Fixed #11585 -- Added ability to translate and prefix URL patterns with a language code as an alternative method for language discovery. Many thanks to Orne Brocaar for his initial work and Carl Meyer for feedback.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16405 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/middleware/locale.py

@@ -1,5 +1,7 @@
-"this is the locale selecting middleware that will look at accept headers"
+"This is the locale selecting middleware that will look at accept headers"
 
+from django.core.urlresolvers import get_resolver, LocaleRegexURLResolver
+from django.http import HttpResponseRedirect
 from django.utils.cache import patch_vary_headers
 from django.utils import translation
 
@@ -18,8 +20,26 @@ class LocaleMiddleware(object):
         request.LANGUAGE_CODE = translation.get_language()
 
     def process_response(self, request, response):
+        language = translation.get_language()
+        translation.deactivate()
+
+        if (response.status_code == 404 and
+                not translation.get_language_from_path(request.path_info)
+                    and self.is_language_prefix_patterns_used()):
+            return HttpResponseRedirect(
+                '/%s%s' % (language, request.get_full_path()))
+
         patch_vary_headers(response, ('Accept-Language',))
         if 'Content-Language' not in response:
-            response['Content-Language'] = translation.get_language()
-        translation.deactivate()
+            response['Content-Language'] = language
         return response
+
+    def is_language_prefix_patterns_used(self):
+        """
+        Returns `True` if the `LocaleRegexURLResolver` is used
+        at root level of the urlpatterns, else it returns `False`.
+        """
+        for url_pattern in get_resolver(None).url_patterns:
+            if isinstance(url_pattern, LocaleRegexURLResolver):
+                return True
+        return False