aldryn-translation-tools 0.0.2

models.TranslationHelperMixin

known_translation_getter()

Signature:

(value, language) = obj.known_translation_getter(field, default=None, language_code=None, any_language=False)

Acts like Parler’s safe_translation_getter(), but respects the fallback preferences as defined in settings.CMS_LANGUAGES and provides both the translated value and the language it represents as a tuple.

This is especially helpful when resolving an object’s absolute url for a given language. If a fallback is used (respecting preference), then the returned language_code can then be used to set the correct context for a reverse() to get a URL consistent to the resulting language.

For example:

from django.utils.translation import override

from aldryn_translation_tools.models import TranslationHelperMixin
from cms.utils.i18n import get_current_language
from parler.models import TranslatableModel, TranslatedFields

class Fruit(TranslationHelperMixin, TranslatableModel):
    translations = TranslatableFields(
        name=models.CharField(...),
        slug=models.CharField(...)
    )

    def get_absolute_url(self, language=None):
        language = language or get_current_language()
        (slug, language) = self.known_translation_getter('slug',
            default=None, language_code=language, any_language=False)
        with override(language):
            return reverse('fruit-detail', kwargs={'slug': slug})

In contrast, if we had only done something like this:

...

    def get_absolute_url(self, language=None)
        language = language or get_current_language()
        slug = self.safe_translation_getter('slug', default=None,
            language_code=language, any_language=False)
        with override(language):
            return reverse('fruit-detail', kwargs={'slug': slug})

Then, if the fruit apple has not yet been translated to FR it is possible that you’ll end up with the slug in a fallback langauge, and the rest of the URL in the requested language, so instead of getting a language-consistent fallback url:

/en/apple/

You might get:

/fr/apple/

Which, at best, would be confusing for site visitors but more likely won’t exist resulting in a NoReverseFound exception or 404 and which clearly is not respecting the fallback preferences set by the developer.