feat: send language to backend on language selection

backend/benefit/helsinkibenefit/urls.py

@@ -26,7 +26,7 @@
     HandlerNoteViewSet,
 )
 from terms.api.v1.views import ApproveTermsOfServiceView
-from users.api.v1.views import CurrentUserView, UserUuidGDPRAPIView
+from users.api.v1.views import CurrentUserView, UserOptionsView, UserUuidGDPRAPIView
 
 router = routers.DefaultRouter()
 router.register(
@@ -70,6 +70,7 @@
     path("v1/company/search/<str:name>/", SearchOrganisationsView.as_view()),
     path("v1/company/get/<str:business_id>/", GetOrganisationByIdView.as_view()),
     path("v1/users/me/", CurrentUserView.as_view()),
+    path("v1/users/options/", UserOptionsView.as_view()),
     path(
         "v1/handlerapplications/<str:application_id>/review/", ReviewStateView.as_view()
     ),

backend/benefit/users/api/v1/views.py

@@ -1,3 +1,4 @@
+from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.contrib.auth.base_user import AbstractBaseUser
 from django.core.exceptions import PermissionDenied
@@ -37,6 +38,25 @@ def _get_current_user(self, request):
         return request.user
 
 
+@extend_schema(description="API for setting currently logged in user's language.")
+class UserOptionsView(APIView):
+    permission_classes = [BFIsAuthenticated]
+
+    def get(self, request):
+        lang = request.GET.get("lang")
+
+        if lang in ["fi", "en", "sv"]:
+            token = request.COOKIES.get("yjdhcsrftoken")
+
+            response = Response(
+                {"lang": lang, "token": token}, status=status.HTTP_200_OK
+            )
+            response.set_cookie(settings.LANGUAGE_COOKIE_NAME, lang, httponly=True)
+            return response
+
+        return Response(status=status.HTTP_400_BAD_REQUEST)
+
+
 class UserUuidGDPRAPIView(GDPRAPIView):
     """GDPR API view that is used from Helsinki profile to query and delete user data."""
 

frontend/benefit/applicant/src/components/header/useHeader.ts

@@ -1,10 +1,12 @@
 import useApplicationQuery from 'benefit/applicant/hooks/useApplicationQuery';
 import { useTranslation } from 'benefit/applicant/i18n';
 import { getLanguageOptions } from 'benefit/applicant/utils/common';
+import { BackendEndpoint } from 'benefit-shared/backend-api/backend-api';
 import { APPLICATION_STATUSES } from 'benefit-shared/constants';
 import { useRouter } from 'next/router';
 import { TFunction } from 'next-i18next';
 import React, { useEffect, useState } from 'react';
+import useBackendAPI from 'shared/hooks/useBackendAPI';
 import useToggle from 'shared/hooks/useToggle';
 import { NavigationItem, OptionType } from 'shared/types/common';
 
@@ -27,6 +29,8 @@ const useHeader = (): ExtendedComponentProps => {
   const { t } = useTranslation();
   const router = useRouter();
   const id = router?.query?.id?.toString() ?? '';
+  const { axios } = useBackendAPI();
+
   const [hasMessenger, setHasMessenger] = useState<boolean>(false);
   const [unreadMessagesCount, setUnredMessagesCount] = useState<
     number | undefined | null
@@ -75,6 +79,10 @@ const useHeader = (): ExtendedComponentProps => {
   ): void => {
     e.preventDefault();
 
+    void axios.get(BackendEndpoint.USER_OPTIONS, {
+      params: { lang: newLanguage.value },
+    });
+
     void router.push({ pathname, query }, asPath, {
       locale: newLanguage.value,
     });

frontend/benefit/shared/src/backend-api/backend-api.ts

@@ -7,6 +7,7 @@ export const BackendEndpoint = {
   LOGOUT: '/oidc/logout/',
   USER: '/oidc/userinfo/',
   USER_ME: 'v1/users/me/',
+  USER_OPTIONS: 'v1/users/options/',
   COMPANY: '/v1/company/',
   APPLICATIONS: '/v1/applications/',
   APPLICATIONS_SIMPLIFIED: '/v1/applications/simplified_list/',