ThumbsUp

Note: Version 0.5.x is a breaking change for #plusminus_tally and #tally, with > 50% speedups.

A ridiculously straightforward and simple package 'o' code to enable voting in your application, a la stackoverflow.com, etc. Allows an arbitrary number of entities (users, etc.) to vote on models.

Mixins

This plugin introduces three mixins to your recipe book:

1. acts_as_voteable : Intended for content objects like Posts, Comments, etc.
2. acts_as_voter : Intended for voting entities, like Users.
3. has_karma : Adds some helpers to acts_as_voter models for calculating karma.

Inspiration

This plugin started as an adaptation / update of vote_fu for use with Rails 3. It adds some speed, removes some cruft, and is adapted for use with ActiveRecord / Arel in Rails 3. It maintains the awesomeness of the original vote_fu.

Installation

Require the gem:

gem 'thumbs_up'

Create and run the ThumbsUp migration:

rails generate thumbs_up
rake db:migrate

Usage

Getting Started

Turn your AR models into something that can be voted upon.

class SomeModel < ActiveRecord::Base
  acts_as_voteable
end

class Question < ActiveRecord::Base
  acts_as_voteable
end

Turn your Users (or any other model) into voters.

class User < ActiveRecord::Base
  acts_as_voter
  # The following line is optional, and tracks karma (up votes) for questions this user has submitted.
  # Each question has a submitter_id column that tracks the user who submitted it.
  # The option :weight value will be multiplied to any karma from that voteable model (defaults to 1).
  # You can track any voteable model.
  has_karma(:questions, :as => :submitter, :weight => 0.5)
end

class Robot < ActiveRecord::Base
  acts_as_voter
end

To cast a vote for a Model you can do the following:

Shorthand syntax

voter.vote_for(voteable)     	# Adds a +1 vote
voter.vote_against(voteable) 	# Adds a -1 vote
voter.vote(voteable, vote) 	# Adds either a +1 or -1 vote: vote => true (+1), vote => false (-1)

voter.vote_exclusively_for(voteable)	# Removes any previous votes by that particular voter, and votes for.
voter.vote_exclusively_against(voteable)	# Removes any previous votes by that particular voter, and votes against.

vote.unvote_for(voteable)  # Clears all votes for that user

Querying votes

Did the first user vote for the Car with id = 2 already?

u = User.first
u.vote_for(Car.find(2))
u.voted_on?(Car.find(2)) #=> true

Did the first user vote for or against the Car with id = 2?

u = User.first
u.vote_for(Car.find(2))
u.voted_for?(Car.find(2)) #=> true
u.voted_against?(Car.find(2)) #=> false

Tallying Votes

You can easily retrieve voteable object collections based on the properties of their votes:

@items = Item.tally.limit(10).where('created_at > ?', 2.days.ago).having('COUNT(votes.id) < 10')

Or for MySQL:

@items = Item.tally.limit(10).where('created_at > ?', 2.days.ago).having('vote_count < 10')

This will select the Items with less than 10 votes, the votes having been cast within the last two days, with a limit of 10 items. This tallies all votes, regardless of whether they are +1 (up) or -1 (down). The #tally method returns an ActiveRecord Relation, so you can chain the normal method calls on to it.

Tallying Rank ("Plusminus")

You most likely want to use this over the normal tally

This is similar to tallying votes, but this will return voteable object collections based on the sum of the differences between up and down votes (ups are +1, downs are -1). For Instance, a voteable with 3 upvotes and 2 downvotes will have a plusminus_tally of 1.

@items = Item.plusminus_tally.limit(10).where('created_at > ?', 2.days.ago).having('plusminus_tally > 10')

Lower level queries

positiveVoteCount = voteable.votes_for
negativeVoteCount = voteable.votes_against
# Votes for minus votes against. If you want more than a few model instances' worth, use `plusminus_tally` instead.
plusminus         = voteable.plusminus

voter.voted_for?(voteable) # True if the voter voted for this object.
voter.vote_count(:up | :down | :all) # returns the count of +1, -1, or all votes

voteable.voted_by?(voter) # True if the voter voted for this object.
@voters = voteable.voters_who_voted

One vote per user!

ThumbsUp by default only allows one vote per user. This can be changed by removing:

In vote.rb:

validates_uniqueness_of :voteable_id, :scope => [:voteable_type, :voter_type, :voter_id]

In the migration, the unique index:

add_index :votes, ["voter_id", "voter_type", "voteable_id", "voteable_type"], :unique => true, :name => "uniq_one_vote_only"

You can also use --unique-voting false when running the generator command:

rails generate thumbs_up --unique-voting false

Testing ThumbsUp

Testing is a bit more than trivial now as our #tally and #plusminus_tally queries don't function properly under SQLite. To set up for testing:

$ mysql -uroot # You may have set a password locally. Change as needed.
  > GRANT ALL PRIVILEGES ON 'thumbs_up_test' to 'test'@'localhost' IDENTIFIED BY 'test';
  > CREATE DATABASE 'thumbs_up_test';
  > exit;

$ rake # Runs the test suite.

Credits

Basic scaffold is from Peter Jackson's work on VoteFu / ActsAsVoteable. All code updated for Rails 3, cleaned up for speed and clarity, karma calculation fixed, and (hopefully) zero introduced bugs.