Respect user language preference in content endpoint

Content API now returns data in user's preferred language when authenticated without language parameter. No breaking changes - existing clients unaffected.

test/api/v3/integration/content/GET-content.test.js

@@ -1,6 +1,7 @@
 import {
   requester,
   translate as t,
+  generateUser,
 } from '../../../../helpers/api-integration/v3';
 import i18n from '../../../../../website/common/script/i18n';
 
@@ -56,4 +57,28 @@ describe('GET /content', () => {
     const res = await requester().get('/content?filter=backgroundsFlat,invalid');
     expect(res).to.not.have.property('backgroundsFlat');
   });
+
+  describe('authenticated user', () => {
+    let user;
+    it('returns content in user\'s preferred language when no language parameter is provided', async () => {
+      user = await generateUser({ 'preferences.language': 'de' });
+      const res = await user.get('/content');
+      expect(res).to.have.nested.property('backgrounds.backgrounds062014.beach');
+      expect(res.backgrounds.backgrounds062014.beach.text).to.equal(i18n.t('backgroundBeachText', 'de'));
+    });
+
+    it('respects language parameter over user\'s preferred language', async () => {
+      user = await generateUser({ 'preferences.language': 'de' });
+      const res = await user.get('/content?language=fr');
+      expect(res).to.have.nested.property('backgrounds.backgrounds062014.beach');
+      expect(res.backgrounds.backgrounds062014.beach.text).to.equal(i18n.t('backgroundBeachText', 'fr'));
+    });
+
+    it('falls back to English if user\'s preferred language is invalid', async () => {
+      user = await generateUser({ 'preferences.language': 'invalid_lang' });
+      const res = await user.get('/content');
+      expect(res).to.have.nested.property('backgrounds.backgrounds062014.beach');
+      expect(res.backgrounds.backgrounds062014.beach.text).to.equal(t('backgroundBeachText'));
+    });
+  });
 });

website/server/controllers/api-v3/content.js

@@ -1,6 +1,7 @@
 import nconf from 'nconf';
 import { langCodes } from '../../libs/i18n';
 import { serveContent } from '../../libs/content';
+import { authWithHeaders } from '../../middlewares/auth';
 
 const IS_PROD = nconf.get('IS_PROD');
 
@@ -66,12 +67,18 @@ api.getContent = {
   method: 'GET',
   url: '/content',
   noLanguage: true,
+  middlewares: [authWithHeaders({ optional: true })],
   async handler (req, res) {
     let language = 'en';
     const proposedLang = req.query.language;
 
     if (proposedLang && langCodes.includes(proposedLang)) {
       language = proposedLang;
+    } else if (res.locals.user && res.locals.user.preferences && res.locals.user.preferences.language) {
+      const userLang = res.locals.user.preferences.language;
+      if (langCodes.includes(userLang)) {
+        language = userLang;
+      }
     }
 
     let filter = req.query.filter || '';