Enhance global exception handling by implementing ProblemDetail

src/main/java/org/example/projectbifrost/exception/GlobalExceptionHandler.java

@@ -2,80 +2,86 @@
 
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.ProblemDetail;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.ErrorResponse;
 import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.client.ResourceAccessException;
-import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
 
-import java.time.LocalDateTime;
+import java.time.Instant;
 
 @ControllerAdvice
 @Slf4j //Structured logging
 public class GlobalExceptionHandler {
+    private static final String TIMESTAMP_PROPERTY = "timestamp";
 
     @ExceptionHandler(LLMException.class)
-    public ResponseEntity<ApiErrorResponse> handleLLMException(LLMException ex) {
+    public ResponseEntity<ProblemDetail> handleLLMException(LLMException ex) {
         HttpStatus status;
         try {
             status = HttpStatus.valueOf(ex.getStatusCode()); //Get the error from OpenRouter
-        } catch (IllegalArgumentException e) {
+        } catch (IllegalArgumentException _) {
             status = HttpStatus.INTERNAL_SERVER_ERROR;
         }
 
         log.warn("LLM Error [{}]: {}", status.value(), ex.getMessage());
 
-        return new ResponseEntity<>(
-                new ApiErrorResponse(LocalDateTime.now(), status.value(), ex.getMessage()),
-                status
-        );
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(status, ex.getMessage());
+        problem.setProperty(TIMESTAMP_PROPERTY, Instant.now().toString());
+        problem.setTitle("LLM Error");
+        return ResponseEntity.status(status).body(problem);
     }
 
     @ExceptionHandler(ResourceAccessException.class)
-    public ResponseEntity<ApiErrorResponse> handleTimeoutException(ResourceAccessException ex) {
+    public ResponseEntity<ProblemDetail> handleTimeoutException(ResourceAccessException ex) {
         log.warn("Timeout connecting to LLM: {}", ex.getMessage());
-        return new ResponseEntity<>(
-                new ApiErrorResponse(LocalDateTime.now(), 504, "Connection timeout. The Gods are taking too long to respond."),
-                HttpStatus.GATEWAY_TIMEOUT
-        );
+
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(HttpStatus.GATEWAY_TIMEOUT, "Connection timeout. The Gods are taking too long to respond.");
+        problem.setProperty(TIMESTAMP_PROPERTY, Instant.now().toString());
+        problem.setTitle("Connection Timeout");
+        return ResponseEntity.status(HttpStatus.GATEWAY_TIMEOUT).body(problem);
     }
 
 
     @ExceptionHandler(MethodArgumentNotValidException.class)
-    public ResponseEntity<ApiErrorResponse> handleValidationException(MethodArgumentNotValidException ex) {
+    public ResponseEntity<ProblemDetail> handleValidationException(MethodArgumentNotValidException ex) {
         log.warn("Validation error - {} field(s) invalid", ex.getBindingResult().getErrorCount());
-        return new ResponseEntity<>(
-                new ApiErrorResponse(LocalDateTime.now(), 400, "Invalid request - check your input"),
-                HttpStatus.BAD_REQUEST
-        );
+
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(HttpStatus.BAD_REQUEST, "Invalid request - check your input");
+        problem.setProperty(TIMESTAMP_PROPERTY, Instant.now().toString());
+        problem.setTitle("Validation Error");
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(problem);
     }
 
     @ExceptionHandler(org.springframework.http.converter.HttpMessageNotReadableException.class)
-    public ResponseEntity<ApiErrorResponse> handleUnreadableMessage(org.springframework.http.converter.HttpMessageNotReadableException ex) {
+    public ResponseEntity<ProblemDetail> handleUnreadableMessage(org.springframework.http.converter.HttpMessageNotReadableException ex) {
         log.warn("Malformed request body: {}", ex.getMostSpecificCause().getMessage());
-        return new ResponseEntity<>(
-                new ApiErrorResponse(LocalDateTime.now(), HttpStatus.BAD_REQUEST.value(), "Malformed request body"),
-                HttpStatus.BAD_REQUEST
-        );
+
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(HttpStatus.BAD_REQUEST, "Malformed request body");
+        problem.setProperty(TIMESTAMP_PROPERTY, Instant.now().toString());
+        problem.setTitle("Malformed Request");
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(problem);
     }
 
 
     @ExceptionHandler(Exception.class)
-    public ResponseEntity<ApiErrorResponse> handleGeneralException(Exception ex) {
+    public ResponseEntity<ProblemDetail> handleGeneralException(Exception ex) {
         //If Spring has something to say about an error(e.g 404), use it!
         if (ex instanceof ErrorResponse er) {
             var status = er.getStatusCode();
             String message = ex.getMessage() != null ? ex.getMessage() : "Request failed";
-            return ResponseEntity.status(status).body(
-                    new ApiErrorResponse(LocalDateTime.now(), status.value(), message)
-            );
+            ProblemDetail problem = ProblemDetail.forStatusAndDetail(status, message);
+            problem.setProperty(TIMESTAMP_PROPERTY, Instant.now().toString());
+            problem.setTitle("Request Error");
+            return ResponseEntity.status(status).body(problem);
         }
         log.error("Unexpected error: ", ex);
-        return new ResponseEntity<>(
-                new ApiErrorResponse(LocalDateTime.now(), 500, "An unexpected error occurred"),
-                HttpStatus.INTERNAL_SERVER_ERROR
-        );
+
+        ProblemDetail problem = ProblemDetail.forStatusAndDetail(HttpStatus.INTERNAL_SERVER_ERROR, "An unexpected error occurred");
+        problem.setProperty(TIMESTAMP_PROPERTY, Instant.now().toString());
+        problem.setTitle("Internal Server Error");
+        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(problem);
     }
 }

src/main/resources/application.properties

@@ -1,3 +1,4 @@
 spring.application.name=ProjectBifrost
+spring.mvc.problemdetails.enabled=true
 openrouter.api.key=${OPENROUTER_API_KEY}
 openrouter.model=poolside/laguna-xs.2:free