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_against(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. This tallies all votes, regardless of whether they are +1 (up) or -1 (down).

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

Tallying Rank ("Plusminus")

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 of 1.

Plusminus 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
:ascending   - Boolean Default false.  If specified true, results will be returned in ascending order (from bottom up)
: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, 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

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.