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       let keys = [];
  64       let nextCursor = 0;
  65       let currentKeys = null;
  66
  67       do {
  68         [nextCursor, currentKeys] = yield scan(nextCursor || 0, 'MATCH', `${internals.kPostsPrefix}:*`);
  69         keys = keys.concat(currentKeys);
  70       } while (nextCursor > 0);
  71
  72       const posts = yield keys.map((key) => hgetall(key));
  73
  74       this.body = posts.sort((a, b) => b.timestamp - a.timestamp);
  75     };
  76   }
  77
  78   /**
  79    * Fetches a single post
  80    *
  81    * @function find
  82    * @memberof PostsHandler
  83    * @instance
  84    * @return {generator} a koa compatible handler generator function
  85    */
  86   find() {
  87
  88     const self = this;
  89
  90     return function * (uuid) {
  91
  92       if (!this.state.user) {
  93         return this.throw('Unauthorized', 401);
  94       }
  95
  96       const hgetall = Pify(self._redis.hgetall.bind(self._redis));
  97
  98       const postKey = `${internals.kPostsPrefix}:${uuid}`;
  99
 100       const post = yield hgetall(postKey);
 101
 102       if (!post) {
 103         this.throw('Post not found', 404);
 104       }
 105
 106       this.body = post;
 107     };
 108   }
 109
 110   /**
 111    * Creates a post
 112    *
 113    * @function create
 114    * @memberof PostsHandler
 115    * @instance
 116    * @return {generator} a koa compatible handler generator function
 117    */
 118   create() {
 119
 120     const self = this;
 121
 122     return function * () {
 123
 124       if (!this.state.user) {
 125         return this.throw('Unauthorized', 401);
 126       }
 127
 128       const hmset = Pify(self._redis.hmset.bind(self._redis));
 129       const hgetall = Pify(self._redis.hgetall.bind(self._redis));
 130       const expire = Pify(self._redis.expire.bind(self._redis));
 131
 132       const uuid = UUID();
 133       const timestamp = Date.now();
 134       const user = this.state.user;
 135
 136       const postKey = `${internals.kPostsPrefix}:${uuid}`;
 137
 138       const post = {
 139         uuid,
 140         content: this.request.body.content,
 141         timestamp,
 142         userId: user.screen_name,
 143         userName: user.name,
 144         userImage: user.profile_image_url_https
 145       };
 146
 147       yield self._validate(post).catch((err) => {
 148
 149         this.throw(err.message, 422);
 150       });
 151
 152       yield hmset(postKey, post);
 153       yield expire(postKey, self._ttl);
 154
 155       this.body = yield hgetall(postKey);
 156     };
 157   }
 158
 159   /**
 160    * Deletes a post
 161    *
 162    * @function delete
 163    * @memberof PostsHandler
 164    * @instance
 165    * @return {generator} a koa compatible handler generator function
 166    */
 167   delete() {
 168
 169     return function * () {};
 170   }
 171
 172   // Validates the post schema
 173
 174   _validate(post) {
 175
 176     const validate = Pify(Joi.validate.bind(Joi));
 177     return validate(post, internals.kPostsSchema);
 178   }
 179 };