Remove /lang/ path for settings.LANGUAGE_CODE

middleware.py

from django.conf import settings
from django.urls.base import is_valid_path
from django.http import HttpResponsePermanentRedirect
from django.middleware.locale import LocaleMiddleware
from django.utils.cache import patch_vary_headers

class RemoveDefaultLanguagePath(LocaleMiddleware):
    def process_response(self, request, response):
        language = get_language()
        if (response.status_code == 404 and request.path_info.startswith('/'+settings.LANGUAGE_CODE+'/')):
            urlconf = getattr(request, 'urlconf', None)
            language_path =  request.path_info[3:]
            if is_valid_path(language_path, urlconf):
                language_url = "%s://%s%s" % (
                    request.is_secure() and 'https' or 'http',
                    request.get_host(), language_path)
                return HttpResponsePermanentRedirect(language_url)
        patch_vary_headers(response, ('Accept-Language',))
        if 'Content-Language' not in response:
            response['Content-Language'] = language
        return response

settings.py

LANGUAGE_CODE='en'

MIDDLEWARE = [
...
    "myapp.middleware.RemoveDefaultLanguagePath",
...
]

Remove default /lang/ path from urls

Make your site SEO Friendly with 301 redirects

It's useful to redirect (301) urls like

/it/dont-eat-pizza-with-pineapple to /dont-eat-pizza-with-pineapple if your default language is setting.LANGUAGE_CODE='it'

it checks if /dont-eat-pizza-with-pineapple is a valid url, then redirects, else stays on page

When it's really useful?

This middleware is PoC for a "bug"

Assume to have a site with multilanguage en/ru/de/it and after a year you want change all links of main language (example: it)
Now google and other spiders knows your old url, like it/about-us but now you want to change it to /about-us because you don't want language-prefix path for default language anymore.

After set prefix_default_language=False into your i18n_patterns at urls.py, you need to teach to google where old page are.
And what's better than a 301 redirect?

If you like it, feel free to star ⭐ or fork my code