Method: GraphQL::Schema::Field#calculate_complexity

Defined in:

lib/graphql/schema/field.rb

#calculate_complexity(query:, nodes:, child_complexity:) ⇒ Object

# File 'lib/graphql/schema/field.rb', line 472

def calculate_complexity(query:, nodes:, child_complexity:)
  if respond_to?(:complexity_for)
    lookahead = GraphQL::Execution::Lookahead.new(query: query, field: self, ast_nodes: nodes, owner_type: owner)
    complexity_for(child_complexity: child_complexity, query: query, lookahead: lookahead)
  elsif connection?
    arguments = query.arguments_for(nodes.first, self)
    max_possible_page_size = nil
    if arguments.respond_to?(:[]) # It might have been an error
      if arguments[:first]
        max_possible_page_size = arguments[:first]
      end

      if arguments[:last] && (max_possible_page_size.nil? || arguments[:last] > max_possible_page_size)
        max_possible_page_size = arguments[:last]
      end
    elsif arguments.is_a?(GraphQL::ExecutionError) || arguments.is_a?(GraphQL::UnauthorizedError)
      raise arguments
    end

    if max_possible_page_size.nil?
      max_possible_page_size = default_page_size || query.schema.default_page_size || max_page_size || query.schema.default_max_page_size
    end

    if max_possible_page_size.nil?
      raise GraphQL::Error, "Can't calculate complexity for #{path}, no `first:`, `last:`, `default_page_size`, `max_page_size` or `default_max_page_size`"
    else
      metadata_complexity = 0
      lookahead = GraphQL::Execution::Lookahead.new(query: query, field: self, ast_nodes: nodes, owner_type: owner)

      lookahead.selections.each do |next_lookahead|
        # this includes `pageInfo`, `nodes` and `edges` and any custom fields
        # TODO this doesn't support procs yet -- unlikely to need it.
        metadata_complexity += next_lookahead.field.complexity
        if next_lookahead.name != :nodes && next_lookahead.name != :edges
          # subfields, eg, for pageInfo -- assumes no subselections
          metadata_complexity += next_lookahead.selections.size
        end
      end

      # Possible bug: selections on `edges` and `nodes` are _both_ multiplied here. Should they be?
      items_complexity = child_complexity - metadata_complexity
      subfields_complexity = (max_possible_page_size * items_complexity) + metadata_complexity
      # Apply this field's own complexity
      apply_own_complexity_to(subfields_complexity, query, nodes)
    end
  else
    apply_own_complexity_to(child_complexity, query, nodes)
  end
end