require 'bigdecimal' require 'stringio' require 'set' module Aws module DynamoDB # @api private class AttributeValue def initialize @marshaler = Marshaler.new @unmarshaler = Unmarshaler.new end def marshal(value) @marshaler.format(value) end def unmarshal(value) @unmarshaler.format(value) end class Marshaler def format(obj) case obj when String then { s: obj } when Numeric then { n: obj.to_s } when StringIO, IO then { b: obj.read } when Set then format_set(obj) else msg = "unsupported type, expected Set, String, Numeric, or " msg << "IO object, got #{obj.class.name}" raise ArgumentError, msg end end private def format_set(set) case set.first when String then { ss: set.map(&:to_s) } when Numeric then { ns: set.map(&:to_s) } when StringIO, IO then { bs: set.map(&:read) } else msg = "set types only support String, Numeric, or IO objects" raise ArgumentError, msg end end end class Unmarshaler def format(obj) type, value = extract_type_and_value(obj) case type when :s then value when :n then BigDecimal.new(value) when :b then StringIO.new(value) when :ss then Set.new(value) when :ns then Set.new(value.map { |n| BigDecimal.new(n) }) when :bs then Set.new(value.map { |b| StringIO.new(b) }) else raise ArgumentError, "unhandled type #{type.inspect}" end end private def extract_type_and_value(obj) case obj when Hash then obj.to_a.first when Struct obj.members.each do |key| value = obj[key] return [key, value] unless value.nil? end else raise ArgumentError, "unhandled type #{obj.inspect}" end end end end end end