Symfony, How to correctly update an entity that has a field of type "File"?

Question

symfony

I welcome everyone! I'm learning Symfony
The problem is this, there is a Task entity that has properties

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * Task
 *
 * @ORM\Table(name="task")
 * @ORM\Entity(repositoryClass="AppBundle\Repository\TaskRepository")
 */
class Task
{
     /**
     * @ORM\Column(type="string", nullable=true)
    */    
    private $originalFileName;
    /**
     * @ORM\Column(type="string", nullable=true)
    */    
    private $fileName;

In which, when saving, the original file name is written, and the hashed file name on the server.
There is a form

<?php
namespace AppBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\Extension\Core\Type\FileType;

class TaskType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
                ->add('taskName',TextType::class)
                ->add('fileName', FileType::class, array('label' => 'Документ'))                
                ;
    }/**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'AppBundle\Entity\Task'
        ));
    }

There is an action editing the entity.
If, when editing an entity that already has an uploaded file, respectively, the originalFileName and fileName fields are filled, if the input file is empty, then the old originalFileName value in the database becomes
null
I implemented the file upload using the
documentation

Answer 1

In the presented code, the fileName property should be overwritten, because you have it specified in the TaskType form. Generally speaking, an UploadedFile instance should be stored in it (or null if the field was not filled when the form was submitted), and your annotation indicates that this is a string field.
You don't need to "map" the file field into an entity (specify 'mapped' => false):

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('taskName',TextType::class)
        ->add('file', FileType::class, [ 'mapped' => false, 'label' => 'Документ'])                
    ;
}

An instance of UploadedFile can be obtained manually:

$uploadedFile = $form['file']->getData();

$fileName = 'myfile.txt';

$uploadedFile->move('public/uploads', $fileName);

$task->setFileName('public/uploads/'.$fileName);