Service Object with on_success and on_failure blocks

service object with on_success and on_failure hooks.rb

#----------------------
# Library code:

class BasicServiceObject
  attr_reader :object
  
  def initialize(o)
    @object = o
  end
end

class ServiceObjectWithHooks < BasicServiceObject
  def perform
    @_perform_called = true
    @_success = yield
    self
  end
  
  def on_success
    ensure_perform_was_called
    yield if @_success
    self
  end

  def on_failure
    ensure_perform_was_called
    yield unless @_success
    self
  end

private
  def ensure_perform_was_called
    return if @_perform_called
    fail "
      the service object action was not wrapped in a `perform` block.
      Example : 
        class FooService < ServiceObjectWithHooks
          def foo
            perform do
               result = object.foo
               Logger.log('object was fooed')
               result
            end
          end
        end
    " 
  end
end


#----------------------
# how to define a new service:

class SaviourService < ServiceObjectWithHooks
  def save_and_do_stuff
   perform do     # MUST wrap in a `perform` block!
      object.save  # <-- your code
   end
  end
end


#----------------------
# how to use the service:

class Foo
  def save
    result = (random_boolean = [true, false].sample)
  end
end

# way 1:
SaviourService.new(Foo.new)
  .save_and_do_stuff
  .on_success do 
    puts 'SUCCESS' 
  end
  .on_failure do 
    puts 'FAILURE' 
  end


# way 2:
operation = SaviourService.new(Foo.new).save_and_do_stuff
# ...
operation.on_success do 
  puts 'SUCCESS' 
end
# ...
operation.on_failure do 
  puts 'FAILURE' 
end

simpler and more compact version.rb

class ServiceObjectWithHooks
  attr_reader :object
  
  def initialize(o)
    @object = o
  end
  
  def on_success
    fail '@success was not defined' unless instance_variable_defined?(:@success)
    yield if @success
    self
  end

  def on_failure
    fail '@success was not defined' unless instance_variable_defined?(:@success)
    yield unless @success
    self
  end
end

#-----------

class Saviour < ServiceObjectWithHooks
  def save
    @success = object.save
    self
  end
end

class Foo
  def save
    result = random_boolean = [true, false].sample
  end
end

#-----------

Saviour.new(Foo.new)
  .save 
  .on_success do puts 'SUCCESS' end
  .on_failure do puts 'FAILURE' end