Likeable is the easiest way to 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
And it also allow your models to be disliked by users:
comment = Comment.find(15)
comment.dislike_count # => 0
current_user.dislike!(comment) # => #<Likeable::Dislike ... >
comment.dislike_count # => 1
comment.dislikes # => [#<Likeable::Dislike ... >]
comment.dislikes.last.user # => #<User ... >
comment.dislikes.last.created_at # => Thu Nov 10 06:16:14 +0200 2011
comment.disliked_by?(current_user) # => true
current_user.all_disliked(Comment) # => [#<Comment ...>, ...]
# Notice `plusminus` method that equals to (like_count - dislike_count)
comment = Comment.find(15)
comment.plusminus # => 0
current_user.dislike!(comment)
comment.plusminus # => -1
comment.disliked_by?(current_user) # => true
current_user.like!(comment)
comment.plusminus # => 1
comment.liked_by?(current_user) # => true
current_user_2.like!(comment)
comment.plusminus # => 2
comment.liked_by?(current_user_2) # => true
# Notice `cancel_like!` method
current_user.cancel_like!(comment)
comment.plusminus # => 1
comment.liked_by?(current_user) # => false
comment.disliked_by?(current_user) # => false
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.
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
If you're using Likeable in Rails this should help you get started
controllers/likes_controller.rb
class LikesController < ApplicationController
def create_like
target = Likeable.find_by_resource_id(params[:resource_name], params[:resource_id])
current_user.like!(target)
redirect_to :back, :notice => 'successfully liked'
end
def create_dislike
target = Likeable.find_by_resource_id(params[:resource_name], params[:resource_id])
current_user.dislike!(target)
redirect_to :back, :notice => 'successfully disliked'
end
def cancel_like
target = Likeable.find_by_resource_id(params[:resource_name], params[:resource_id])
current_user.cancel_like!(target)
redirect_to :back, :notice => 'successfully canceled'
end
end
config/routes.rb
match 'likes/:resource_name/:resource_id/like' => "likes#create_like", :as => :like
match 'likes/:resource_name/:resource_id/dislike' => "likes#create_dislike", :as => :dislike
match 'likes/:resource_name/:resource_id/cancel' => "likes#cancel_like", :as => :cancel_like
helpers/like_helper.rb
def like_link_for(target)
link_to "like it!", like_path(:resource_name => target.class, :resource_id => target.id)
end
def dislike_link_for(target)
link_to "dislike it!", dislike_path(:resource_name => target.class, :resource_id => target.id)
end
def cancel_like_link_for(target)
link_to "cancel like!", cancel_like_path(:resource_name => target.class, :resource_id => target.id)
end
Then in any view you can simply call the helper methods to give your user a link
<%- if @user.likes? @comment || @user.dislikes? @comment -%>
<%- if @user.likes? @comment -%>
<%= dislike_link_for @comment %>
<%- else -%>
<%= like_link_for @comment %>
<%- end -%>
<%= cancel_like_link_for @comment %>
<%- end -%>
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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Richard Schneeman for Gowalla <3
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