urlHeaderToSign.put("x-url", new SignedHeaderValueMessageProcessor<String>(su.getPath()));
urlHeaderToSign.put("x-user", new SignedHeaderValueMessageProcessor<String>("notification"));
NotificationMessageEnricher signer = new NotificationMessageEnricher(urlHeaderToSign);
signer.setMessageProcessor(new MethodInvokingMessageProcessor(notificationUtils, "signMessageHeaders"));
MessageTransformingHandler mth = new MessageTransformingHandler(signer);
mth.setBeanName(platformType + "Signer");
mth.setBeanFactory(context.getBeanFactory());
mth.setChannelResolver(channelResolver);
mth.setOutputChannel(outputChannel);
mth.setRequiresReply(false);
signChannel.subscribe(mth);
DefaultHttpHeaderMapper hm = new DefaultHttpHeaderMapper();
hm.setUserDefinedHeaderPrefix("");
String[] names = {"Accept", "x-url", "x-signature", "x-user"};