Pre-format data before validation

Hello @DavidBinaud I guess you are looking for callbackBeforeUpdate | Grocery CRUD - A PHP CRUD Generator Library and callbackBeforeInsert | Grocery CRUD - A PHP CRUD Generator Library functions. You can now also do the validation there and return a custom message, for example (copied from the documentation):

$crud->callbackBeforeInsert(function ($stateParameters) {
    if ($stateParameters->data['status'] === 'Rejected') {
          $errorMessage = new \GroceryCrud\Core\Error\ErrorMessage();
          return $errorMessage->setMessage("You can't add a Rejected status\n");
    }

    return $stateParameters;
});