Statelogic is a yet another take on state management for your models. It’s tailored specially for ActiveRecord and is different from other frameworks in that it has its main goal in scoping validation rules and callbacks depending on the model’s state to emphasis actual model state consistency over merely formal… whatever…

• State transitions validation.

• State-scoped validations.

• State-scoped lifecycle callbacks (before|after_save, etc)

• ???????

• PROFIT!!!11

_Please review these carefully as they may be incompatible with your existing code._

• for all defined states also adds named_scopes :“#{attr_name}is#{state_name}” for example if state is :new, tries to add named_scope :new (it fails) and then it adds :state_is_new so the named_scope for state :new is still accessible

  by Petr Chalupa (github.com/pitrch)

_Please review these carefully as they may be incompatible with your existing code._

• adds finder methods in the form of +find_all_#{state}(*args)+ (Order.find_all_ready) sugg. by ares

• adds named scope named after corresponding state (Order.paid) sugg. by ares

• no longer redefines existing methods with the same names, issues warnings instead

• forces state names to underscore notation when used as part of method names

gem install statelogic

Installable as a plugin too.

rdoc.info/projects/omg/statelogic

Please report via Github issue tracking.

class Order < ActiveRecord::Base
  ...
  statelogic :attribute => :state do # +:state+ is the default value, may be omitted
    # you get methods +unpaid?+ and +was_unpaid?+.
    # may be more than one initial state.
    initial_state 'unpaid' do
      transitions_to 'ready', 'suspended' # won't let you change to wrong states
    end
    state 'ready' do # you get +ready?+, +was_ready?+; +Order.ready+, +Order.state_is_ready+; named scopes and +Order.find_all_ready+ finder
      transitions_to 'redeemed', 'suspended'
      validates_presence_of :txref # scoped validations
      before_save :prepare_for_plucking # scoped callbacks
    end
    state 'redeemed' do # likewise
      transitions_to 'suspended'
      validates_presence_of :txref, :redeemed_at, :facility_id # scoped validations
    end
    state 'suspended' do # you guess
      transitions_to 'unpaid', 'ready', 'redeemed'
      validate do |order|
        order.errors.add(:txref, :invalid) if order.txref && order.txref !~ /\AREF/
      end
    end
  end
  ...
end

order = Order.new
order.state = 'wtf'
order.txref = 'orly'
order.valid? # Please note that state transition checks are done during
             # the validation step as well, and the error is added to
             # the model's +errors+ collection on the state column and
             # will appear on your form. Standard ActiveRecord's error
             # message +:inclusion+ is used. Override it with Rails i18n
             # for something more specific if it's to be displayed to user.

• Petr Chalupa (github.com/pitrch)

• github.com/omg/threadpool – Thread pool implementation

• github.com/omg/peanuts – Ruby <-> XML mapping

• github.com/omg/slash – HTTP/REST client

Copyright © 2009 Igor Gunko, released under the MIT license