CODEWITHSUNDEEP
springspring-webfluxfluxserver-sent-events
ivanjermakov
ivanjermakov

Reputation: 1294

Spring WebFlux detect client disconnect

Suppose the following @RestController:

@GetMapping("listen")
public Flux<Object> listen() {
    return Flux.create(sink -> process(sink));
}

And somewhere

sink.next(new Object());

This code has no information about sink state or completion

Tried using isCanceled, it returns false every time.

Is it possible to detect is FluxSink is still being used by the client?

Upvotes: 8

Views: 4386

Answers (3)

阿呆先生
阿呆先生

Reputation: 1

You can try deploying it on another server to test, as I've also encountered this issue when deploying and debugging locally.

Upvotes: 0

SalutonMondo
SalutonMondo

Reputation: 709

the accepted answer is only work combined with "sever send event", the server send periodical event to client, when the client is disconnected the subscription will be canceled. as the document says https://docs.spring.io/spring-framework/docs/current/reference/html/web-reactive.html#webflux-codecs-streaming

Upvotes: 0

JEY
JEY

Reputation: 7133

In spring-webflux if the client close the connection the subscription will be canceled and disposed. If in the process method you add a callback onCancel and onDispose you will see that.

private <T> void process(final FluxSink<T> sink) {
    sink.onCancel(new Disposable() {
        @Override
        public void dispose() {
            System.out.println("Flux Canceled");
        }
    });

    sink.onDispose(new Disposable() {

        @Override
        public void dispose() {
            System.out.println("Flux dispose");
        }
    });
}

Then send an http request to your endpoint and cancel it before your flux complete. You will see that both callbacks are triggered.

Upvotes: 6

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