add server to monorepo.

packages/server/src/api/middleware/I18nMiddleware.ts

@@ -0,0 +1,22 @@
+import { Container } from 'typedi';
+import { Request, Response, NextFunction } from 'express';
+import { lowerCase } from 'lodash';
+
+/**
+ * Set the language from request `accept-language` header
+*  or default application language.
+ */
+export default (req: Request, res: Response, next: NextFunction) => {
+  const Logger = Container.get('logger');
+  const I18n = Container.get('i18n');
+
+  // Parses the accepted language from request object.
+  const language = lowerCase(req.headers['accept-language']) || 'en';
+
+  Logger.info('[i18n_middleware] set locale language to i18n.', {
+    language,
+    user: req.user,
+  });
+  // Initialise the global localization.
+  I18n.init(req, res, next);
+};