impl server side translation instance

apps/app/src/server/routes/apiv3/page/create-page.ts

@@ -1,6 +1,6 @@
 import { allOrigin } from '@growi/core';
 import type {
-  IPage, IUser, IUserHasId, Lang,
+  IPage, IUser, IUserHasId,
 } from '@growi/core';
 import { ErrorV3 } from '@growi/core/dist/models';
 import { isCreatablePage, isUserPage, isUsersHomepage } from '@growi/core/dist/utils/page-path-utils';
@@ -9,7 +9,6 @@ import type { Request, RequestHandler } from 'express';
 import type { ValidationChain } from 'express-validator';
 import { body } from 'express-validator';
 import mongoose from 'mongoose';
-import { i18n } from 'next-i18next';
 
 import { SupportedAction, SupportedTargetModel } from '~/interfaces/activity';
 import type { IApiv3PageCreateParams } from '~/interfaces/apiv3';
@@ -23,6 +22,7 @@ import {
 import type { PageDocument, PageModel } from '~/server/models/page';
 import PageTagRelation from '~/server/models/page-tag-relation';
 import { configManager } from '~/server/service/config-manager';
+import { getTranslation } from '~/server/service/i18next';
 import loggerFactory from '~/utils/logger';
 
 import { apiV3FormValidator } from '../../../middlewares/apiv3-form-validator';
@@ -44,9 +44,8 @@ async function generateUntitledPath(parentPath: string, basePathname: string, in
 }
 
 async function determinePath(_parentPath?: string, _path?: string, optionalParentPath?: string): Promise<string> {
-  const locale = configManager.getConfig('crowi', 'app:globalLang') as Lang;
+  const { t } = await getTranslation();
 
-  const t = i18n?.getFixedT(locale);
   const basePathname = t?.('create_page.untitled') || 'Untitled';
 
   if (_path != null) {

apps/app/src/server/service/i18next.ts

@@ -0,0 +1,41 @@
+import type { Lang } from '@growi/core';
+import type { TFunction, i18n } from 'i18next';
+import { createInstance } from 'i18next';
+import resourcesToBackend from 'i18next-resources-to-backend';
+
+import { defaultLang, initOptions } from '^/config/i18next.config';
+
+import { configManager } from './config-manager';
+
+
+const initI18next = async(lang: Lang = defaultLang) => {
+  const i18nInstance = createInstance();
+  await i18nInstance
+    .use(
+      resourcesToBackend(
+        (language: string, namespace: string) => {
+          return import(`^/public/static/locales/${language}/${namespace}.json`);
+        },
+      ),
+    )
+    .init({
+      ...initOptions,
+      lng: lang,
+    });
+  return i18nInstance;
+};
+
+type Translation = {
+  t: TFunction,
+  i18n: i18n
+}
+
+export async function getTranslation(lang?: Lang): Promise<Translation> {
+  const globalLang = configManager.getConfig('crowi', 'app:globalLang') as Lang;
+  const i18nextInstance = await initI18next(globalLang);
+
+  return {
+    t: i18nextInstance.getFixedT(lang ?? globalLang),
+    i18n: i18nextInstance,
+  };
+}