user.rb

require 'bcrypt'
require 'securerandom'

class User
  include DataMapper::Resource
  include BCrypt

  property :id, Serial
  property :email, String, :required => true, :index => :login, :unique => true, :unique_index => true, :format => :email_address
  property :password_hash,  Text, :required => true, :index => :login
  property :password_salt, Text, :required => true, :writer => :protected
  property :auth_token, Text
  property :name, String, :unique => true, :required => true, :length => 3..30, :message => "Your name must not be blank and at least 3 characters.", :unique_index => true

  attr_accessor :password, :password_confirmation, :password_needed,
                :_csrf, :password_reset, :pid, :gender, :main_name, :char_name,
                :id_base, :id_hair, :id_head, :id_torso, :id_legs, :id_weapon

  validates_presence_of :password_confirmation, :password, :if => :password_needed?
  validates_length_of :password, :min => 6, :max => 255, :if => :password_needed?
  validates_confirmation_of :password, :if => :password_needed?

  before :valid?, :make_password

  def change_password(the_pass)
    self.password_hash = BCrypt::Password.create(the_pass)
  end

  def make_password
    if new? or !self.forgotten.nil?
      self.email.to_s.downcase unless self.email.nil?
      self.password_salt = [Array.new(6){rand(256).chr}.join].pack("m").chomp
      password = [Array.new(14){rand(256).chr}.join].pack("m").chomp if password.nil?
      self.password_hash = BCrypt::Password.create(password + self.password_salt)
      self.char_name = name if new?
    end
    password
  end

  def crypted_pass
    pass = attribute_get(:password_hash)
    return nil if pass.nil?
    BCrypt::Password.new(pass)
  end
  alias_method :crypted_password, :crypted_pass

  def forgotten_token
    token = SecureRandom.hex(16)
    self.forgotten = token
    self.forgotten_at = DateTime.now
    token
  end

  def new_account?
    new?
  end

  def password_needed?
    new? or password_reset
  end

  def reset_password
    token = forgotten_token
    save!
    Pony.mail() # snip
  end

  def authenticate(password)
    crypted_pass == (password)
  end

  def self.authenticate(username, password)
    u = first(:email => username.to_s.downcase)
    if u && u.authenticate(password)
      u
    else
      nil
    end
  end
end