gistfile1.php

<?php

namespace ME\MainPageBundle\Response;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\Form\Form;

class FormErrorResponse extends JsonResponse {

    public function __construct(Form $form, $status = 400, $headers = array()) {
        $errors = $this->getFormErrors($form);
        parent::__construct(array('errors' => $errors), $status, $headers);
    }

    protected function getFormErrors(Form $form) {
        $errors = array();

        if ($form->hasChildren()) {
            foreach ($form->getChildren() as $child) {
                if (!$child->isValid()) {
                    $errors[$child->getName()] = $this->getFormErrors($child);
                }
            }
        } else {
            foreach ($form->getErrors() as $key => $error) {
                $errors[] = $error->getMessage();
            }
        }

        return $errors;
    }

}