Revision: Thu, 25 Apr 2024 01:18:30 GMT

Column wrappers and typecast

In some cases, you might want to wrap the value using a custom value object (similarly to DateTime columns which are wrapped as DateTimeImmutable). It can be achieved by creating a custom column wrapper and typecasting the column value to it.

Typecast using callable

In order to define a column wrapper, we have to implement an object with a static factory method. We will use the UUID column and the castValue() method as an example.

php
use Ramsey\Uuid\Uuid as UuidBody;
use Ramsey\Uuid\UuidInterface;
use Cycle\Database\DatabaseInterface;

final class Uuid
{
    private function __construct(
        private UuidInterface $uuid;
    ) {
    }

    public function __toString(): string
    {
        return $this->uuid->toString();
    }

    public static function create(): static
    {
        return new static(
            UuidBody::uuid4()
        );
    }

    public static function castValue(string $value, DatabaseInterface $db): static
    {
        return new static(
            UuidBody::fromString($value)
        );
    }
}

Note
The castValue method will receive the raw value content and the database it's associated with. Make sure to implement the __toString method on your wrapper to store it in the database. See below how to use a custom serialization strategy.

Assign to entity

To assign a column wrapper to an entity use the column option typecast. You can specify typecast as any callable: function name, a method name (using :: separator or declaring as array).

php
use Cycle\Annotated\Annotation\Entity;
use Cycle\Annotated\Annotation\Column;

#[Entity]
class User
{
    #[Column(type: 'primary')]
    private $id;

    #[Column(type: 'string', typecast: [Uuid::class, 'castValue'])]
    private Uuid $uuid;
}

Note
In the example we've declared a typecast rule to the uuid field. By default ORM will process the rule using default Typecast Handlers that allows using for callables.

We can use this column wrapper after the schema update:

php
$user = new User();
$user->uuid = Uuid::create();

$manager = new \Cycle\ORM\EntityManager($orm);
$manager->persist($user);
$manager->run();

The column will be automatically wrapped upon retrieving the entity from the database:

php
$user = $orm->getRepository(User::class)->findOne();

print_r($user);

To change the wrapped column value you have to create new object:

php
$user = $orm->getRepository(User::class)->findOne();
$user->uuid = Uuid::create();

$manager = new \Cycle\ORM\EntityManager($orm);
$manager->persist($user);
$manager->run();

Uncast Raw Values

In some cases you might want to store values in the database in binary form, you can achieve that by implementing Cycle\Database\Injection\ValueInterface in order to gain access to low-level query compilation:

php
use Ramsey\Uuid\Uuid as UuidBody;
use Ramsey\Uuid\UuidInterface;
use Cycle\Database\DatabaseInterface;
use Cycle\Database\Injection\ValueInterface;

class Uuid implements ValueInterface
{
    private function __construct(
        private UuidInterface $uuid;
    ) {
    }
    
    public function rawValue(): string
    {
        return $this->uuid->getBytes();
    }

    public function rawType(): int
    {
        return \PDO::PARAM_LOB;
    }

    public function __toString(): string
    {
        return $this->uuid->toString();
    }

    public static function create(): static
    {
        return new static(
            UuidBody::uuid4()
        );
    }

    public static function castValue(string $value, DatabaseInterface $db): static
    {
        if (is_resource($value)) {
            // postgres
            $value = fread($value, 16);
        }

        return new static(
            UuidBody::fromBytes($value)
        );
    }
}

Now, the Uuid column will be stored in a blob form.

You can also implement the Expression or Parameter interfaces in your column wrapper to achieve more complex logic.

Enum typecast

The default Typecast Handlers supports for typecast values to Enum classes since ORM v2.2.0.

Note
You should update the cycle/annotated package to v3.2.0 if you want to use the feature in atributes.

Note
The ORM and the DBAL support Backed Enums only, not Pure Enums.

php
enum UserType: string
{
    case Guest = 'guest';
    case User = 'user';
    case Admin = 'admin';
}

To use the ability you should specify the enum class name in the column option typecast.

php
use Cycle\Annotated\Annotation\Entity;
use Cycle\Annotated\Annotation\Column;

#[Entity]
class User
{
    #[Column(type: 'primary')]
    private $id;

    #[Column(type: 'string', typecast: UserType::class)]
    private UserType $type;
}

Note
All incorrect enum values will be casted to null. And, of course, you can use the enum type to create a DB-level restriction:

php
#[Column(type: 'enum(guest,user,admin)', typecast: UserType::class)]

Column wrapper

Column wrapper looks like a magical. When you declared in the column option typecast a class name, the ORM will check the class contains the typecast method. If the method exists then ORM will use that method (DeclaredClass::typecast()) to create casted value for entity field.

Note
Cycle ORM had the column wrapers feature since a 1.x version and by the reason the feature has migrated to v2.0.

You should consider that magical behavior when you are declaring some enum in the typecast column option: ORM could use Enum::typecast method to create casted value instead of the BackedEnum::tryFrom.

php
enum UserType: string
{
    case Guest = 'guest';
    case User = 'user';
    case Admin = 'admin';

    public static function typecast(string $value): self
    {
        return self::from($value);
    }
}
php
use Cycle\Annotated\Annotation\Entity;
use Cycle\Annotated\Annotation\Column;

#[Entity]
class User
{
    #[Column(type: 'primary')]
    private $id;

    #[Column(
        type: 'string',
        typecast: UserType::class // will be converted to [UserType::class, 'typecast']
    )]
    private UserType $type;
}
2.x
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