Django

import re
from typing import Optional
from doti18n import LocaleData

# Initialize your locales (supports JSON, YAML, XML)
i18n = LocaleData("locales")
pattern = re.compile(r"[a-z]{2}")

class I18nMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        accept_language = request.headers.get('Accept-Language')
        language = self._get_best_match_language(accept_language)
        request.locale = language
        response = self.get_response(request)
        return response

    @staticmethod
    def _get_best_match_language(accept_language: Optional[str]) -> str:
        if not accept_language:
            return i18n.default_locale

        for match in re.finditer(pattern, accept_language):
            language_code = match.group()
            if language_code in i18n.loaded_locales:
                return language_code

        return i18n.default_locale

MIDDLEWARE = [
    # ... other middleware ...
    'path.to.your.middleware.I18nMiddleware',
]

from django.http import JsonResponse

def main(request):
    t = i18n[request.locale].main

    return JsonResponse({"message": t.hello})

import re
from django.http import JsonResponse, HttpRequest
from django.urls import path
from doti18n import LocaleData

i18n = LocaleData("locales")
pattern = re.compile(r"[a-z]{2}")

def get_language_code(request: HttpRequest) -> str:
    """
    Parses the Accept-Language header and returns the best matching locale code.
    """
    accept_language = request.headers.get("Accept-Language", "")

    if not accept_language:
        return i18n.default_locale

    for match in re.finditer(pattern, accept_language):
        language_code = match.group()
        if language_code in i18n.loaded_locales:
            return language_code

    return i18n.default_locale

def main(request: HttpRequest):
    language_code = get_language_code(request)
    t = i18n[language_code].main

    return JsonResponse({"message": t.hello})

urlpatterns = [
    path('', main),
]