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Symfony Mapper
Component
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Object mapping
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
#[ORM\Entity]
class Book
{
#[ORM\Id, ORM\GeneratedValue]
public ?int $id;
#[ORM\Column]
public ?string $title;
}
namespace App\ValueObject;
readonly class Book
{
public function __construct(
public string $id,
public string $title
) {}
}
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2015
2016 2017 2018 2019 2020 2021 2022 2023
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https://www.youtube.com/watch?v=taGGa2MAyG4
Kevin Dunglas presents API Platform
2015
2016 2017 2018 2019 2020 2021 2022 2023
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https://dunglas.dev/2016/11/api-platform-2-0-released-creating-powerful-web-apis-has-never-been-so-easy/
2016
2015 2017 2018 2019 2020 2021 2022 2023
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https://github.com/api-platform/schema-generator/issues/42
2016
2015 2017 2018 2019 2020 2021 2022 2023
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Joel Wurtz (jolicode) works on an AstGenerator component https://github.com/symfony/symfony/pull/17516
2016
2015 2017 2018 2019 2020 2021 2022 2023
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https://github.com/api-platform/core/issues/212
2017
2015 2016 2018 2019 2020 2021 2022 2023
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https://github.com/api-platform/core/issues/212
2017
2015 2016 2018 2019 2020 2021 2022 2023
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GuilhemN takes the AST directly into the serializer’s normalizer https://github.com/symfony/symfony/pull/22051
2017
2015 2016 2018 2019 2020 2021 2022 2023
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My fork of his patch is still available, this was working quite nicely! https://github.com/soyuka/symfony/commits/SERIALIZERAST/
2017
2015 2016 2018 2019 2020 2021 2022 2023
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Joel Wurtz continues working on this and proposes another approach the AutoMapper https://github.com/symfony/symfony/pull/30248
2019
2015 2016 2018
2017 2020 2021 2022 2023
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AutoMapper is a simple little library built to solve a deceptively complex problem - getting
rid of code that mapped one object to another. This type of code is rather dreary and boring
to write, so why not invent a tool to do it for us?
Automapper (.NET)
https://automapper.org/
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PR was closed for housekeeping, didn’t got the votes to be merged.
2023
2015 2016 2018
2017 2020 2021 2022
2019
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My bad
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2023
2015 2016 2018
2017 2020 2021 2022
2019
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2023
2015 2016 2018
2017 2020 2021 2022
2019
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https://symfonycasts.com/screencast/api-platform-extending/state-options
state options + entityClass magic
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Object mapping
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
#[ORM\Entity]
class Book
{
#[ORM\Id, ORM\GeneratedValue]
public ?int $id;
#[ORM\Column]
public ?string $title;
}
namespace App\ValueObject;
readonly class Book
{
public function __construct(
public string $id,
public string $title
) {}
}
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➔ Handling legacy data representations
➔ Mapping from database model to DTO
objects
➔ Data segregation
➔ Splitting, merging objects
➔ DDD
When do we need object mapping?
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➔ Spring
https://github.com/FasterXML/jackson
➔ .NET
https://automapper.org
➔ Java
https://modelmapper.org
➔ Ruby Object Mapper (ROM)
https://rom-rb.org/
➔ Java Map Struct
https://mapstruct.org
Object mapping in other
programming languages:
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Do you think Symfony
should provide an
Object Mapper
component ?
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Mapping in PHP
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use App\ValueObject\Book;
$data = $client->request('GET', 'https://example.com/books/1')->toArray();
try {
$person = (new \CuyZ\Valinor\MapperBuilder())
->mapper()
->map(Book::class, $data);
} catch (\CuyZ\Valinor\Mapper\MappingError $error) {
// Detailed error handling
}
Valinor takes care of the construction and validation of raw inputs (JSON, plain arrays,
etc.) into objects, ensuring a perfectly valid state. It allows the objects to be used
without having to worry about their integrity during the whole application lifecycle.
https://valinor.cuyz.io/
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use AutoMapper\AutoMapper;
use App\Entity\Book as BookEntity;
use App\ValueObject\Book;
$automapper = AutoMapper::create();
$source = new BookEntity();
$target = $automapper->map($source, Book::class);
AutoMapper uses a convention-based matching algorithm to match up source to destination values.
AutoMapper is geared towards model projection scenarios to flatten complex object models to DTOs
and other simple objects, whose design is better suited for serialization, communication, messaging,
or simply an anti-corruption layer between the domain and application layer.
Automapper https://automapper.jolicode.com/
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use App\Entity\Book as BookEntity;
use App\ValueObject\Book;
#[AsMapper(from: BookEntity::class, to: Book::class)]
class BookEntityToDtoMapper implements MapperInterface
{
public function load(object $from, string $toClass, array $context): object
{
$entity = $from;
return new Book($entity->getId());
}
public function populate(object $from, object $to, array $context): object
{
$to->id = (string) $from->getId();
$to->title = $from->getTitle();
return $to;
}
}
MicroMapper: The Tiny,
Underwhelming
Data Mapper for Symfony!
https://github.com/SymfonyCasts/micro-mapper
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More packages in PHP
➔ thephpleague/object-mapper
https://github.com/thephpleague/object-mapper
➔ rekalogika/mapper
https://github.com/rekalogika/mapper
➔ michelsalib/BCCAutoMapperBundle
https://github.com/michelsalib/BCCAutoMapperBundle
➔ Nylle/PHP-AutoMapper
https://github.com/Nylle/PHP-AutoMapper
➔ idr0id/Papper (inspired by .Net)
https://github.com/idr0id/Papper
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Object hydration
Hydration is filling an
object with data
Data Mapper pattern (often used by ORMs), hydrate
an object from relational data (often represented
using arrays).
https://martinfowler.com/bliki/OrmHate.html
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Object mapping
Transforming an object to
another object
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➔ The need exists
➔ A Symfony interface would allow
more implementations/bundles
to switch over to
➔ Automapper works well with
Forms, API Platform, Messenger
etc.)
[RFC] ObjectMapper · Issue #54476 · symfony/symfony · GitHub
Why another component ?
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The common vision
of the Symfony community
/**
* @template T of object
*/
interface ObjectMapperInterface
{
/**
* @param object $source The object to map from
* @param T|class-string|null $target The object or class to map to
*
* @return T
*/
public function map(object $source, object|string|null $target = null): object;
}
[RFC] ObjectMapper · Issue #54476 · symfony/symfony · GitHub
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Differences with the Serializer
➔ Separation of concerns
➔ Json Encoder component
➔ Compose with Symfony components
(validation + mapping)
➔ Map only objects
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Map an object to another object
➔ No collection mapping yet (loop over your collection structure and
transform objects)
➔ Mapping transformations and configuration (property renaming,
concatenation, splitting, value transformation)
➔ Minimal interface to allow more implementations (MapStruct-like,
Automapper for performances, etc.)
Definition of the Symfony Object Mapper
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Are you ready to see
some code?
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Metadata abstraction
namespace Symfony\Component\ObjectMapper\Metadata;
/**
* Factory to create Mapper metadata.
*/
interface ObjectMapperMetadataFactoryInterface
{
/**
* @param array $context
*
* @return list
*/
public function create(object $object, ?string $property = null, array $context = []): array;
}
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Metadata abstraction
namespace Symfony\Component\ObjectMapper\Metadata;
readonly class Mapping
{
/**
* @param string|class-string|null $source The property or the class to map from
* @param string|class-string|null $target The property or the class to map to
* @param mixed $if A boolean, Symfony service name or a callable that instructs whether to map
* @param mixed $transform A Symfony service name or a callable that transform the value during mapping
*/
public function __construct(
public ?string $target = null,
public ?string $source = null,
public mixed $if = null,
public mixed $transform = null,
) {}
}
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Attribute-based implementation
namespace Symfony\Component\ObjectMapper\Attribute;
#[\Attribute(\Attribute::TARGET_CLASS | \Attribute::TARGET_PROPERTY | \Attribute::TARGET_METHOD |
\Attribute::IS_REPEATABLE)]
readonly class Map
{
/**
* @param string|class-string|null $source The property or the class to map from
* @param string|class-string|null $target The property or the class to map to
* @param mixed $if A boolean, Symfony service name or a callable that instructs whether to map
* @param mixed $transform A Symfony service name or a callable that transform the value during mapping
*/
public function __construct(
public ?string $target = null,
public ?string $source = null,
public mixed $if = null,
public mixed $transform = null,
) {
}
}
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Attribute-based implementation
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
#[ORM\Entity]
class Book
{
#[ORM\Id, ORM\GeneratedValue]
public ?int $id;
#[ORM\Column]
public ?string $title;
}
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Attribute-based implementation
namespace App\Entity;
use App\ValueObject\Book as BookDTO;
use Doctrine\ORM\Mapping as ORM;
use Symfony\ObjectMapper\Attribute\Map;
#[ORM\Entity, Map(target: BookDTO::class)]
class Book
{
#[ORM\Id, ORM\GeneratedValue]
public ?int $id;
#[ORM\Column]
public ?string $title;
}
use Symfony\Component\ObjectMapper\ObjectMapper;
use App\ValueObject\Book as BookDTO;
$book = $repository->find(1); // Retrieve a Book somehow;
assert((new ObjectMapper)->map($book) instanceof BookDTO);
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Hydrate an existing instance
namespace App\ValueObject;
use App\Entity\BookEntity;
readonly class Book
{
public function __construct(
public string $id,
public string $title
) {}
}
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namespace App\ValueObject;
use App\Entity\BookEntity;
use Symfony\ObjectMapper\Attribute\Map;
#[Map(target: BookEntity::class)]
readonly class Book
{
public function __construct(
#[Map(transform: 'intval')]
public string $id,
public string $title
) {}
}
use Symfony\Component\ObjectMapper\ObjectMapper;
use App\ValueObject\Book as BookDTO;
$dto = new BookDTO(id: '1', title: 'updated');
$book = $repository->find(1); // Retrieve a Book somehow;
$book = (new ObjectMapper)->map($dto, $book);
assert($book->title === 'updated');
Hydrate an existing instance
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| \Attribute::IS_REPEATABLE)]
readonly class Map
{
/**
* @param string|class-string|null $source The property or the class to map from
* @param string|class-string|null $target The property or the class to map to
* @param mixed $if A boolean, Symfony service name or a callable that instructs whether
to map
* @param mixed $transform A Symfony service name or a callable that transform the value
during mapping
*/
public function __construct(
public ?string $target = null,
public ?string $source = null,
public mixed $if = null,
public mixed $transform = null,
) {
}
}
Transformations
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namespace App\ValueObject;
use App\Entity\BookEntity;
use Symfony\ObjectMapper\Attribute\Map;
#[Map(target: BookEntity::class)]
readonly class Book
{
public function __construct(
#[Map(transform: 'intval')]
public string $id,
#[Map(transform: static function ($title) { return ucfirst($title); })]
public string $title
) {}
}
https://wiki.php.net/rfc/closures_in_const_expr
Transform with a callable
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namespace App\Mapping;
use Symfony\Component\ObjectMapper\TransformCallableInterface;
use App\Entity\Book;
/**
* @implements TransformCallableInterface
*/
class TransformCallable implements TransformCallableInterface
{
public function __invoke(mixed $value, object $object): mixed
{
return ucfirst($value);
}
}
Transform with a service
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namespace App\Entity;
use Symfony\Component\ObjectMapper\Attribute\Map;
use App\ValueObject\Book as BookDTO;
use App\Mapping\TransformCallable;
#[Map(BookDTO::class)]
class Book
{
#[ORM\Column]
#[Map(target: 'title', transform: TransformCallable::class)]
public string $title;
}
Transform with a service
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\Attribute::IS_REPEATABLE)]
readonly class Map
{
/**
* @param string|class-string|null $source The property or the class to map from
* @param string|class-string|null $target The property or the class to map to
* @param mixed $if A boolean, Symfony service name or a callable that instructs whether
to map
* @param mixed $transform A Symfony service name or a callable that transform the value
during mapping
*/
public function __construct(
public ?string $target = null,
public ?string $source = null,
public mixed $if = null,
public mixed $transform = null,
) {
}
}
Conditionnal mapping
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use App\ValueObject\User as UserDTO;
use Symfony\Component\ObjectMapper\Attribute\Map;
#[Map(target: UserDTO::class)]
class User
{
#[Map(if: false)] // This will never be mapped to UserDTO
public ?string $password = null;
}
Conditional Mapping
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#[Map(target: User::class)]
final class UserDTO
{
#[Map(target: 'firstName', transform: [self::class, 'toFirstName'])]
#[Map(target: 'lastName', transform: [self::class, 'toLastName'])]
public string $username;
public static function toFirstName(string $v): string {
return explode(' ', $v)[0] ?? null;
}
public static function toLastName(string $v): string {
return explode(' ', $v)[1] ?? null;
}
}
Multiple targets on a property
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#[Map(target: PublishedBlogPost::class, if: static function ($value, $source) {
return $source->status === 'published';
})]
#[Map(target: DraftBlogPost::class, if: static function ($value, $source) {
return $source->status === 'draft';
})]
final class BlogPost
{
public ?string $status;
}
Multiple targets on a class
https://wiki.php.net/rfc/closures_in_const_expr
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I see you…
Can I define my mapping on:
➔ the target instead of the source ?
➔ on a mapper class (like
MicroMapper or MapStruct) ?
➔ Mapper builder (like valinor)
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Create your own ObjectMapperMetadataFactory!
use Symfony\Component\ObjectMapper\Attribute\Map;
use Symfony\Component\ObjectMapper\ObjectMapper;
use Symfony\Component\ObjectMapper\ObjectMapperInterface;
#[Map(source: Source::class, target: Target::class)]
class AToBMapper implements ObjectMapperInterface
{
public function __construct(private readonly ObjectMapper $objectMapper)
{
}
#[Map(source: 'propertyA', target: 'propertyD')]
#[Map(source: 'propertyB', if: false)]
public function map(object $source, object|string|null $target = null): object
{
return $this->objectMapper->map($source, $target);
}
}
See the MapStructMapperMetadataFactory
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API Platform
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namespace App\ApiResource;
#[ApiResource]
readonly class Book
{
public function __construct(public string $id, public string $title) {}
}
1. Define the API Resources with a PHP class
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namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
#[ORM\Entity]
class Book
{
#[ORM\Column]
public ?string $title;
}
namespace App\ApiResource;
use App\Entity\Book as BookEntity;
use ApiPlatform\Doctrine\Orm\State\Options;
#[ApiResource(stateOptions: new Options(entityClass: BookEntity::class))]
readonly class Book
{
public function __construct(public string $id, public string $title) {}
}
2. Provide a data source (Doctrine Entity)
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST RESPONSE
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST
App\Entity\Book {
id: 1
title: 'Animal Farm'
}
RESPONSE
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST RESPONSE
App\ApiResource\Book {
title: '1984'
}
App\Entity\Book {
id: 1
title: 'Animal Farm'
}
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https://symfony.com/doc/current/serializer.html
use App\ApiResource\Book;
use Symfony\Component\Serializer\Normalizer\AbstractNormalizer;
// ...
$book = new Book('1984');
$serializer->deserialize($jsonData, Book::class, 'json', [
AbstractNormalizer::OBJECT_TO_POPULATE => $book,
]);
// instead of returning a new object, $book is updated instead
The serializer can also be used to update an existing object. You can do this by
configuring the object_to_populate serializer context option:
Deserializing in an Existing Object
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST RESPONSE
App\ApiResource\Book {
id: 1
title: 'Animal Farm'
}
?
App\ApiResource\Book {
title: '1984'
}
App\Entity\Book {
id: 1
title: 'Animal Farm'
}
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namespace App\ApiResource;
use App\Entity\Book as BookEntity;
use ApiPlatform\Doctrine\Orm\State\Options;
#[ApiResource(stateOptions: new Options(entityClass: BookEntity::class))]
readonly class Book
{
public function __construct(public string $title) {}
}
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namespace App\ApiResource;
use App\Entity\Book as BookEntity;
use ApiPlatform\Doctrine\Orm\State\Options;
use Symfony\ObjectMapper\Attribute\Map;
#[ApiResource(stateOptions: new Options(entityClass: BookEntity::class))]
#[Map(target: BookEntity::class)]
readonly class Book
{
public function __construct(public string $title) {}
}
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST RESPONSE
App\ApiResource\Book {
id: '1'
title: 'Animal Farm'
}
$mapper->map($book);
App\Entity\Book {
id: 1
title: 'Animal Farm'
}
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST RESPONSE
App\ApiResource\Book {
title: '1984'
}
App\ApiResource\Book {
id: '1'
title: 'Animal Farm'
}
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST RESPONSE
App\ApiResource\Book {
id: '1'
title: '1984'
}
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST RESPONSE
App\Entity\Book {
id: 1
title: 'Animal Farm'
}
$mapper->map($bookDto, $book);
App\ApiResource\Book {
id: '1'
title: '1984'
}
App\Entity\Book {
id: 1
title: '1984'
}
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST RESPONSE
App\ApiResource\Book {
id: '1'
title: '1984'
}
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PUT /books/1
Content-Type: "application/json"
{"title": "1984"}
200 OK
Content-Type: "application/json"
{"title": "1984", "id": "1"}
REQUEST RESPONSE
App\ApiResource\Book {
title: '1984'
}
App\ApiResource\Book {
id: '1'
title: '1984'
}
App\Entity\Book {
id: 1
title: '1984'
}
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https://github.com/api-platform/core/pull/6801
API Platform integration
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What about
performances?
And @joel’s AutoMapper
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/**
* @template T of object
*/
interface ObjectMapperInterface
{
/**
* @param object $source The object to map from
* @param T|class-string|null $target The object or class to map to
*
* @return T
*/
public function map(object $source, object|string|null $target = null): object;
}
[RFC] ObjectMapper · Issue #54476 · symfony/symfony · GitHub
One interface to rule them all!
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[RFC] ObjectMapper · Issue #54476 · symfony/symfony · GitHub
Dumping code is more efficient
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[RFC] ObjectMapper · Issue #54476 · symfony/symfony · GitHub
Reflection is slow?
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Automapper
────────────────────────────────────────────
Language Files Lines Blanks Comments Code Complexity
────────────────────────────────────────────
PHP 53 4597 751 1216 2630 230
────────────────────────────────────────────
scc --include-ext php --exclude-dir Tests .
Complexity
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Complexity
Object Mapper
────────────────────────────────────────────
Language Files Lines Blanks Comments Code Complexity
────────────────────────────────────────────
PHP 12 615 86 235 294 41
────────────────────────────────────────────
scc --include-ext php --exclude-dir Tests .
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No content
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symfony/object-mapper
➔ Object Mapper interface
➔ Low complexity implementation
➔ Improves our work daily
➔ Is a good complement to other
components (Validator, HttpKernel,
Serializer)
➔ Dumped object mappers
github.com/symfony/symfony/pull/51741
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Web and Cloud Experts
➔ Web development (PHP, JS, Go, Rust...)
➔ Support & hosting (FrankenPHP) apps
➔ Consultancy & maintenance
➔ UX & UI design
➔ [email protected] 💌
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Thanks!
Sponsor me at github.com/soyuka
Comment on the object mapper component:
github.com/symfony/symfony/pull/51741
[email protected]
@s0yuka
soyuka.me
soyuka.bsky.social