Acts As Votable (aka Acts As Likeable)

Acts As Votable is a Ruby Gem specifically written for Rails/ActiveRecord models. The main goals of this gem are:

Allow any model to be voted on, like/dislike, upvote/downvote, etc.
Allow any model to be voted under arbitrary scopes.
Allow any model to vote. In other words, votes do not have to come from a user, they can come from any model (such as a Group or Team).
Provide an easy to write/read syntax.

Installation

Supported Ruby and Rails versions

Ruby 1.8.7, 1.9.2, 1.9.3
Ruby 2.0.0, 2.1.0
Rails 3.0, 3.1, 3.2
Rails 4.0, 4.1+

Install

Just add the following to your Gemfile.

gem 'acts_as_votable', '~> 0.10.0'

And follow that up with a bundle install.

Database Migrations

Acts As Votable uses a votes table to store all voting information. To generate and run the migration just use.

rails generate acts_as_votable:migration
rake db:migrate

You will get a performance increase by adding in cached columns to your model's tables. You will have to do this manually through your own migrations. See the caching section of this document for more information.

Usage

Votable Models

class Post < ActiveRecord::Base
  acts_as_votable
end

@post = Post.new(:name => 'my post!')
@post.save

@post.liked_by @user
@post.votes_for.size # => 1

Like/Dislike Yes/No Up/Down

Here are some voting examples. All of these calls are valid and acceptable. The more natural calls are the first few examples.

@post.liked_by @user1
@post.downvote_from @user2
@post.vote_by :voter => @user3
@post.vote_by :voter => @user4, :vote => 'bad'
@post.vote_by :voter => @user5, :vote => 'like'

By default all votes are positive, so @user3 has cast a 'good' vote for @post.

@user1, @user3, and @user5 all voted in favor of @post.

@user2 and @user4 on the other had has voted against @post.

Just about any word works for casting a vote in favor or against post. Up/Down, Like/Dislike, Positive/Negative... the list goes on-and-on. Boolean flags true and false are also applicable.

Revisiting the previous example of code.

# positive votes
@post.liked_by @user1
@post.vote_by :voter => @user3
@post.vote_by :voter => @user5, :vote => 'like'

# negative votes
@post.downvote_from @user2
@post.vote_by :voter => @user2, :vote => 'bad'

# tally them up!
@post.votes_for.size # => 5
@post.get_likes.size # => 3
@post.get_upvotes.size # => 3
@post.get_dislikes.size # => 2
@post.get_downvotes.size # => 2

Active Record scopes are provided to make life easier.

@post.votes_for.up.by_type(User)
@post.votes_for.down
@user1.votes.up
@user1.votes.down
@user1.votes.up.by_type(Post)

Once scoping is complete, you can also trigger a get for the voter/votable

@post.votes_for.up.by_type(User).voters
@post.votes_for.down.by_type(User).voters

@user.votes.up.for_type(Post).votables
@user.votes.up.votables

You can also 'unvote' a model to remove a previous vote.

@post.liked_by @user1
@post.unliked_by @user1

@post.disliked_by @user1
@post.undisliked_by @user1

Unvoting works for both positive and negative votes.

Examples with scopes

You can add a scope to your vote

# positive votes
@post.liked_by @user1, :vote_scope => 'rank'
@post.vote_by :voter => @user3, :vote_scope => 'rank'
@post.vote_by :voter => @user5, :vote => 'like', :vote_scope => 'rank'

# negative votes
@post.downvote_from @user2, :vote_scope => 'rank'
@post.vote_by :voter => @user2, :vote => 'bad', :vote_scope => 'rank'

# tally them up!
@post.find_votes_for(:vote_scope => 'rank').size # => 5
@post.get_likes(:vote_scope => 'rank').size # => 3
@post.get_upvotes(:vote_scope => 'rank').size # => 3
@post.get_dislikes(:vote_scope => 'rank').size # => 2
@post.get_downvotes(:vote_scope => 'rank').size # => 2

# votable model can be voted under different scopes
# by the same user
@post.vote_by :voter => @user1, :vote_scope => 'week'
@post.vote_by :voter => @user1, :vote_scope => 'month'

@post.votes_for.size # => 2
@post.find_votes_for(:vote_scope => 'week').size # => 1
@post.find_votes_for(:vote_scope => 'month').size # => 1

Adding weights to your votes

You can add weight to your vote. The default value is 1.

# positive votes
@post.liked_by @user1, :vote_weight => 1
@post.vote_by :voter => @user3, :vote_weight => 2
@post.vote_by :voter => @user5, :vote => 'like', :vote_scope => 'rank', :vote_weight => 3

# negative votes
@post.downvote_from @user2, :vote_scope => 'rank', :vote_weight => 1
@post.vote_by :voter => @user2, :vote => 'bad', :vote_scope => 'rank', :vote_weight => 3

# tally them up!
@post.find_votes_for(:vote_scope => 'rank').sum(:vote_weight) # => 6
@post.get_likes(:vote_scope => 'rank').sum(:vote_weight) # => 6
@post.get_upvotes(:vote_scope => 'rank').sum(:vote_weight) # => 6
@post.get_dislikes(:vote_scope => 'rank').sum(:vote_weight) # => 4
@post.get_downvotes(:vote_scope => 'rank').sum(:vote_weight) # => 4

The Voter

You can have your voters acts_as_voter to provide some reserve functionality.

class User < ActiveRecord::Base
  acts_as_voter
end

@user.likes @article

@article.votes.size # => 1
@article.likes.size # => 1
@article.dislikes.size # => 0

To check if a voter has voted on a model, you can use voted_for?. You can check how the voter voted by using voted_as_when_voted_for.

@user.likes @comment1
@user.up_votes @comment2
# user has not voted on @comment3

@user.voted_for? @comment1 # => true
@user.voted_for? @comment2 # => true
@user.voted_for? @comment3 # => false

@user.voted_as_when_voted_for @comment1 # => true, he liked it
@user.voted_as_when_voted_for @comment2 # => false, he didnt like it
@user.voted_as_when_voted_for @comment3 # => nil, he has yet to vote

You can also check whether the voter has voted up or down.

@user.likes @comment1
@user.dislikes @comment2
# user has not voted on @comment3

@user.voted_up_on? @comment1 # => true
@user.voted_down_on? @comment1 # => false

@user.voted_down_on? @comment2 # => true
@user.voted_up_on? @comment2 # => false

@user.voted_up_on? @comment3 # => false
@user.voted_down_on? @comment3 # => false

Aliases for methods voted_up_on? and voted_down_on? are: voted_up_for?, voted_down_for?, liked? and disliked?.

Also, you can obtain a list of all the objects a user has voted for. This returns the actual objects instead of instances of the Vote model. All objects are eager loaded

@user.find_voted_items

@user.find_up_voted_items
@user.find_liked_items

@user.find_down_voted_items
@user.find_disliked_items

Members of an individual model that a user has voted for can also be displayed. The result is an ActiveRecord Relation.

@user.get_voted Comment

@user.get_up_voted Comment

@user.get_down_voted Comment

Registered Votes

Voters can only vote once per model. In this example the 2nd vote does not count because @user has already voted for @shoe.

@user.likes @shoe
@user.likes @shoe

@shoe.votes # => 1
@shoe.likes # => 1

To check if a vote counted, or registered, use vote_registered? on your model after voting. For example:

@hat.liked_by @user
@hat.vote_registered? # => true

@hat.liked_by => @user
@hat.vote_registered? # => false, because @user has already voted this way

@hat.disliked_by @user
@hat.vote_registered? # => true, because user changed their vote

@hat.votes.size # => 1
@hat.positives.size # => 0
@hat.negatives.size # => 1

To permit duplicates entries of a same voter, use option duplicate. Also notice that this will limit some other methods that didn't deal with multiples votes, in this case, the last vote will be considered.

@hat.vote_by voter: @user, :duplicate => true

Caching

To speed up perform you can add cache columns to your votable model's table. These columns will automatically be updated after each vote. For example, if we wanted to speed up @post we would use the following migration:

class AddCachedVotesToPosts < ActiveRecord::Migration
  def self.up
    add_column :posts, :cached_votes_total, :integer, :default => 0
    add_column :posts, :cached_votes_score, :integer, :default => 0
    add_column :posts, :cached_votes_up, :integer, :default => 0
    add_column :posts, :cached_votes_down, :integer, :default => 0
    add_column :posts, :cached_weighted_score, :integer, :default => 0
    add_column :posts, :cached_weighted_total, :integer, :default => 0
    add_column :posts, :cached_weighted_average, :float, :default => 0.0
    add_index  :posts, :cached_votes_total
    add_index  :posts, :cached_votes_score
    add_index  :posts, :cached_votes_up
    add_index  :posts, :cached_votes_down
    add_index  :posts, :cached_weighted_score
    add_index  :posts, :cached_weighted_total
    add_index  :posts, :cached_weighted_average

    # Uncomment this line to force caching of existing votes
    # Post.find_each(&:update_cached_votes)
  end

  def self.down
    remove_column :posts, :cached_votes_total
    remove_column :posts, :cached_votes_score
    remove_column :posts, :cached_votes_up
    remove_column :posts, :cached_votes_down
    remove_column :posts, :cached_weighted_score
    remove_column :posts, :cached_weighted_total
    remove_column :posts, :cached_weighted_average
  end
end

cached_weighted_average can be helpful for a rating system, e.g.:

Order by average rating:

Post.order(:cached_weighted_average => :desc)

Display average rating:

<%= post.weighted_average.round(2) %> / 5
<!-- 3.5 / 5 -->

Testing

All tests follow the RSpec format and are located in the spec directory. They can be run with:

rake spec

Changes

Fixes for votable voter model

In version 0.8.0, there are bugs for a model that is both votable and voter.
Some name-conflicting methods are renamed:

Renamed Votable.votes to votes_for
Renamed Votable.vote to vote_by,
Removed Votable.vote_by alias (was an alias for :vote_up)
Renamed Votable.unvote_for to unvote_by
Renamed Votable.find_votes to find_votes_for
Renamed Votable.up_votes to get_upvotes
- and its aliases :get_true_votes, :get_ups, :get_upvotes, :get_likes, :get_positives, :get_for_votes
Renamed Votable.down_votes to get_downvotes
- and its aliases :get_false_votes, :get_downs, :get_downvotes, :get_dislikes, :get_negatives

License

Acts as votable is released under the MIT License.

TODO

Pass in a block of options when creating acts_as. Allow for things like disabling the aliasing
Smarter language syntax. Example: @user.likes will return all of the votables that the user likes, while @user.likes @model will cast a vote for @model by @user.
The aliased methods are referred to by using the terms 'up/down' and/or 'true/false'. Need to come up with guidelines for naming these methods.
Create more aliases. Specifically for counting votes and finding votes.

vietqhoang/acts_as_votable