service.rb

# Service module
#
# Example usage :
# ```
#   class SayHello
#     include Service
#
#     attr_accessor :name
#
#     def call
#       puts "Hello #{name} !"
#     end
#   end
#
#   SayHello.call(name: "toto")
# ```

module Service
  def self.included(base)
    base.class_eval do
      # Proxy to #call instance method
      def self.call(*args)
        new(*args).call
      end
    
      # Service initializer
      def initialize(args={})
        unless args.is_a?(Hash)
          raise ArgumentError, "provided 'args' should be a hash."
        end

        args.each { |k,v| send("#{k.to_s}=", v) }
      end
    end
  end
end

Hon! Clever :)
Merci pour le détail du pourquoi.