class Aws::Xml::ErrorHandler

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

def error(context)
  body = context.http_response.body_contents
  if body.empty?
    code = http_status_error_code(context)
    message = ''
  else
    code, message = extract_error(body, context)
  end
  errors_module = context.client.class.errors_module
  errors_module.error_class(code).new(context, message)
end

def error_code(body, context)
  if matches = body.match(/<Code>(.+?)<\/Code>/)
    remove_prefix(unescape(matches[1]), context)
  else
    http_status_error_code(context)
  end
end

def error_message(body)
  if matches = body.match(/<Message>(.+?)<\/Message>/m)
    unescape(matches[1])
  else
    ''
  end
end

def extract_error(body, context)
  [
    error_code(body, context),
    error_message(body),
  ]
end

def http_status_error_code(context)
  status_code = context.http_response.status_code
  {
    302 => 'MovedTemporarily',
    304 => 'NotModified',
    400 => 'BadRequest',
    403 => 'Forbidden',
    404 => 'NotFound',
    412 => 'PreconditionFailed',
    413 => 'RequestEntityTooLarge',
  }[status_code] || "Http#{status_code}Error"
end

def remove_prefix(error_code, context)
  if prefix = context.config.api.metadata['errorPrefix']
    error_code.sub(/^#{prefix}/, '')
  else
    error_code
  end
end

def unescape(str)
  CGI.unescapeHTML(str)
end