implemented async-only locale middleware

Author: amirreza8002

django_async_extensions/amiddleware/locale.py

@@ -0,0 +1,81 @@
+from django.conf import settings
+from django.conf.urls.i18n import is_language_prefix_patterns_used
+from django.http import HttpResponseRedirect
+from django.urls import get_script_prefix, is_valid_path
+from django.utils import translation
+from django.utils.cache import patch_vary_headers
+
+from django_async_extensions.amiddleware.base import AsyncMiddlewareMixin
+
+
+class AsyncLocaleMiddleware(AsyncMiddlewareMixin):
+    """
+    Parse a request and decide what translation object to install in the
+    current thread context. This allows pages to be dynamically translated to
+    the language the user desires (if the language is available).
+    """
+
+    response_redirect_class = HttpResponseRedirect
+
+    async def process_request(self, request):
+        urlconf = getattr(request, "urlconf", settings.ROOT_URLCONF)
+        (
+            i18n_patterns_used,
+            prefixed_default_language,
+        ) = is_language_prefix_patterns_used(urlconf)
+        language = translation.get_language_from_request(
+            request, check_path=i18n_patterns_used
+        )
+        language_from_path = translation.get_language_from_path(request.path_info)
+        if (
+            not language_from_path
+            and i18n_patterns_used
+            and not prefixed_default_language
+        ):
+            language = settings.LANGUAGE_CODE
+        translation.activate(language)
+        request.LANGUAGE_CODE = translation.get_language()
+
+    async def process_response(self, request, response):
+        language = translation.get_language()
+        language_from_path = translation.get_language_from_path(request.path_info)
+        urlconf = getattr(request, "urlconf", settings.ROOT_URLCONF)
+        (
+            i18n_patterns_used,
+            prefixed_default_language,
+        ) = is_language_prefix_patterns_used(urlconf)
+
+        if (
+            response.status_code == 404
+            and not language_from_path
+            and i18n_patterns_used
+            and prefixed_default_language
+        ):
+            # Maybe the language code is missing in the URL? Try adding the
+            # language prefix and redirecting to that URL.
+            language_path = "/%s%s" % (language, request.path_info)
+            path_valid = is_valid_path(language_path, urlconf)
+            path_needs_slash = not path_valid and (
+                settings.APPEND_SLASH
+                and not language_path.endswith("/")
+                and is_valid_path("%s/" % language_path, urlconf)
+            )
+
+            if path_valid or path_needs_slash:
+                script_prefix = get_script_prefix()
+                # Insert language after the script prefix and before the
+                # rest of the URL
+                language_url = request.get_full_path(
+                    force_append_slash=path_needs_slash
+                ).replace(script_prefix, "%s%s/" % (script_prefix, language), 1)
+                # Redirect to the language-specific URL as detected by
+                # get_language_from_request(). HTTP caches may cache this
+                # redirect, so add the Vary header.
+                redirect = self.response_redirect_class(language_url)
+                patch_vary_headers(redirect, ("Accept-Language", "Cookie"))
+                return redirect
+
+        if not (i18n_patterns_used and language_from_path):
+            patch_vary_headers(response, ("Accept-Language",))
+        response.headers.setdefault("Content-Language", language)
+        return response