Rails 3.1 feature: has_secure_password

gistfile1.rb

$ rails console
ruby-1.9.3-p0 :001 > user = User.new
 => #<User id: nil, username: nil, password_digest: nil, created_at: nil, updated_at: nil> 
ruby-1.9.3-p0 :002 > user = User.new username: 't.baba', password: 'hogehoge', password_confirmation: 'hogehoge'
 => #<User id: nil, username: "t.baba", password_digest: "$2a$10$HaXYndWU/kgCYopLf5nyb.PnX2QN0BQeKjECuoreZ2qO...", created_at: nil, updated_at: nil> 
ruby-1.9.3-p0 :003 > user.save!
Binary data inserted for `string` type on column `password_digest`
 => true
ruby-1.9.3-p0 :005 > user.authenticate 'hoge'
 => false 
ruby-1.9.3-p0 :006 > user.authenticate 'hogehoge'
 => #<User id: 2, username: "t.baba", password_digest: "$2a$10$HaXYndWU/kgCYopLf5nyb.PnX2QN0BQeKjECuoreZ2qO...", created_at: "2011-12-22 14:56:11", updated_at: "2011-12-22 14:56:11">

migration.rb

class CreateUsers < ActiveRecord::Migration
  def change
    create_table :users do |t|
      t.string :username
      t.string :password_digest

      t.timestamps
    end
  end
end

sessions_create.rb

user = User.find_by_username params[:username]
if user.authenticate params[:password]
  # 成功時の動作
else
  # 失敗時の動作
end

user.rb

class User < ActiveRecord::Base
  has_secure_password
end