class Product < ActiveRecord::Base
+ has_many :line_items
+ has_many :orders, :through => :line_items
+
validates_presence_of :title, :description, :image_url
validates_numericality_of :price
validate :price_must_be_at_least_a_penny
:with => %r{\.(gif|jpg|png)$}i,
:message => "must be a URL for GIF, JPG, or PNG image."
+ def self.find_products_for_sale
+ find(:all,
+ :conditions => "date_available <= now() and (date_available_until is null or date_available_until >= now())",
+ :order => :title)
+ end
+
protected
def price_must_be_at_least_a_penny
errors.add(:price, 'should be at least 0.01') if price.nil? || price < 0.01