Added Validation to API requests.

- Added Symfony Validation Lib.
- Updated API DTOs to include validation constraints.

src/EventSubscriber/ApiExceptionSubscriber.php

@@ -10,6 +10,7 @@ use Symfony\Component\HttpKernel\Event\ExceptionEvent;
 use Symfony\Component\HttpKernel\KernelEvents;
 use Symfony\Component\HttpFoundation\JsonResponse;
 use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
+use Symfony\Component\Validator\Exception\ValidationFailedException;
 
 class ApiExceptionSubscriber implements EventSubscriberInterface
 {
@@ -34,7 +35,25 @@ class ApiExceptionSubscriber implements EventSubscriberInterface
              * low-level exception, which should *not* be exposed
              */
             if ($e instanceof HttpExceptionInterface) {
-                $apiErrorMsg->setExtraData('detail', $e->getMessage());
+                //Check if it's a Validation error.
+                // When using MapRequestPayload() ValidationErrors throw HttpExceptions.
+                $prev = $e->getPrevious();
+                if ($prev instanceof ValidationFailedException) {
+                    //Get validation error details.
+                    $errorList = [];
+                    $violationList = $prev->getViolations();
+                    foreach ($violationList as $violation) {
+                        $errorList[] = [
+                            'field' => $violation->getPropertyPath(),
+                            'message' => $violation->getMessage(),
+                        ];
+                    }
+                    $apiErrorMsg->setExtraData('detail', "Validation Error. See errorList for details");
+                    $apiErrorMsg->setExtraData('errorList', $errorList);
+                } else {
+                    //Get exception error message.
+                    $apiErrorMsg->setExtraData('detail', $e->getMessage());
+                }
             }
         }