logging an encoded (Bcrypt) password Mono<String> with org.slf4j.Logger-CodePudding

I'm trying to figure out how to log a Mono<String> password with slf4j but it would always return a Monotype.

logger.info(login.getPassword() " " userRepository.findPasswordByUsername(login.getUsername()));

and

logger.info(login.getPassword() " " userRepository.findPasswordByUsername(login.getUsername()).toString());

the first 2 logging tries above return the literal password (from the request) and MonoNext

and ofc you cant use .block()

which just throws

"block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-3"

yes i'm aware that i can pass a Subscriber / Consumer for onNext() like:

.subscribe(x -> System.out.println( x.toString()))

to get some output but how would i do that with a logger only, is there even a way ?

login represents a user retrieved from a request. The password is properly stored and encoded (Bycrypt) beforehand ofc (doesn't seem to be the issue). Using spring-boot-starter-webflux, spring-boot-starter-data-r2dbc, spring-boot-starter-security

What am i missing ? Thanks in Advance.

CodePudding user response：

that is correct you should not block in a reactive application, neither should you subscribe in this usercase, as your application is most likely a producer, and the calling client is the consumer that subscribes.

what you are looking for is the doOn operators, that handles side effects. Logging is a side effect, its something you want to do on the side without disturbing the current flow. For instance update something, increment something, or in your case write to a log.

what you want os probably the doOnSuccess operator

example (i have not chacked against a compiler since im on mobile), but something like this.

function Mono<Login> foobar(Login login) {
    return userRepository.findPasswordByUsername(login.getUsername)
                .doOnSuccess(pwd -> {
                    logger.info(login.getPassword()   " "   pwd);
                }).thenReturn(login);
}

CodePudding user response：

Reactive programming requires a different way of thinking about flow of data.

As you mentioned, you should never block as it goes against the principles of reactive programming.

I would start by reading this https://www.baeldung.com/java-string-from-mono for your specific question.