Switch locale based on URL

src/core/i18n/utils.js

@@ -80,3 +80,17 @@ export function isRtlLang(lang) {
 export function getDirection(lang) {
   return isRtlLang(lang) ? 'rtl' : 'ltr';
 }
+
+export function getLangFromRouter(renderProps) {
+  if (renderProps) {
+    // Get the lang from the url param by default
+    // if it exists.
+    if (renderProps.params && renderProps.params.lang) {
+      return getLanguage(renderProps.params.lang);
+    } else if (renderProps.location && renderProps.location.query &&
+               renderProps.location.query.lang) {
+      return getLanguage(renderProps.location.query.lang);
+    }
+  }
+  return defaultLang;
+}

src/core/server/base.js

@@ -19,8 +19,7 @@ import ServerHtml from 'core/containers/ServerHtml';
 import config from 'config';
 import { setJWT } from 'core/actions';
 import log from 'core/logger';
-import setLanguage from 'core/i18n/middleware';
-import { getDirection, langToLocale } from 'core/i18n/utils';
+import { getDirection, getLangFromRouter, langToLocale } from 'core/i18n/utils';
 import I18nProvider from 'core/i18n/Provider';
 import Jed from 'jed';
 
@@ -45,8 +44,6 @@ function baseServer(routes, createStore, { appInstanceName = appName } = {}) {
   const app = new Express();
   app.disable('x-powered-by');
 
-  app.use(setLanguage);
-
   app.use(logRequests);
 
   // Sets X-Frame-Options
@@ -114,7 +111,7 @@ function baseServer(routes, createStore, { appInstanceName = appName } = {}) {
         fs.readFileSync(path.join(config.get('basePath'), 'dist/sri.json'))
       ) : {};
 
-      const lang = res.locals.lang;
+      const lang = getLangFromRouter(renderProps);
       const dir = getDirection(lang);
       const locale = langToLocale(lang);
 

src/disco/routes.js

@@ -8,7 +8,7 @@ export default (
   <Route path="/" component={App}>
     <IndexRoute component={DiscoPane} />
     <Route
-      path="/:locale/firefox/discovery/pane/:version/:platform/:compatibilityMode"
+      path="/:lang/firefox/discovery/pane/:version/:platform/:compatibilityMode"
       component={DiscoPane}
     />
   </Route>

tests/client/core/i18n/test_utils.js

@@ -1,4 +1,5 @@
 import * as utils from 'core/i18n/utils';
+import config from 'config';
 
 
 describe('i18n utils', () => {
@@ -142,4 +143,45 @@ describe('i18n utils', () => {
       assert.equal(utils.isValidLang('pt'), true);
     });
   });
+
+  describe('getLangFromRouter()', () => {
+    it('should return default lang if no lang is provided', () => {
+      const fakeRenderProps = {};
+      assert.equal(utils.getLangFromRouter(fakeRenderProps), config.get('defaultLang'));
+    });
+
+    it('should return lang if provided via the URL', () => {
+      const fakeRenderProps = {
+        params: {
+          lang: 'fr',
+        },
+      };
+      assert.equal(utils.getLangFromRouter(fakeRenderProps), 'fr');
+    });
+
+    it('should return lang if provided via a query param', () => {
+      const fakeRenderProps = {
+        location: {
+          query: {
+            lang: 'pt-PT',
+          },
+        },
+      };
+      assert.equal(utils.getLangFromRouter(fakeRenderProps), 'pt-PT');
+    });
+
+    it('should use url param if both that and query string are present', () => {
+      const fakeRenderProps = {
+        params: {
+          lang: 'fr',
+        },
+        location: {
+          query: {
+            lang: 'pt-PT',
+          },
+        },
+      };
+      assert.equal(utils.getLangFromRouter(fakeRenderProps), 'fr');
+    });
+  });
 });