Featured Items Listing

Rails
1

Hey All,

Say I have a website with articles and events and I want to create an
index of featured items which will have a mixture of articles and
events. I presume I’d create a FeaturedItem model/table with the
following:

featured_class <-- ‘Article’ or ‘Event’
featured_id <-- id of Article or Event
position <-- position in featured list

When I pull the featured items from the database, I’m gonna wanna pull
the corresponding item from the featured_class table. What’s the best
way to do this, other than:

if FeaturedItem.featured_class == ‘Article’
Article.find()…
elsif FeaturedItem.featured_class == ‘Event’
Event.find()…
end

Is there anyway to create functionality that will allow me to do
something like this:

FeaturedItem.featured_class.find()…

or something similar
???

2

What you want is a polymorphic association between Feature? and both
Article and Event. Check out the Rails API for ActiveRecord::Base and
look for the heading “Polymorphic Associations”

3

the corresponding item from the featured_class table. What’s the best

FeaturedItem.featured_class.find()…

class Article < ActiveRecord::Base
has_one :featured_thing, :as => :featureable
end

class Event < ActiveRecord::Base
has_one :featured_thing, :as => :featureable
end

id :integer

featureable_id :integer

featureable_type :string

class FeaturedThing < ActiveRecord::Base
belongs_to :featureable, :polymorphic => true

def featureable_thing
self.featurable_type.constantize.find_by_id(self.featurable_id)
end
end

Maybe?

Then you could do say…

FeaturedThing.find(:all).each do |ft|
puts ft.featureable_thing.title # assuming both Articles and Events
have
# a title
end