How to treat BLOB column as string in Doctrine?

Question

Using Doctrine 3.1 - In my entity I have this column:

    #[ORM\Column(type: 'blob')]
    private $dataJpg;

If I make it string, PHP complains that resource is used and it cannot assign it during hydration. The problem is that I dont want to use resources at all, I want the binary data in its string form.

It is easy to work with resource when doing getter:

    public function getDataJpg(): ?string
    {
        $jpgData = $this->dataJpg;
        /** @var resource|null $jpgData*/
        if ($jpgData !== null) {
            return stream_get_contents($jpgData);
        }
        return null;
    }

But for setter I do not know how to approach it. I get string variable which I want to persist, but I cannot assign it to a resource. A workaround would be to fopen('php://memory') but I dont like that.

I need a way to tell doctrine to hydrate blob data as strings, so that I can get and set strings only and not care about resources.

Answer 1

For those interested, as suggested by @BERKUT in the comment, here is the custom type I made:

<?php

declare(strict_types=1);

namespace App\DBAL\Types;

use Doctrine\DBAL\ParameterType;
use Doctrine\DBAL\Platforms\AbstractPlatform;
use Doctrine\DBAL\Types\ConversionException;
use Doctrine\DBAL\Types\Type;

class BlobStringType extends Type
{
    /**
     * {@inheritDoc}
     */
    public function getSQLDeclaration(array $column, AbstractPlatform $platform): string
    {
        return $platform->getBlobTypeDeclarationSQL($column);
    }

    public function getName(): string
    {
        return 'blob_string';
    }

    /**
     * {@inheritDoc}
     */
    public function getBindingType(): ParameterType
    {
        return ParameterType::LARGE_OBJECT;
    }

    /**
     * {@inheritDoc}
     **/
    public function convertToPHPValue($value, AbstractPlatform $platform): mixed
    {
        if ($value === null) {
            return null;
        }

        if (is_string($value)) {
            return $value;
        }

        if (! is_resource($value)) {
            throw new ConversionException('Could not convert database value to string.');
        }

        if (stream_get_contents($value)) {
            return stream_get_contents($value);
        }

        throw new ConversionException('Could not convert database value to string.');
    }

    /**
     * {@inheritDoc}
     */
    public function convertToDatabaseValue($value, AbstractPlatform $platform): mixed
    {
        if (is_null($value)) {
            return null;
        }

        if (is_string($value)) {
            $value = $this->convertStringToResource($value);
        }

        return $value;
    }

    /**
     * @return resource
     */
    public function convertStringToResource(string $value)
    {
        $fp = fopen('php://temp', 'rb+');
        assert(is_resource($fp));
        fwrite($fp, $value);
        fseek($fp, 0);

        return $fp;
    }
}