For the latest stable version, please use Spring Security 6.4.2!

EnableReactiveMethodSecurity

Spring Security supports method security using Reactor’s Context which is setup using ReactiveSecurityContextHolder. For example, this demonstrates how to retrieve the currently logged in user’s message.

For this to work the return type of the method must be a org.reactivestreams.Publisher (i.e. Mono/Flux) or the function must be a Kotlin coroutine function. This is necessary to integrate with Reactor’s Context.

Java
Kotlin

Authentication authentication = new TestingAuthenticationToken("user", "password", "ROLE_USER");

Mono<String> messageByUsername = ReactiveSecurityContextHolder.getContext()
	.map(SecurityContext::getAuthentication)
	.map(Authentication::getName)
	.flatMap(this::findMessageByUsername)
	// In a WebFlux application the `subscriberContext` is automatically setup using `ReactorContextWebFilter`
	.subscriberContext(ReactiveSecurityContextHolder.withAuthentication(authentication));

StepVerifier.create(messageByUsername)
	.expectNext("Hi user")
	.verifyComplete();

val authentication: Authentication = TestingAuthenticationToken("user", "password", "ROLE_USER")

val messageByUsername: Mono<String> = ReactiveSecurityContextHolder.getContext()
	.map(SecurityContext::getAuthentication)
	.map(Authentication::getName)
	.flatMap(this::findMessageByUsername) // In a WebFlux application the `subscriberContext` is automatically setup using `ReactorContextWebFilter`
	.subscriberContext(ReactiveSecurityContextHolder.withAuthentication(authentication))

StepVerifier.create(messageByUsername)
	.expectNext("Hi user")
	.verifyComplete()

with this::findMessageByUsername defined as:

Java
Kotlin

Mono<String> findMessageByUsername(String username) {
	return Mono.just("Hi " + username);
}

fun findMessageByUsername(username: String): Mono<String> {
	return Mono.just("Hi $username")
}

Below is a minimal method security configuration when using method security in reactive applications.

Java
Kotlin

@EnableReactiveMethodSecurity
public class SecurityConfig {
	@Bean
	public MapReactiveUserDetailsService userDetailsService() {
		User.UserBuilder userBuilder = User.withDefaultPasswordEncoder();
		UserDetails rob = userBuilder.username("rob")
			.password("rob")
			.roles("USER")
			.build();
		UserDetails admin = userBuilder.username("admin")
			.password("admin")
			.roles("USER","ADMIN")
			.build();
		return new MapReactiveUserDetailsService(rob, admin);
	}
}

@EnableReactiveMethodSecurity
class SecurityConfig {
	@Bean
	fun userDetailsService(): MapReactiveUserDetailsService {
		val userBuilder: User.UserBuilder = User.withDefaultPasswordEncoder()
		val rob = userBuilder.username("rob")
			.password("rob")
			.roles("USER")
			.build()
		val admin = userBuilder.username("admin")
			.password("admin")
			.roles("USER", "ADMIN")
			.build()
		return MapReactiveUserDetailsService(rob, admin)
	}
}

Consider the following class:

Java
Kotlin

@Component
public class HelloWorldMessageService {
	@PreAuthorize("hasRole('ADMIN')")
	public Mono<String> findMessage() {
		return Mono.just("Hello World!");
	}
}

@Component
class HelloWorldMessageService {
	@PreAuthorize("hasRole('ADMIN')")
	fun findMessage(): Mono<String> {
		return Mono.just("Hello World!")
	}
}

Or, the following class using Kotlin coroutines:

Kotlin

@Component
class HelloWorldMessageService {
    @PreAuthorize("hasRole('ADMIN')")
    suspend fun findMessage(): String {
        delay(10)
        return "Hello World!"
    }
}

Combined with our configuration above, @PreAuthorize("hasRole('ADMIN')") will ensure that findByMessage is only invoked by a user with the role ADMIN. It is important to note that any of the expressions in standard method security work for @EnableReactiveMethodSecurity. However, at this time we only support return type of Boolean or boolean of the expression. This means that the expression must not block.

When integrating with WebFlux Security, the Reactor Context is automatically established by Spring Security according to the authenticated user.

Java
Kotlin

@EnableWebFluxSecurity
@EnableReactiveMethodSecurity
public class SecurityConfig {

	@Bean
	SecurityWebFilterChain springWebFilterChain(ServerHttpSecurity http) throws Exception {
		return http
			// Demonstrate that method security works
			// Best practice to use both for defense in depth
			.authorizeExchange(exchanges -> exchanges
				.anyExchange().permitAll()
			)
			.httpBasic(withDefaults())
			.build();
	}

	@Bean
	MapReactiveUserDetailsService userDetailsService() {
		User.UserBuilder userBuilder = User.withDefaultPasswordEncoder();
		UserDetails rob = userBuilder.username("rob")
			.password("rob")
			.roles("USER")
			.build();
		UserDetails admin = userBuilder.username("admin")
			.password("admin")
			.roles("USER","ADMIN")
			.build();
		return new MapReactiveUserDetailsService(rob, admin);
	}
}

@EnableWebFluxSecurity
@EnableReactiveMethodSecurity
class SecurityConfig {
	@Bean
	open fun springWebFilterChain(http: ServerHttpSecurity): SecurityWebFilterChain {
		return http {
			authorizeExchange {
				authorize(anyExchange, permitAll)
			}
			httpBasic { }
		}
	}

	@Bean
	fun userDetailsService(): MapReactiveUserDetailsService {
		val userBuilder: User.UserBuilder = User.withDefaultPasswordEncoder()
		val rob = userBuilder.username("rob")
			.password("rob")
			.roles("USER")
			.build()
		val admin = userBuilder.username("admin")
			.password("admin")
			.roles("USER", "ADMIN")
			.build()
		return MapReactiveUserDetailsService(rob, admin)
	}
}

You can find a complete sample in hellowebflux-method