module SAML2::Bindings::HTTP_POST

def decode(post_params)
  base64 = post_params['SAMLRequest'] || post_params['SAMLResponse']
  raise MissingMessage unless base64
  raise MessageTooLarge if base64.bytesize > SAML2.config[:max_message_size]
  xml = begin
    Base64.decode64(base64)
  rescue ArgumentError
    raise CorruptMessage
  end
  message = Message.parse(xml)
  [message, post_params['RelayState']]
end

def encode(message, relay_state: nil)
  xml = message.to_s(pretty: false)
  key = message.is_a?(Request) ? 'SAMLRequest' : 'SAMLResponse'
  post_params = { key => Base64.encode64(xml) }
  post_params['RelayState'] = relay_state if relay_state
  post_params
end