Server/src/main/java/de/towerdefence/server/auth/JWT.java

package de.towerdefence.server.auth;

import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.oauth2.core.oidc.user.OidcUser;
import org.springframework.security.oauth2.server.resource.authentication.JwtAuthenticationConverter;
import org.springframework.security.web.authentication.logout.LogoutHandler;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponentsBuilder;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

@Component
public class JWT implements LogoutHandler {
    private static final String REALM_ACCESS_CLAIM = "realm_access";
    private static final String ROLES_CLAIM = "roles";
    private static final String ROLE_PREFIX = "ROLE_";
    private static final String OIDC_LOGOUT_ROUTE = "/protocol/openid-connect/logout";
    private static final String OIDC_TOKEN_HINT_QUERY_PARAMETER = "id_token_hin";

    @Autowired
    private RestTemplate template;

    @Override
    public void logout(HttpServletRequest request, HttpServletResponse response, Authentication authentication) {
        OidcUser user = (OidcUser) authentication.getPrincipal();
        String endSessionEndpoint = user.getIssuer() + OIDC_LOGOUT_ROUTE;
        UriComponentsBuilder builder = UriComponentsBuilder
                .fromUriString(endSessionEndpoint)
                .queryParam(OIDC_TOKEN_HINT_QUERY_PARAMETER, user.getIdToken().getTokenValue());

        ResponseEntity<String> logoutResponse = template.getForEntity(builder.toUriString(), String.class);
        if (logoutResponse.getStatusCode().is2xxSuccessful()) {
            System.out.println("Logged out successfully");
        } else {
            System.out.println("Failed to logout");
        }
    }

    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)) {
                return grantedAuthorities;
            }

            Object rolesClaim = realmAccess.get(ROLES_CLAIM);
            if (!(rolesClaim instanceof List<?>)) {
                return grantedAuthorities;
            }
            for (Object role : (List<?>) rolesClaim) {
                assert role instanceof String;
                grantedAuthorities.add(new SimpleGrantedAuthority(ROLE_PREFIX + role));
            }

            return grantedAuthorities;
        });
        return jwtAuthenticationConverter;
    }
}