class Aws::Json::ErrorHandler

def call(context)
  @handler.call(context).on(300..599) do |response|
    response.error = error(context)
    response.data = nil
  end
end

def error(context)
  error_code, error_message = extract_error(context)
  svc = context.client.class.name.split('::')[1]
  errors_module = Aws.const_get(svc).const_get(:Errors)
  errors_module.error_class(error_code).new(context, error_message)
end

def extract_error(context)
  json = MultiJson.load(context.http_response.body_contents)
  error_code = json['code'] || json['__type']
  error_code ||= context.http_response.headers['x-amzn-errortype']
  error_code = error_code.split('#').last
  if error_code == 'RequestEntityTooLarge'
    error_message = 'Request body must be less than 1 MB'
  else
    error_message = json['message'] || json['Message']
  end
  [error_code, error_message]
end