Add automatic language redirector

fab.config.json5

@@ -1,6 +1,7 @@
 // For more information, see https://fab.dev/kb/configuration
 {
   plugins: {
+    './src/server/languageRedirect.js': {},
     '@fab/input-static': {
       dir: 'public'
     },

package-lock.json

@@ -13447,6 +13447,11 @@
         }
       }
     },
+    "locale": {
+      "version": "0.1.0",
+      "resolved": "https://registry.npmjs.org/locale/-/locale-0.1.0.tgz",
+      "integrity": "sha1-O1v3BhT9q0isPj+8ZIFHy2VEO94="
+    },
     "locate-path": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/locate-path/-/locate-path-5.0.0.tgz",

package.json

@@ -35,6 +35,7 @@
     "gatsby-transformer-json": "^2.8.0",
     "i18next": "^19.8.4",
     "jquery": "^3.5.1",
+    "locale": "^0.1.0",
     "node-sass": "^4.14.1",
     "react": "^16.13.1",
     "react-dom": "^16.13.1",

src/server/languageRedirect.js

@@ -0,0 +1,37 @@
+const config = require("../../config"), locale = require("locale");
+
+let supported = new locale.Locales(conifg.languages);
+let defaultLang = "en";
+
+export default ({ Router }) => {
+    Router.on("*", checkLang);
+};
+
+async function checkLang({ request }) {
+    const { url } = request
+
+    let requestURL = new URL(url);
+
+    config.languages.forEach((language) => {
+        if(requestURL.pathname.startsWith("/"+language+"/")) {
+            return;
+        }
+    });
+
+    let headers = request.headers;
+
+    let selectedLanguage = defaultLang;
+
+    if(headers.has("Accept-Language")) {
+        let languageHeader = headers.get("Accept-Language");
+
+        let requestLocales = new locale.Locales(languageHeader);
+
+        selectedLanguage = requestLocales.best(supported);
+    }
+    
+    requestURL.pathname = "/"+selectedLanguage+requestURL.pathname;
+        
+    return Response.redirect(requestURL.toString(), 302);
+  }
+