Using DDD architecture with zend-db in Slim 4
Slim 4 provides a skeleton that uses DDD directory style. By this, we can implement DDD architecture easier. Let’s try with zend-db for it. In this post, I assume that you already uses Twig as view template engine like in previous post.
Requirements
First, we need to require zend-db via composer:
$ composer require zendframework/zend-db \
zendframework/zend-hydrator \
--sort-packages
We are going to make pages to display post table record(s) with the following data:
# create and use database
create database slim;
use slim;
# create table
create table post(id int not null primary key auto_increment, title varchar(50) not null, content text not null);
# insert data
insert into post(title, content) values('first post', 'first post content');
insert into post(title, content) values('second post', 'second post content');
Database Configuration
<?php
// app/settings.php
// ...
return function (ContainerBuilder $containerBuilder) {
$containerBuilder->addDefinitions([
// ...
'db' => [
'username' => 'root',
'password' => '',
'driver' => 'pdo_mysql',
'database' => 'slim',
'host' => 'localhost',
'driver_options' => [
\PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\'',
],
],
// ...
],
]);
};
We can register database configuration at app/settings.php, for example, use MySQL database as configured above.
DB Service
We are using service named Zend\Db\Adapter\AdapterInterface, so we can register as follow in app/dependencies.php:
<?php
// app/dependencies.php
declare(strict_types=1);
use DI\ContainerBuilder;
use Psr\Container\ContainerInterface;
use Zend\Db\Adapter\Adapter;
use Zend\Db\Adapter\AdapterInterface;
return function (ContainerBuilder $containerBuilder) {
$containerBuilder->addDefinitions([
// ...
AdapterInterface::class => function (ContainerInterface $c) {
return new Adapter($c->get('settings')['db']);
},
// ...
]);
};
Domain
a. Post class:
<?php
// src/Domain/Post/Post.php
declare(strict_types=1);
namespace App\Domain\Post;
final class Post
{
public $id;
public $title;
public $content;
public const TABLE = 'post';
public function __construct(Post $post = null)
{
if ($post instanceof Post) {
$this->id = +$post->id;
$this->title = ucwords($post->title);
$this->content = ucfirst($post->content);
}
}
}
b. PostRepository interface:
<?php
// src/Domain/Post/PostRepository.php
declare(strict_types=1);
namespace App\Domain\Post;
interface PostRepository
{
public function findAll(): array;
public function findPostOfId(int $id): Post;
}
c. PostNotFoundException class:
<?php
// src/Domain/Post/PostNotFoundException.php
declare(strict_types=1);
namespace App\Domain\Post;
use App\Domain\DomainException\DomainRecordNotFoundException;
class PostNotFoundException extends DomainRecordNotFoundException
{
public $message = 'The post you requested does not exist.';
}
Infrastructure
We can create a repository that implements App\Domain\Post\PostRepository, eg: named ZendDbPostRepository:
<?php
// src/Infrastructure/Persitence/Post/ZendDbPostRepository.php
declare(strict_types=1);
namespace App\Infrastructure\Persistence\Post;
use function compact;
use App\Domain\Post\Post;
use App\Domain\Post\PostNotFoundException;
use App\Domain\Post\PostRepository;
use Zend\Db\TableGateway\AbstractTableGateway;
class ZendDbPostRepository implements PostRepository
{
private $tableGateway;
public function __construct(AbstractTableGateway $tableGateway)
{
$this->tableGateway = $tableGateway;
}
public function findAll(): array
{
$results = $this->tableGateway->select();
$posts = [];
foreach ($results as $result) {
$posts[] = new Post($result);
}
return $posts;
}
public function findPostOfId(int $id): Post
{
$current = $this->tableGateway->select(compact('id'))->current();
if (! $current) {
throw new PostNotFoundException();
}
return new Post($current);
}
}
The Repository class above needs to be registered to app/repositories.php:
<?php
// app/repositories.php
declare(strict_types=1);
use App\Domain\Post\Post;
use App\Domain\Post\PostRepository;
use App\Infrastructure\Persistence\Post\ZendDbPostRepository;
use DI\ContainerBuilder;
use Psr\Container\ContainerInterface;
use Zend\Db\Adapter\AdapterInterface;
use Zend\Db\ResultSet\HydratingResultSet;
use Zend\Db\TableGateway\TableGateway;
use Zend\Hydrator\ObjectPropertyHydrator;
return function (ContainerBuilder $containerBuilder) {
$containerBuilder->addDefinitions([
// ...
PostRepository::class => function (ContainerInterface $c) {
$tableGateway = new TableGateway(
Post::TABLE,
$c->get(AdapterInterface::class),
null,
new HydratingResultSet(new ObjectPropertyHydrator(), new Post())
);
return new ZendDbPostRepository($tableGateway);
},
// ...
]);
};
Application
For application, we can create 2 classes to display all posts and display post by id.
a. All posts via PostPage class
<?php
// src/Application/Page/PostPage.php
declare(strict_types=1);
namespace App\Application\Page;
use App\Domain\Post\PostRepository;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\RequestHandlerInterface;
use Slim\Psr7\Response;
use Slim\Views\Twig;
class PostPage implements RequestHandlerInterface
{
private $view;
private $postRepository;
public function __construct(Twig $view, PostRepository $postRepository)
{
$this->view = $view;
$this->postRepository = $postRepository;
}
public function handle(ServerRequestInterface $request) : ResponseInterface
{
return $this->view->render(
new Response(),
'page/post/index.html.twig',
[
'posts' => $this->postRepository->findAll(),
]
);
}
}
b. Post By Id via PostPageDetail class
<?php
// src/Application/Page/PostPageDetail.php
declare(strict_types=1);
namespace App\Application\Page;
use App\Domain\DomainException\DomainRecordNotFoundException;
use App\Domain\Post\PostRepository;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\RequestHandlerInterface;
use Slim\Exception\HttpNotFoundException;
use Slim\Psr7\Response;
use Slim\Views\Twig;
class PostPageDetail implements RequestHandlerInterface
{
private $view;
private $postRepository;
public function __construct(Twig $view, PostRepository $postRepository)
{
$this->view = $view;
$this->postRepository = $postRepository;
}
public function handle(ServerRequestInterface $request) : ResponseInterface
{
$id = +$request->getAttribute('id');
try {
$post = $this->postRepository->findPostOfId($id);
} catch (DomainRecordNotFoundException $e) {
throw new HttpNotFoundException($request, $e->getMessage());
}
return $this->view->render(
new Response(),
'page/post/detail.html.twig',
[
'post' => $post,
]
);
}
}
Routing
Now, time to register routing:
<?php
// app/routes.php
declare(strict_types=1);
use App\Application\Page\PostPage;
use App\Application\Page\PostPageDetail;
use Slim\App;
use Slim\Handlers\Strategies\RequestHandler;
return function (App $app) {
$routeCollector = $app->getRouteCollector();
$routeCollector->setDefaultInvocationStrategy(
new RequestHandler(true)
);
$app->get('/posts', PostPage::class);
$app->get('/posts/{id:[0-9]+}', PostPageDetail::class);
};
View
a. templates/page/post/index.html.twig:
{# templates/page/post/index.html.twig #}
{% extends "layout.html.twig" %}
{% block body %}
{% for post in posts %}
<h3> {{ post.title }} </h3>
<p> {{ post.content }} </p>
{% endfor %}
{% endblock %}
b. templates/page/post/detail.html.twig:
{# templates/page/post/detail.html.twig #}
{% extends "layout.html.twig" %}
{% block body %}
<h3> {{ post.title }} </h3>
<p> {{ post.content }} </p>
{% endblock %}
Run PHP Server
php -S localhost:8080 -t public
Now, we can see the pages, http://localhost:8080/posts for all posts:
and http://localhost:8080/posts/1 for detail post:
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