A convention-based state machine that complements your models without stealing the show.
Multiple state machines are supported.
Add this line to your application's Gemfile:
gem 'transitionable'And then execute:
$ bundle
class Event
# By default, Transitionable assumes including class defines the following constants BEFORE including this module:
#
# * STATES
# * TRANSITIONS
STATES = {
STAGED: 'staged',
STARTED: 'started',
COMPLETED: 'completed'
}.freeze
TRANSITIONS = [
{ from: STATES[:STAGED], to: STATES[:STARTED] },
{ from: STATES[:STARTED], to: STATES[:COMPLETED] }
].freeze
include Transitionable
# specifies the column that needs to be transitioned
transition :some_state
endProvides the following helpers
event.staged?
event.started?
event.completed?Provides 2 validation methods
event.validate_transition(target_state: 'new_state')
# => returns true or false
event.validate_transition!(target_state: 'new_state')
# => returns true or raises Transitionable::InvalidStateTransition exceptionclass Event
DELIVERY_STATES = {
STAGED: 'staged',
STARTED: 'started',
COMPLETED: 'completed'
}.freeze
PREP_STATES = {
COOKING: 'cooking',
COOKED: 'cooked'
}.freeze
DELIVERY_TRANSITIONS = [
{ from: DELIVERY_STATES[:STAGED], to: DELIVERY_STATES[:STARTED] },
{ from: DELIVERY_STATES[:STARTED], to: DELIVERY_STATES[:COMPLETED] }
].freeze
PREP_TRANSITIONS = [
{ from: PREP_STATES[:COOKING], to: PREP_STATES[:COOKED] }
]
include Transitionable
transition :delivery_state, DELIVERY_STATES, DELIVERY_TRANSITIONS
transition :prep_state, PREP_STATES, PREP_TRANSITIONS
endProvides the following helpers
event.staged?
event.started?
event.completed?
event.cooking?
event.cooked?Provides 2 validation methods
event.validate_transition(target_state: 'new_state')
# => returns true or false
# optionally, validate_transition also yield an error object when transition is invalid.
event.validate_transition(target_state: 'new_state') do |error|
# You can do things like:
Airbrake.notify(error, attributes) # sends the error along with including model's attributes
end
event.validate_transition!(target_state: 'new_state')
# => returns true or raises Transitionable::InvalidStateTransition exception- Each state must be unique across all state machines in the model. Otherwise,
InvalidStateTransitionexception will thrown as Transitionable attempts to define the same helper method multiple times. - For the same reason,
"#{state}?"must not be defined in your model for each of your state.
After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/transitionable.
The gem is available as open source under the terms of the MIT License.