Spring Keycloak: Get User ID

Question

I have developed a Spring Boot Webservice and use Keycloak for Access Management. The website stores some userdata in a database. I try to connect these data with the user logged in.

At the moment I store the username with the data. But I like to store the user id instead the username. How can I do that?

I try to get SecurityContext by this:

@Bean
@Scope(scopeName = WebApplicationContext.SCOPE_REQUEST, proxyMode = ScopedProxyMode.TARGET_CLASS)
public KeycloakSecurityContext getKeycloakSecurityContext() {
    return ((KeycloakPrincipal<KeycloakSecurityContext>) getRequest().getUserPrincipal()).getKeycloakSecurityContext();
}

But I get an error:

There was an unexpected error (type=Internal Server Error, status=500).
Error creating bean with name 'scopedTarget.getKeycloakSecurityContext'
defined in com.SiteApplication: Bean instantiation via factory method
failed; nested exception is
org.springframework.beans.BeanInstantiationException: Failed to
instantiate [org.keycloak.KeycloakSecurityContext]: Factory method
'getKeycloakSecurityContext' threw exception; nested exception is
java.lang.ClassCastException:
org.keycloak.adapters.springsecurity.token.KeycloakAuthenticationToken
cannot be cast to org.keycloak.KeycloakPrincipal

Is this the right way? What is missing?

Thank you!

Answer 1

I found a much simpler solution than the above:

    @GetMapping
    public ResponseEntity getEndpoint(String someParam, HttpServletRequest request) {
        KeycloakAuthenticationToken principal = (KeycloakAuthenticationToken) request.getUserPrincipal();
        String userId = principal.getAccount().getKeycloakSecurityContext().getIdToken().getSubject();

        //....do something

        return new ResponseEntity(HttpStatus.OK);
    }

I think the exception you are getting above is because you are trying to cast getRequest().getUserPrincipal() to KeycloakPrincipal<KeycloakSecurityContext> while it is of type KeycloakAuthenticationToken, so ((KeycloakAuthenticationToken) getRequest().getUserPrincipal()) would work.

Answer 2

I've done something similar in our code.

public class AuthenticationTokenProcessingFilter extends GenericFilterBean {

        @Override
        public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

            if (!(request instanceof HttpServletRequest)) {
                throw new RuntimeException("Expecting a HTTP request");
            }

            RefreshableKeycloakSecurityContext context = (RefreshableKeycloakSecurityContext) request.getAttribute(KeycloakSecurityContext.class.getName());

            if (context == null) {
                handleNoSecurityContext(request, response, chain);
                return;
            }

            AccessToken accessToken = context.getToken();
            Integer userId = Integer.parseInt(accessToken.getOtherClaims().get("user_id").toString());

            chain.doFilter(request, response);
        }

}

Before you can do this you must add the user_id to the access tokens being issued by keycloak. You can do this through a mapper as shown in the screenshot below.

Also, don't forgot to add the processing filter from above to your application lifecycle by adding a @Bean method to your application class.

@Configuration
@EnableAutoConfiguration(exclude = {FallbackWebSecurityAutoConfiguration.class, SpringBootWebSecurityConfiguration.class, DataSourceAutoConfiguration.class})
@ComponentScan
@EnableAsync
public class MyServiceClass {

    public static void main(String[] args) {
        Properties properties = new Properties();
        new SpringApplicationBuilder(MyServiceClass.class)
                .properties(properties)
                .bannerMode(Banner.Mode.OFF)
                .run(args);
    }


    @Bean
    public AuthenticationTokenProcessingFilter authFilter() {
        return new AuthenticationTokenProcessingFilter();
    }

}