LF8/src/main/java/de/szut/lf8_starter/security/KeycloakSecurityConfig.java

package de.szut.lf8_starter.security;

import java.util.*;
import java.util.stream.Collectors;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Profile;
import org.springframework.http.HttpMethod;
import org.springframework.security.config.Customizer;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.authority.mapping.GrantedAuthoritiesMapper;
import org.springframework.security.core.session.SessionRegistry;
import org.springframework.security.core.session.SessionRegistryImpl;
import org.springframework.security.oauth2.core.oidc.user.OidcUserAuthority;
import org.springframework.security.oauth2.core.user.OAuth2UserAuthority;
import org.springframework.security.oauth2.server.resource.authentication.JwtAuthenticationConverter;
import org.springframework.security.oauth2.server.resource.authentication.JwtGrantedAuthoritiesConverter;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.security.web.authentication.session.RegisterSessionAuthenticationStrategy;
import org.springframework.security.web.authentication.session.SessionAuthenticationStrategy;
import org.springframework.security.web.session.HttpSessionEventPublisher;
import org.springframework.security.web.util.matcher.AntPathRequestMatcher;

@Configuration
@EnableWebSecurity
class KeycloakSecurityConfig {

    private static final String GROUPS = "groups";
    private static final String REALM_ACCESS_CLAIM = "realm_access";
    private static final String ROLES_CLAIM = "roles";

    private final KeycloakLogoutHandler keycloakLogoutHandler;

    KeycloakSecurityConfig(KeycloakLogoutHandler keycloakLogoutHandler) {
        this.keycloakLogoutHandler = keycloakLogoutHandler;
    }

    @Bean
    public SessionRegistry sessionRegistry() {
        return new SessionRegistryImpl();
    }

    @Bean
    protected SessionAuthenticationStrategy sessionAuthenticationStrategy() {
        return new RegisterSessionAuthenticationStrategy(sessionRegistry());
    }

    @Bean
    public HttpSessionEventPublisher httpSessionEventPublisher() {
        return new HttpSessionEventPublisher();
    }


    @Bean
    public SecurityFilterChain resourceServerFilterChain(HttpSecurity http) throws Exception {

        http.authorizeHttpRequests(auth -> auth
                .requestMatchers(new AntPathRequestMatcher("/welcome"))
                .permitAll()
                .requestMatchers(
                        new AntPathRequestMatcher("/swagger"),
                        new AntPathRequestMatcher("/swagger-ui/**"),
                        new AntPathRequestMatcher("/v3/api-docs/**"))
                .permitAll()
                .requestMatchers(new AntPathRequestMatcher("/hello/**"))
                .hasRole("user")
                .requestMatchers(new AntPathRequestMatcher("/roles"))
                .authenticated()
                .requestMatchers(new AntPathRequestMatcher("/"))
                .permitAll()
                .anyRequest()
                .authenticated()).oauth2ResourceServer(spec -> spec.jwt(Customizer.withDefaults()));
        return http.build();
    }

    @Bean
    public JwtAuthenticationConverter jwtAuthenticationConverter() {
        JwtAuthenticationConverter jwtAuthenticationConverter = new JwtAuthenticationConverter();
        jwtAuthenticationConverter.setJwtGrantedAuthoritiesConverter(jwt -> {
            List<GrantedAuthority> grantedAuthorities = new ArrayList<>();

            Map<String, Object> realmAccess = jwt.getClaim(REALM_ACCESS_CLAIM);
            if (realmAccess != null && realmAccess.containsKey(ROLES_CLAIM)) {
                List<String> roles = (List<String>) realmAccess.get(ROLES_CLAIM);
                for (String role : roles) {
                    grantedAuthorities.add(new SimpleGrantedAuthority("ROLE_" + role));
                }
            }

            return grantedAuthorities;
        });
        return jwtAuthenticationConverter;
    }
}