如何使用基于 ZfcBase-DbMapper 的模型在 Apigility 驱动的应用程序中构建嵌套响应？

Question

我正在开发 RESTful 网络应用程序 -- Apigility driven and based on the Zend Framework 2. For the model layer I'm using the ZfcBase DbMapper。该模型基本上由两个实体组成：Project 和 Image (1:n)，目前是这样实现的：

ProjectCollection extends Paginator
ProjectEntity
ProjectMapper extends AbstractDbMapper
ProjectService implements ServiceManagerAwareInterface
ProjectServiceFactory implements FactoryInterface

Image 的相同结构。

请求资源 (/projects[/:id]) 时，响应的项目 entity/entities 应包含 its/their Image 个实体的列表。

那么，can/should这个1:n结构是如何实现的呢？

子问题：

是否 [DbMapper] 提供一些 "magic" 来检索这样的树结构 "automatically" 而无需编写 JOINs（或使用 ORM） ?
[Apigility] 是否提供一些 "magic" 用于构建嵌套响应？

{
    "_links": {
        "self": {
            "href": "http://myproject-api.misc.loc/projects?page=1"
        },
        "first": {
            "href": "http://myproject-api.misc.loc/projects"
        },
        "last": {
            "href": "http://myproject-api.misc.loc/projects?page=1"
        }
    },
    "_embedded": {
        "projects": [
            {
                "id": "1",
                "title": "project_1",
                "images": [
                    {
                        "id": "1",
                        "title": "image_1"
                    },
                    {
                        "id": "2",
                        "title": "image_2"
                    }
                ],
                "_links": {
                    "self": {
                        "href": "http://myproject-api.misc.loc/projects/1"
                    }
                }
            },
            {
                "id": "2",
                "title": "project_2",
                "images": [
                    {
                        "id": "3",
                        "title": "image_3"
                    },
                    {
                        "id": "4",
                        "title": "image_4"
                    }
                ],
                "_links": {
                    "self": {
                        "href": "http://myproject-api.misc.loc/projects/1"
                    }
                }
            }
        ]
    },
    "page_count": 1,
    "page_size": 25,
    "total_items": 1
}

编辑

我目前得到的输出是：

/projects/:id

{
    "id": "1",
    "title": "...",
    ...
    "_embedded": {
        "images": [
            {
                "id": "1",
                "project_id": "1",
                "title": "...",
                ...
                "_links": {
                    "self": {
                        "href": "http://myproject-api.misc.loc/images/1"
                    }
                }
            },
            {
                "id": "2",
                "project_id": "1",
                "title": "...",
                ...
                "_links": {
                    "self": {
                        "href": "http://myproject-api.misc.loc/images/2"
                    }
                }
            },
            {
                "id": "3",
                "project_id": "1",
                "title": "...",
                ...
                "_links": {
                    "self": {
                        "href": "http://myproject-api.misc.loc/images/3"
                    }
                }
            }
        ]
    },
    "_links": {
        "self": {
            "href": "http://myproject-api.misc.loc/projects/1"
        }
    }
}

所以它适用于一个单一的对象。但不适用于集合，其中单个项目包含更多集合：

/projects

{
    "_links": {
        "self": {
            "href": "http://myproject-api.misc.loc/projects?page=1"
        },
        "first": {
            "href": "http://myproject-api.misc.loc/projects"
        },
        "last": {
            "href": "http://myproject-api.misc.loc/projects?page=24"
        },
        "next": {
            "href": "http://myproject-api.misc.loc/projects?page=2"
        }
    },
    "_embedded": {
        "projects": [
            {
                "id": "1",
                "title": "...",
                ... <-- HERE I WANT TO GET ["images": {...}, {...}, {...}]
                "_links": {
                    "self": {
                        "href": "http://myproject-api.misc.loc/projects/1"
                    }
                }
            },
            {
                "id": "2",
                "title": "...",
                ... <-- HERE I WANT TO GET ["images": {...}, {...}, {...}]
                "_links": {
                    "self": {
                        "href": "http://myproject-api.misc.loc/projects/2"
                    }
                }
            },
            {
                "id": "3",
                "title": "...",
                ... <-- HERE I WANT TO GET ["images": {...}, {...}, {...}]
                "_links": {
                    "self": {
                        "href": "http://myproject-api.misc.loc/projects/3"
                    }
                }
            }
        ]
    },
    "page_count": 24,
    "page_size": 3,
    "total_items": 72
}

编辑

我编辑了我的代码并向目标迈出了一步。

它无法工作，因为我的 ProjectService#getProjects() 只是从数据库返回项目数据，没有用图像丰富：

public function getProjects() {
    return $this->getMapper()->findAll();
}

编辑为：

public function getProjects() {
    $projects = $this->getMapper()->findAll();
    foreach ($projects as $key => $project) {
        $images = $this->getImageService()->getImagesForProject($project['id']);
        $projects[$key]['images'] = $images;
    }
    return $projects;
}

和ProjectMapper#findAll()

public function findAll() {
    $select = $this->getSelect();
    $adapter = $this->getDbAdapter();
    $paginatorAdapter = new DbSelect($select, $adapter);
    $collection = new ProjectCollection($paginatorAdapter);
    return $collection;
}

编辑为：

public function findAll() {
    $select = $this->getSelect();
    $adapter = $this->getDbAdapter();
    $paginatorAdapter = new DbSelect($select, $adapter);
    // @todo Replace the constants with data from the config and request.
    $projects = $paginatorAdapter->getItems(0, 2);
    $projects = $projects->toArray();
    return $projects;
}

现在我得到了想要的输出：

{
    "_links": {
        "self": {
            "href": "http://myproject-api.misc.loc/projects"
        }
    },
    "_embedded": {
        "projects": [
            {
                "id": "1",
                "title": "...",
                ...
                "_embedded": {
                    "images": [
                        {
                            "id": "1",
                            "project_id": "1",
                            "title": "...",
                            ...
                            "_links": {
                                "self": {
                                    "href": "http://myproject-api.misc.loc/images/1"
                                }
                            }
                        },
                        {
                            ...
                        },
                        {
                            ...
                        }
                    ]
                },
                "_links": {
                    "self": {
                        "href": "http://myproject-api.misc.loc/projects/1"
                    }
                }
            },
            {
                "id": "2",
                "title": "...",
                ...
                "_embedded": {
                    "images": [
                        ...
                    ]
                },
                ...
            }
        ]
    },
    "total_items": 2
}

但这个解决方案有点糟糕，不是吗？我实际上在做的是：我只是替换了 Apigility 数据检索功能的一部分……无论如何，我不喜欢这个解决方案，想找到一个更好的解决方案（"Apigility conform solution"）。

Answer 1

我没有使用 db-mapper 的经验，但我认为可以为您回答问题 2。

如果您提取的项目资源（一个数组）有一个键 images 保存一个 Hal\Collection 类型的对象，它会自动提取这个集合并按照您在 Hal 示例中显示的那样呈现它。

发生这个"magic"是因为在Hal.phpon line 563.

的renderEntity方法中调用了extractEmbeddedCollection

编辑

你写你想要的：

["images": {...}, {...}, {...}]

但你真正应该瞄准的是：

{
    "id": "2",
    "title": "...",
    "_links": {
        "self": {
            "href": "http://myproject-api.misc.loc/projects/2"
        }
    },
    "_embedded": {
        "images": [ 
            {...}, 
            {...}, 
            {...}
        ]
    }
}

你如何提取你的对象？您是否在元数据地图中注册了水龙头？

你应该尝试 return 这样的事情：

use ZF\Hal\Collection

...

$images = new Collection($arrayOfImages);

$project['images'] = $images;

那么它应该可以工作（我不知道还能怎么解释）。

Answer 2

我终于找到了解决办法。（再次感谢GitHub上的@poisa for his solution suggestion。）简而言之，想法是用嵌套的（image）项目列表丰富（projects）列表项目水化步。我实际上不太喜欢这种方式，因为它对我来说在水化水平上的模型逻辑太多了。但它有效。我们开始吧：

/module/Portfolio/config/module.config.php

return array(
    ...
    'zf-hal' => array(
        'metadata_map' => array(
            ...
            'Portfolio\V2\Rest\Project\ProjectEntity' => array(
                'entity_identifier_name' => 'id',
                'route_name' => 'portfolio.rest.project',
                'route_identifier_name' => 'id',
                'hydrator' => 'Portfolio\V2\Rest\Project\ProjectHydrator',
            ),
            'Portfolio\V2\Rest\Project\ProjectCollection' => array(
                'entity_identifier_name' => 'id',
                'route_name' => 'portfolio.rest.project',
                'route_identifier_name' => 'id',
                'is_collection' => true,
            ),
            ...
        ),
    ),
);

Portfolio\Module

class Module implements ApigilityProviderInterface {

    ...

    public function getHydratorConfig() {
        return array(
            'factories' => array(
                // V2
                'Portfolio\V2\Rest\Project\ProjectHydrator' => function(ServiceManager $serviceManager) {
                    $projectHydrator = new ProjectHydrator();
                    $projectHydrator->setImageService($serviceManager->getServiceLocator()->get('Portfolio\V2\Rest\ImageService'));
                    return $projectHydrator;
                }
            ),
        );
    }

    ...

}

Portfolio\V2\Rest\Project\ProjectHydrator

namespace Portfolio\V2\Rest\Project;

use Zend\Stdlib\Hydrator\ClassMethods;
use Portfolio\V2\Rest\Image\ImageService;

class ProjectHydrator extends ClassMethods {

    /**
     * @var ImageService
     */
    protected $imageService;

    /**
     * @return ImageService the $imageService
     */
    public function getImageService() {
        return $this->imageService;
    }

    /**
     * @param ImageService $imageService
     */
    public function setImageService(ImageService $imageService) {
        $this->imageService = $imageService;
        return $this;
    }

    /*
     * Doesn't need to be implemented:
     * the ClassMethods#hydrate(...) handle the $data already as wished.
     */
    /*
    public function hydrate(array $data, $object) {
        $object = parent::hydrate($data, $object);
        if ($object->getId() !== null) {
            $images = $this->imageService->getImagesForProject($object->getId());
            $object->setImages($images);
        }
        return $object;
    }
    */

    /**
     * @see \Zend\Stdlib\Hydrator\ClassMethods::extract()
     */
    public function extract($object) {
        $array = parent::extract($object);
        if ($array['id'] !== null) {
            $images = $this->imageService->getImagesForProject($array['id']);
            $array['images'] = $images;
        }
        return $array;
    }

}

Portfolio\V2\Rest\Project\ProjectMapperFactory

namespace Portfolio\V2\Rest\Project;

use Zend\ServiceManager\ServiceLocatorInterface;

class ProjectMapperFactory {

    public function __invoke(ServiceLocatorInterface $serviceManager) {
        $mapper = new ProjectMapper();
        $mapper->setDbAdapter($serviceManager->get('PortfolioDbAdapter_V2'));
        $mapper->setEntityPrototype($serviceManager->get('Portfolio\V2\Rest\Project\ProjectEntity'));
        $projectHydrator = $serviceManager->get('HydratorManager')->get('Portfolio\V2\Rest\Project\ProjectHydrator');
        $mapper->setHydrator($projectHydrator);
        return $mapper;
    }

}

Portfolio\V2\Rest\Project\ProjectMapper

namespace Portfolio\V2\Rest\Project;

use ZfcBase\Mapper\AbstractDbMapper;
use Zend\Paginator\Adapter\DbSelect;
use Zend\Db\ResultSet\HydratingResultSet;

class ProjectMapper extends AbstractDbMapper {

    ...

    /**
     * Provides a collection of all the available projects.
     *
     * @return \Portfolio\V2\Rest\Project\ProjectCollection
     */
    public function findAll() {
        $resultSetPrototype = new HydratingResultSet(
            $this->getHydrator(),
            $this->getEntityPrototype()
        );
        $select = $this->getSelect();
        $adapter = $this->getDbAdapter();
        $paginatorAdapter = new DbSelect($select, $adapter, $resultSetPrototype);
        $collection = new ProjectCollection($paginatorAdapter);
        return $collection;
    }

    /**
     * Provides a project by ID.
     *
     * @param int $id
     * @return \Portfolio\V2\Rest\Project\ProjectEntity
     */
    public function findById($id) {
        $select = $this->getSelect();
        $select->where(array(
            'id' => $id,
        ));
        $entity = $this->select($select)->current();
        return $entity;
    }

    ...

}

正如我在 GitHub 上的 post 中所说的那样，如果这个解决方案是 "Apigility conform"，那么从 Apigility 核心团队的某个人那里得到反馈会很棒，而且，如果不是，什么是更好的/"correct" 解决方案。

如何使用基于 ZfcBase-DbMapper 的模型在 Apigility 驱动的应用程序中构建嵌套响应？

How to build nested responses in an Apigility driven application with a ZfcBase-DbMapper based model?

php

datamapper

one-to-many

zend-framework2

laminas-api-tools

编辑