118 lines
3.9 KiB
Python
118 lines
3.9 KiB
Python
from __future__ import annotations
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from django.conf import settings
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from django.http import HttpRequest, HttpResponseRedirect
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from django.utils.cache import add_never_cache_headers, patch_vary_headers
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from django.utils.translation import (
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get_language_from_request,
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get_supported_language_variant,
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)
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class FirstVisitLanguageRedirectMiddleware:
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"""Redirect first-visit requests to a supported language path."""
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SKIP_PREFIXES = (
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"/admin",
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"/cms",
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"/dashboard",
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"/manage",
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"/api",
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"/static",
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"/media",
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"/i18n/setlang",
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)
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def __init__(self, get_response):
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self.get_response = get_response
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self.language_cookie_name = getattr(
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settings, "LANGUAGE_COOKIE_NAME", "django_language"
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)
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self.default_language = settings.LANGUAGE_CODE.split("-")[0].lower()
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self.supported_languages = {
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code.split("-")[0].lower() for code, _label in settings.LANGUAGES
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}
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def __call__(self, request: HttpRequest):
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redirect_url = self._build_redirect_url(request)
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if redirect_url:
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return HttpResponseRedirect(redirect_url)
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response = self.get_response(request)
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if self._should_disable_home_cache(request):
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patch_vary_headers(response, ("Accept-Language", "Cookie"))
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add_never_cache_headers(response)
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return response
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def _build_redirect_url(self, request: HttpRequest) -> str | None:
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if request.method != "GET":
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return None
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if self.language_cookie_name in request.COOKIES:
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return None
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path = request.path_info or "/"
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if self._should_skip_path(path):
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return None
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if self._is_localized_path(path):
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return None
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target_lang = self._preferred_language(request)
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if not target_lang or target_lang == self.default_language:
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return None
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if path == "/":
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localized_path = f"/{target_lang}/"
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else:
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localized_path = f"/{target_lang}{path}"
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query = request.META.get("QUERY_STRING")
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if query:
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return f"{localized_path}?{query}"
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return localized_path
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def _should_skip_path(self, path: str) -> bool:
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for prefix in self.SKIP_PREFIXES:
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if path == prefix or path.startswith(f"{prefix}/"):
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return True
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return False
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def _is_localized_path(self, path: str) -> bool:
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parts = [part for part in path.split("/") if part]
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if not parts:
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return False
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return parts[0].lower() in self.supported_languages
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def _preferred_language(self, request: HttpRequest) -> str | None:
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matched = get_language_from_request(request, check_path=False)
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if matched:
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normalized = matched.split("-")[0].lower()
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if (
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normalized in self.supported_languages
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and normalized != self.default_language
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):
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return normalized
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# Fallback to raw Accept-Language parsing for unprefixed default routes.
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header = request.META.get("HTTP_ACCEPT_LANGUAGE", "")
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for item in header.split(","):
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raw_lang = item.split(";", 1)[0].strip()
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if not raw_lang:
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continue
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try:
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variant = get_supported_language_variant(raw_lang)
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except LookupError:
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continue
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normalized = variant.split("-")[0].lower()
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if normalized in self.supported_languages:
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return normalized
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return None
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def _should_disable_home_cache(self, request: HttpRequest) -> bool:
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if request.method != "GET":
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return False
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if self.language_cookie_name in request.COOKIES:
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return False
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path = request.path_info or "/"
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if path != "/":
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return False
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return not self._is_localized_path(path)
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