Voting

A Binomial proportion confidence interval voting system with scope and cache enabled.

Voting uses Binomial proportion confidence interval to calculate the voting. Inspired on Evan Miller Article and used by Reddit, Yelp, Digg and probably other, Voting gives you cache and option to work with scopes over a binary voting system.

If you are looking for 5 stars voting system, check Rating 🌟

Add the following code on your Gemfile and run bundle install:

gem 'voting'

Run the following task to create a Voting migration:

rails g voting:install

Then execute the migrations to create the tables voting_votes and voting_votings:

rake db:migrate

Just add the callback voting to your model:

class Author < ApplicationRecord
  voting
end

Now this model can vote or receive votes.

You can vote on some resource using integer or string as value:

author_1 = Author.first
author_2 = Author.last
resource = Comment.last

author_1.vote(resource, 1)  # +1 vote
author_2.vote(resource, -1) # -1 vote

This mehod will return the status of a Voting::Vote object as positive, negative or none.

author   = Author.first
resource = Comment.last

author.vote(resource, 1).status # 'positive'
author.vote(resource, -1)       # 'negative'
author.vote(resource, -1)       # 'none'

A voted resource exposes a cached data about it state:

resource = Comment.last

resource.voting

It will return a Voting::Voting object that keeps:

author: the author of this vote;

estimate: the Binomial proportion confidence interval value;

negative: the sum of negative votes for this resource;

positive: the sum of positive votes for this resource;

resource: the self object that received this vote;

scopeable: the object used as scope;

You can retrieve the vote an author gave to a specific resource:

author   = Author.last
resource = Comment.last

author.vote_for resource

It will return a Voting::Vote object that keeps:

author: the author of vote;

resource: the resource that received the vote;

negative: the -1 value when vote was negative;

positive: the 1 value when vote was positive;

scopeable: the object used as scope;

Maybe you want just to know if some author already voted some resource and receive true or false:

author   = Author.last
resource = Comment.last

author.voted? resource

If you want to know if the vote was positive or negative, just pass a symbol about it:

author.voted? resource, :negative
author.voted? resource, :positive

You can retrieve all votes received by some resource:

resource = Article.last

resource.votes

It will return a collection of Voting::Vote object.

In the same way you can retrieve all votes that some author made:

author = Author.last

author.voted

It will return a collection of Voting::Vote object.

You can list resource ordered by voting data:

Comment.order_by_voting

It will return a collection of resource ordered by estimate desc as default. The order column and direction can be changed:

Comment.order_by_voting :negative, :asc

It will return a collection of resource ordered by Voting::Voting table data.

Maybe you want to recover all records, so you can add the suffix _records on relations:

author   = Author.last
resource = Comment.last

author.vote resource, 1

author.voting_records

author.voted_records

comment.voting_records

If you have a model that will only be able to vote but not to receive a vote, configure it as author. An author model still can be voted, but won't generate a Voting record with all values as zero to warm up the cache.

voting as: :author

You can to use alias to directly call vote with positive or negative data.

author   = Author.last
resource = Comment.last

author.up   resource # +1
author.down resource # -1

down: makes a negative vote;

up: makes a positive vote;

The toggle functions works out of box, so if you vote up twice or vote twice down, the vote will be canceled. When you do that, the vote record is not destroyed instead, it receives zero on negative and positive column.

All methods accepts a scope param to be persisted with the vote or to be searched:

category = Category.last

author.down     resource,            scope: category
author.up       resource,            scope: category
author.vote     resource, 1,         scope: category
author.vote_for resource,            scope: category
author.voted    resource,            scope: category
author.voted?   resource, :negative, scope: category
author.voted?   resource, :positive, scope: category

resource.votes  scope: category
author  .voted  scope: category
resource.votign scope: category

If you need to warm up a record with scope, you need to setup the scoping relation.

class Resource < ApplicationRecord
  voting scoping: :categories
end

Now, when a resource is created, the cache will be generated for each related category as scopeable.

• Evan Miller
• Jonathan Landy
• Wilson Score Interval
• How to Count Thumb-Ups and Thumb-Downs