1 files changed, 113 insertions, 0 deletions
diff --git a/lib/handlers/auth.js b/lib/handlers/auth.js
new file mode 100644
index 0000000..1db9494
--- /dev/null
+++ b/lib/handlers/auth.js
@@ -0,0 +1,113 @@
+'use strict';
+
+const Co = require('co');
+const JsonWebToken = require('jsonwebtoken');
+const Pify = require('pify');
+const TwitterHelper = require('../twitter_helper');
+
+const internals = {};
+
+internals.kRedirectUrl = 'https://api.twitter.com/oauth/authenticate?oauth_token=';
+internals.kLoginRedirect = '/login';
+
+internals.signJsonWebToken = Pify(JsonWebToken.sign);
+
+/**
+ * Handles the HTTP requests for auth related operations.
+ *
+ * @class AuthHandler
+ * @param {Dasein.tConfiguration} config The configuration to
+ * initialize.
+ */
+module.exports = internals.AuthHandler = class AuthHandler {
+
+  constructor(config) {
+
+    this._twitterHelper = new TwitterHelper(config.twitter);
+    this._jwtConfig = config.jwt;
+  }
+
+  /**
+   * Triggers the twitter login flow. Redirects to twitter's oauth
+   * request page
+   *
+   * @function login
+   * @memberof AuthHandler
+   * @instance
+   * @return {generator} a koa compatible handler generator function
+   */
+  login() {
+
+    const twitterHelper = this._twitterHelper;
+
+    return function *handleLogin() {
+
+      const requestToken = yield twitterHelper.getRequestToken();
+      const loginUrl = `${internals.kRedirectUrl}${requestToken.oAuthToken}`;
+
+      this.body = { loginUrl };
+    };
+  }
+
+  /**
+   * Handles twitter's callback. Fetches the oAuth Verifier, attempts to
+   * obtain a user object and responds with the JWT
+   *
+   * @function callback
+   * @memberof AuthHandler
+   * @instance
+   * @return {generator} a koa compatible handler generator function
+   */
+  callback() {
+
+    const self = this;
+
+    return function *handleCallback() {
+
+      if (this.request.query.denied) {
+        return this.throw(401);
+      }
+
+      const oAuthToken = this.request.body.oAuthToken;
+      const oAuthVerifier = this.request.body.oAuthVerifier;
+      let user;
+
+      try {
+        const accessToken = yield self._twitterHelper.getAccessToken(oAuthToken, oAuthVerifier);
+        user = yield self._twitterHelper.getUser(accessToken.oAuthAccessToken, accessToken.oAuthAccessTokenSecret);
+      }
+      catch (err) {
+        console.error(err.stack || err.message || err);
+        return this.throw(401);
+      }
+
+      const expiresAt = Date.now() + self._jwtConfig.duration * 1000;
+
+      const token = yield self._getToken(user);
+
+      const response = {
+        expiresAt,
+        user,
+        token
+      };
+
+      this.body = response;
+    };
+  }
+
+  // Generates a JSON Web Token
+
+  _getToken(payload) {
+
+    const self = this;
+
+    return Co(function * () {
+
+      const token = yield internals.signJsonWebToken(payload, self._jwtConfig.secret, {
+        expiresIn: self._jwtConfig.duration
+      });
+
+      return token;
+    });
+  }
+};