gistfile1.rb

class ManyLevels
  extend HashMapper
  map from('/name'),            to('/tag_attributes/name')
  map from('/properties/type'), to('/tag_attributes/type')
  map from('/tagid'),           to('/tag_id')
  map from('/properties/egg'),  to('/chicken')
end

input =      {
  :name => 'ismael',
  :tagid => 1,
  :properties => {
    :type => 'BLAH',
    :egg => 33
  }
}

ManyLevels.normalize(input)

# outputs:
     {
  :tag_id => 1,
  :chicken => 33,
  :tag_attributes => {
    :name => 'ismael',
    :type => 'BLAH'
  }
}