Body in serverRequest is null with ServerRequest(Spring Webflux)-CodePudding

I sent the request as below.

curl -d "{""key1"":""value1"", ""key2"":""value2""}" \
-H "Content-Type: application/json" \
-X POST http://localhost:8080/myApi/test

And write route configure as below

RouterFunctions.route()
               .path("/myApi", builder -> builder
                   .POST("/test", handler::test))
               .build();

In handler::test,

public Mono<ServerResponse> test(ServerRequest serverRequest) {
    System.out.println(serverRequest.headers());
    serverRequest.bodyToMono(String.class).subscribe(System.out::println);
    return  ServerResponse.ok().body(Mono.just("ok"), String.class);
}

But result is as below.

[Host:"localhost:8080", User-Agent:"curl/7.77.0", Accept:"*/*", Content-Type:"application/json", content-length:"26"]

I add one line to check body is null, and result is as below.

System.out.println(serverRequest.bodyToMono(String.class).toProcessor().peek());

null

Is there any way to extract body from ServerRequest?

CodePudding user response：

You are not supposed to subscribe explicitly to the publisher in WebFlux. If you run in debug mode and put breakpoint on return statement you would see

Caused by: java.lang.IllegalStateException: Only one connection receive subscriber allowed.

In run-time this error is not visible because subscribe is async and your code exited even before it.

In any case, the correct implementation would look like

public Mono<ServerResponse> test(ServerRequest serverRequest) {
    return serverRequest.bodyToMono(String.class)
            .doOnNext(System.out::println)
            .flatMap(body -> ServerResponse.ok()
                    .body(BodyInserters.fromValue("ok"))
            );
}