state_machine

https://github.com/pluginaweek/state_machine

Ruby

Adds support for creating state machines for attributes on any Ruby class

StateMachine::Transition#before

Runs the machine's +before+ callbacks for this transition.  Only
callbacks that are configured to match the event, from state, and to
state will be invoked.

Once the callbacks are run, they cannot be run again until this transition
is reset.

Source | Google | Stack overflow

Edit

git clone [email protected]:pluginaweek/state_machine.git

cd state_machine

open lib/state_machine/transition.rb

Contribute

# Make a new branch

git checkout -b -your-name--update-docs-StateMachine--Transition-before-for-pr

# Commit to git

git add lib/state_machine/transition.rbgit commit -m "better docs for StateMachine::Transition#before"

# Open pull request

gem install hub # on a mac you can `brew install hub`

hub fork

git push <your name> -your-name--update-docs-StateMachine--Transition-before-for-pr

hub pull-request

# Celebrate!