Spring: How to make a filter throw a custom exception?

Question

I created a filter which authenticate each request header for JWT token:

public class JWTAuthenticationFilter extends GenericFilterBean {

    private UserDetailsService customUserDetailsService;
    private static Logger logger = LoggerFactory.getLogger(JWTAuthenticationFilter.class);
    private final static UrlPathHelper urlPathHelper = new UrlPathHelper();

    public JWTAuthenticationFilter(UserDetailsService customUserDetailsService) {
        this.customUserDetailsService = customUserDetailsService;
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
        Authentication authentication = AuthenticationService.getAuthentication((HttpServletRequest) request, customUserDetailsService);
        SecurityContextHolder.getContext().setAuthentication(authentication);
        if (authentication == null) {
            logger.debug("failed authentication while attempting to access " + urlPathHelper.getPathWithinApplication((HttpServletRequest) request));
        }
        filterChain.doFilter(request, response);
    }

}

I want to throw a custom exception, and that exception returns a response:

@ResponseStatus(value=HttpStatus.SOMECODE, reason="There was an issue with the provided authentacion information")  // 409
public class CustomAuthenticationException extends RuntimeException {

    private static final long serialVersionUID = 6699623945573914987L;

}

How should I do this ? What is the best design to catch such exception thrown by filters ? Is there any kind of exception handling mechanism provided by the Spring security that I can use and catch everythin in one point ? Is there any other way to throw custom exceptions in a filter ?

Note: there is another question here which its accepted answer doesn't answer my question. I want to return a response before getting to any controller.

Error cases I want to handle: 1. Client sends an empty value for the Authorization header. 2. Client sends a malformed token

In both cases I get a response with 500 HTTP status code. I want to get 4XX code back.

Answer 1

Take a look at @ControllerAdvice

Here's an example from my project.

@ControllerAdvice
@RestController
public class GlobalExceptionHandler {

    private final Logger log = Logger.getLogger(this.getClass().getSimpleName());

    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ExceptionHandler(value = RuntimeException.class)
    public Response handleBaseException(RuntimeException e) {
        log.error("Error", e);
        Error error = new Error(HttpStatus.BAD_REQUEST.value(), HttpStatus.BAD_REQUEST.name());
        return Response.status(HttpStatus.BAD_REQUEST.value()).error(error, null).build();
    }

    @ResponseStatus(HttpStatus.NOT_FOUND)
    @ExceptionHandler(value = NoHandlerFoundException.class)
    public Response handleNoHandlerFoundException(Exception e) {
        log.error("Error", e);
        Error error = new Error(HttpStatus.NOT_FOUND.value(), HttpStatus.NOT_FOUND.name());
        return Response.status(HttpStatus.NOT_FOUND.value()).error(error, null).build();
    }

    @ExceptionHandler(value = AuthenticationCredentialsNotFoundException.class)
    public Response handleException(AuthenticationCredentialsNotFoundException e) {     
        log.error("Error", e);
        Error error = new Error(ErrorCodes.INVALID_CREDENTIALS_CODE, ErrorCodes.INVALID_CREDENTIALS_MSG);
        return Response.status(ErrorCodes.INVALID_CREDENTIALS_CODE).error(error, null).build();
    }

    @ResponseStatus(HttpStatus.UNAUTHORIZED)
    @ExceptionHandler(value = UnauthorisedException.class)
    public Response handleNotAuthorizedExceptionException(UnauthorisedException e) {        
//      log.error("Error", e);
        return Response.unauthorized().build();
    }

    @ExceptionHandler(value = Exception.class)
    public String handleException(Exception e) {
        log.error("Error", e);
        return e.getClass().getName() + " 14" + e.getMessage();
    }


}

Edit

I believe you can response.sendError inside do Filter method.

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
    Authentication authentication = AuthenticationService.getAuthentication((HttpServletRequest) request, customUserDetailsService);
    SecurityContextHolder.getContext().setAuthentication(authentication);
    if (authentication == null) {
        logger.debug("failed authentication while attempting to access " + urlPathHelper.getPathWithinApplication((HttpServletRequest) request));
        response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Invalid authentication.");
        setUnauthorizedResponse(response);
        return;
    }
    filterChain.doFilter(request, response);
}

public void setUnauthorizedResponse(HttpServletResponse response) {
    response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
    response.setContentType("application/json");
    Response unAuthorizedResponse = Response.unauthorized().build();
    try {
        PrintWriter out = response.getWriter();
        out.println(unAuthorizedResponse.toJsonString());
    } catch (IOException e) {
        log.error("Error", e);
    }
}