Enumerator Strategies

strategies.rb

# importing method
def import_items(source)
  if SECTION_SOURCES.include? source.name
    Strategies::SectionStrategy.items(@repository, source.id).each(&method(:import_item))
  else
    Strategies::ItemsStrategy.items(@repository, source.id).each(&method(:import_item))
  end
end

# strategies

module SampleAPI
  module Imports
    module Strategies
      module ItemsStrategy
        def self.items(repository, source_id)
          Enumerator.new do |yielder|
            offset = 0
            limit  = repository.class::ITEMS_PAGINATION_LIMIT

            loop do
              items = repository.items(
                source_id: source_id,
                filters: {
                  offset: offset,
                  limit: limit
                }
              )['items']

              raise StopIteration if items.empty?

              items.each { |item| yielder << item }
              offset += limit
            end
          end
        end
      end
    end
  end
end

module SampleAPI
  module Imports
    module Strategies
      module SectionStrategy
        MAX_ITEMS_PER_SECTION = 10_000

        def self.items(repository, source_id)
          Enumerator.new do |yielder|
            section_ids =
              repository
              .sections(source_id: source_id)['items']
              .map { |json| json['id'] }

            section_ids.each do |section_id|
              sections_record_count = repository.items(
                source_id: source_id,
                filters: {
                  offset: 0,
                  limit: repository.class::ITEMS_PAGINATION_LIMIT,
                  'sectionCode' => section_id
                }
              )['recordCount']

              if sections_record_count <= MAX_ITEMS_PER_SECTION
                import_items_for_section_id(repository, source_id, section_id, yielder)
              else
                sub_section_ids = repository.sections_children(
                  source_id: source_id,
                  section_id: section_id
                )['items'].map { |json| json['id'] }
                sub_section_ids.each do |sub_section_id|
                  import_items_for_section_id(repository, source_id, sub_section_id, yielder)
                end
              end
            end
          end
        end

        def self.import_items_for_section_id(repository, source_id, section_id, yielder)
          limit = repository.class::ITEMS_PAGINATION_LIMIT
          offset = 0
          loop do
            items = repository.items(
              source_id: source_id,
              filters: {
                offset: offset,
                limit: limit,
                'sectionCode' => section_id
              }
            )['items']

            raise StopIteration if items.empty?

            items.each { |item| yielder << item }
            offset += limit
          end
        end
      end
    end
  end
end