Handle NoResourceFoundException in error controller

Added handling for NoResourceFoundException to return a 404 status.

Author: filipesantana18

oidc/src/main/java/oidc/web/CustomErrorController.java

@@ -41,6 +41,7 @@
 
 import static oidc.saml.AuthnRequestContextConsumer.REDIRECT_URI_VALID;
 import static org.springframework.http.HttpStatus.BAD_REQUEST;
+import static org.springframework.http.HttpStatus.NOT_FOUND;
 
 @RestController
 public class CustomErrorController implements org.springframework.boot.web.servlet.error.ErrorController {
@@ -77,6 +78,13 @@ public Object error(HttpServletRequest request) {
         if (error != null && error.getCause() != null) {
             error = error.getCause();
         }
+        // Short-circuit for non-existent resource requests (e.g. security scans)
+        if (error instanceof NoResourceFoundException) {
+            LOG.debug("No resource found: " + error.getMessage());
+            boolean hasStatus = result.containsKey("status") && !result.get("status").equals(999);
+            HttpStatus code = hasStatus ? HttpStatus.resolve((Integer) result.get("status")) : NOT_FOUND;
+            return ResponseEntity.status(code != null ? code : NOT_FOUND).build();
+        }
         boolean status = result.containsKey("status") && !result.get("status").equals(999) && !result.get("status").equals(500);
         HttpStatus statusCode = status ? HttpStatus.resolve((Integer) result.get("status")) : BAD_REQUEST;
         if (error != null) {