redis_model.rb

require 'redis/list'
require 'redis/value'

class RedisModel
  include ActiveModel::Validations
  include ActiveModel::Conversion
  extend ActiveModel::Naming
  
  attr_accessor :id
  
  def initialize(attributes = {})
    attributes.each { |name, value| send("#{name}=", value) }
  end
  
  def self.create(attributes)
    model.new(attributes).save
  end
  
  def self.first
    find(rlist("#{key}:all").first)
  end
  
  def self.find(id)
    rvalue("#{key}:#{id}").value
  end
  
  def self.last
    find(rlist("#{key}:all").last)
  end
  
  def self.collect(ids)
    ids.collect { |id| find(id) }
  end
  
  def self.collect_by_key(key)
    collect(rlist(key).values)
  end
  
  def destroy
    rvalue("#{self.class.key}:#{self.id}").delete
    rlist("#{self.class.key}:all").delete(self.id)
  end
  
  def new_record?
    id.nil?
  end
  
  def save
    if valid?
      self.id = ActiveSupport::SecureRandom.hex(16) if new_record?
      
      rvalue("#{self.class.key}:#{self.id}").value = self
      rlist("#{self.class.key}:all") << self.id
      
      return true
    else
      return false
    end
  end
  
  # Redis helpers
  
  def self.key
    model_name.tableize
  end

  def self.rvalue(key)
    Redis::Value.new(key, :marshal => true)
  end
  
  def rvalue(key)
    self.class.rvalue(key)
  end
  
  def self.rlist(key)
    Redis::List.new(key)
  end

  def rlist(key)
    self.class.rlist(key)
  end
  
  def persisted?
    false
  end
end