How to modify each broker message for each receiver inside a channel individually in Spring Boot?

Question

I'm sending a message to a channel but have to modify it for each client.

Anyone with experience on how to do that?

Answer 1

There you go.

Spring offers interceptors for incoming and outgoing channels. So simply add an interceptor and you're ready to catch every in- and outgoing message and do whatever you want to.

First your config:

...

@Autowired
private InboundMessagesChannelInterceptor inboundMessagesChannelInterceptor;

@Autowired
private OutboundMessagesChannelInterceptor outboundMessagesChannelInterceptor;

@Override
public void configureClientInboundChannel(ChannelRegistration registration) {
    registration.interceptors(inboundMessagesChannelInterceptor);
}

@Override
public void configureClientOutboundChannel(ChannelRegistration registration) {
    registration.interceptors(outboundMessagesChannelInterceptor);
}

...

and your interceptor:

@Component
public class OutboundMessagesChannelInterceptor implements ChannelInterceptor {

    @Override
    public Message<?> preSend(Message<?> message, MessageChannel channel) {
        // modify your message as needed
        return message;
    }

}

Thats it.