1st stage, only language switch.

Thank you, MomentQYC ( https://github.com/MomentQYC ).
Your first attemt encourage me.

1 files changed, 151 insertions, 49 deletions

diff --git a/src/app.ts b/src/app.ts
index 0708081..febc67d 100755
--- a/src/app.ts
+++ b/src/app.ts
@@ -1,6 +1,20 @@
 import express from "express";
 import hbs from "express-handlebars";
 import cookieParser from "cookie-parser";
+import i18next from "i18next";
+import Backend from "i18next-fs-backend";
+import { LanguageDetector, handle } from 'i18next-http-middleware';
+import { createRequire } from 'module';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import path from 'path';
+
+const require = createRequire(import.meta.url);
+const handlebarsI18next = require('handlebars-i18next');
+
+// ESモジュールで__dirnameを再現
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 import routes from "./routes.js";
 import frontend from "./routes/frontend.js";
@@ -11,6 +25,7 @@ import staticPages from "./routes/static.js";
 import magicLink from "./routes/magicLink.js";
 
 import { initEmailService } from "./lib/email.js";
+import { getI18nHelpers } from "./helpers.js";
 import {
     activityPubContentType,
     alternateActivityPubContentType,
@@ -20,55 +35,142 @@ const app = express();
 
 app.locals.sendEmails = initEmailService();
 
-// View engine //
-const hbsInstance = hbs.create({
-    defaultLayout: "main",
-    partialsDir: ["views/partials/"],
-    layoutsDir: "views/layouts/",
-    helpers: {
-        plural: function (number: number, text: string) {
-            var singular = number === 1;
-            // If no text parameter was given, just return a conditional s.
-            if (typeof text !== "string") return singular ? "" : "s";
-            // Split with regex into group1/group2 or group1(group3)
-            var match = text.match(/^([^()\/]+)(?:\/(.+))?(?:\((\w+)\))?/);
-            // If no match, just append a conditional s.
-            if (!match) return text + (singular ? "" : "s");
-            // We have a good match, so fire away
-            return (
-                (singular && match[1]) || // Singular case
-                match[2] || // Plural case: 'bagel/bagels' --> bagels
-                match[1] + (match[3] || "s")
-            ); // Plural case: 'bagel(s)' or 'bagel' --> bagels
-        },
-        json: function (context: any) {
-            return JSON.stringify(context);
+// ESモジュールで__dirnameを再現する部分を関数化
+const getLocalesPath = () => {
+    const __filename = fileURLToPath(import.meta.url);
+    const __dirname = dirname(__filename);
+    return path.join(__dirname, '..', 'locales');
+};
+
+async function initializeApp() {
+    // Cookies //
+    app.use(cookieParser());
+
+    // カスタム言語検出ミドルウェア
+    // app.use((req, res, next) => {
+    //     const acceptLanguage = req.headers['accept-language'];
+    //     if (acceptLanguage && acceptLanguage.includes('ja')) {
+    //         res.cookie('i18next', 'ja', {
+    //             maxAge: 365 * 24 * 60 * 60 * 1000,
+    //             httpOnly: true,
+    //             sameSite: 'lax'
+    //         });
+    //     }
+    //     next();
+    // });
+
+    // i18next configuration
+    await i18next
+        .use(Backend)
+        .use(LanguageDetector)
+        .init({
+            backend: {
+                loadPath: path.join(getLocalesPath(), '{{lng}}.json'),
+            },
+            fallbackLng: 'en',
+            preload: ['en', 'ja'],
+            supportedLngs: ['en', 'ja'],
+            nonExplicitSupportedLngs: true,
+            load: 'languageOnly',
+            debug: true,
+            detection: {
+                order: ['header', 'cookie'],
+                lookupHeader: 'accept-language',
+                lookupCookie: 'i18next',
+                caches: ['cookie']
+            },
+            interpolation: {
+                escapeValue: false
+            }
+        });
+
+    app.use(handle(i18next));
+
+    // 言語を明示的に切り替える
+    app.use((req, res, next) => {
+        const currentLanguage = i18next.language;
+        i18next.changeLanguage(req.language);
+        const newLanguage = i18next.language;
+        console.log('Language Change:', {
+            header: req.headers['accept-language'],
+            detected: req.language,
+            currentLanguage: currentLanguage,
+            newLanguage: newLanguage
+        });
+        next();
+    });
+
+    // デバッグ用
+    app.use((req, res, next) => {
+        console.log('Language Detection:', {
+            header: req.headers['accept-language'],
+            detected: req.language,
+            i18next: i18next.language
+        });
+        next();
+    });
+
+    // View engine //
+    const hbsInstance = hbs.create({
+        defaultLayout: "main",
+        partialsDir: ["views/partials/"],
+        layoutsDir: "views/layouts/",
+        helpers: {
+            plural: function (number: number, text: string) {
+                var singular = number === 1;
+                // If no text parameter was given, just return a conditional s.
+                if (typeof text !== "string") return singular ? "" : "s";
+                // Split with regex into group1/group2 or group1(group3)
+                var match = text.match(/^([^()\/]+)(?:\/(.+))?(?:\((\w+)\))?/);
+                // If no match, just append a conditional s.
+                if (!match) return text + (singular ? "" : "s");
+                // We have a good match, so fire away
+                return (
+                    (singular && match[1]) || // Singular case
+                    match[2] || // Plural case: 'bagel/bagels' --> bagels
+                    match[1] + (match[3] || "s")
+                ); // Plural case: 'bagel(s)' or 'bagel' --> bagels
+            },
+            json: function (context: any) {
+                return JSON.stringify(context);
+            },
+            // i18nextヘルパーを追加
+            ...getI18nHelpers()
         },
-    },
-});
-app.engine("handlebars", hbsInstance.engine);
-app.set("view engine", "handlebars");
-app.set("hbsInstance", hbsInstance);
-
-// Static files //
-app.use(express.static("public"));
-
-// Body parser //
-app.use(express.json({ type: alternateActivityPubContentType }));
-app.use(express.json({ type: activityPubContentType }));
-app.use(express.json({ type: "application/json" }));
-app.use(express.urlencoded({ extended: true }));
-
-// Cookies //
-app.use(cookieParser());
-
-// Router //
-app.use("/", staticPages);
-app.use("/", frontend);
-app.use("/", activitypub);
-app.use("/", event);
-app.use("/", group);
-app.use("/", magicLink);
-app.use("/", routes);
+    });
+
+    // i18nextHelperの呼び出し方法を変更
+    if (typeof handlebarsI18next === 'function') {
+        handlebarsI18next(hbsInstance.handlebars, i18next);
+    } else if (typeof handlebarsI18next.default === 'function') {
+        handlebarsI18next.default(hbsInstance.handlebars, i18next);
+    } else {
+        console.error('handlebars-i18next helper is not properly loaded');
+    }
+
+    app.engine("handlebars", hbsInstance.engine);
+    app.set("view engine", "handlebars");
+    app.set("hbsInstance", hbsInstance);
+
+    // Static files //
+    app.use(express.static("public"));
+
+    // Body parser //
+    app.use(express.json({ type: alternateActivityPubContentType }));
+    app.use(express.json({ type: activityPubContentType }));
+    app.use(express.json({ type: "application/json" }));
+    app.use(express.urlencoded({ extended: true }));
+
+    // Router //
+    app.use("/", staticPages);
+    app.use("/", frontend);
+    app.use("/", activitypub);
+    app.use("/", event);
+    app.use("/", group);
+    app.use("/", magicLink);
+    app.use("/", routes);
+}
+
+initializeApp().catch(console.error);
 
 export default app;