Module: ApolloFederation::EntitiesField

Defined in:
lib/apollo-federation/entities_field.rb

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/apollo-federation/entities_field.rb', line 8

def self.included(base)
  base.extend(ClassMethods)
end

Instance Method Details

#_entities(representations:) ⇒ Object 



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# File 'lib/apollo-federation/entities_field.rb', line 29

def _entities(representations:)
  final_result = Array.new(representations.size)
  grouped_references_with_indices =
    representations
    .map
    .with_index { |r, i| [r, i] }
    .group_by { |(r, _i)| r[:__typename] }

  maybe_lazies = grouped_references_with_indices.map do |typename, references_with_indices|
    references = references_with_indices.map(&:first)
    indices = references_with_indices.map(&:last)

    # TODO: Use warden or schema?
    type = context.warden.get_type(typename)
    if type.nil? || type.kind != GraphQL::TypeKinds::OBJECT
      # TODO: Raise a specific error class?
      raise "The _entities resolver tried to load an entity for type \"#{typename}\"," \
            ' but no object type of that name was found in the schema'
    end

    # TODO: What if the type is an interface?
    type_class = class_of_type(type)

    if type_class.underscore_reference_keys
      references.map! do |reference|
        reference.transform_keys do |key|
          GraphQL::Schema::Member::BuildType.underscore(key.to_s).to_sym
        end
      end
    end

    if type_class.respond_to?(:resolve_references)
      results = type_class.resolve_references(references, context)
    elsif type_class.respond_to?(:resolve_reference)
      results = references.map { |reference| type_class.resolve_reference(reference, context) }
    else
      results = references
    end

    context.schema.after_lazy(results) do |resolved_results|
      resolved_results.zip(indices).each do |result, i|
        final_result[i] = context.schema.after_lazy(result) do |resolved_value|
          # TODO: This isn't 100% correct: if (for some reason) 2 different resolve_reference
          # calls return the same object, it might not have the right type
          # Right now, apollo-federation just adds a __typename property to the result,
          # but I don't really like the idea of modifying the resolved object
          context[resolved_value] = type
          resolved_value
        end
      end
    end
  end

  # Make sure we've resolved the outer level of lazies so we can return an array with a possibly lazy
  # entry for each requested entity
  GraphQL::Execution::Lazy.all(maybe_lazies).then do
    final_result
  end
end