fix(pdfengines): read metadata better webhook error - fixes #1148

pkg/modules/pdfengines/routes.go

@@ -500,6 +500,11 @@ func readMetadataRoute(engine gotenberg.PdfEngine) api.Route {
 
 			err = c.JSON(http.StatusOK, res)
 			if err != nil {
+				if strings.Contains(err.Error(), "request method or response status code does not allow body") {
+					// High probability that the user is using the webhook
+					// feature. It does not make sense for this route.
+					return api.ErrNoOutputFile
+				}
 				return fmt.Errorf("return JSON response: %w", err)
 			}