Use Redis to Make your Ruby objects Likeable!

I no longer use this gem in production (it was written for Gowalla), if you do and want to help me maintain it, let me know @schneems.

You like this

Likeable will allow your models to be liked by users, just drop a few lines of code into your model and you're good to go.

    class Comment
      include Likeable

      # ...
    end

    class User
      include Likeable::UserMethods

      # ...
    end

    Likeable.setup do |likeable|
      likeable.redis   = Redis.new
    end

    comment = Comment.find(15)
    comment.like_count                  # => 0
    current_user.like!(comment)         # => #<Likeable::Like ... >
    comment.like_count                  # => 1
    comment.likes                       # => [#<Likeable::Like ... >]
    comment.likes.last.user             # => #<User ... >
    comment.likes.last.created_at       # => Wed Jul 27 19:34:32 -0500 2011

    comment.liked_by?(current_user)     # => true

    current_user.all_liked(Comment)     # => [#<Comment ...>, ...]

    liked_comment = Likeable.find_by_resource_id("Comment", 15)
    liked_comment == comment            # => true

This library doesn't do dislikes, if you want something with more flexibility check out opinions.

Screencast

You can view a screencast of likeable in action on youtube. There is also an example Likeable rails application that you can use to follow along.

Setup

Gemfile:

gem 'likeable'

Next set up your Redis connection in initializers/likeable.rb:

    Likeable.setup do |likeable|
      likeable.redis  = Redis.new
    end

Then add the Likeable::UserMethods module to models/user.rb:

    class User
      include Likeable::UserMethods
    end

Finally add Likeable module to any model you want to be liked:

    class Comment
      include Likeable
    end

Rails Info

If you're using Likeable in Rails this should help you get started

controllers/likes_controller.rb

  class LikesController < ApplicationController

    def create
      target = Likeable.find_by_resource_id(params[:resource_name], params[:resource_id])
      current_user.like!(target)
      redirect_to :back, :notice => 'success'
    end

    def destroy
      target = Likeable.find_by_resource_id(params[:resource_name], params[:resource_id])
      current_user.unlike!(target)
      redirect_to :back, :notice => 'success'
    end
  end

config/routes.rb

    delete  'likes/:resource_name/:resource_id' => "likes#destroy", :as => 'like'
    post    'likes/:resource_name/:resource_id' => "likes#create",  :as => 'like'

helpers/like_helper.rb

    def like_link_for(target)
      link_to "like it!!", like_path(:resource_name => target  .class, :resource_id => target.id), :method => :post
    end

    def unlike_link_for(target)
      link_to "unlike it!!", like_path(:resource_name => target.class, :resource_id => target.id), :method => :delete
    end

Then in any view you can simply call the helper methods to give your user a link

    <%- if @user.likes? @comment -%>
      <%= unlike_link_for @comment  %>
    <%- else -%>
      <%= like_link_for @comment %>
    <%- end -%>

Why

We chose Redis because it is screaming fast, and very simple to work with. By using redis for likeable we take load off of our relational database and speed up individual calls retrieve information about the "liked" state of an object. If you're not using redis in production, and don't want to, there are many other great liking/voting libraries out there such as thumbs up.

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      RedisRedisRedisRedi   RedisRedisRedisRedi
     RedisRedisRedisRedisRedisRedisRe       Redi
    RedisRedisRedisRedisRedisRedisRe         Redi
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   RedisRedisRedisRedisRedisRedisRedisRedis      R
  RedisRedisRedisRedisRedisRedisRedisRedisRedi  Red
  RedisRedisRedisRedisRedisRedisRedisRedisRedisRe R
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Authors

Richard Schneeman for Gowalla <3

Contribution

Fork away. If you want to chat about a feature idea, or a question you can find me on the twitters @schneems. Put any major changes into feature branches. Make sure all tests stay green, and make sure your changes are covered.

schneems/likeable