StateMachines Active Record Integration
The Active Record 5.1+ integration adds support for database transactions, automatically saving the record, named scopes, validation errors.
Installation
Add this line to your application's Gemfile:
gem 'state_machines-activerecord'
And then execute:
$ bundle
Or install it yourself as:
$ gem install state_machines-activerecord
Usage
For the complete usage guide, see http://www.rubydoc.info/github/state-machines/state_machines-activerecord/StateMachines/Integrations/ActiveRecord
Example
class Vehicle < ApplicationRecord
state_machine :initial => :parked do
before_transition :parked => any - :parked, :do => :put_on_seatbelt
after_transition any => :parked do |vehicle, transition|
vehicle.seatbelt = 'off'
end
around_transition :benchmark
event :ignite do
transition :parked => :idling
end
state :first_gear, :second_gear do
validates :seatbelt_on, presence: true
end
end
def put_on_seatbelt
...
end
def benchmark
...
yield
...
end
end
Scopes
Usage of the generated scopes (assuming default column state
):
Vehicle.with_state(:parked) # also plural #with_states
Vehicle.without_states(:first_gear, :second_gear) # also singular #without_state
State driven validations
As mentioned in StateMachines::Machine#state
, you can define behaviors,
like validations, that only execute for certain states. One important
caveat here is that, due to a constraint in ActiveRecord's validation
framework, custom validators will not work as expected when defined to run
in multiple states. For example:
class Vehicle < ApplicationRecord
state_machine do
state :first_gear, :second_gear do
validate :speed_is_legal
end
end
end
In this case, the :speed_is_legal validation will only get run for the :second_gear state. To avoid this, you can define your custom validation like so:
class Vehicle < ApplicationRecord
state_machine do
state :first_gear, :second_gear do
validate {|vehicle| vehicle.speed_is_legal}
end
end
end
Contributing
- Fork it ( https://github.com/state-machines/state_machines-activerecord/fork )
- Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) - Push to the branch (
git push origin my-new-feature
) - Create a new Pull Request