Passing variables to Rails StateMachine gem transitions

Question

Is it possible to send variables in the the transition? i.e.

@car.crash!(:crashed_by => current_user)

I have callbacks in my model but I nee

Answer 1

Another common pattern (see the state_machine docs) that saves you from having to pass variables between the controller and model is to dynamically define a state-checking method within the callback method. This wouldn't be very elegant in the example given above, but might be preferable in cases where the model needs to handle the same variable(s) in different states. For example, if you have 'crashed', 'stolen', and 'borrowed' states in your Car model, all of which can be associated with a responsible Person, you could have:

state :crashed, :stolen, :borrowed do
  def blameable?
    true
  end

state all - [:crashed, :stolen, :borrowed] do
  def blameable?
    false
  end

Then in the controller, you can do something like:

car.blame_person(person) if car.blameable?