How to access the validator results in an TYPO3 Extbase action? - fluid

Question

I have an Extbase module with a new/create-action. The model has the #validate annotation in it.
So far so good, everything's working.
But: I don't like how the form-errors are presented in the view. I'd like to add a CSS class like error in the view to the fields that are not correctly filled in.
But the only way to access the errors in the form seems to be through the <f:form.validationResults>-Viewhelper.
When I try to debug the results with <f:debug>{validationResults}</f:debug> I get a NULL value.
How do I access an error for a single field?
Actually, I'd prefer to access the errors in the controller, so I could pass an array to the view with the fields that contain an error.
I'm using Fluid and TYPO3 9.5

Answer 1

Such Fluid template should work out-of-the-box:
<f:form.validationResults>
<f:if condition="{validationResults.flattenedErrors}">
<ul>
<f:for each="{validationResults.flattenedErrors}" key="propertyPath" as="errors">
<li>
{propertyPath}: <ul>
<f:for each="{errors}" as="error">
<li>{error}</li>
</f:for>
</ul>
</li>
</f:for></ul>
</f:if>
</f:form.validationResults>
Another approach,
You can also write own ViewHelper to display error messages as you want in your own form HTML markup:
<?php
namespace VENDOR\Yourext\ViewHelpers;
use TYPO3\CMS\Extbase\Utility\DebuggerUtility;
use TYPO3Fluid\Fluid\Core\ViewHelper\AbstractViewHelper;
/**
* #author Marcus Biesioroff biesior#gmail.com>
*
* ViewHelper for displaying custom-designed errors
*
* Usage:
* {namespace yvh=VENDOR\Yourext\ViewHelpers}
* or in ext_tables.php:
* $GLOBALS['TYPO3_CONF_VARS']['SYS']['fluid']['namespaces']['yvh'] = ['VENDOR\Yourext\ViewHelpers'];
*
* <yvh:myError key="yourObj.somefield" flattenedErrors="{validationResults.flattenedErrors}"/>
*/
class MyErrorViewHelper extends AbstractViewHelper
{
protected $escapeOutput = false;
public function initializeArguments()
{
parent::initializeArguments();
$this->registerArgument('key', 'sring', 'Name of the field for which errors should be displayed');
$this->registerArgument('flattenedErrors', 'mixed', 'Flatenned errors if any');
}
public function render()
{
$flattenedErrors = $this->arguments['flattenedErrors'];
if (is_null($flattenedErrors)) return null;
// DebuggerUtility::var_dump($flattenedErrors);
$key = $this->arguments['key'];
if (is_array($flattenedErrors) && array_key_exists($key, $flattenedErrors)) {
$errMsg = $flattenedErrors[$key][0]->getMessage();
return "<div class='my-very-own-error-class'>$errMsg</div>";
}
return null;
}
}
Remember, that you'll need to wrap your fields with <f anyway to get the flattenErrors array;
{namespace yvh=VENDOR\Yourext\ViewHelpers}
<f:form.validationResults>
<div>
<label for="name">Name (required)</label>
<f:form.textfield property="name"/>
<yvh:myError key="yourObj.name" flattenedErrors="{validationResults.flattenedErrors}"/>
</div>
<div>
<label for="slug">Slug (required)</label><br/>
<f:form.textfield property="slug"/>
<yvh:myError key="yourObj.slug" flattenedErrors="{validationResults.flattenedErrors}"/>
</div>
<div>
<label for="buildYear">Year of build (required)</label>
<f:form.textfield property="buildYear"/>
<yvh:myError key="yourObj.buildYear" flattenedErrors="{validationResults.flattenedErrors}"/>
</div>
</f:form.validationResults>