+'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);
+ }
+};
git.r.bdr.sh / rbdr / dasein / commitdiff