[Django]-Django parler TranslatableSlugMixin translates from English to another language, but once translated cannot be translated back returns 404

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Ok so I’ve figured out how to make this work and it turns out it’s a combination of things…

  1. Using the default Django CMS chooser was a mistake:

    {% language_chooser "menu/language_chooser.html" %}

    This leads to the URLs I described above:

    /en/blog/english-slug
/fr/blog/english-slug
/de/blog/english-slug

    Reading the Django Parler docs led me to using their language navigation menu:

    {% for lang_code, title in LANGUAGES %}
        {% get_language_info for lang_code as lang %}
        {% get_translated_url lang_code as tr_url %}
        {% if tr_url %}<li{% if lang_code == LANGUAGE_CODE %} class="is-selected"{% endif %}><a href="{{ tr_url }}" hreflang="{{ lang_code }}">{{ lang.name_local|capfirst }}</a></li>{% endif %}
{% endfor %}

    This leads to the urls pointing to the correct location:

    /en/blog/english-slug
/fr/blog/french-slug
/de/blog/german-slug

  2. For the Django Parler navigation to work I needed to update the get_absolute_url() in the model to handle different languages. I did that as follows:

    from django.utils.translation import get_language

from parler.models import TranslatableModel, TranslatedFields

class Article(TranslatableModel):

    ...

    def get_absolute_url(self):
        language = get_language()
        if self.has_translation(language):
            slug = self.safe_translation_getter('slug', language_code=language)
            return reverse('blog:article_detail', kwargs={'slug': slug})
        # no translation so fallback to all article list
        return reverse('blog:article_list')

Phew! That was a headache! Hopefully this helps somebody else in the future!

P.S. During my research I came across this blog app that seems really great:

https://github.com/nephila/djangocms-blog

It helped me get to the bottom of this nightmare!

UPDATE

Looking at the get_absolute_url() in djangocms-blog (link above), they have a far better solution to the problem. Their implementation is:

from django.utils.translation import get_language

from parler.models import TranslatableModel, TranslatedFields

class Article(TranslatableModel):

    ...

    def get_absolute_url(self, lang=None):
        if not lang or lang not in self.get_available_languages():
            lang = self.get_current_language()
        if not lang or lang not in self.get_available_languages():
            lang = get_language()
        with switch_language(self, lang):
            slug = self.safe_translation_getter('slug', language_code=lang, any_language=True)
            return reverse('blog:article_detail', kwargs={'slug': slug})

Thanks nephila, this has saved me from a lot of cursing and frustration 🙂

👤tdsymonds

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