[FIXED] HttpServletResponse didnt return proper message

Issue

public class ApiKeyFilter implements Filter {
    private final Logger log = LoggerFactory.getLogger(ApiKeyFilter.class);
    private final ApiKeyRepository apiKeyRepository;
    private final SecurityModule securityModule;
    private final JsonUtils jsonUtils;

    @Autowired
    public ApiKeyFilter(ApiKeyRepository apiKeyRepository, SecurityModule securityModule, JsonUtils jsonUtils) {
        this.apiKeyRepository = apiKeyRepository;
        this.securityModule = securityModule;
        this.jsonUtils = jsonUtils;
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        //Convert request to httpRequest
        RequestWrapper requestWrapper = new RequestWrapper((HttpServletRequest) servletRequest);
        HttpServletResponse httpServletResponse = (HttpServletResponse)servletResponse;

        String xApiKey = requestWrapper.getHeader("x-api-key");
        String sortBodySign = requestWrapper.getHeader("sort-body-sign");

//BLABLABLA Logic

       
             //Compare with client's API key
            if (!apiKeyObject.getSignature().equalsIgnoreCase(Hex.toHexString(messageDigest))) {
                log.error("Invalid signature, expected: {}, received: {}", Hex.toHexString(messageDigest), apiKeyObject.getSignature());
                httpServletResponse.sendError(HttpServletResponse.SC_PRECONDITION_FAILED,
                        StatusCode.getStatusMessage(StatusCode.VERIFY_SIGNATURE_FAIL));
                return;
            }
         } catch (RuntimeException ex){
             log.error("Exception happened: {}", ex.getMessage());
             httpServletResponse.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Internal Server Error");
             return;
         }
    filterChain.doFilter(requestWrapper, servletResponse);

    }

I am new to spring boot httpServletResponse. May i know why my sendError function didnt return the error message as i write. This is the response message :

{"timestamp":"2021-09-10T09:00:54.146+00:00","status":412,"error":"Precondition Failed"}

I wish to return the message into the response as well.

example :

{"timestamp":"2021-09-11T02:17:06.948+00:00","status":602,"error":"Http Status 602","message":"Invalid Authorization Signature"}

Solution

In your ApiKeyFilter you should only throw a custom runtime exception (InvalidAuthorizationSignatureException) instead.

public class InvalidAuthorizationSignatureException extends RuntimeException {
    public InvalidAuthorizationSignatureException(String errorMessage, Throwable err) {
        super(errorMessage, err);
    }
}

Then you need an ExceptionHandler for this exception that would set the HTTP status and message.

@ControllerAdvice
public class CustomRestExceptionHandler extends ResponseEntityExceptionHandler {

    @ExceptionHandler({ InvalidAuthorizationSignatureException.class })
    public ResponseEntity<Object> handleInvalidAuthorizationSignature(InvalidAuthorizationSignatureException ex, WebRequest request) {
        ApiError apiError = new ApiError(HttpStatus.SC_PRECONDITION_FAILED, StatusCode.getStatusMessage(StatusCode.VERIFY_SIGNATURE_FAIL), errors);
        return new ResponseEntity<Object>(apiError, new HttpHeaders(), apiError.getStatus());
    }
}

For more details check https://www.baeldung.com/global-error-handler-in-a-spring-rest-api.

Answered By - João Dias