Merge branch 'release/1.0.0'HEADmain

5 files changed, 739 insertions, 0 deletions

diff --git a/lib/dasein.js b/lib/dasein.js
new file mode 100644
index 0000000..5b8486a
--- /dev/null
+++ b/lib/dasein.js
@@ -0,0 +1,165 @@
+'use strict';
+
+const Koa = require('koa');
+const KoaBodyParser = require('koa-bodyparser');
+const KoaJwt = require('koa-jwt');
+const KoaRoute = require('koa-route');
+const KoaSend = require('koa-send');
+const KoaStatic = require('koa-static');
+const Path = require('path');
+
+const AuthHandler = require('./handlers/auth');
+const PostsHandler = require('./handlers/posts');
+const CommentsHandler = require('./handlers/comments');
+
+const internals = {};
+
+internals.k401Location = '/401.html';
+internals.kMainLocation = '/';
+
+/**
+ * The Dasein class is the main entry point for the application.
+ *
+ * @class Dasein
+ * @param {Dasein.tConfiguration} config the initialization options to
+ * extend the instance
+ */
+module.exports = internals.Dasein = class Dasein {
+
+  constructor(config) {
+
+    Object.assign(this, config);
+  }
+
+  /**
+   * Initializes the application and starts listening. Also prints a
+   * nice robotic banner with information.
+   *
+   * @function run
+   * @memberof Dasein
+   * @instance
+   */
+  run() {
+
+    this._initializeServer();
+    this._startServer();
+    this._printBanner();
+
+    return Promise.resolve();
+  }
+
+  // Initializes the Koa application and all the handlers.
+
+  _initializeServer() {
+
+    const self = this;
+
+    this._app = Koa();
+
+    this._app.use(KoaStatic(this.staticDirectory));
+    this._app.use(KoaBodyParser());
+
+    // Error handler
+
+    this._app.use(function * (next) {
+
+      try {
+        yield next;
+      }
+      catch (err) {
+        this.status = err.status || 500;
+
+        const response = {
+          error: err.message,
+          status: this.status
+        };
+
+        if (response.status === 401) {
+          response.error === 'Protected resource, use Authorization header to get access';
+        }
+
+        this.body = response;
+
+        this.app.emit('error', err, this);
+      }
+    });
+
+    this._app.use(KoaJwt({
+      secret: this.jwt.secret,
+      passthrough: true
+    }));
+
+    this._initializeAuthRoutes();
+    this._initializePostsRoutes();
+    this._initializeCommentsRoutes();
+
+    this._app.use(function * () {
+
+      yield KoaSend(this, Path.join(self.staticDirectory, 'index.html'));
+    });
+
+  }
+
+  // Initialize routes for auth
+
+  _initializeAuthRoutes() {
+
+    const authHandler = new AuthHandler({
+      jwt: this.jwt,
+      twitter: this.twitter
+    });
+    this._app.use(KoaRoute.get('/api/auth/login', authHandler.login()));
+    this._app.use(KoaRoute.post('/api/auth/callback', authHandler.callback()));
+  }
+
+  // Initialize routes for posts
+
+  _initializePostsRoutes() {
+
+    const postsHandler = new PostsHandler({
+      ttl: this.ttl,
+      redis: this.redis
+    });
+    this._app.use(KoaRoute.get('/api/posts', postsHandler.findAll()));
+    this._app.use(KoaRoute.get('/api/posts/:id', postsHandler.find()));
+    this._app.use(KoaRoute.post('/api/posts', postsHandler.create()));
+    this._app.use(KoaRoute.delete('/api/posts/:id', postsHandler.delete()));
+
+  }
+
+  // Initialize routes for comments
+
+  _initializeCommentsRoutes() {
+
+    const commentsHandler = new CommentsHandler({
+      ttl: this.ttl,
+      redis: this.redis
+    });
+    this._app.use(KoaRoute.get('/api/posts/:postId/comments', commentsHandler.findAll()));
+    this._app.use(KoaRoute.post('/api/posts/:postId/comments', commentsHandler.create()));
+  }
+
+  // Starts listening
+
+  _startServer() {
+
+    this._app.listen(this.port);
+  }
+
+  // Prints the banner.
+
+  _printBanner() {
+
+    console.log('        .');
+    console.log('       /');
+    console.log('    +-----+');
+    console.log(`    | o o |  - Listening Gladly, Try me on port: ${this.port}`);
+    console.log('    +-----+');
+    console.log('  +---------+');
+    console.log(' /|    [][] |\\');
+    console.log(' ||         | |');
+    console.log(' ||         |  \\c');
+    console.log(' ^+---------+');
+    console.log('      (.) ');
+  }
+};
diff --git a/lib/handlers/auth.js b/lib/handlers/auth.js
new file mode 100644
index 0000000..1db9494
--- /dev/null
+++ b/lib/handlers/auth.js
@@ -0,0 +1,113 @@
+'use strict';
+
+const Co = require('co');
+const JsonWebToken = require('jsonwebtoken');
+const Pify = require('pify');
+const TwitterHelper = require('../twitter_helper');
+
+const internals = {};
+
+internals.kRedirectUrl = 'https://api.twitter.com/oauth/authenticate?oauth_token=';
+internals.kLoginRedirect = '/login';
+
+internals.signJsonWebToken = Pify(JsonWebToken.sign);
+
+/**
+ * Handles the HTTP requests for auth related operations.
+ *
+ * @class AuthHandler
+ * @param {Dasein.tConfiguration} config The configuration to
+ * initialize.
+ */
+module.exports = internals.AuthHandler = class AuthHandler {
+
+  constructor(config) {
+
+    this._twitterHelper = new TwitterHelper(config.twitter);
+    this._jwtConfig = config.jwt;
+  }
+
+  /**
+   * Triggers the twitter login flow. Redirects to twitter's oauth
+   * request page
+   *
+   * @function login
+   * @memberof AuthHandler
+   * @instance
+   * @return {generator} a koa compatible handler generator function
+   */
+  login() {
+
+    const twitterHelper = this._twitterHelper;
+
+    return function *handleLogin() {
+
+      const requestToken = yield twitterHelper.getRequestToken();
+      const loginUrl = `${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;
+    });
+  }
+};
diff --git a/lib/handlers/comments.js b/lib/handlers/comments.js
new file mode 100644
index 0000000..14bd137
--- /dev/null
+++ b/lib/handlers/comments.js
@@ -0,0 +1,140 @@
+'use strict';
+
+const Joi = require('joi');
+const Pify = require('pify');
+const Redis = require('redis');
+const UUID = require('uuid/v4');
+
+const internals = {};
+
+internals.kPostsPrefix = 'posts';
+internals.kCommentsPrefix = 'comments';
+internals.kMaxCommentSize = 255;
+
+internals.kCommentsSchema = Joi.object().keys({
+  uuid: Joi.string().required(),
+  content: Joi.string().max(internals.kMaxCommentSize).required(),
+  timestamp: Joi.number().integer().required(),
+  userId: Joi.string().required(),
+  userName: Joi.string().required(),
+  userImage: Joi.string().required()
+});
+
+/**
+ * Handles the HTTP requests for comment related operations
+ *
+ * @class CommentsHandler
+ * @param {Dasein.tConfiguration} config The configuration to
+ * initialize.
+ */
+module.exports = internals.CommentsHandler = class CommentsHandler {
+  constructor(config) {
+
+    this._ttl = config.ttl;
+    this._redis = Redis.createClient(config.redis);
+
+    // Log an error if it happens.
+    this._redis.on('error', (err) => {
+
+      console.error(err);
+    });
+  }
+
+  /**
+   * Fetches all available comments
+   *
+   * @function findAll
+   * @memberof CommentsHandler
+   * @instance
+   * @return {generator} a koa compatible handler generator function
+   */
+  findAll() {
+
+    const self = this;
+
+    return function * (postId) {
+
+      if (!this.state.user) {
+        return this.throw('Unauthorized', 401);
+      }
+
+      const scan = Pify(self._redis.scan.bind(self._redis));
+      const hgetall = Pify(self._redis.hgetall.bind(self._redis));
+
+      const commentsKey = `${internals.kCommentsPrefix}:${postId}:*`;
+      let keys = [];
+      let nextCursor = 0;
+      let currentKeys = null;
+
+      do {
+        [nextCursor, currentKeys] = yield scan(nextCursor || 0, 'MATCH', commentsKey);
+        keys = keys.concat(currentKeys);
+      } while (nextCursor > 0);
+
+      const comments = yield keys.map((key) => hgetall(key));
+
+      this.body = comments.sort((a, b) => a.timestamp - b.timestamp);
+    };
+  }
+
+  /**
+   * Creates a comment
+   *
+   * @function create
+   * @memberof CommentsHandler
+   * @instance
+   * @return {generator} a koa compatible handler generator function
+   */
+  create() {
+
+    const self = this;
+
+    return function * (postId) {
+
+      if (!this.state.user) {
+        return this.throw('Unauthorized', 401);
+      }
+
+      const hmset = Pify(self._redis.hmset.bind(self._redis));
+      const hgetall = Pify(self._redis.hgetall.bind(self._redis));
+      const expire = Pify(self._redis.expire.bind(self._redis));
+
+      const uuid = UUID();
+      const timestamp = Date.now();
+      const user = this.state.user;
+
+      const postKey = `${internals.kPostsPrefix}:${postId}`;
+      const commentKey = `${internals.kCommentsPrefix}:${postId}:${uuid}`;
+
+      const comment = {
+        uuid,
+        content: this.request.body.content,
+        timestamp,
+        userId: user.screen_name,
+        userName: user.name,
+        userImage: user.profile_image_url_https
+      };
+
+      yield self._validate(comment).catch((err) => {
+
+        this.throw(err.message, 422);
+      });
+
+      yield hmset(commentKey, comment);
+      yield expire(commentKey, self._ttl * 100); // this is me being lazy :(
+                                                 // comments will last at most 100 bumps
+                                                 // but will disappear eventually
+      yield expire(postKey, self._ttl); // bumps the parent comment TTL
+
+      this.body = yield hgetall(commentKey);
+    };
+  }
+
+  // Validates the comment schema
+
+  _validate(comment) {
+
+    const validate = Pify(Joi.validate.bind(Joi));
+    return validate(comment, internals.kCommentsSchema);
+  }
+};
diff --git a/lib/handlers/posts.js b/lib/handlers/posts.js
new file mode 100644
index 0000000..b5e4f0e
--- /dev/null
+++ b/lib/handlers/posts.js
@@ -0,0 +1,179 @@
+'use strict';
+
+const Joi = require('joi');
+const Pify = require('pify');
+const Redis = require('redis');
+const UUID = require('uuid/v4');
+
+const internals = {};
+
+internals.kPostsPrefix = 'posts';
+internals.kMaxPostSize = 255;
+
+internals.kPostsSchema = Joi.object().keys({
+  uuid: Joi.string().required(),
+  content: Joi.string().max(internals.kMaxPostSize).required(),
+  timestamp: Joi.number().integer().required(),
+  userId: Joi.string().required(),
+  userName: Joi.string().required(),
+  userImage: Joi.string().required()
+});
+
+/**
+ * Handles the HTTP requests for posts related operations
+ *
+ * @class PostsHandler
+ * @param {Dasein.tConfiguration} config The configuration to
+ * initialize.
+ */
+module.exports = internals.PostsHandler = class PostsHandler {
+  constructor(config) {
+
+    this._ttl = config.ttl;
+    this._redis = Redis.createClient(config.redis);
+
+    // Log an error if it happens.
+    this._redis.on('error', (err) => {
+
+      console.error(err);
+    });
+  }
+
+  /**
+   * Fetches all available posts
+   *
+   * @function findAll
+   * @memberof PostsHandler
+   * @instance
+   * @return {generator} a koa compatible handler generator function
+   */
+  findAll() {
+
+    const self = this;
+
+    return function * () {
+
+      if (!this.state.user) {
+        return this.throw('Unauthorized', 401);
+      }
+
+      const scan = Pify(self._redis.scan.bind(self._redis));
+      const hgetall = Pify(self._redis.hgetall.bind(self._redis));
+
+      let keys = [];
+      let nextCursor = 0;
+      let currentKeys = null;
+
+      do {
+        [nextCursor, currentKeys] = yield scan(nextCursor || 0, 'MATCH', `${internals.kPostsPrefix}:*`);
+        keys = keys.concat(currentKeys);
+      } while (nextCursor > 0);
+
+      const posts = yield keys.map((key) => hgetall(key));
+
+      this.body = posts.sort((a, b) => b.timestamp - a.timestamp);
+    };
+  }
+
+  /**
+   * Fetches a single post
+   *
+   * @function find
+   * @memberof PostsHandler
+   * @instance
+   * @return {generator} a koa compatible handler generator function
+   */
+  find() {
+
+    const self = this;
+
+    return function * (uuid) {
+
+      if (!this.state.user) {
+        return this.throw('Unauthorized', 401);
+      }
+
+      const hgetall = Pify(self._redis.hgetall.bind(self._redis));
+
+      const postKey = `${internals.kPostsPrefix}:${uuid}`;
+
+      const post = yield hgetall(postKey);
+
+      if (!post) {
+        this.throw('Post not found', 404);
+      }
+
+      this.body = post;
+    };
+  }
+
+  /**
+   * Creates a post
+   *
+   * @function create
+   * @memberof PostsHandler
+   * @instance
+   * @return {generator} a koa compatible handler generator function
+   */
+  create() {
+
+    const self = this;
+
+    return function * () {
+
+      if (!this.state.user) {
+        return this.throw('Unauthorized', 401);
+      }
+
+      const hmset = Pify(self._redis.hmset.bind(self._redis));
+      const hgetall = Pify(self._redis.hgetall.bind(self._redis));
+      const expire = Pify(self._redis.expire.bind(self._redis));
+
+      const uuid = UUID();
+      const timestamp = Date.now();
+      const user = this.state.user;
+
+      const postKey = `${internals.kPostsPrefix}:${uuid}`;
+
+      const post = {
+        uuid,
+        content: this.request.body.content,
+        timestamp,
+        userId: user.screen_name,
+        userName: user.name,
+        userImage: user.profile_image_url_https
+      };
+
+      yield self._validate(post).catch((err) => {
+
+        this.throw(err.message, 422);
+      });
+
+      yield hmset(postKey, post);
+      yield expire(postKey, self._ttl);
+
+      this.body = yield hgetall(postKey);
+    };
+  }
+
+  /**
+   * Deletes a post
+   *
+   * @function delete
+   * @memberof PostsHandler
+   * @instance
+   * @return {generator} a koa compatible handler generator function
+   */
+  delete() {
+
+    return function * () {};
+  }
+
+  // Validates the post schema
+
+  _validate(post) {
+
+    const validate = Pify(Joi.validate.bind(Joi));
+    return validate(post, internals.kPostsSchema);
+  }
+};
diff --git a/lib/twitter_helper.js b/lib/twitter_helper.js
new file mode 100644
index 0000000..6edf030
--- /dev/null
+++ b/lib/twitter_helper.js
@@ -0,0 +1,142 @@
+'use strict';
+
+const Co = require('co');
+const OAuth = require('oauth');
+const Pify = require('pify');
+
+const internals = {};
+
+internals.kRequestTokenUrl = 'https://api.twitter.com/oauth/request_token';
+internals.kAccessTokenUrl = 'https://api.twitter.com/oauth/access_token';
+internals.kVerifyCredentialsUrl = 'https://api.twitter.com/1.1/account/verify_credentials.json';
+internals.kOauthVersion = '1.0A';
+internals.kOauthSignatureMethod = 'HMAC-SHA1';
+
+/**
+ * Helper to communicate with the twitter API
+ *
+ * @class TwitterHelper
+ * @param {Dasein.tTwitterConfiguration} config the configuration to
+ * initialize the twitter API
+ * @see {@link https://dev.twitter.com/web/sign-in/implementing|Implementing
+ * Sign in with Twitter}
+ *
+ */
+module.exports = internals.TwitterHelper = class TwitterHelper {
+
+  constructor(config) {
+
+    this._oAuth = new OAuth.OAuth(
+      internals.kRequestTokenUrl,
+      internals.kAccessTokenUrl,
+      config.consumerKey,
+      config.consumerSecret,
+      internals.kOauthVersion,
+      null,
+      internals.kOauthSignatureMethod
+    );
+  }
+
+  /**
+   * Calls the API to get a request token.
+   *
+   * @function getRequestToken
+   * @memberof TwitterHelper
+   * @instance
+   * @return {Promise<TwitterHelper.tRequestToken>} the request token response
+   */
+  getRequestToken() {
+
+    const self = this;
+
+    return Co(function * () {
+
+      const getOAuthRequestToken = Pify(self._oAuth.getOAuthRequestToken.bind(self._oAuth), { multiArgs: true });
+      const [oAuthToken, oAuthTokenSecret] = yield getOAuthRequestToken();
+
+      /**
+       * The request token and secret pair from the twitter API
+       *
+       * @memberof TwitterHelper
+       * @typedef {object} tRequestToken
+       * @property {string} oAuthToken The oAuth request token
+       * @property {string} oAuthTokenSecret The oAuth request token
+       * secret
+       */
+      return {
+        oAuthToken,
+        oAuthTokenSecret
+      };
+    });
+  }
+
+  /**
+   * Calls the API to get an access token
+   *
+   * @function getAccessToken
+   * @memberof TwitterHelper
+   * @instance
+   * @param {string} oAuthToken An oAuth request token
+   * @param {string} oAuthVerifier An oAuth verifier sent from the
+   * twitter callback
+   * @return {Promise<TwitterHelper.tAccessToken>} the acess token response
+   */
+  getAccessToken(oAuthToken, oAuthVerifier) {
+
+    const self = this;
+
+    return Co(function * () {
+
+      const getOAuthAccessToken = Pify(self._oAuth.getOAuthAccessToken.bind(self._oAuth), { multiArgs: true });
+      const [oAuthAccessToken, oAuthAccessTokenSecret] = yield getOAuthAccessToken(oAuthToken,
+                                                                                   '',
+                                                                                   oAuthVerifier);
+
+      /**
+       * The access token and secret pair from the twitter API
+       *
+       * @memberof TwitterHelper
+       * @typedef {object} tAccessToken
+       * @property {string} oAuthAccessToken The oAuth access token
+       * @property {string} oAuthAccessTokenSecret The oAuth access token
+       * secret
+       */
+      return {
+        oAuthAccessToken,
+        oAuthAccessTokenSecret
+      };
+    });
+  }
+
+  /**
+   * Gets a user object from twitter
+   *
+   * @function getUser
+   * @memberof TwitterHelper
+   * @instance
+   * @param {string} oAuthAccessToken An oAuth access token
+   * @param {string} oAuthAccessTokenSecret An oAuth access token secret
+   * @return {Promise<external:TwitterUser>} the user object from
+   * twitter
+   */
+  getUser(oAuthAccessToken, oAuthAccessTokenSecret) {
+
+    const self = this;
+
+    return Co(function * () {
+
+      const get = Pify(self._oAuth.get.bind(self._oAuth), { multiArgs: true });
+      const [userResponse] = yield get(internals.kVerifyCredentialsUrl,
+                                       oAuthAccessToken,
+                                       oAuthAccessTokenSecret);
+
+      /**
+       * The twitter user from the API
+       * @external TwitterUser
+       * @see {@link https://dev.twitter.com/overview/api/users|Twitter
+       * Api Overview: Users}
+       */
+      return JSON.parse(userResponse);
+    });
+  }
+};