What is a step alias input?

  • A step alias input renames a step's parameter to a different organizer instance method, using a one-key hash in in:: {step_parameter_name: :organizer_method_name}.

    class CalculateDoubled
  include ConvenientService::Standard::Config

  attr_reader :number

  def initialize(number:)
    @number = number
  end

  def result
    success(doubled: number * 2)
  end
end

class AwardLoyaltyPoints
  include ConvenientService::Standard::Config

  step CalculateDoubled,
    in: {number: :count},
    out: {doubled: :points}

  private

  def count
    21
  end
end

result = AwardLoyaltyPoints.result

result.success?
# => true

result.data[:points]
# => 42

  • in: {number: :count} calls count on the organizer (AwardLoyaltyPoints) and passes its return value as number: to the step (CalculateDoubled).

  • As a rule of thumb, the organizer method name is always on the right side of the hash, the step's parameter name is always on the left.

  • Use a step alias input when the organizer has no method matching the step's parameter name, or when the matching organizer method already serves another purpose. Here the step needs number:, but the organizer's method is named count.

  • Like a usual step input, the aliased organizer method can be private - count is private above.

See also

Sources