How can I get my custom ResponseEntityExceptionHandler or OAuth2ExceptionRenderer to handle Exceptions raised by Spring security on a pure resource server?
We implemented a
@ControllerAdvice
@RestController
public class GlobalExceptionHandler extends ResponseEntityExceptionHandler {
so whenever there is an error on the resource server we want it to answer with
{
  "message": "...",
  "type": "...",
  "status": 400
}
The resource server uses the application.properties setting:
security.oauth2.resource.userInfoUri: http://localhost:9999/auth/user
to authenticate and authorize a request against our auth server.
However any spring security error will always bypass our exception handler at
    @ExceptionHandler(InvalidTokenException.class)
    public ResponseEntity<Map<String, Object>> handleInvalidTokenException(InvalidTokenException e) {
        return createErrorResponseAndLog(e, 401);
    }
and produce either
{
  "timestamp": "2016-12-14T10:40:34.122Z",
  "status": 403,
  "error": "Forbidden",
  "message": "Access Denied",
  "path": "/api/templates/585004226f793042a094d3a9/schema"
}
or
{
  "error": "invalid_token",
  "error_description": "5d7e4ab5-4a88-4571-b4a4-042bce0a076b"
}
So how do I configure the security exception handling for a resource server? All I ever find are examples on how to customize the Auth Server by implementing a custom OAuth2ExceptionRenderer. But I can't find where to wire this to the resource server's security chain.
Our only configuration/setup is this:
@SpringBootApplication
@Configuration
@ComponentScan(basePackages = {"our.packages"})
@EnableAutoConfiguration
@EnableResourceServer
                Spring security exceptions can be directly handled by adding custom filters and constructing the response body. To handle these exceptions at a global level via @ExceptionHandler and @ControllerAdvice, we need a custom implementation of AuthenticationEntryPoint.
Exception Handling in Spring Boot helps to deal with errors and exceptions present in APIs so as to deliver a robust enterprise application. This article covers various ways in which exceptions can be handled in a Spring Boot Project.
As noted in previous comments the request is rejected by the security framework before it reaches the MVC layer so @ControllerAdvice is not an option here.
There are 3 interfaces in the Spring Security framework that may be of interest here:
You can create implementations of each of these Interfaces in order to customize the response sent for various events: successful login, failed login, attempt to access protected resource with insufficient permissions.
The following would return a JSON response on unsuccessful login attempt:
@Component
public class RestAuthenticationFailureHandler implements AuthenticationFailureHandler
{
  @Override
  public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response,
      AuthenticationException ex) throws IOException, ServletException
  {
    response.setStatus(HttpStatus.FORBIDDEN.value());
    
    Map<String, Object> data = new HashMap<>();
    data.put("timestamp", new Date());
    data.put("status",HttpStatus.FORBIDDEN.value());
    data.put("message", "Access Denied");
    data.put("path", request.getRequestURL().toString());
    
    OutputStream out = response.getOutputStream();
    com.fasterxml.jackson.databind.ObjectMapper mapper = new ObjectMapper();
    mapper.writeValue(out, data);
    out.flush();
  }
}
You also need to register your implementation(s) with the Security framework. In Java config this looks like the below:
@Configuration
@EnableWebSecurity
@ComponentScan("...")
public class SecurityConfiguration extends WebSecurityConfigurerAdapter
{
  @Override
  public void configure(HttpSecurity http) throws Exception
  {
    http
       .addFilterBefore(corsFilter(), ChannelProcessingFilter.class)
       .logout()
       .deleteCookies("JESSIONID")
       .logoutUrl("/api/logout")
       .logoutSuccessHandler(logoutSuccessHandler())
       .and()
       .formLogin()
       .loginPage("/login")
       .loginProcessingUrl("/api/login")
       .failureHandler(authenticationFailureHandler())
       .successHandler(authenticationSuccessHandler())
       .and()
       .csrf()
       .disable()
       .exceptionHandling()
       .authenticationEntryPoint(authenticationEntryPoint())
       .accessDeniedHandler(accessDeniedHandler());
  }
  /**
   * @return Custom {@link AuthenticationFailureHandler} to send suitable response to REST clients in the event of a
   *         failed authentication attempt.
   */
  @Bean
  public AuthenticationFailureHandler authenticationFailureHandler()
  {
    return new RestAuthenticationFailureHandler();
  }
  /**
   * @return Custom {@link AuthenticationSuccessHandler} to send suitable response to REST clients in the event of a
   *         successful authentication attempt.
   */
  @Bean
  public AuthenticationSuccessHandler authenticationSuccessHandler()
  {
    return new RestAuthenticationSuccessHandler();
  }
  /**
   * @return Custom {@link AccessDeniedHandler} to send suitable response to REST clients in the event of an attempt to
   *         access resources to which the user has insufficient privileges.
   */
  @Bean
  public AccessDeniedHandler accessDeniedHandler()
  {
    return new RestAccessDeniedHandler();
  }
}
                        In case if you're using @EnableResourceServer, you may also find convenient to extend ResourceServerConfigurerAdapter instead of WebSecurityConfigurerAdapter in your @Configuration class. By doing this, you may simply register a custom AuthenticationEntryPoint by overriding configure(ResourceServerSecurityConfigurer resources) and using resources.authenticationEntryPoint(customAuthEntryPoint()) inside the method. 
Something like this:
@Configuration
@EnableResourceServer
public class CommonSecurityConfig extends ResourceServerConfigurerAdapter {
    @Override
    public void configure(ResourceServerSecurityConfigurer resources) throws Exception {
        resources.authenticationEntryPoint(customAuthEntryPoint());
    }
    @Bean
    public AuthenticationEntryPoint customAuthEntryPoint(){
        return new AuthFailureHandler();
    }
}
There's also a nice OAuth2AuthenticationEntryPoint that can be extended (since it's not final) and partially re-used while implementing a custom AuthenticationEntryPoint. In particular, it adds "WWW-Authenticate" headers with error-related details.
You are not able to make use of Spring MVC Exception handler annotations such as @ControllerAdvice because spring security filters kicks in much before Spring MVC.
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