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"""Jinja2's i18n functionality is not exactly the same as Django's.
In particular, the tags names and their syntax are different:
1. The Django ``trans`` tag is replaced by a _() global.
2. The Django ``blocktrans`` tag is called ``trans``.
(1) isn't an issue, since the whole ``makemessages`` process is based on
converting the template tags to ``_()`` calls. However, (2) means that
those Jinja2 ``trans`` tags will not be picked up my Django's
``makemessage`` command.
There aren't any nice solutions here. While Jinja2's i18n extension does
come with extraction capabilities built in, the code behind ``makemessages``
unfortunately isn't extensible, so we can:
* Duplicate the command + code behind it.
* Offer a separate command for Jinja2 extraction.
* Try to get Django to offer hooks into makemessages().
* Monkey-patch.
We are currently doing that last thing. It turns out there we are lucky
for once: It's simply a matter of extending two regular expressions.
Credit for the approach goes to:
import re
from import makemessages
from django.template import engines
from django.template.base import BLOCK_TAG_START, BLOCK_TAG_END
from django.utils.translation import template as trans_real
strip_whitespace_right = re.compile(r"(%s-?\s*(trans|pluralize).*?-%s)\s+" % (BLOCK_TAG_START, BLOCK_TAG_END), re.U)
strip_whitespace_left = re.compile(r"\s+(%s-\s*(endtrans|pluralize).*?-?%s)" % (BLOCK_TAG_START, BLOCK_TAG_END), re.U)
def strip_whitespaces(src):
src = strip_whitespace_left.sub(r'\1', src)
src = strip_whitespace_right.sub(r'\1', src)
return src
# this regex looks for {% trans %} blocks that don't have 'trimmed' or 'notrimmed' set.
# capturing {% endtrans %} ensures this doesn't affect DTL {% trans %} tags.
trans_block_re = re.compile(
re.U | re.DOTALL
def apply_i18n_trimmed_policy(src, engine):
# if env.policies["ext.i18n.trimmed"]: insert 'trimmed' flag on jinja {% trans %} blocks.
i18n_trim_policy = engine.get("OPTIONS", {}).get("policies", {}).get("ext.i18n.trimmed")
if not i18n_trim_policy:
return src
return trans_block_re.sub(r"\1 trimmed \2", src)
class Command(makemessages.Command):
def add_arguments(self, parser):
super(Command, self).add_arguments(parser)
parser.add_argument('--jinja2-engine-name', default=None, dest='jinja_engine')
def _get_default_jinja_template_engine(self):
# dev's note: i would love to have this easy default: --jinja2-engine-name=jinja2
# but as currently implemented, django-jinja's engine's name defaults to 'backend'.
# see:
# for now, the default engine will be the first one exactly matching our backend's path.
return [e for e in engines.templates.values() if e["BACKEND"] == "django_jinja.backend.Jinja2"][0]
def handle(self, *args, **options):
old_endblock_re = trans_real.endblock_re
old_block_re = trans_real.block_re
old_constant_re = trans_real.constant_re
old_templatize = trans_real.templatize
# Extend the regular expressions that are used to detect
# translation blocks with an "OR jinja-syntax" clause.
trans_real.endblock_re = re.compile(
trans_real.endblock_re.pattern + '|' + r"""^-?\s*endtrans\s*-?$""")
trans_real.block_re = re.compile(
trans_real.block_re.pattern + '|' + r"""^-?\s*trans(?:\s+(?:no)?trimmed)?(?:\s+(?!'|")(?=.*?=.*?)|\s*-?$)""")
trans_real.plural_re = re.compile(
trans_real.plural_re.pattern + '|' + r"""^-?\s*pluralize(?:\s+.+|-?$)""")
trans_real.constant_re = re.compile(r""".*?_\(((?:".*?(?<!\\)")|(?:'.*?(?<!\\)')).*?\)""")
if options['jinja_engine']:
jinja_engine = engines[options['jinja_engine']]
jinja_engine = self._get_default_jinja_template_engine()
def my_templatize(src, origin=None, **kwargs):
new_src = strip_whitespaces(src)
new_src = apply_i18n_trimmed_policy(new_src, jinja_engine)
return old_templatize(new_src, origin, **kwargs)
trans_real.templatize = my_templatize
super(Command, self).handle(*args, **options)
trans_real.endblock_re = old_endblock_re
trans_real.block_re = old_block_re
trans_real.templatize = old_templatize
trans_real.constant_re = old_constant_re