Symfony 2 Form Error Serializer. May be used for AJAX form validation. Allows tree and flat array styles for errors.

FormErrorsSerializer.php

class FormErrorsSerializer {

    public function serializeFormErrors(\Symfony\Component\Form\Form $form, $flat_array = false, $add_form_name = false, $glue_keys = '_')
    {
        $errors = array();
        $errors['global'] = array();
        $errors['fields'] = array();

        foreach ($form->getErrors() as $error) {
            $errors['global'][] = $error->getMessage();
        }

        $errors['fields'] = $this->serialize($form);

        if ($flat_array) {
            $errors['fields'] = $this->arrayFlatten($errors['fields'],
                $glue_keys, (($add_form_name) ? $form->getName() : ''));
        }


        return $errors;
    }

    private function serialize(\Symfony\Component\Form\Form $form)
    {
        $local_errors = array();
        foreach ($form->getIterator() as $key => $child) {

            foreach ($child->getErrors() as $error){
                $local_errors[$key] = $error->getMessage();
            }

            if (count($child->getIterator()) > 0) {
                $local_errors[$key] = $this->serialize($child);
            }
        }

        return $local_errors;
    }

    private function arrayFlatten($array, $separator = "_", $flattened_key = '') {
        $flattenedArray = array();
        foreach ($array as $key => $value) {

            if(is_array($value)) {

                $flattenedArray = array_merge($flattenedArray,
                    $this->arrayFlatten($value, $separator,
                        (strlen($flattened_key) > 0 ? $flattened_key . $separator : "") . $key)
                );

            } else {
                $flattenedArray[(strlen($flattened_key) > 0 ? $flattened_key . $separator : "") . $key] = $value;
            }
        }
        return $flattenedArray;
    }

}

Nice little script, tested on 3.0.2 and works but it through an exception when the submit button came into the foreach so I had to make sure that wasn't serialized.

private function serialize(\Symfony\Component\Form\Form $form)
    {
        $local_errors = array();
        foreach ($form->getIterator() as $key => $child) {

            foreach ($child->getErrors() as $error){
                $local_errors[$key] = $error->getMessage();
            }

            if (count($child->getIterator()) > 0) {
                if (!$child instanceof \Symfony\Component\Form\SubmitButton) {
                    $local_errors[$key] = $this->serialize($child);
                }
            }
        }

        return $local_errors;
    }

Great for simply returning the template error string to the view via AJAX. +1

it does not return dates and choices in radio in the serialized response

Updated version of this to keep all the error properties intact. Added an unserializer to apply the errors back to the form if you intend to store the errors into a database or cache.

https://gist.github.com/linxlad/3ec76c181f717fba532bf43484b7c970