ServiceObject for Ruby on Rails

  def some_action_on_book
    service = CreateMyBookService.new(params[:isbn])
    service.run do |s|
      s.get_info_from_isbn_api
      s.get_availability_with_library
      s.save_my_book
    end
    if service.result
      render json: { result: 'success', message: 'Successfully saved the book data' }
    else
      render json: { result: 'failure', messages: service.error_messages }
    end
  end

gem 'service_object'

  def some_action_on_book
    service = CreateMyBookService.new(params[:isbn])
    service.run do |s|
      s.get_info_from_isbn_api
      s.get_availability_with_library
      s.save_my_book
    end
    if service.result
      render json: { result: 'success', message: 'Successfully saved the book data' }
    else
      render json: { result: 'failure', messages: service.error_messages }
    end
  end

class CreateMyBookService < ServiceObject::Base
  def initialize(isbn)
    super # This is necessary
    @isbn = isbn
    @book_info = nil
    @my_book = MyBook.new # ActiveRecord Model
    @isbn_api = IsbnApi.new(@isbn) # Non-AR Model
    @library_api = LibraryApi.new # Non-AR Model
  end

  def get_info_from_isbn_api
    @book_info = @isbn_api.get_all_info
  end

  def get_availability_with_library
    @availability = @library_api.get_availability(@isbn)
  rescue Net::HTTPError => e
    # You can re-throw you own error, too.
    raise YourError, 'Failed to get availability from library'
  end

  def save_my_book
    @my_book.update!(
      available: @availability,
      name: @book_info.title,
      author: @book_info.author,
      isbn: @isbn
     )
  end
end

  def some_action_on_content_file
    service = UploadContentService.new(content_params, session[:user_id])
    service.execute do |s| # execute is alias of #run
      s.upload_file
      s.transaction do
        s.save_content_data
        s.update_user
      end
    end

    if service.executed_successfully? # executed_successfully is alias of #result
      render json: { result: 'success', message: 'Successfully uploaded your content' }
    else
      render json: { result: 'failure', messages: service.error_messages }
    end
  end

class UploadContentService < ServiceObject::Base
  def initialize(params, user_id)
    super
    @content = Content.new(params)
    @file = ContentFile.new(params[:file_path])
    @user = User.find(user_id)
  end

  def upload_file
    raise YourFileError, "File Type needs to be one of #{ContentFile::TYPES.join('/')}" unless @file.allowed_file_type?
    @file.build_permission_info
    @file.queue_upload_job! # Let's assume this throws ContentFile::YourOwnEnqueueError when failing.
  end

  def save_content_data
    @content.update!(active: true)
  end

  def update_user
    @user.contents_counter += 1 # This is just a contrived sample. Use counter_cache
    @user.save!
  end

  # Custom error process by overriding the originally defined #process_exception.
  def process_exception(e)
    if e.is_a? ActiveRecord::ActiveRecordError 
      # When DB persistence fails, revert uploading file, too.
      rollback_uploaded_file
      @errors.add flattened_active_model_error(e.record) # This method is provided for convenience
    elsif e.class.in? [ContentFile::YourOwnEnqueueError, YourFileError]
      # This is still known error.
      logger.warn 'File upload had an issue.'
      @errors.add e.message
    else
      # Other errors are unexpected, so let the system fail by re-raising the error. 
      raise e  
    end
  end
  
  def rollback_uploaded_file
    if @file.respond_to?(:queued?) && @file.queued?
      @file.delete_queue_job
    end
  end
end