ActiveSupport、Hash#to_query
>> require "rubygems" => true >> require "active_support" => true >> Hash.from_xml([{:foo => 1, :bar => 2}, {:baz => 3}].to_xml).to_query => "records%5B%5D%5Bbar%5D=2&records%5B%5D%5Bfoo%5D=1&records%5B%5D%5Bbaz%5D=3" >> Hash.from_xml([].to_xml).to_query => ""