v3: port getContent route caching responses to disk

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

@@ -0,0 +1,25 @@
+import {
+  requester,
+  translate as t,
+} from '../../../../helpers/api-v3-integration.helper';
+import i18n from '../../../../../common/script/i18n';
+
+describe('GET /content', () => {
+  it('returns content (and does not require authentication)', async () => {
+    let res = await requester().get('/content');
+    expect(res).to.have.deep.property('backgrounds.backgrounds062014.beach');
+    expect(res.backgrounds.backgrounds062014.beach.text).to.equal(t('backgroundBeachText'));
+  });
+
+  it('returns content not in English', async () => {
+    let res = await requester().get('/content?language=de');
+    expect(res).to.have.deep.property('backgrounds.backgrounds062014.beach');
+    expect(res.backgrounds.backgrounds062014.beach.text).to.equal(i18n.t('backgroundBeachText', 'de'));
+  });
+
+  it('falls back to English if the desired language is not found', async () => {
+    let res = await requester().get('/content?language=wrong');
+    expect(res).to.have.deep.property('backgrounds.backgrounds062014.beach');
+    expect(res.backgrounds.backgrounds062014.beach.text).to.equal(t('backgroundBeachText'));
+  });
+});

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

@@ -0,0 +1,106 @@
+import common from '../../../../common';
+import _ from 'lodash';
+import { langCodes } from '../../libs/api-v3/i18n';
+import Q from 'q';
+import fsCallback from 'fs';
+import path from 'path';
+
+// Transform fs methods that accept callbacks in ones that return promises
+const fs = {
+  readFile: Q.denodeify(fsCallback.readFile),
+  writeFile: Q.denodeify(fsCallback.writeFile),
+  stat: Q.denodeify(fsCallback.stat),
+  mkdir: Q.denodeify(fsCallback.mkdir),
+};
+
+let api = {};
+
+function walkContent (obj, lang) {
+  _.each(obj, (item, key, source) => {
+    if (_.isPlainObject(item) || _.isArray(item)) return walkContent(item, lang);
+    if (_.isFunction(item) && item.i18nLangFunc) source[key] = item(lang);
+  });
+}
+
+// After the getContent route is called the first time for a certain language
+// the response is saved on disk and subsequentially served directly from there to reduce computation.
+// Example: if `cachedContentResponses.en` is true it means that the response is cached
+let cachedContentResponses = {};
+
+// Language key set to true while the cache file is being written
+let cacheBeingWritten = {};
+
+_.each(langCodes, code => {
+  cachedContentResponses[code] = false;
+  cacheBeingWritten[code] = false;
+});
+
+
+const CONTENT_CACHE_PATH = path.join(__dirname, '/../../../build/content_cache/');
+
+async function saveContentToDisk (language, content) {
+  try {
+    cacheBeingWritten[language] = true;
+
+    await fs.stat(CONTENT_CACHE_PATH); // check if the directory exists, if it doesn't an error is thrown
+    await fs.writeFile(`${CONTENT_CACHE_PATH}${language}.json`, content, 'utf8');
+
+    cacheBeingWritten[language] = false;
+    cachedContentResponses[language] = true;
+  } catch (err) {
+    if (err.code === 'ENOENT' && err.syscall === 'stat') { // the directory doesn't exists, create it and retry
+      await fs.mkdir(CONTENT_CACHE_PATH);
+      return saveContentToDisk(language, content);
+    } else {
+      cacheBeingWritten[language] = false;
+      // TODO log error
+      return;
+    }
+  }
+}
+
+/**
+ * @api {get} /content Get all available content objects. Does not require authentication.
+ * @apiVersion 3.0.0
+ * @apiName ContentGet
+ * @apiGroup Content
+ *
+ * @apiParam {string} language Optional query parameter, the  language code used for the items' strings. Defaulting to english
+ *
+ * @apiSuccess {Object} content All the content available on Habitica
+ */
+api.getContent = {
+  method: 'GET',
+  url: '/content',
+  async handler (req, res) {
+    let language = 'en';
+    let proposedLang = req.query.language && req.query.language.toString();
+
+    if (proposedLang in cachedContentResponses) {
+      language = proposedLang;
+    }
+
+    let content;
+
+    // is the content response for this language cached?
+    if (cachedContentResponses[language] === true) {
+      content = await fs.readFile(`${CONTENT_CACHE_PATH}${language}.json`, 'utf8');
+    } else { // generate the response
+      content = _.cloneDeep(common.content);
+      walkContent(content, language);
+      content = JSON.stringify(content);
+    }
+
+    res.set({
+      'Content-Type': 'application/json',
+    });
+    res.status(200).send(content);
+
+    // save the file in background unless it's already cached or being written right now
+    if (cachedContentResponses[language] !== true && cacheBeingWritten[language] !== true) {
+      saveContentToDisk(language, content);
+    }
+  },
+};
+
+module.exports = api;