Coffin is a project mainly written in PYTHON and SHELL, based on the BSD-3-Clause license.
Jinja2 adapter for Django
Coffin currently makes the following Django tags available in Jinja:
{% cache %} - has currently an incompatibility: The second argument (the fragment name) needs to be specified with surrounding quotes if it is supposed to be a literal string, according to Jinja2 syntax. It will otherwise be considered an identifer and resolved as a variable.
{% load %} - is actually a no-op in Coffin, since templatetag libraries are always loaded. See also "Custom Filters and extensions".
{% spaceless %}
{% url %} - additionally, a "view"|url()
filter is also
available.
{% with %}
{% csrf_token %}
Django filters that are ported in Coffin:
Note that for the most part, you can simply use filters written for Django
directly in Coffin. For example, django.contrib.markup
"just works" (tm).
The template-related functionality of the following contrib modules has been ported in Coffin:
coffin.contrib.syndication
.Jinja 2's i18n
extension is hooked up with Django, and a custom version
of makemessages supports string extraction from both Jinja2 and Django
templates.
When using Auto Escape you will notice that marking something as a Safestrings with Django will not affect the rendering in Jinja 2. To fix this you can monkeypatch Django to produce Jinja 2 compatible Safestrings::
'''Monkeypatch Django to mimic Jinja2 behaviour'''
from django.utils import safestring
if not hasattr(safestring, '__html__'):
safestring.SafeString.__html__ = lambda self: str(self)
safestring.SafeUnicode.__html__ = lambda self: unicode(self)
Simply use the render_to_response
replacement provided by coffin::
from coffin.shortcuts import render_to_response
render_to_response('template.html', {'var': 1})
This will render template.html
using Jinja2, and returns a
HttpResponse
.
To have your HTTP 404 and 500 template rendered using Jinja, replace the line::
from django.conf.urls.defaults import *
in your urls.py
(it should be there by default), with::
from coffin.conf.urls.defaults import *
Coffin uses the same templatetag library approach as Django, meaning
your app has a templatetags
directory, and each of it's modules
represents a "template library", providing new filters and tags.
A custom Library
class in coffin.template.Library
can be used
to register Jinja-specific components.
Coffin can automatically make your existing Django filters usable in Jinja, but not your custom tags - you need to rewrite those as Jinja extensions manually.
Example for a Jinja-enabled template library::
from coffin import template
register = template.Library()
register.filter('plenk', plenk) # Filter for both Django and Jinja
register.tag('foo', do_foo) # Django version of the tag
register.tag(FooExtension) # Jinja version of the tag
register.object(my_function_name) # A global function/object
register.test(my_test_name) # A test function
You may also define additional extensions, filters, tests and globals via your settings.py
::
JINJA2_FILTERS = (
'path.to.myfilter',
)
JINJA2_TESTS = {
'test_name': 'path.to.mytest',
}
JINJA2_EXTENSIONS = (
'jinja2.ext.do',
)
When porting Django functionality, Coffin currently tries to avoid Django's silent-errors approach, instead opting to be explicit. Django was discussing the same thing before it's 1.0 release (*), but was constrained by backwards-compatibility concerns. However, if you are converting your templates anyway, it might be a good opportunity for this change.
(*) http://groups.google.com/group/django-developers/browse_thread/thread/f323338045ac2e5e
coffin.template.loader
is a port of django.template.loader
and
comes with a Jinja2-enabled version of get_template()
.
coffin.template.Template
is a Jinja2-Template that supports the
Django render interface (being passed an instance of Context), and uses
Coffin's global Jinja2 environment.
coffin.interop
exposes functionality to manually convert Django
filters to Jinja2 and vice-versa. This is also what Coffin's Library
object uses.
A Jinja2-enabled version of add_to_builtins
can be found in the
django.template
namespace.
You may specify additional arguments to send to the Environment
via JINJA2_ENVIRONMENT_OPTIONS
::
from jinja2 import StrictUndefined
JINJA2_ENVIRONMENT_OPTIONS = {
'autoescape': False,
'undefined': StrictUndefined,
}
These is an incomplete list things that Coffin does not yet and possibly never will, requiring manual changes on your part:
The slice
filter works differently in Jinja2 and Django.
Replace it with Jinja's slice syntax: x[0:1]
.
Jinja2's default
filter by itself only tests the variable for
existance. To match Django's behaviour, you need to pass True
as the second argument, so that it will also provide the default
value for things that are defined but evalute to False
Jinja2's loop variable is called loop
, but Django's forloop
.
Implementing an equivalent to Django's cycle-tag might be difficult,
see also Django tickets #5908 and #7501. Jinja's own facilities
are the forloop.cycle()
function and the global function
cycler
.
The add
filter might not be worth being implemented. {{ x+y }}
is a pretty basic feature of Jinja2, and could almost be lumped
together with the other Django->Jinja2 syntax changes.
Django-type safe strings passed through the context are not converted and therefore not recognized by Jinja2. For example, a notable place were this would occur is the HTML generation of Django Forms.
The {% autoescape %} tag is immensily difficult to port and currently not supported.
Literal strings from within a template are not automatically
considered "safe" by Jinja2, different from Django. According to
Armin Ronacher, this is a design limitation that will not be changed,
due to many Python builtin functions and methods, whichyou are free
to use in Jinja2, expecting raw, untainted strings and thus not being
able to work with Jinja2's Markup
string.
Use the nose framework:
http://somethingaboutorange.com/mrl/projects/nose/