Framework Integration

This library is framework-agnostic by design. It works with any PHP framework without requiring wrapper packages, while still offering deep integration possibilities.

Do We Need Wrapper Libraries?

Feature	Without Wrapper	With Wrapper
Basic usage	✅ Works	✅ Works
Collection factory	1 line setup	Auto-configured
Code generation	bin/dto generate	artisan dto:generate
Request → DTO	Manual	Auto via injection
Validation	Manual integration	Native framework validators
IDE support	✅ Full	✅ Full

Quick Setup

Laravel

// app/Providers/AppServiceProvider.php
use PhpCollective\Dto\Dto\Dto;

public function boot(): void
{
    // Enable Laravel collections for DTO collection fields
    Dto::setCollectionFactory(fn (array $items) => collect($items));
}

Symfony

// src/Kernel.php or an event listener
use PhpCollective\Dto\Dto\Dto;

// In boot or kernel.request listener
Dto::setCollectionFactory(fn (array $items) => new ArrayCollection($items));

CakePHP

// config/bootstrap.php or Application.php
use PhpCollective\Dto\Dto\Dto;
use Cake\Collection\Collection;

Dto::setCollectionFactory(fn (array $items) => new Collection($items));

CakePHP projectAs() and Special Fields

CakePHP 5.3+ introduces projectAs() for projecting ORM results directly into DTOs. Some CakePHP features use underscore-prefixed field names:

• _joinData - BelongsToMany pivot table data
• _matchingData - Data from matching() queries

These field names are fully supported:

<!-- config/dto.xml -->
<dto name="Tag" immutable="true">
    <field name="id" type="int"/>
    <field name="name" type="string"/>
    <field name="_joinData" type="Tagged"/>
</dto>

<dto name="UserWithMatching" immutable="true">
    <field name="id" type="int"/>
    <field name="username" type="string"/>
    <field name="_matchingData" type="MatchingData"/>
</dto>

The generated methods use proper camelCase (the leading underscore is stripped for method/constant names):

// Field: _joinData
$tag->getJoinData();      // getter
$tag->withJoinData($data); // immutable setter
TagDto::FIELD_JOIN_DATA;   // constant

// Field: _matchingData
$user->getMatchingData();
$user->withMatchingData($data);
UserWithMatchingDto::FIELD_MATCHING_DATA;

Usage with CakePHP's projectAs():

// BelongsToMany with _joinData
$posts = $postsTable->find()
    ->contain(['Tags'])
    ->projectAs(PostDto::class)
    ->toArray();

foreach ($posts as $post) {
    foreach ($post->getTags() as $tag) {
        $pivotData = $tag->getJoinData(); // Access pivot table data
    }
}

// Matching query with _matchingData
$users = $usersTable->find()
    ->matching('Roles', fn ($q) => $q->where(['Roles.id' => 1]))
    ->projectAs(UserWithMatchingDto::class)
    ->toArray();

foreach ($users as $user) {
    $matchingRoles = $user->getMatchingData(); // Access matched association data
}

Controller Usage

Laravel

use App\Dto\UserDto;
use Illuminate\Http\Request;

class UserController extends Controller
{
    public function store(Request $request): JsonResponse
    {
        // From validated request
        $dto = new UserDto($request->validated());

        // Or with ignoreMissing for partial updates
        $dto = UserDto::createFromArray($request->all(), ignoreMissing: true);

        // Use Laravel collection methods on DTO collections
        $activeUsers = $dto->getRoles()->filter(fn ($role) => $role->isActive());

        return response()->json($dto->toArray());
    }

    public function show(int $id): JsonResponse
    {
        $user = User::findOrFail($id);
        $dto = new UserDto($user->toArray());

        return response()->json($dto);
    }
}

Symfony

use App\Dto\UserDto;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\JsonResponse;

class UserController extends AbstractController
{
    #[Route('/users', methods: ['POST'])]
    public function store(Request $request): JsonResponse
    {
        $data = json_decode($request->getContent(), true);
        $dto = new UserDto($data);

        return $this->json($dto->toArray());
    }
}

CakePHP

use App\Dto\UserDto;

class UsersController extends AppController
{
    public function add()
    {
        if ($this->request->is('post')) {
            $dto = new UserDto($this->request->getData());

            // Use CakePHP collection methods
            $items = $dto->getItems()->filter(fn ($item) => $item->getQuantity() > 0);

            // ... save logic
        }
    }
}

Validation

The library includes built-in DTO validation for:

• required fields
• PHP-native type enforcement
• common field rules such as minLength, maxLength, min, max, and pattern

Framework validators still matter for request validation, business rules, custom messages, and cross-field constraints. A practical setup is:

1. Let the DTO handle structural validation and type-safe hydration.
2. Use your framework validator for request-specific or domain-specific rules.
3. Optionally map validationRules() into framework-native rules if you want to reuse DTO metadata.

Laravel

use Illuminate\Support\Facades\Validator;

$dto = UserDto::createFromArray($request->all(), ignoreMissing: true);

$dtoRules = $dto->validationRules();

$validator = Validator::make($dto->toArray(), [
    'name' => [
        'required',
        'string',
        'min:' . ($dtoRules['name']['minLength'] ?? 0),
        'max:' . ($dtoRules['name']['maxLength'] ?? 255),
    ],
    'email' => [
        'required',
        'email',
        'unique:users',
    ],
]);

if ($validator->fails()) {
    return response()->json(['errors' => $validator->errors()], 422);
}

validationRules() returns framework-agnostic metadata such as minLength and pattern. Laravel does not consume that structure directly, so map it into Laravel rule strings or objects first.

If you want to centralize that mapping, extract it into a small helper such as laravelRulesFromDto(UserDto $dto): array and keep request-specific rules on top of the DTO-derived baseline.

Symfony

use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Component\Validator\Validator\ValidatorInterface;

class UserController extends AbstractController
{
    public function store(Request $request, ValidatorInterface $validator): JsonResponse
    {
        $dto = new UserDto(json_decode($request->getContent(), true));

        // DTO construction already applies built-in field validation.
        // Use Symfony Validator for richer request or business rules.
        $violations = $validator->validate($dto->toArray(), new Assert\Collection([
            'name' => [new Assert\NotBlank(), new Assert\Length(['max' => 255])],
            'email' => [new Assert\NotBlank(), new Assert\Email()],
        ]));

        if (count($violations) > 0) {
            return $this->json(['errors' => (string) $violations], 422);
        }

        return $this->json($dto->toArray());
    }
}

The same pattern works well in Symfony with a helper that converts validationRules() output into an Assert\Collection.

See Validation for more validation patterns.

Code Generation

The CLI tool works the same way in any framework:

# Generate DTOs from config
vendor/bin/dto generate --config-path=config/ --src-path=src/ --namespace=App

# Or with XML
vendor/bin/dto generate --config-path=config/ --src-path=src/ --namespace=App --format=xml

Framework-Specific Paths

Framework	Config Path	Output Path	Namespace
Laravel	config/dto.php	app/Dto	App\Dto
Symfony	config/dto.xml	src/Dto	App\Dto
CakePHP	config/dto.php	src/Dto	App\Dto

Composer Scripts

Add to your composer.json for convenience:

{
    "scripts": {
        "dto:generate": "vendor/bin/dto generate --config-path=config/ --src-path=src/ --namespace=App"
    }
}

Then run: composer dto:generate

What Wrapper Packages Could Add

While not required, framework-specific packages could provide:

Potential Laravel Package Features

Feature	Current (Manual)	With Package
Collection factory	1 line in ServiceProvider	Auto-configured
Request → DTO	new UserDto($request->validated())	UserDto::fromRequest($request)
Route binding	Manual	Route::dto(UserDto::class)
Artisan command	bin/dto generate	php artisan dto:generate
Config publishing	Manual	php artisan vendor:publish

// Hypothetical Laravel package usage
public function store(UserDto $dto): JsonResponse  // Auto-injected from request
{
    return response()->json($dto);
}

Potential Symfony Bundle Features

Feature	Current (Manual)	With Bundle
Collection factory	Kernel listener	Auto-configured
Request → DTO	Manual JSON decode	ParamConverter
Console command	bin/dto generate	bin/console dto:generate
Autowiring	Manual	Service definitions

// Hypothetical Symfony bundle usage
#[Route('/users', methods: ['POST'])]
public function store(#[MapRequestPayload] UserDto $dto): JsonResponse
{
    return $this->json($dto);
}

Comparison With Other Libraries

Library	Framework Integration
php-collective/dto	Framework-agnostic, optional adapters
spatie/laravel-data	Laravel-only, deep integration
cuyz/valinor	Framework-agnostic + optional Symfony bundle
symfony/serializer	Symfony-native, usable standalone

Philosophy

This library follows the approach of cuyz/valinor and similar tools:

1. Core library - Works everywhere, no dependencies
2. Optional adapters - Framework-specific convenience packages
3. No lock-in - Switch frameworks without changing DTOs

Input Transformation

Unlike spatie/laravel-data which has built-in Casts and Transformers, this library keeps transformation simple:

Recommended Patterns

Pre-process data before DTO creation:

// Sanitize input
$data = $request->validated();
$data['name'] = trim($data['name'] ?? '');
$data['email'] = strtolower($data['email'] ?? '');

$dto = new UserDto($data);

Use a static factory method:

class UserDto extends AbstractDto
{
    public static function fromRequest(Request $request): static
    {
        $data = $request->validated();

        // Transform as needed
        $data['name'] = trim($data['name'] ?? '');

        return new static($data);
    }
}

Use the factory config option for objects:

// config/dto.php
'Payment' => [
    'fields' => [
        'amount' => [
            'type' => '\Money\Money',
            'factory' => 'Money\Parser::parse',
        ],
    ],
],

Why No Built-in Transformers?

1. Performance - Runtime callbacks slow down the optimized setFromArrayFast path
2. Simplicity - Code generation produces simple, debuggable code
3. Flexibility - Pre-processing works with any transformation library
4. Framework choice - Use Laravel's mutators, Symfony's normalizers, or plain PHP

Service Container Integration

Laravel

// app/Providers/AppServiceProvider.php
public function register(): void
{
    $this->app->bind(OrderDto::class, function ($app, $params) {
        return new OrderDto($params['data'] ?? []);
    });
}

Symfony

# config/services.yaml
services:
    App\Dto\OrderDto:
        autoconfigure: false
        autowire: false

DTOs are typically instantiated directly rather than through the container, as they're data holders, not services.

Doctrine ORM Integration

Generated DTOs work well with Doctrine for read-optimized queries.

Partial Select + DTO Hydration

The recommended approach: fetch only needed fields as arrays, then hydrate DTOs:

use App\Dto\UserSummaryDto;

// Fetch partial data as array (fast - no entity hydration)
$rows = $entityManager->createQuery(
    'SELECT u.id, u.name, u.email
     FROM App\Entity\User u
     WHERE u.active = true'
)->getArrayResult();

// Hydrate generated DTOs
$users = array_map(fn($row) => new UserSummaryDto($row), $rows);

// All generated methods available
foreach ($users as $user) {
    echo $user->getName();
    echo $user->getEmail();
}

Why Not SELECT NEW?

Doctrine's SELECT NEW passes positional arguments:

SELECT NEW App\Dto\UserDto(u.id, u.name, u.email)
// Calls: new UserDto($id, $name, $email)

Generated DTOs expect an array:

new UserDto(['id' => 1, 'name' => 'John', 'email' => 'john@example.com'])

Using getArrayResult() + DTO hydration gives the same performance benefits while working with generated DTOs.

However, if you prefer Doctrine's native SELECT NEW syntax, you can use mapper classes.

Doctrine SELECT NEW with Mappers

Generate mapper classes alongside your DTOs:

vendor/bin/dto generate --mapper

This creates mapper classes that extend DTOs with positional constructors:

src/Dto/
├── UserSummaryDto.php           # Standard DTO (array constructor)
└── Mapper/
    └── UserSummaryDtoMapper.php # Mapper (positional constructor)

Generated Mapper Structure:

namespace App\Dto\Mapper;

use App\Dto\UserSummaryDto;

class UserSummaryDtoMapper extends UserSummaryDto
{
    public function __construct(
        int $id,
        string $name,
        ?string $email
    ) {
        parent::__construct([
            'id' => $id,
            'name' => $name,
            'email' => $email,
        ]);
    }
}

Usage with Doctrine:

use App\Dto\Mapper\UserSummaryDtoMapper;

// Use the mapper in SELECT NEW
$users = $entityManager->createQuery(
    'SELECT NEW App\Dto\Mapper\UserSummaryDtoMapper(u.id, u.name, u.email)
     FROM App\Entity\User u
     WHERE u.active = true'
)->getResult();

// Results are fully-functional DTOs
foreach ($users as $user) {
    echo $user->getName();    // All getter methods work
    echo $user->toArray();    // Serialization works
}

// Type hints work - mapper IS-A DTO
function processUser(UserSummaryDto $dto): void { /* ... */ }
processUser($users[0]);  // Works because UserSummaryDtoMapper extends UserSummaryDto

Benefits of Mappers:

Feature	getArrayResult + DTO	SELECT NEW + Mapper
Performance	✅ Fast	✅ Fast
Type safety	✅ Full	✅ Full
Code style	Manual mapping	Native DQL
Single query	✅ Yes	✅ Yes
IDE support	✅ Full	✅ Full

Both approaches produce identical results. Choose based on preference:

• getArrayResult: More explicit, works with any DTO
• SELECT NEW + Mapper: Native DQL syntax, requires --mapper flag

DTO Definition for Query Results

Define lightweight DTOs for specific queries:

// config/dto.php
return Schema::create()
    ->dto(Dto::create('UserSummary')->fields(
        Field::int('id'),
        Field::string('name'),
        Field::string('email'),
    ))
    ->toArray();

With Query Builder

$qb = $entityManager->createQueryBuilder();
$rows = $qb->select('o.id', 'o.total', 'c.name AS customerName')
   ->from(Order::class, 'o')
   ->join('o.customer', 'c')
   ->where('o.status = :status')
   ->setParameter('status', 'completed')
   ->getQuery()
   ->getArrayResult();

$orders = array_map(fn($row) => new OrderSummaryDto($row), $rows);

Repository Pattern

class UserRepository extends ServiceEntityRepository
{
    /**
     * @return UserSummaryDto[]
     */
    public function findActiveSummaries(): array
    {
        $rows = $this->createQueryBuilder('u')
            ->select('u.id', 'u.name', 'u.email')
            ->where('u.active = true')
            ->getQuery()
            ->getArrayResult();

        return array_map(fn($row) => new UserSummaryDto($row), $rows);
    }
}

Entity to DTO Conversion

For converting full entities to DTOs:

// Simple conversion
$user = $entityManager->find(User::class, 1);
$dto = new UserDto($user->toArray());

// Or with a static factory
class UserDto extends AbstractDto
{
    public static function fromEntity(User $user): static
    {
        return new static([
            'id' => $user->getId(),
            'name' => $user->getName(),
            'email' => $user->getEmail(),
            'roles' => $user->getRoles()->map(fn ($r) => [
                'id' => $r->getId(),
                'name' => $r->getName(),
            ])->toArray(),
        ]);
    }
}

Why Use DTOs with Doctrine?

Approach	Use Case
Entity directly	Internal domain logic, persistence
DTO via getArrayResult	Simple queries, manual mapping
DTO via SELECT NEW + Mapper	Native DQL syntax, type-safe results
DTO from Entity	When you need the full entity first, then transform

Benefits of DTOs for query results:

• Performance: Only hydrate needed fields, no proxy objects
• API safety: No lazy-loading surprises in JSON responses
• Clear contracts: DTOs define exactly what the API returns
• Immutability: Use immutable DTOs for read-only data

Further Reading

• Custom Collection Types
• Validation
• Migration Guide