This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Security 6.4.1!spring-doc.cn

Kotlin Configuration

Spring Security Kotlin configuration has been available since Spring Security 5.3. It lets users configure Spring Security by using a native Kotlin DSL.spring-doc.cn

Spring Security provides a sample application to demonstrate the use of Spring Security Kotlin Configuration.spring-doc.cn

HttpSecurity

How does Spring Security know that we want to require all users to be authenticated? How does Spring Security know we want to support form-based authentication? There is a configuration class (called SecurityFilterChain) that is being invoked behind the scenes. It is configured with the following default implementation:spring-doc.cn

import org.springframework.security.config.annotation.web.invoke

@Bean
open fun filterChain(http: HttpSecurity): SecurityFilterChain {
    http {
        authorizeHttpRequests {
            authorize(anyRequest, authenticated)
        }
        formLogin { }
        httpBasic { }
    }
    return http.build()
}

Make sure to import the invoke function in your class, as the IDE will not always auto-import the method, causing compilation issues.

The default configuration (shown in the preceding listing):spring-doc.cn

Ensures that any request to our application requires the user to be authenticatedspring-doc.cn
Lets users authenticate with form-based loginspring-doc.cn
Lets users authenticate with HTTP Basic authenticationspring-doc.cn

Note that this configuration parallels the XML namespace configuration:spring-doc.cn

<http>
	<intercept-url pattern="/**" access="authenticated"/>
	<form-login />
	<http-basic />
</http>

Multiple HttpSecurity Instances

We can configure multiple HttpSecurity instances, just as we can have multiple <http> blocks. The key is to register multiple SecurityFilterChain @Beans. The following example has a different configuration for URLs that start with /api/:spring-doc.cn

import org.springframework.security.config.annotation.web.invoke

@Configuration
@EnableWebSecurity
class MultiHttpSecurityConfig {
    @Bean                                                            (1)
    public fun userDetailsService(): UserDetailsService {
        val users: User.UserBuilder = User.withDefaultPasswordEncoder()
        val manager = InMemoryUserDetailsManager()
        manager.createUser(users.username("user").password("password").roles("USER").build())
        manager.createUser(users.username("admin").password("password").roles("USER","ADMIN").build())
        return manager
    }

    @Order(1)                                                        (2)
    @Bean
    open fun apiFilterChain(http: HttpSecurity): SecurityFilterChain {
        http {
            securityMatcher("/api/**")                               (3)
            authorizeHttpRequests {
                authorize(anyRequest, hasRole("ADMIN"))
            }
            httpBasic { }
        }
        return http.build()
    }

    @Bean                                                            (4)
    open fun formLoginFilterChain(http: HttpSecurity): SecurityFilterChain {
        http {
            authorizeHttpRequests {
                authorize(anyRequest, authenticated)
            }
            formLogin { }
        }
        return http.build()
    }
}

1	Configure Authentication as usual.
2	Create an instance of `SecurityFilterChain` that contains `@Order` to specify which `SecurityFilterChain` should be considered first.
3	The `http.securityMatcher` states that this `HttpSecurity` is applicable only to URLs that start with `/api/`
4	Create another instance of `SecurityFilterChain`. If the URL does not start with `/api/`, this configuration is used. This configuration is considered after `apiFilterChain`, since it has an `@Order` value after `1` (no `@Order` defaults to last).