on official Api-Platform website there is a General Design Considerations page.
Last but not least, to create Event Sourcing-based systems, a convenient approach is:
- to persist data in an event store using a custom data persister
- to create projections in standard RDBMS (Postgres, MariaDB...) tables or views
- to map those projections with read-only Doctrine entity classes and to mark those classes with @ApiResource
You can then benefit from the built-in Doctrine filters, sorting, pagination, auto-joins, etc provided by API Platform.
So, I tried to implement this approach with one simplification (one DB is used, but with separated reads and writes).
But failed... there is a problem, which I don't know how to resolve, so kindly asking you for a help!
I created a User Doctrine entity and annotated fields I want to expose with @Serializer\Groups({"Read"}). I will omit it here as it's very generic.
User resource in yaml format for api-platform:
# config/api_platform/entities/user.yaml
App\Entity\User\User:
attributes:
normalization_context:
groups: ["Read"]
itemOperations:
get: ~
collectionOperations:
get:
access_control: "is_granted('ROLE_ADMIN')"
So, as it's shown above User Doctrine entity is read-only, as only GET methods are defined.
Then I created a CreateUser DTO:
# src/Dto/User/CreateUser.php
namespace App\Dto\User;
use App\Validator as AppAssert;
use Symfony\Component\Validator\Constraints as Assert;
final class CreateUser
{
/**
* @var string
* @Assert\NotBlank()
* @Assert\Email()
* @AppAssert\FakeEmailChecker()
*/
public $email;
/**
* @var string
* @Assert\NotBlank()
* @AppAssert\PlainPassword()
*/
public $plainPassword;
}
CreateUser resource in yaml format for api-platform:
# config/api_platform/dtos/create_user.yaml
App\Dto\User\CreateUser:
itemOperations: {}
collectionOperations:
post:
access_control: "is_anonymous()"
path: "/users"
swagger_context:
tags: ["User"]
summary: "Create new User resource"
So, here you can see that only one POST method is defined, exactly for creation of a new User.
And here what router shows:
$ bin/console debug:router
---------------------------------- -------- -------- ------ -----------------------
Name Method Scheme Host Path
---------------------------------- -------- -------- ------ -----------------------
api_create_users_post_collection POST ANY ANY /users
api_users_get_collection GET ANY ANY /users.{_format}
api_users_get_item GET ANY ANY /users/{id}.{_format}
I also added a custom DataPersister to handle POST to /users. In CreateUserDataPersister::persist I used Doctrine entity to write data, but for this case it doesn't matter as Api-platform do not know anything about how DataPersister will write it.
So, from the concept - it's a separation of reads and writes.
Reads are performed by Doctrine's DataProvider shipped with Api-platform, and writes are performed by custom DataPersister.
# src/DataPersister/CreateUserDataPersister.php
namespace App\DataPersister;
use ApiPlatform\Core\DataPersister\DataPersisterInterface;
use App\Dto\User\CreateUser;
use App\Entity\User\User;
use Doctrine\ORM\EntityManagerInterface;
class CreateUserDataPersister implements DataPersisterInterface
{
private $manager;
public function __construct(EntityManagerInterface $manager)
{
$this->manager = $manager;
}
public function supports($data): bool
{
return $data instanceof CreateUser;
}
public function persist($data)
{
$user = new User();
$user
->setEmail($data->email)
->setPlainPassword($data->plainPassword);
$this->manager->persist($user);
$this->flush();
return $user;
}
public function remove($data)
{
}
}
When I perform a request to create new User:
POST https://{{host}}/users
Content-Type: application/json
{
"email": "test@custom.domain",
"plainPassword": "123qweQWE"
}
Problem!
I'm getting a 400 response ... "hydra:description": "No item route associated with the type "App\Dto\User\CreateUser"." ...
However, a new record is added to database, so custom DataPersister works ;)
According to General Design Considerations separations of writes and reads are implemented, but not working as expected.
I'm pretty sure, that I could be missing something to configure or implement. So, that's why it's not working.
Would be happy to get any help!
Update 1:
The problem is in \ApiPlatform\Core\Bridge\Symfony\Routing\RouteNameResolver::getRouteName(). At lines 48-59 it iterates through all routes trying to find appropriate route for:
$operationType = 'item'$resourceClass = 'App\Dto\User\CreateUser'
But $operationType = 'item' is defined only for $resourceClass = 'App\Entity\User\User', so it fails to find the route and throws an exception.
Update 2:
So, the question could sound like this:
How it's possible to implement separation of reads and writes (CQS?) using Doctrine entity for reads and DTO for writes, both residing on the same route, but with different methods?
Update 3:
- store data to other persistence layers (ElasticSearch, MongoDB, external web services...)
- not publicly expose the internal model mapped with the database through the API
- use a separate model for read operations and for updates by implementing patterns such as CQRS
Yes! I want that... but how to achieve it in my example?
