gistfile1.rbx

# Need to handle all of these....

# [x] Reservation.find(123) 
# [ ] Reservation.find(123,456,769)
# [ ] Reservation.find(:all)
# [ ] Reservation.find(:all, :conditions => ['foo = ?', 'bar'])

module Cacheable
  @@store = nil
  
  def self.store(backing_store)
    @@store = backing_store
    self
  end
  
  def cache
    @@store
  end
  
  def self.find(*opts)
    return super(*opts) unless opts.first.kind_of?(Integer)
    key = cache_key_for(opts.first)
    return cache[key] if cache.include? key
    returning(super(*opts)) do |record|
      cache[key] = record
    end    
  end
  
  protected
  
  def self.cache_key_for(id)    
    prefix = ancestors.collect(&:name)[0..2].compact.join(':').downcase
    "%s:%s" % [prefix, id.to_s]
  end
end

CACHE = {} # this is defined by Rails....

class Foo
  include Cacheable::store(CACHE)
end

puts Foo.new.cache # yay!