git.r.bdr.sh - rbdr/dasein/blob - lib/handlers/posts.js

   1 'use strict';
   2
   3 const Joi = require('joi');
   4 const Pify = require('pify');
   5 const Redis = require('redis');
   6 const UUID = require('uuid/v4');
   7
   8 const internals = {};
   9
  10 internals.kPostsPrefix = 'posts';
  11 internals.kMaxPostSize = 255;
  12
  13 internals.kPostsSchema = Joi.object().keys({
  14   uuid: Joi.string().required(),
  15   content: Joi.string().max(internals.kMaxPostSize).required(),
  16   timestamp: Joi.number().integer().required(),
  17   userId: Joi.string().required(),
  18   userName: Joi.string().required(),
  19   userImage: Joi.string().required()
  20 });
  21
  22 /**
  23  * Handles the HTTP requests for posts related operations
  24  *
  25  * @class PostsHandler
  26  * @param {Dasein.tConfiguration} config The configuration to
  27  * initialize.
  28  */
  29 module.exports = internals.PostsHandler = class PostsHandler {
  30   constructor(config) {
  31
  32     this._ttl = config.ttl;
  33     this._redis = Redis.createClient(config.redis);
  34
  35     // Log an error if it happens.
  36     this._redis.on('error', (err) => {
  37
  38       console.error(err);
  39     });
  40   }
  41
  42   /**
  43    * Fetches all available posts
  44    *
  45    * @function findAll
  46    * @memberof PostsHandler
  47    * @instance
  48    * @return {generator} a koa compatible handler generator function
  49    */
  50   findAll() {
  51
  52     const self = this;
  53
  54     return function * () {
  55
  56       if (!this.state.user) {
  57         return this.throw('Unauthorized', 401);
  58       }
  59
  60       const scan = Pify(self._redis.scan.bind(self._redis));
  61       const hgetall = Pify(self._redis.hgetall.bind(self._redis));
  62
  63       const cursor = parseInt(this.request.query.cursor) || 0;
  64       const [nextCursor, keys] = yield scan(cursor, 'MATCH', `${internals.kPostsPrefix}:*`);
  65
  66       if (nextCursor > 0) {
  67         this.append('Link', `<${this.request.origin}${this.request.path}?cursor=${nextCursor}>; rel="next"`);
  68       }
  69
  70       const posts = yield keys.map((key) => hgetall(key));
  71
  72       this.body = posts;
  73     };
  74   }
  75
  76   /**
  77    * Fetches a single post
  78    *
  79    * @function find
  80    * @memberof PostsHandler
  81    * @instance
  82    * @return {generator} a koa compatible handler generator function
  83    */
  84   find() {
  85
  86     const self = this;
  87
  88     return function * (uuid) {
  89
  90       if (!this.state.user) {
  91         return this.throw('Unauthorized', 401);
  92       }
  93
  94       const hgetall = Pify(self._redis.hgetall.bind(self._redis));
  95
  96       const postKey = `${internals.kPostsPrefix}:${uuid}`;
  97
  98       const post = yield hgetall(postKey);
  99
 100       if (!post) {
 101         this.throw('Post not found', 404);
 102       }
 103
 104       this.body = post;
 105     };
 106   }
 107
 108   /**
 109    * Creates a post
 110    *
 111    * @function create
 112    * @memberof PostsHandler
 113    * @instance
 114    * @return {generator} a koa compatible handler generator function
 115    */
 116   create() {
 117
 118     const self = this;
 119
 120     return function * () {
 121
 122       if (!this.state.user) {
 123         return this.throw('Unauthorized', 401);
 124       }
 125
 126       const hmset = Pify(self._redis.hmset.bind(self._redis));
 127       const hgetall = Pify(self._redis.hgetall.bind(self._redis));
 128       const expire = Pify(self._redis.expire.bind(self._redis));
 129
 130       const uuid = UUID();
 131       const timestamp = Date.now();
 132       const user = this.state.user;
 133
 134       const postKey = `${internals.kPostsPrefix}:${uuid}`;
 135
 136       const post = {
 137         uuid,
 138         content: this.request.body.content,
 139         timestamp,
 140         userId: user.screen_name,
 141         userName: user.name,
 142         userImage: user.profile_image_url_https
 143       };
 144
 145       yield self._validate(post).catch((err) => {
 146
 147         this.throw(err.message, 422);
 148       });
 149
 150       yield hmset(postKey, post);
 151       yield expire(postKey, self._ttl);
 152
 153       this.body = yield hgetall(postKey);
 154     };
 155   }
 156
 157   /**
 158    * Deletes a post
 159    *
 160    * @function delete
 161    * @memberof PostsHandler
 162    * @instance
 163    * @return {generator} a koa compatible handler generator function
 164    */
 165   delete() {
 166
 167     return function * () {};
 168   }
 169
 170   // Validates the post schema
 171
 172   _validate(post) {
 173
 174     const validate = Pify(Joi.validate.bind(Joi));
 175     return validate(post, internals.kPostsSchema);
 176   }
 177 };