how to return json encoded form errors in symfony

Question

I want to create a webservice to which I submit a form, and in case of errors, returns a JSON encoded list that tells me which field is wrong.

currently I only get a

Answer 1

I've finally found the solution to this problem here, it only needed a small fix to comply to latest symfony changes and it worked like a charm:

The fix consists in replacing line 33

if (count($child->getIterator()) > 0) {

with

if (count($child->getIterator()) > 0 && ($child instanceof \Symfony\Component\Form\Form)) {

because, with the introduction in symfony of Form\Button, a type mismatch will occur in serialize function which is expecting always an instance of Form\Form.

You can register it as a service:

services:
form_serializer:
    class:        Wooshii\SiteBundle\FormErrorsSerializer

and then use it as the author suggest:

$errors = $this->get('form_serializer')->serializeFormErrors($form, true, true);

Answer 2

This does the trick for me

 $errors = [];
 foreach ($form->getErrors(true, true) as $formError) {
    $errors[] = $formError->getMessage();
 }

Answer 3

This will do the trick. This static method runs recursively through the Symfony\Component\Form\FormErrorIterator delivered by calling $form->getErrors(true, false).

<?php


namespace App\Utils;


use Symfony\Component\Form\FormInterface;
use Symfony\Component\Form\FormError;
use Symfony\Component\Form\FormErrorIterator;

class FormUtils
{
    public static function generateErrorsArrayFromForm(FormInterface $form)
    {
        $result = [];
        foreach ($form->getErrors(true, false) as $formError) {
            if ($formError instanceof FormError) {
                $result[$formError->getOrigin()->getName()] = $formError->getMessage();
            } elseif ($formError instanceof FormErrorIterator) {
                $result[$formError->getForm()->getName()] = self::generateErrorsArrayFromForm($formError->getForm());
            }
        }
        return $result;
    }
}

Here is the result :

{
    "houseworkSection": "All the data of the housework section must be set since the section has been requested.",
    "foodSection": {
        "requested": {
            "requested": "This value is not valid."
        }
    }
}

Answer 4

PHP has associative arrays, meanwhile JS has 2 different data structures : object and arrays.

The JSON you want to obtain is not legal and should be :

{
"status":400,
"errorMsg":"Bad Request",
"errorReport": {
        "taskfield" : "Task cannot be blank",
        "taskdatefield" : "Task date needs to be within the month"
    }
}

So you may want to do something like this to build your collection :

$errorCollection = array();
foreach($errors as $error){
     $errorCollection[$error->getId()] = $error->getMessage();
}

(assuming the getId() method exist on $error objects)

Answer 5

I am using this, it works quiet well:

/**
 * List all errors of a given bound form.
 *
 * @param Form $form
 *
 * @return array
 */
protected function getFormErrors(Form $form)
{
    $errors = array();

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

    // Fields
    foreach ($form as $child /** @var Form $child */) {
        if (!$child->isValid()) {
            foreach ($child->getErrors() as $error) {
                $errors[$child->getName()][] = $error->getMessage();
            }
        }
    }

    return $errors;
}

Answer 6

By reading other people's answers I ended up improving it to my needs. I use it in Symfony 3.4.

To be used in a controller like this:

$formErrors = FormUtils::getErrorMessages($form);

return new JsonResponse([
    'formErrors' => $formErrors,
]);

With this code in a separate Utils class

<?php

namespace MyBundle\Utils;

use Symfony\Component\Form\FormError;
use Symfony\Component\Form\FormInterface;

class FormUtils
{
    /**
     * @param FormInterface $form
     * @return array
     */
    public static function getErrorMessages(FormInterface $form)
    {
        $formName = $form->getName();
        $errors = [];

        /** @var FormError $formError */
        foreach ($form->getErrors(true, true) as $formError) {
            $name = '';
            $thisField = $formError->getOrigin()->getName();
            $origin = $formError->getOrigin();
            while ($origin = $origin->getParent()) {
                if ($formName !== $origin->getName()) {
                    $name = $origin->getName() . '_' . $name;
                }
            }
            $fieldName = $formName . '_' . $name . $thisField;
            /**
             * One field can have multiple errors
             */
            if (!in_array($fieldName, $errors)) {
                $errors[$fieldName] = [];
            }
            $errors[$fieldName][] = $formError->getMessage();
        }

        return $errors;
    }
}