To enable method security, first, annotate the Spring Security configurations class with @EnableReactiveMethodSecurity:

@EnableReactiveMethodSecurity
public class SpringSecurityWebFluxConfig {
    …
}

After that, for any method that you would like to have some security features for, use all of the various security-related annotations discussed in previous chapters:

@GetMapping("/movies")
@PreAuthorize("hasRole('ADMIN')")
public Flux<Movie> getAllMovies() {
  return reactiveMovieRepository.findAll();
}

In the preceding method, we are directing Spring Security that the method execution for getAllMovies() should be allowed if the user is authenticated and has the ADMIN role granted.