feat: add middleware to auto select user language

src/ol_openedx_course_translations/ol_openedx_course_translations/apps.py

@@ -3,7 +3,7 @@
 """
 
 from django.apps import AppConfig
-from edx_django_utils.plugins import PluginSettings
+from edx_django_utils.plugins import PluginSettings, PluginURLs
 from openedx.core.djangoapps.plugins.constants import ProjectType, SettingsType
 
 
@@ -15,9 +15,19 @@ class OLOpenedXCourseTranslationsConfig(AppConfig):
     name = "ol_openedx_course_translations"
 
     plugin_app = {
+        PluginURLs.CONFIG: {
+            ProjectType.LMS: {
+                PluginURLs.NAMESPACE: "",
+                PluginURLs.REGEX: "^api/ol-openedx-course-translations/",
+                PluginURLs.RELATIVE_PATH: "urls",
+            }
+        },
         PluginSettings.CONFIG: {
             ProjectType.CMS: {
                 SettingsType.COMMON: {PluginSettings.RELATIVE_PATH: "settings.common"},
             },
+            ProjectType.LMS: {
+                SettingsType.COMMON: {PluginSettings.RELATIVE_PATH: "settings.common"},
+            },
         },
     }

src/ol_openedx_course_translations/ol_openedx_course_translations/middleware.py

@@ -0,0 +1,80 @@
+# python
+import re
+
+from django.conf import settings
+from django.http import HttpResponseRedirect
+from django.utils.deprecation import MiddlewareMixin
+from opaque_keys.edx.keys import CourseKey
+from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
+from openedx.core.djangoapps.lang_pref import LANGUAGE_KEY
+from openedx.core.djangoapps.user_api.preferences.api import set_user_preference
+
+
+class CourseLanguageCookieMiddleware(MiddlewareMixin):
+    """
+    Sets language preference cookie and user preference based on course language.
+    Also ensures that for admin URLs, the language is always set to 'en'.
+    """
+
+    COURSE_URL_REGEX = re.compile(
+        rf"^/courses/(?P<course_key>{settings.COURSE_KEY_REGEX})(?:/|$)",
+        re.IGNORECASE,
+    )
+    COOKIE_NAME = "openedx-language-preference"
+
+    def process_response(self, request, response):
+        path = getattr(request, "path_info", request.path)
+
+        # Force 'en' language for admin, sysadmin, and instructor dashboard URLs
+        if (
+            path.startswith("/admin")
+            or path.startswith("/sysadmin")
+            or "instructor" in path
+        ):
+            cookie_val = request.COOKIES.get(self.COOKIE_NAME)
+            needs_reload = cookie_val and cookie_val != "en"
+            if needs_reload:
+                response.set_cookie(
+                    self.COOKIE_NAME,
+                    "en",
+                    max_age=60 * 60 * 24 * 180,
+                    httponly=False,
+                    samesite="Lax",
+                )
+                if hasattr(request, "user") and request.user.is_authenticated:
+                    set_user_preference(request.user, LANGUAGE_KEY, "en")
+                return HttpResponseRedirect(request.get_full_path())
+            return response
+
+        match = self.COURSE_URL_REGEX.match(path)
+        if not match:
+            return response
+
+        course_key_str = match.group("course_key")
+        try:
+            course_key = CourseKey.from_string(course_key_str)
+            overview = CourseOverview.get_from_id(course_key)
+        except Exception:  # noqa: BLE001
+            return response
+
+        language = getattr(overview, "language", None)
+        response.set_cookie(
+            self.COOKIE_NAME,
+            language or "",
+            max_age=60 * 60 * 24 * 180,
+            httponly=False,
+            samesite="Lax",
+        )
+
+        # Set user preference if authenticated
+        if language and hasattr(request, "user") and request.user.is_authenticated:
+            set_user_preference(request.user, LANGUAGE_KEY, language)
+
+        # Redirect if cookie is not present or is different from the desired language
+        cookie_val = request.COOKIES.get(self.COOKIE_NAME)
+        needs_reload = language and (cookie_val != language)
+        if needs_reload:
+            url = request.get_full_path()
+            return HttpResponseRedirect(url)
+
+        return response

src/ol_openedx_course_translations/ol_openedx_course_translations/urls.py

@@ -0,0 +1,24 @@
+"""
+URL configuration for ol_openedx_course_translations app.
+"""
+
+from django.conf import settings
+from django.urls import path, re_path
+
+from ol_openedx_course_translations.views import (
+    CourseLanguageView,
+    ResetUserLanguageView,
+)
+
+urlpatterns = [
+    re_path(
+        rf"course-language/{settings.COURSE_KEY_PATTERN}$",
+        CourseLanguageView.as_view(),
+        name="ol_openedx_course_language",
+    ),
+    path(
+        "user/reset-language/",
+        ResetUserLanguageView.as_view(),
+        name="ol_openedx_reset_user_language",
+    ),
+]

src/ol_openedx_course_translations/ol_openedx_course_translations/views.py

@@ -0,0 +1,63 @@
+"""
+API Views for ol_openedx_course_translations App
+"""
+
+from opaque_keys.edx.keys import CourseKey
+from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
+from openedx.core.djangoapps.lang_pref import LANGUAGE_KEY
+from openedx.core.djangoapps.user_api.preferences.api import set_user_preference
+from rest_framework import status
+from rest_framework.permissions import IsAuthenticated
+from rest_framework.response import Response
+from rest_framework.views import APIView
+
+
+class CourseLanguageView(APIView):
+    """
+    API View to retrieve the language of a specified course.
+    """
+
+    def get(self, request, course_key_string):  # noqa: ARG002
+        if not course_key_string:
+            return Response(
+                {"error": "Missing course_key parameter."},
+                status=status.HTTP_400_BAD_REQUEST,
+            )
+        try:
+            course_key = CourseKey.from_string(course_key_string)
+            course = CourseOverview.get_from_id(course_key)
+        except Exception:  # noqa: BLE001
+            return Response(
+                {"error": "Invalid course_key or course not found."},
+                status=status.HTTP_404_NOT_FOUND,
+            )
+        return Response({"language": course.language})
+
+
+class ResetUserLanguageView(APIView):
+    """
+    API endpoint to reset user's language preference and cookie to English.
+    """
+
+    permission_classes = [IsAuthenticated]
+    COOKIE_NAME = "openedx-language-preference"
+
+    def post(self, request):
+        # Set user preference
+        set_user_preference(request.user, LANGUAGE_KEY, "en")
+
+        # Prepare response
+        response = Response(
+            {"detail": "Language reset to English."}, status=status.HTTP_200_OK
+        )
+
+        # Set cookie like middleware
+        response.set_cookie(
+            self.COOKIE_NAME,
+            "en",
+            max_age=60 * 60 * 24 * 180,
+            httponly=False,
+            samesite="Lax",
+        )
+
+        return response

src/ol_openedx_course_translations/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "ol-openedx-course-translations"
-version = "0.1.0"
+version = "0.1.2"
 description = "An Open edX plugin to translate courses"
 authors = [
   {name = "MIT Office of Digital Learning"}
@@ -18,6 +18,9 @@ dependencies = [
 [project.entry-points."cms.djangoapp"]
 ol_openedx_course_translations = "ol_openedx_course_translations.apps:OLOpenedXCourseTranslationsConfig"
 
+[project.entry-points."lms.djangoapp"]
+ol_openedx_course_translations = "ol_openedx_course_translations.apps:OLOpenedXCourseTranslationsConfig"
+
 [build-system]
 requires = ["hatchling"]
 build-backend = "hatchling.build"