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 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

Rails 3

Just add the following to your Gemfile.

gem 'acts_as_votable'

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.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 :voter => @user3
@post.vote :voter => @user4, :vote => 'bad'
@post.vote :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 :voter => @user3
@post.vote :voter => @user5, :vote => 'like'

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

# tally them up!
@post.votes.size # => 5
@post.likes.size # => 3
@post.upvotes.size # => 3
@post.dislikes.size # => 2
@post.downvotes.size # => 2

Active Record scopes are provided to make life easier.

@post.votes.up.by_type(User)
@post.votes.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.up.by_type(User).voters
@post.votes.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.unlike_by @user1

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

Unvoting works for both positive and negative votes.

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

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

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_up, :integer, :default => 0
    add_column :posts, :cached_votes_down, :integer, :default => 0
    add_index  :posts, :cached_votes_total
    add_index  :posts, :cached_votes_up
    add_index  :posts, :cached_votes_down
  end

  def self.down
    remove_column :posts, :cached_votes_total
    remove_column :posts, :cached_votes_up
    remove_column :posts, :cached_votes_down
  end
end

Testing

All tests follow the RSpec format and are located in the spec directory

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.

• Need to test a model that is votable as well as a voter

• 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.