fix: update language cookie if langauge cookie is not same as user's …

…language preference

CHANGELOG.rst

@@ -17,6 +17,10 @@ Unreleased
 ----------
 * nothing unreleased
 
+[4.17.4]
+--------
+* fix: update language cookie if langauge cookie is not same as user's language preference
+
 [4.17.3]
 --------
 * feat: replacing non encrypted fields of blackboard config model with encypted ones

enterprise/__init__.py

@@ -2,4 +2,4 @@
 Your project description goes here.
 """
 
-__version__ = "4.17.3"
+__version__ = "4.17.4"

enterprise/middleware.py

@@ -67,6 +67,18 @@ def process_request(self, request):
                     # Ignore errors related to user preferences not found.
                     pass
 
+                # This is to handle a bug where a user is logged in multiple tabs/browsers.
+                # User updates the language preference in one tab. After update, user's language preference
+                # in the database and language cookie in the browser is set to new language.
+                # But in the other tab/browser, user still has the old language cookie. So when the user
+                # refreshes the page, the language cookie is sent to the server and overrides the user's preference.
+                # NOTE: The assumption here is to consider user's language preference as the single source of truth.
+                cookie_lang = request.COOKIES.get(settings.LANGUAGE_COOKIE_NAME)
+                if user_pref and cookie_lang and cookie_lang != user_pref:
+                    # pylint: disable=protected-access
+                    request._anonymous_user_cookie_lang = user_pref
+                    request.COOKIES[settings.LANGUAGE_COOKIE_NAME] = user_pref
+
                 # If user's language preference is not set and enterprise customer has a default language configured
                 # then set the default language as the learner's language
                 if not user_pref and not is_request_from_mobile_app(request):

tests/test_middleware.py

@@ -8,6 +8,7 @@
 import ddt
 from pytest import mark
 
+from django.conf import settings
 from django.contrib.sessions.middleware import SessionMiddleware
 from django.test.client import Client, RequestFactory
 
@@ -156,3 +157,19 @@ def test_cookie_not_set_for_mobile_requests(self):
 
             # Make sure the set cookie is not called for anonymous users
             assert getattr(self.request, '_anonymous_user_cookie_lang', None) is None
+
+    def test_middleware_when_cookie_lang_is_different_from_user_pref(self):
+        """
+        Validate that when user pref and cookie language are set but have different values
+        then the middleware updates the cookie with user preference value.
+        """
+        user_pref_lang = 'ar'
+        cookie_lang = 'en'
+        self.request.COOKIES[settings.LANGUAGE_COOKIE_NAME] = cookie_lang
+
+        with mock.patch('enterprise.middleware.get_user_preference') as mock_get_user_preference:
+            mock_get_user_preference.return_value = user_pref_lang
+            self.middleware.process_request(self.request)
+
+            assert self.request.COOKIES[settings.LANGUAGE_COOKIE_NAME] == user_pref_lang
+            assert getattr(self.request, '_anonymous_user_cookie_lang', None) == user_pref_lang