INVALID.

If you are overriding some of these settings in tests, you should override the entire TEMPLATES setting instead.

django.template.loader

get_template() and select_template()

In Django 1.8 get_template() and select_template() return a backend-dependent Template instead of a django.template.Template.

For example, if get_template() loads a template with a DjangoTemplates backend, then it returns a django.template.backends.django.Template.

Template objects must provide a render() method whose signature differs slightly from the Django template language’s render().

Instead of:

from django.template import Context
from django.template.loader import get_template

template = get_template('hello.html')
html = template.render(Context({'name': 'world'}))

You should write:

from django.template.loader import get_template

template = get_template('hello.html')
html = template.render({'name': 'world'})

And instead of:

from django.template import RequestContext
from django.template.loader import get_template

template = get_template('hello.html')
html = template.render(RequestContext(request, {'name': 'world'}))

You should write:

from django.template.loader import get_template

template = get_template('hello.html')
html = template.render({'name': 'world'}, request)

Passing a Context or a RequestContext is still possible when the template is loaded by a DjangoTemplates backend but it’s deprecated and won’t be supported in Django 1.10.

If you’re loading a template while you’re rendering another template with the Django template language and you have access to the current context, for instance in the render() method of a template tag, you can use the current Engine directly. Instead of:

from django.template.loader import get_template
template = get_template('included.html')

You can write:

template = context.template.engine.get_template('included.html')

This will load the template with the current engine without triggering the multiple template engines machinery, which is usually the desired behavior. Unlike previous solutions, this returns a django.template.Template, like get_template() used to in Django 1.7 and earlier, avoiding all backwards-compatibility problems.

get_template_from_string()

Private API get_template_from_string(template_code) was removed in Django 1.8 because it had no way to choose an engine to compile the template.

Three alternatives are available.

If you control the project’s setting, you can use one of the configured engines:

from django.template import engines

template = engines['django'].from_string(template_code)

This returns a backend-dependent Template object.

For trivial templates that don’t need context processors nor anything else, you can create a bare-bones engine and use its from_string() method:

from django.template import Engine

template = Engine().from_string(template_code)

This returns a django.template.Template because Engine is part of the Django template language’s APIs. The multiple template engines machinery isn’t involved here.

Finally, if you have access to the current context, you can use the same trick as above:

template = context.template.engine.from_string(template_code)

Template()

To a lesser extent, instantiating a template with Template(template_code) suffers from the same issue as get_template_from_string().

It still works when the TEMPLATES setting defines exactly one DjangoTemplates backend, but pluggable applications can’t control this requirement.

The last two solutions described in the previous section are recommended in that case.

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