How to configure dynamic language switching for API responses using i18n_patterns in Django?

Question

I am working on a Django project and need to implement multilingual support for my REST API. I want the API to return responses in the selected language based on the URL prefix (e.g., /en/, /ml/) using i18n_patterns.

I’ve done the following:

1. In settings.py, I’ve defined the available languages:

   LANGUAGES = [
       ('en', 'English'),
       ('ml', 'Malayalam'),
   ]
   LANGUAGE_CODE = 'en'  
   

2. I’ve added 'django.middleware.locale.LocaleMiddleware' to the MIDDLEWARE setting:

   MIDDLEWARE = [
       ...  # other middlewares
       'django.middleware.locale.LocaleMiddleware',
   ]
   
   

3. In the project’s urls.py, I’ve used i18n_patterns to ensure the URLs are prefixed with the language code:

   from django.conf.urls.i18n import i18n_patterns
   
   urlpatterns = [
       path('admin/', admin.site.urls),
       path('auth/', include('accounts.urls')),
       path('app/', include('app.urls'))
   ] + static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)
   
   urlpatterns = i18n_patterns(*urlpatterns)
   
   

   The Issue:

   While I can specify the language via the URL (e.g., /ml/ for Malayalam), the API responses are not being automatically translated to the selected language. The responses remain in English even when the Accept-Language header or language prefix is set to another language (e.g., Malayalam)

   What I Expect:

   • I expect the API responses to be auto-translated into the selected language (e.g., Malayalam) based on the URL prefix or Accept-Language header.

   What I Have Tried:

   • I’ve confirmed that LocaleMiddleware is active in MIDDLEWARE.

   • I’ve ensured that the correct language prefix is included in the URL (e.g., /ml/)

   My Questions:

   1. Is there any additional configuration required to automatically translate API responses based on the selected language?

   2. How can I ensure that the API responses are dynamically translated into the correct language (e.g., Malayalam) based on the URL prefix or Accept-Language headers?

   Any help or code examples would be greatly appreciated!

Answer 1

1. Is there any additional configuration required to automatically translate API responses based on the selected language?

Yes, there are a few additional steps you need to take to ensure your API responses are automatically translated:

• Mark strings for translation: Use gettext or gettext_lazy in your views, serializers, and models to mark strings that need translation.
• Generate and compile translation files: Use django-admin makemessages and django-admin compilemessages to create and compile .po and .mo files for each language.
• Ensure LocaleMiddleware is correctly configured: It should be placed after SessionMiddleware and CommonMiddleware in your MIDDLEWARE settings.
• Set LOCALE_PATHS: Ensure Django knows where to find your translation files by setting LOCALE_PATHS in settings.py.

2. How can I ensure that the API responses are dynamically translated into the correct language (e.g., Malayalam) based on the URL prefix or Accept-Language headers?

To dynamically translate API responses based on the URL prefix or Accept-Language header:

1. Use i18n_patterns in urls.py: Wrap your URL patterns with i18n_patterns to enable language prefixes (e.g., /ml/, /en/).

   from django.conf.urls.i18n import i18n_patterns
   from django.urls import path, include
   
   urlpatterns = [
       path('admin/', admin.site.urls),
       path('auth/', include('accounts.urls')),
       path('app/', include('app.urls'))
   ]
   
   urlpatterns = i18n_patterns(*urlpatterns)
   

2. Ensure LocaleMiddleware is active: The LocaleMiddleware automatically activates the language based on the URL prefix or Accept-Language header. Ensure it’s in your MIDDLEWARE:

   MIDDLEWARE = [
       ...
       'django.middleware.locale.LocaleMiddleware',  # After SessionMiddleware and CommonMiddleware
       ...
   ]
   

3. Mark strings for translation in your views: Use gettext or gettext_lazy to mark strings that need translation. For example:

   from django.utils.translation import gettext as _
   
   def my_view(request):
       output = _("Hello, world!")
       return Response({"message": output})
   

4. Generate and compile translation files:

   • Run django-admin makemessages -l ml to generate .po files for Malayalam.
   • Edit the .po files to add translations.
   • Run django-admin compilemessages to compile .po files into .mo files.

That's it I think!