[symfony] Handling error

(1) List up errors

if( $form->isValid() ) {
    // ...
} else {
    // get a ConstraintViolationList
    $errors = $this->get('validator')->validate( $user );
    $result = '';

    // iterate on it
    foreach( $errors as $error ) {
        // Do stuff with:
        //   $error->getPropertyPath() : the field that caused the error
        //   $error->getMessage() : the error message
    }
}

(2) Frontend

$.extend({
    ajaxData: function($button, options) {
        var defaultOptions = {
            type: 'POST',            beforeSend: function() {
                $button.prop('disabled', true);            },            complete: function() {
                $button.prop('disabled', false);            },            success: function(data) {
                window.location.reload();            },            error: function(xhr) {
                if (xhr.responseJSON) {
                    for (k in xhr.responseJSON) {
                        msg = xhr.responseJSON[k];                        if(k == '_global') {

                        } else {
                            $('[name="'+k+'"]').after($('<span class="error" />').text(msg));                        }
                    }
                }
            }
        };
        $.ajax($.extend({}, defaultOptions, options));    }
}); 

(3) Backend

private function getFormErrors($form)
{
    $errors = array('_global' => array());    foreach ($form->getErrors() as $e) {
        $errors['_global'][] = $e->getMessage();    }
    foreach ($form as $field) {
        if (!$this->hasError($field)) {
            continue;        }

        $view = $field->createView();
        $fieldErros = $field->getErrors();        foreach ($fieldErros as $e) {
            $errors[$view->vars['full_name']] = $e->getMessage();        }
    }

    return $errors;}

private function hasError($field)
{
    if (count($field->getErrors()) > 0) {
        return true;    }

    foreach ($field as $child) {
        if ($this->hasError($child)) {
            return true;        }
    }

    return false;}