Implement Twitter backend

package.json

@@ -34,6 +34,7 @@
     "babel-core": "^6.26.0",
     "babel-loader": "^7.1.2",
     "babel-plugin-transform-object-rest-spread": "^6.26.0",
+    "babel-polyfill": "^6.26.0",
     "babel-preset-env": "^1.6.1",
     "compression-webpack-plugin": "^1.0.1",
     "css-loader": "^0.28.11",

src/models/twitter.js

+import m from 'mithril';
+import Raven from 'raven-js';
+
+const TWITTER_CONSUMER_KEY = 'Ur9mJuJ3c074G71UD2Nk9yefZ';
+const TWITTER_CONSUMER_SECRET = 'BtaPdb67kctOaenIpwzAVptBHSwlpUG8GPidl0vdO3qoLGPho6';
+const TWITTER_AUTH_ENDPOINT = 'https://api.twitter.com/oauth2/token';
+const TWITTER_TIMELINE_ENDPOINT = 'https://api.twitter.com/1.1/statuses/user_timeline.json';
+const TWITTER_SCREEN_NAME = 'AMIV_ETHZ';
+
+export default class Twitter {
+  constructor() {
+    this.bearerToken = undefined;
+    this.tweets = [];
+  }
+
+  /**
+   * Perform Application-only authentication.
+   * Returns a bearer token which can be used for further interaction with the Twitter API.
+   * https://developer.twitter.com/en/docs/basics/authentication/overview/application-only
+   */
+  static async authenticate() {
+    // Only authenticate once
+    if (this.bearerToken !== undefined) {
+      return this.bearerToken;
+    }
+
+    // Encode credentials string
+    const credentials = btoa(
+      `${encodeURI(TWITTER_CONSUMER_KEY)}:${encodeURI(TWITTER_CONSUMER_SECRET)}`
+    );
+
+    // Await the bearer token
+    await m
+      .request({
+        method: 'POST',
+        url: TWITTER_AUTH_ENDPOINT,
+        data: {
+          grant_type: 'client_credentials',
+        },
+        serialize: m.buildQueryString,
+        headers: {
+          Authorization: `Basic ${credentials}`,
+          'Content-Type': 'application/x-www-form-urlencoded',
+        },
+      })
+      .then(result => {
+        // Ensure the API returns the expected token type
+        if (result.token_type !== 'bearer') {
+          Raven.captureException(
+            Error(`Twitter API returned unexpected token type: ${result.token_type}`)
+          );
+          return;
+        }
+        this.bearerToken = result.access_token;
+      })
+      .catch(error => {
+        Raven.captureException(error);
+      });
+
+    return this.bearerToken;
+  }
+
+  /**
+   * Load AMIV_ETHZ timeline.
+   * https://developer.twitter.com/en/docs/tweets/timelines/api-reference/get-statuses-user_timeline.html
+   */
+  static async loadTimeline() {
+    // Wait for authentication to succeed
+    const token = await this.authenticate();
+
+    m
+      .request({
+        method: 'GET',
+        url: TWITTER_TIMELINE_ENDPOINT,
+        data: {
+          screen_name: TWITTER_SCREEN_NAME,
+          count: 20,
+        },
+        headers: {
+          Authorization: `Bearer ${token}`,
+        },
+      })
+      .then(tweets => {
+        this.tweets = tweets;
+      })
+      .catch(error => {
+        Raven.captureException(error);
+      });
+  }
+}

webpack.config.js

 const config = {
   context: `${__dirname}/src`, // `__dirname` is root of project and `src` is source
 
-  entry: './index.js',
+  entry: ['babel-polyfill', './index.js'],
 
   output: {
     path: `${__dirname}/dist`, // `dist` is the destination
@@ -26,7 +26,7 @@ const config = {
         use: [
           {
             loader: 'babel-loader',
-            options: { presets: [['env', { targets: "last 2 years"}]] },
+            options: { presets: [['env', { targets: 'last 2 years' }]] },
           },
         ],
       },
@@ -47,7 +47,7 @@ const config = {
           {
             loader: 'string-replace-loader', // Adds /#! prefix to local urls
             options: {
-              search: '\[(.*)\]\((\/(?!dist).*)\)',
+              search: '[(.*)]((/(?!dist).*))',
               replace: '(/#!$1',
               flags: 'g',
             },
@@ -71,7 +71,7 @@ const config = {
           {
             loader: 'string-replace-loader', // Adds /#! prefix to local urls
             options: {
-              search: '\[(.*)\]\((\/(?!dist).*)\)',
+              search: '[(.*)]((/(?!dist).*))',
               replace: '(/#!$1',
               flags: 'g',
             },
@@ -129,7 +129,6 @@ const config = {
     },
   },
 
-
   devtool: 'eval-source-map', // Default development sourcemap
 };