Server Sent Events using Spring WebFlux and EventSource

Question

I am working on Server Sent Events.

Reference Link: http://sinhamohit.com/writing/spring-boot-reactive-sse

The above example includes SSE with Spring Boot and WebFlux.

Is there any example available with Spring WebFlux and HTML5 EventSource?

Answer 1

Create simple project with WebFlux. Below is controller method for server sent event:

@GetMapping(value = "/notifyonEvent", produces = 
MediaType.TEXT_EVENT_STREAM_VALUE)  
public Flux<String> getData() {
Random r = new Random();
int low = 0;
int high = 50;
return Flux.fromStream(Stream.generate(() -> r.nextInt(high - low) + low)
    .map(s -> String.valueOf(s))
    .peek((msg) -> {
        LOGGER.info(msg);
    }))
    .map(s -> s)
    .delayElements(Duration.ofSeconds(1));
}

Client side

var source = new EventSource("YOURAPP_URL/notifyonEvent");
source.onmessage = function(event) {
  console.log(event.data);
};