diff --git a/docs/ref/templates/upgrading.txt b/docs/ref/templates/upgrading.txt index b592cd9f86c..e47b3fc3e7c 100644 --- a/docs/ref/templates/upgrading.txt +++ b/docs/ref/templates/upgrading.txt @@ -99,9 +99,13 @@ entire :setting:`TEMPLATES` setting instead. ------------------------------------------------------------------------------------------------ In Django 1.8 :func:`~django.template.loader.get_template` and -:func:`~django.template.loader.select_template` returns a backend-dependent +:func:`~django.template.loader.select_template` return a backend-dependent ``Template`` instead of a :class:`django.template.Template`. +For example, if :func:`~django.template.loader.get_template` loads a template +with a :class:`~django.template.backends.django.DjangoTemplates` backend, then +it returns a ``django.template.backends.django.Template``. + ``Template`` objects must provide a :meth:`~django.template.backends.base.Template.render` method whose signature differs slightly from the Django template language's @@ -147,7 +151,6 @@ 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 :class:`~django.template.Engine` directly. Instead of:: - from django.template.loader import get_template template = get_template('included.html') @@ -157,31 +160,52 @@ You can write:: 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 :class:`django.template.Template`, +like :func:`~django.template.loader.get_template` used to in Django 1.7 and +earlier, avoiding all backwards-compatibilty 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. There -are two solutions to replace it. +1.8 because it had no way to choose an engine to compile the template. -You can use a template engine's ``from_string()`` method:: +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) -Or you can use the same trick as above, if you have access to the current -context:: +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 :class:`django.template.Template` because +:class:`~django.template.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.engine.from_string(template_code) -Or you can instantiate a :class:`~django.template.Template` directly:: +``Template()`` +============== - from django.template import Template +To a lesser extent, instantiating a template with ``Template(template_code)`` +suffers from the same issue as ``get_template_from_string()``. - template = Template(template_code) +It still works when the :setting:`TEMPLATES` setting defines exactly one +:class:`~django.template.backends.django.DjangoTemplates` backend, but +pluggable applications can't control this requirement. -The last solution requires that :setting:`TEMPLATES` defines exactly one -:class:`~django.template.backends.django.DjangoTemplates` backend. That engine -will automatically be used to render the template. +The last two solutions described in the previous section are recommended in +that case.