Method: GraphQL::Dataloader::ActiveRecordAssociationSource#fetch

Defined in:
lib/graphql/dataloader/active_record_association_source.rb

#fetch(records) ⇒ Object 



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# File 'lib/graphql/dataloader/active_record_association_source.rb', line 31

def fetch(records)
  record_classes = Set.new.compare_by_identity
  associated_classes = Set.new.compare_by_identity
  scoped_fetch = !@scope.nil?
  records.each do |record|
    if scoped_fetch
      assoc = record.association(@association)
      assoc.reset
    end
    if record_classes.add?(record.class)
      reflection = record.class.reflect_on_association(@association)
      if !reflection.polymorphic? && reflection.klass
        associated_classes.add(reflection.klass)
      end
    end
  end

  available_records = []
  associated_classes.each do |assoc_class|
    already_loaded_records = dataloader.with(RECORD_SOURCE_CLASS, assoc_class).results.values
    available_records.concat(already_loaded_records)
  end

  ::ActiveRecord::Associations::Preloader.new(records: records, associations: @association, available_records: available_records, scope: @scope).call

  loaded_associated_records = records.map { |r|
    assoc = r.association(@association)
    lar = assoc.target
    if scoped_fetch
      assoc.reset
    end
    lar
  }

  if !scoped_fetch
    # Don't cache records loaded via scope because they might have reduced `SELECT`s
    # Could check .select_values here?
    records_by_model = {}
    loaded_associated_records.flatten.each do |record|
      if record
        updates = records_by_model[record.class] ||= {}
        updates[record.id] = record
      end
    end
    records_by_model.each do |model_class, updates|
      dataloader.with(RECORD_SOURCE_CLASS, model_class).merge(updates)
    end
  end

  loaded_associated_records
end