Experimenting with Ports

experimenting_with_ports.rb

class Port
  attr_accessor :output_port

  def initialize(inner_port = nil)
    inner_port.output_port = self if inner_port
    @inner_port = inner_port
  end

  def perform(*args)
    @inner_port.perform(*args)
  end

  def success!(*args)
    @output_port.success!(*args)
    raise Done
  end

  def fail!(*args)
    @output_port.fail!(*args)
    raise Done
  end

  def execute(*args, &block)
    original_output_port = @output_port
    @output_port = Output.new(block)
    perform(*args)
  rescue Done
    # do nothing
  ensure
    @output_port = original_output_port
  end

  class Done < Exception; end

  class Output
    def initialize(block)
      block.call(self)
    end

    def success!(*args)
      @success_block.call(*args)
      raise Done
    end

    def fail!(*args)
      @failure_block.call(*args)
      raise Done
    end

    def success(&block)
      @success_block = block
    end

    def failure(&block)
      @failure_block = block
    end
  end
end

class Interactor < Port
  def perform(a_symbol)
    fail! unless a_symbol.is_a? Symbol

    success!(a_symbol.to_s.length)
    success!('oh dears')
  end
end

class Gateway < Port
  def perform(*args)
    new_args = args.map(&:to_sym)
    super(*new_args)
  end

  def success!(*args)
    super(*args.map { |a| a*100 })
  end
end


Gateway.new(Interactor.new).execute('some argument') do |result|
  result.success do |res|
    puts 'HURRAY', res
  end

  result.failure do
    raise 'Oh noes'
  end
end