app/models/product.rb

   1 class Product < ActiveRecord::Base
   2   has_many :line_items
   3   has_many :orders, :through => :line_items
   4
   5   validates_presence_of :title, :description, :image_url
   6   validates_numericality_of :price
   7   validate :price_must_be_at_least_a_penny
   8   validates_uniqueness_of :title
   9   validates_format_of :image_url,
  10                       :with    => %r{\.(gif|jpg|png)$}i,
  11                       :message => "must be a URL for GIF, JPG, or PNG image."
  12
  13   def self.find_products_for_sale
  14     find(:all,
  15       :conditions => "date_available <= now() and (date_available_until is null or date_available_until >= now())",
  16       :order => :title)
  17   end
  18
  19 protected
  20   def price_must_be_at_least_a_penny
  21     errors.add(:price, 'should be at least 0.01') if price.nil? || price < 0.01
  22   end
  23 end