sudosaket/yolonews

A shameless Hacker News clone. Because YOLO.

YOLONews

A shameless Hacker News clone. Because YOLO.

Built with VueJS, Java and Redis.

Redis Schema

Users

Every user is represented by the following fields:

A Redis hash named user:<user id> with the following fields:

id -> user ID
username -> The username
password -> Hashed password, PBKDF2(salt|password) note: | means concatenation
email -> Optional, used to show gravatars
karma -> User karma, earned visiting the site and posting good stuff
createdTime -> Registration time (unix time)
modifiedTime -> Modified time (unix time)

Additionally for every user there is the following key:

username.to.id:<lowercase_username> -> User ID

This is used to lookup users by name.

Frequency of user posting is limited by a key named user:<user_id>:submitted_recently with TTL 15 minutes. If a user attempts to post before that key has expired an error message notifies the user of the amount of time until posting is permitted.

Authentication

Users receive an authentication token after a valid pair of username/password is received. The representation is a simple Redis key in the form:

auth:<lowercase_token> -> User ID

Posts

Posts are represented as an hash with key name post:<post id>. The hash has the following fields:

id -> Post id
title -> Post title
url -> Post url
userId => The User ID that posted the post
createdTime -> Post creation time. Unix time.
modifiedTime -> Post edited time. Unix time.
score -> Post score. See source to check how this is computed.
rank -> Post score adjusted by age: RANK = SCORE / AGE^ALPHA
upvotes -> Counter with number of upvotes
downvotes -> Counter with number of downvotes
deleted -> 1 if post is deleted.

Note: upvotes, downvotes fields are also available in other ways but we denormalize for speed.

Also recently posted urls have a key named url:<actual full url> with TTL 48 hours and set to the post ID of a recently posted post having this url.

This is to make sure that the same content is not duplicated in a short amount of time.

Post is never deleted, but just marked as deleted adding the "deleted" field with value 1 to the post object. However when the post is rendered into HTML, it should be displayed as "[deleted post]" text.

Votes

Every post has a sorted set with user upvotes and downvotes. The keys are named respectively post.upvotes:<post id> and post.downvotes:<post id>.

In the sorted sets the score is the unix time of the vote creation, the element is the user ID of the voting user.

Posting a post should automatically register an upvote from the user posting the post.

Saved posts

The system stores a list of upvoted posts and downvoted posts for every user using sorted sets named user:<user id>:upvoted and user:<user id>:downvoted, indexed by unix time. The value of the sorted set elements is the <post id>.

Submitted posts

Like saved post every user has an associated sorted set with posts he/she posted. The key is called user:<user id>:posts. Again the score is the unix time and the element is the post id.

Top and Latest posts

posts.latest is used to generate the "Latest Posts" page. It is a sorted set where the score is the Unix time the post was posted, and the value is the post ID.

posts.top is used to generate the "Top Posts" page. It is a sorted set where the score is the "RANK" of the post, and the value is the post ID.

TODO

• Comments system
• Social login options
• Custom css