Automatically Logout Banned Users (#12037)

* wip

* logout banned users, fix and refactor language library and middleware

* req.locals -> res.locals

* fix tests

* redirect to login page

website/server/libs/language.js

@@ -0,0 +1,52 @@
+import accepts from 'accepts';
+import _ from 'lodash';
+import {
+  translations,
+  defaultLangCodes,
+  multipleVersionsLanguages,
+} from './i18n';
+
+function getUniqueListOfLanguages (languages) {
+  const acceptableLanguages = _(languages).map(lang => lang.slice(0, 2)).uniq().value();
+
+  const uniqueListOfLanguages = _.intersection(acceptableLanguages, defaultLangCodes);
+
+  return uniqueListOfLanguages;
+}
+
+function checkForApplicableLanguageVariant (originalLanguageOptions) {
+  const languageVariant = _.find(originalLanguageOptions, accepted => {
+    const trimmedAccepted = accepted.slice(0, 2);
+
+    return multipleVersionsLanguages[trimmedAccepted];
+  });
+
+  return languageVariant;
+}
+
+export function getLanguageFromBrowser (req) {
+  const originalLanguageOptions = accepts(req).languages();
+  const uniqueListOfLanguages = getUniqueListOfLanguages(originalLanguageOptions);
+  const baseLanguage = (uniqueListOfLanguages[0] || '').toLowerCase();
+  const languageMapping = multipleVersionsLanguages[baseLanguage];
+
+  if (languageMapping) {
+    let languageVariant = checkForApplicableLanguageVariant(originalLanguageOptions);
+
+    if (languageVariant) {
+      languageVariant = languageVariant.toLowerCase();
+    } else {
+      return 'en';
+    }
+
+    return languageMapping[languageVariant] || baseLanguage;
+  }
+  return baseLanguage || 'en';
+}
+
+export function getLanguageFromUser (user, req) {
+  const preferredLang = user && user.preferences && user.preferences.language;
+  const lang = translations[preferredLang] ? preferredLang : getLanguageFromBrowser(req);
+
+  return lang;
+}