Piper.rb

Installation

Add this line to your application’s Gemfile:

“by gem “piper-rb”

“

Usage

super basic

The most basic element of Piper is a pipe. Just think of it as a condition step. If no keywords are used, then (in accordance to Ruby conventions) the last line of code is taken as the step’s condition:

“by require “piper-rb”

class YourSuperbService < PiperService attribute :input, Types::Any

pipe “input is Numeric” do input.is_a? Numeric end

pipe “input is greater than 100?” do false

200 == 100

input > 100

end

pipe “input is less than 1000?” do input < 1000 end end

YourSuperbService.new(input: 200).call

=> Success(true)

YourSuperbService.new(input: “asd”).call

=> Failure()

“

keywords for more control

If you want to specify the condition, object to be returned and the error message, there are keywords for this:

• condition (aliase: cond)
• result_object (aliases: object, rslt)
• message (aliases: fail_message, mssg)

“by require “piper-rb”

class YourFineService < PiperService attribute :input, Types::Any

pipe “input is Numeric” do message { “The input must be Numeric.” }

input.is_a? Numeric

end

pipe “input is greater than 100?” do cond { input > 100 }

200 == 100

end

pipe “input is less than 1000?” do object { input }

input < 1000

end end

YourFineService.new(input: 200).call

=> Success(200)

YourFineService.new(input: “asd”).call

=> Failure()

“

you can access last step’s object with last_result:

“by require “piper-rb”

class YourGreatService < PiperService attribute :input, Types::Any

pipe “this step`s result should be passed to..." do input * 30 end

pipe “…to this step” do cond { last_result == input * 30 } object { last_result } end end

YourGreatService.new(input: 20).call

=> Success(600)

“

you can nest services, calling them in a pipe passes their result:

“by require “piper-rb”

class YourMajesticService < PiperService attribute :input, Types::Any

pipe :nothing_to_see_here do true end

pipe :calling_nested_service do YourFlamboyantService.new(nested_input: input * 20).call end end

class YourFlamboyantService < PiperService attribute :nested_input, Types::Any

pipe :simple_step do message { “I am the one who knocks!” } nested_input >= 300 end

end

YourMajesticService.new(input: 20).call

=> Success(true)

YourMajesticService.new(input: 2).call

=> Failure()

“