README

etel/identifier

Contracts and ready-to-use trait implementations for typed identifier value objects in PHP 8.4+.

Installation

composer require etel/identifier

To use UUID-based identifiers, also require symfony/uid:

composer require symfony/uid

Concepts

An identifier is an immutable value object that wraps a raw value (integer, string, or UUID) and exposes it through a typed $value property and a string representation via $string.

Every identifier type carries a PREFIX constant used as a human-readable namespace in its string form (e.g. usr_42, order_01JV3BWXYZ). An empty prefix is valid but prevents IdentifierResolver from distinguishing the type by string.

Defining an identifier

Implement one of the sub-interfaces and use the matching trait:

Integer identifier (positive integers only):

use Etel\Identifier\IntegerIdentifier;
use Etel\Identifier\Implementation\Integer\IntegerIdentifierTrait;

final class UserId implements IntegerIdentifier
{
    use IntegerIdentifierTrait;

    public const string PREFIX = 'usr_';
}

$id = new UserId(42);
$id->value;  // 42
$id->string; // "usr_42"

UserId::fromString('usr_42');     // UserId(42)
UserId::tryFromString('usr_abc'); // null

UUID v7 / Base58 identifier (time-sortable, URL-safe):

use Etel\Identifier\UuidIdentifier;
use Etel\Identifier\Implementation\Uuid\Uuid7Base58IdentifierTrait;
use Symfony\Component\Uid\Uuid;

final class OrderId implements UuidIdentifier
{
    use Uuid7Base58IdentifierTrait;

    public const string PREFIX = 'order_';
}

$id = new OrderId(Uuid::v7());
$id->value;  // UuidV7 instance
$id->string; // "order_1BvBMSEYstWetqTFn5Au4m"

OrderId::fromString('order_1BvBMSEYstWetqTFn5Au4m'); // OrderId instance

String identifier:

use Etel\Identifier\StringIdentifier;
use Etel\Identifier\Implementation\String\StringIdentifierTrait;

final class CountryCode implements StringIdentifier
{
    use StringIdentifierTrait;

    public const string PREFIX = 'country.';
}

$id = new CountryCode('UA');
$id->value;  // "UA"
$id->string; // "country.UA"

Available traits

Integer

String

UUID

If the built-in traits don't fit, you can implement the appropriate interface directly.

Identifiable

Mark domain objects that own an identifier with the Identifiable interface:

use Etel\Identifier\Identifiable;

final class User implements Identifiable
{
    public function __construct(public readonly UserId $id, ... ) {}
}

Resolving identifiers by string

IdentifierResolver allows resolving an identifier from its string representation without knowing the concrete type in advance. Implementations decide how identifier types are registered:

use Etel\Identifier\IdentifierResolver;

$resolver->fromString('usr_42');             // UserId(42)
$resolver->fromString('order_1BvBMSEY...'); // OrderId instance
$resolver->tryFromString('unknown_x');       // null

Todo list

• more types
• resolver implementations