java - Catching exception thrown in AuthenticationProvider

Question

I am implementing custom 'AuthenticationProvider'. If not authenticated I am throwing exception inside 'authenticate' function as shown below.

public class DelegatingLdapAuthenticationProvider implements AuthenticationProvider {

    private ActiveDirectoryLdapAuthenticationProvider primaryProvider;
    private List<ActiveDirectoryLdapAuthenticationProvider> secondaryProviders = new ArrayList<>();

    public DelegatingLdapAuthenticationProvider() {

    }

    @Override
    public Authentication authenticate(Authentication authentication) throws AuthenticationException {
        Authentication result = null;
        AuthenticationException exception = null;
        try {
            result = primaryProvider.authenticate(authentication);
        } catch (AuthenticationException e) {
            exception = e;
            for (ActiveDirectoryLdapAuthenticationProvider secondaryProvider : secondaryProviders) {
                try {
                    result = secondaryProvider.authenticate(authentication);
                    if (result.isAuthenticated()) {
                            break;
                    }
                } catch (AuthenticationException e1) {
                            exception = e;
                }
            }
        }
        if (result == null || !result.isAuthenticated()) {
            throw exception;
    }

    return result;
}

I have global exception handler as shown below.

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler({NoPermissionException.class})
    @ResponseBody
    @ResponseStatus(value = HttpStatus.FORBIDDEN)
    public Map<String, String> noPermission(NoPermissionException e) {
        return createErrorResponse(e, "Don't have permissions");
    }

    @ExceptionHandler({Exception.class})
    @ResponseBody
    @ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR)
    public Map<String, String> exceptionInProcessing(Exception e) {
        return createErrorResponse(e, "Unable to process. Unknown error occurred: " + e.getMessage());
    }

    private Map<String, String> createErrorResponse(Exception e, String errorMessage) {
        Map<String, String> errorResponse = new HashMap<>();
        errorResponse.put("message", errorMessage);
        errorResponse.put("reason", e.toString());
        return errorResponse;
    }
}

When exception is thrown inside the 'authenticate' function, global exception handler is not being called. For all the other exceptions it is being called. I want to catch the exception inside global exception handler and return custom error message. How can I do that? Any help appreciated. Thanks in advance.

Answer 1

The GlobalExceptionHandler is for controller exception handler, but the AuthenticationProvider is still in filter, if you want to handler the AuthenticationException, you need to handle it to implement AuthenticationEntryPoint and override the commence method.

public void commence(HttpServletRequest request, HttpServletResponse response,
        AuthenticationException authException) throws IOException, ServletException

AuthenticationException and AccessDeniedException have already been handled by ExceptionTranslationFilter. You just need to inject AuthenticationEntryPoint and AccessDeniedHandler(which handle AccessDeniedException)

Or you can catch these exception in filter and then handle it in filer, like AuthenticationFailureHandler in AbstractAuthenticationProcessingFilter