sample_datamapper_user.rb

require "dm-core"
require "dm-validations"
require "dm-timestamps"
require "digest"

class User
  include DataMapper::Resource
  
  property :id, Serial
  property :username, String, :required => true, :unique => true
  property :email, String
  property :encrypted_password, String
  property :salt, String

  attr_accessor :password, :password_confirmation

  validates_present :password, :password_confirmation
  validates_is_confirmed :password

  before :save do
    self.salt = self.object_id.to_s + rand.to_s
    self.encrypted_password = encrypt(password)
  end
  
  def match_password?(password)
    encrypted_password == encrypt(password)
  end

  private

  def encrypt(string)
    Digest::SHA1.hexdigest("#{string}-blah-#{salt}")
  end

end