acts_as_similar – A basic similarity activerecord plugin

I had a need to find items that were similar to an item. I looked at acts_as_recommendable, and while this was very nice plugin, it was too slow when working with large data sets. I also decided that the results I needed didn’t need to be scientifically accurate, just a rough match. So I created this plugin to allow for a very elementary way to find items that are similar to the object you are working with. This works best when used with a has_many :through relationship.
Basically all it is doing is looking for other objects of the same class, that have some related value.

Git it here: http://github.com/randy-girard/acts_as_similar/tree/master

Example 1

Look for similar playlists, using the videos as what defines similarity.
This will look for all playlists that have a similar video as the playlist you are looking against.

class Playlist
  has_many :playlists_videos
  has_many :videos, :through => :playlists_videos
  acts_as_similar :videos
end

Example 2

Look for similar playlists, using the title of the playlist as the similarity item.
This will look for all playlists that have a similar title as the playlist you are looking against.

class Playlist
  has_many :playlists_videos
  has_many :videos, :through => :playlists_videos
  acts_as_similar :field => :title
end

Example 3

Look for similar playlists, using the video_id of the playlists_videos as the similarity item.
This will look for all playlists that have a similar video_id as the playlist you are looking against.

class Playlist
  has_many :playlists_videos
  has_many :videos, :through => :playlists_videos
  acts_as_similar :playlists_videos, :field => :video_id
end

Execute

@playlist = Playlist.first
@playlist.similar

Note: This is a work in progress.