Symfony 3 PHP 7 Serialize all form errors before storing to cache and retrieve them again.

PrepareFormErrorsForCache.php

<?php

namespace OpenObjects\Bundle\CoreBundle\Util;

use Symfony\Component\Form\Form;
use Symfony\Component\Form\FormError;
use Symfony\Component\Serializer\Encoder\JsonEncoder;
use Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer;
use Symfony\Component\Serializer\Serializer;
use Symfony\Component\Validator\ConstraintViolation;

/**
 * The FormUtil class is responsible for preparing form errors for caching.
 *
 * Class FormUtil
 * @package OpenObjects\Bundle\CoreBundle\Util
 */
class FormUtil
{
    /**
     * List all errors of a given bound form.
     *
     * @param Form $form
     *
     * @return array
     */
    public static function getFormErrorsToSerialized(Form $form)
    {
        $errors = array();

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

        // Fields
        foreach ($form as $child /** @var Form $child */) {
            foreach ($child as $element) {
                if (!$element->isValid()) {
                    foreach ($element->getErrors() as $error) {
                        $errors[$child->getName()]['message'] = $error->getMessage();
                        $errors[$child->getName()]['messageTemplate'] = $error->getMessageTemplate();
                        $errors[$child->getName()]['messagePluralization'] = $error->getMessagePluralization();
                        $errors[$child->getName()]['messageParameters'] = $error->getMessageParameters();
                        $errors[$child->getName()]['cause'] = $errors[$child->getName()];
                        $errorCause = $error->getCause();
                        $errors[$child->getName()]['cause']['plural'] = $errorCause->getPlural();
                        $errors[$child->getName()]['cause']['propertyPath'] = $errorCause->getPropertyPath();
                        $errors[$child->getName()]['cause']['invalidValue'] = $errorCause->getInvalidValue();
                        $errors[$child->getName()]['cause']['constraint'] = serialize($errorCause->getConstraint());
                        $errors[$child->getName()]['cause']['code'] = $errorCause->getCode();
                        $errors[$child->getName()]['cause']['cause'] = $errorCause->getCause();
                    }
                }
            }

            if (!$child->isValid()) {
                foreach ($child->getErrors() as $error) {
                    $errors[$child->getName()]['message'] = $error->getMessage();
                    $errors[$child->getName()]['messageTemplate'] = $error->getMessageTemplate();
                    $errors[$child->getName()]['messagePluralization'] = $error->getMessagePluralization();
                    $errors[$child->getName()]['messageParameters'] = $error->getMessageParameters();
                    $errors[$child->getName()]['cause'] = $errors[$child->getName()];

                    if ($errorCause = $error->getCause()) {
                        $errors[$child->getName()]['cause']['plural'] = $errorCause->getPlural();
                        $errors[$child->getName()]['cause']['propertyPath'] = $errorCause->getPropertyPath();
                        $errors[$child->getName()]['cause']['invalidValue'] = $errorCause->getInvalidValue();
                        $errors[$child->getName()]['cause']['constraint'] = serialize($errorCause->getConstraint());
                        $errors[$child->getName()]['cause']['code'] = $errorCause->getCode();
                        $errors[$child->getName()]['cause']['cause'] = $errorCause->getCause();
                    }
                }
            }
        }


        $serializer = new Serializer(
            [new GetSetMethodNormalizer()],
            ['json' => new JsonEncoder()]
        );

        return  $serializer->serialize($errors, 'json');
    }

    /**
     * Apply an array of errors to form elements.
     *
     * @param Form $form
     * @param array $formErrors
     * @return Form
     */
    public static function applyErrorsToForm(Form &$form, array $formErrors)
    {
        foreach ($formErrors as $field => $errors) {
            if ($field == 'global') {
                $errorObject = new FormError($errors);
                $form->addError($errorObject);
            } else {

                if (isset($errors['cause']['cause'])) {
                    $errors['cause']['propertyPath'] = $errors['cause']['cause']['propertyPath'] ?? 'children[' . $field . '].data';
                    $errors['cause']['invalidValue'] = $errors['cause']['cause']['invalidValue'] ?? null;
                    $errors['cause']['plural'] = $errors['cause']['cause']['plural'] ?? null;
                    $errors['cause']['code'] = $errors['cause']['cause']['code'] ?? null;
                    $errors['cause']['constraint'] = $errors['cause']['cause']['constraint'];
                }

                $constraint = null;
                if (isset($errors['cause']['constraint'])) {
                    $constraint = unserialize($errors['cause']['constraint']);
                }

                // Unravel cause
                $constraintViolation = new ConstraintViolation(
                    $errors['cause']['message'],
                    $errors['cause']['messageTemplate'],
                    $errors['cause']['messageParameters'],
                    $form,
                    $errors['cause']['propertyPath'] ?? $field . '.data',
                    $errors['cause']['invalidValue'] ?? '',
                    $errors['cause']['plural'] ?? null,
                    $errors['cause']['code'] ?? null,
                    $constraint,
                    $errors['cause']['cause'] ?? null
                );

                $errorObject = new FormError(
                    $errors['message'],
                    $errors['messageTemplate'] ?? null,
                    $errors['messageParameters'] ?? [],
                    $errors['messagePluralization'] ?? null,
                    $constraintViolation
                );
                $form->get($field)->addError($errorObject);
            }
        }

        return $form;
    }

    /**
     * Apply an array of values to a form.
     *
     * @param Form $form
     * @param array $formValues
     * @return Form
     */
    public static function applyValuesToForm(Form &$form, array $formValues)
    {
        foreach ($formValues as $field => $value) {
            if ($form->has($field)) {
                $form->get($field)->setData($value);
            }
        }

        return $form;
    }
}