Introduction

Simple Data Objects is a lightweight PHP 8.4+ library for creating typed Data Transfer Objects (DTOs) using constructor property promotion (or plain typed properties — see below) and PHP attributes.

Why Simple Data Objects?

DTOs are ubiquitous in modern PHP applications — they carry data between layers, validate input from HTTP requests, and serialize to/from APIs. Yet most implementations involve a lot of repetitive plumbing code.

Simple Data Objects removes that plumbing:

use StdOut\SimpleDataObjects\BaseData;
use StdOut\SimpleDataObjects\Attributes\Rules;
use StdOut\SimpleDataObjects\Attributes\Cast;
use StdOut\SimpleDataObjects\Casts\DateTimeCast;

class CreateOrderData extends BaseData
{
    public function __construct(
        #[Rules(['required', 'string', 'max:200'])]
        public readonly string $title,

        #[Rules(['required', 'email'])]
        public readonly string $customerEmail,

        #[Cast(new DateTimeCast('Y-m-d'))]
        public readonly DateTime $deliveryDate,

        public readonly ?string $notes = null,
    ) {}
}

// Validate + hydrate in one step
$order = CreateOrderData::fromValidated($request->all());

$order->title;           // 'New laptop'
$order->deliveryDate;    // DateTime object
$order->toArray();       // ['title' => ..., 'customerEmail' => ..., 'deliveryDate' => '2025-01-15', ...]
$order->toJson();        // JSON string

Core Concepts

Hydration

from() is a universal factory: it accepts arrays, Eloquent models and any Arrayable, stdClass, JsonSerializable, any Traversable, JSON strings, and plain objects. Nested DTOs, enums, and collections are resolved automatically. tryFrom() returns null instead of throwing; fromResult() goes further and never throws either, collecting every field's error (dot-pathed for nested DTOs and collections) instead of stopping at the first one.

Serialization

toArray() and toJson() serialize the object back to its wire format. Casts apply in both directions — hydration reads them, serialization writes them.

Attributes

All behaviour is declared on the constructor parameters:

• #[Cast(...)] — type conversion for dates, booleans, JSON, encryption, …
• #[Rules([...])] — Laravel validation rules
• #[Hidden] — exclude from toArray() output
• #[IgnoreIfNull] — omit null fields from output
• #[Flatten] — inline nested DTO fields into the parent array
• #[MapPropertyName] / #[MapInputName] / #[MapOutputName] / #[TransformKeys] — key remapping

Performance

Reflection runs once per class per process, results are cached in memory. Enable file-based cache with MetadataRegistry::setStoragePath() to have opcache pre-compile all metadata across requests.

Requirements

Dependency	Version
PHP	^8.4
illuminate/contracts	^10 | ^11 | ^12 | ^13
illuminate/support	^10 | ^11 | ^12 | ^13
illuminate/validation	^10 | ^11 | ^12 | ^13

Works standalone — no Laravel application required. Validation uses the library's own minimal validator bootstrap when no container is available.