---
title: "AttachableUploadElementInterface"
manual: "LIA Form"
version: "2.2"
permalink: "https://docs.typo3.org/permalink/lia/lia_form:attachableuploadelement@2.2"
source: "FormElements/AttachableUploadElement.rst"
rendered: "2026-09-29T13:27:41+00:00"
---

# AttachableUploadElementInterface {#attachableuploadelement}

The `EmailFinisher` of this extension attaches uploaded files to the mail
when the finisher option `attachUploads` is enabled. By default only the
core `FileUpload` element is considered.

A custom form element that stores uploaded files can opt in by implementing
`LIA\LiaForm\Domain\Model\FormElements\AttachableUploadElementInterface`.
No finisher override and no service re-binding is needed.

## Contract {#contract}

The element value returned by the `FormRuntime` must be `null`, a
`TYPO3\CMS\Extbase\Domain\Model\FileReference`, a
`TYPO3\CMS\Core\Resource\FileInterface`, or an array or
`TYPO3\CMS\Extbase\Persistence\ObjectStorage` of those. `null` entries
are skipped. Any other value makes the finisher throw a `FinisherException`,
so a broken upload element fails loudly instead of sending a mail without its
attachments.

## Example {#example}

**EXT:my_extension/Classes/Domain/Model/FormElements/MyUploadElement.php**

```php
<?php
declare(strict_types=1);

namespace MY\MyExtension\Domain\Model\FormElements;

use LIA\LiaForm\Domain\Model\FormElements\AttachableUploadElementInterface;
use TYPO3\CMS\Form\Domain\Model\FormElements\AbstractFormElement;

final class MyUploadElement extends AbstractFormElement implements AttachableUploadElementInterface
{
    // Wire the UploadedFileReferenceConverter in initializeFormElement()
    // as the core FileUpload element does; the finisher does the rest.
}
```

Whether a mail gets attachments at all is still decided per finisher through
`attachUploads` in the form definition.