Callbacks

around_transition Callback

• Callbacks invoked around a transition so long as the given requirements match the transition
• Wrap transitions, executing code both before and after

Defintion

• Defined in the exact same manner as before/after callbacks except the transition must be yielded to in order to finish running it

• If defining around callbacks using blocks, you must yield within the transition by directly calling the block (since yielding is not allowed within blocks):

  class Vehicle
    state_machine do
      around_transition do |block|
        Benchmark.measure { block.call }
      end
  
      around_transition do |vehicle, block|
        logger.info "vehicle was #{state}..."
        block.call
        logger.info "...and is now #{state}"
      end
  
      around_transition do |vehicle, transition, block|
        logger.info "before #{transition.event}: #{vehicle.state}"
        block.call
        logger.info "after #{transition.event}: #{vehicle.state}"
      end
    end
  end
  

  referencing the block is similar to doing so within an actual method definition in that it is always the last argument.

• if you're defining around callbacks using method references, yield like normal:

  class Vehicle
    state_machine do
      around_transition :benchmark
      ...
    end
  
    def benchmark
      Benchmark.measure { yield }
    end
  end
  

See before_transition for all possible configurations for defining callbacks.