ThumbsUp

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

Querying votes

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

u = User.first
u.voted_on?(Car.find(2))

Tallying Votes

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

@items = Item.tally(
  {  :at_least => 1,
      :at_most => 10000,
      :start_at => 2.weeks.ago,
      :end_at => 1.day.ago,
      :limit => 10,
      :order => "items.name DESC"
  })

This will select the Items with between 1 and 10,000 votes, the votes having been cast within the last two weeks (not including today), then display the 10 last items in an alphabetical list.

Tally Options:

:start_at    - Restrict the votes to those created after a certain time
:end_at      - Restrict the votes to those created before a certain time
:conditions  - A piece of SQL conditions to add to the query
:limit       - The maximum number of voteables to return
:order       - A piece of SQL to order by. Eg 'votes.count desc' or 'voteable.created_at desc'
:at_least    - Item must have at least X votes
:at_most     - Item may not have more than X votes

Lower level queries

positiveVoteCount = voteable.votes_for
negativeVoteCount = voteable.votes_against
plusminus         = voteable.plusminus  # Votes for minus votes against.

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:

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

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.