Php 如何使用基于ZfcBase DbMapper的模型在敏捷性驱动的应用程序中构建嵌套响应？

我正在开发一个RESTful web应用程序——由驱动并基于。对于模型层，我使用了。该模型基本上由两个实体组成：

Project

和

Image

（

1:n

），目前的实现方式如下：

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

use ZF\Hal\Collection

...

$images = new Collection($arrayOfImages);

$project['images'] = $images;

图像的结构相同

当请求资源（
/projects[/:id]
）时，响应的项目实体应包含其
图像
实体的列表

那么，这个
1:n
结构应该如何实现呢？

子问题：

[
DbMapper
]是否提供了一些“魔法”来“自动”检索这样的树结构，而无需编写
JOIN
s（或使用ORM）

[
Apigility
]是否为构建嵌套响应提供了一些“魔力”



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"
        }
    }
}

{
    "_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
}

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

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,
            ),
            ...
        ),
    ),
);

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;
                }
            ),
        );
    }

    ...

}

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;
    }

}

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;
    }

}

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;
    }

    ...

}

因此，它适用于单个对象。但不适用于集合，其中单个项目包括更多集合：

/projects

{
    "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"
        }
    }
}

{
    "_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
}

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

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,
            ),
            ...
        ),
    ),
);

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;
                }
            ),
        );
    }

    ...

}

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;
    }

}

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;
    }

}

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;
    }

    ...

}

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;
}

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;
}

以及
项目映射器#findAll（）

{
    "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"
        }
    }
}

{
    "_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
}

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

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,
            ),
            ...
        ),
    ),
);

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;
                }
            ),
        );
    }

    ...

}

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;
    }

}

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;
    }

}

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;
    }

    ...

}

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;
}

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
}

但这是一个有点糟糕的解决方案，不是吗？我实际上在做的是：我只是在替换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，我想找到一个更好的解决方案（“符合Apigility的解决方案”）。
我没有使用db mapper的经验，但我想我可以为您回答问题2

如果提取的项目资源（数组）具有一个键
images
，该键保存类型为
Hal\Collection
的对象，它将自动提取该集合，并按照您在Hal示例中所示进行渲染

之所以出现这种“魔力”，是因为在
Hal.php
中的
renderEntity
方法中调用了
extractedembeddedcollection

编辑
你写下你想要的：

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

但你真正应该做到的是：

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

如何提取对象？您是否在元数据映射中注册了一个查询器

您应该尝试返回如下内容：

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

use ZF\Hal\Collection

...

$images = new Collection($arrayOfImages);

$project['images'] = $images;

然后它应该会起作用（我不知道如何解释它）。
我终于找到了解决方案。（再次感谢@在GitHub上的支持。）简言之，我们的想法是在水合步骤上使用嵌套的（
图像
）项目列表来丰富（
项目
）列表项目。我其实不太喜欢这种方式，因为对我来说，在水合水平上有太多的模型逻辑。但它是有效的。我们开始：

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

{
    "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"
        }
    }
}

{
    "_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
}

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

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,
            ),
            ...
        ),
    ),
);

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;
                }
            ),
        );
    }

    ...

}

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;
    }

}

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;
    }

}

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;
    }

    ...

}

Portfolio\Module

{
    "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"
        }
    }
}

{
    "_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
}

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

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,
            ),
            ...
        ),
    ),
);

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;
                }
            ),
        );
    }

    ...

}

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;
    }

}

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;
    }

}

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;
    }

    ...

}

Portfolio\V2\Rest\Project\projector

{
    "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"
        }
    }
}

{
    "_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
}

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

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,
            ),
            ...
        ),
    ),
);

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;
                }
            ),
        );
    }

    ...

}

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;
    }

}

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;
    }

}

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;
    }

    ...

}

Portfolio\V2\Rest\Project\ProjectMapperFactory

{
    "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"
        }
    }
}

{
    "_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
}

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

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,
            ),
            ...
        ),
    ),
);

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;
                }
            ),
        );
    }

    ...

}

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;
    }

}

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;
    }

}

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;
    }

    ...

}

Portfolio\V2\Rest\Project\ProjectMapper

{
    "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"
        }
    }
}

{
    "_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
}

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

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,
            ),
            ...
        ),
    ),
);

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;
                }
            ),
        );
    }

    ...

}

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;
    }

}

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;
    }

}

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上的帖子中所说的，如果能从Apigility核心团队得到反馈就太好了，无论这个解决方案是否“符合Apigility标准”，如果不是，还有什么更好的/正确的解决方案。
感谢您的回答！我终于让它工作了--几乎。。。我的实体
Project
具有属性images，但其类型为
Zend\Paginator\Paginator
。它适用于单个对象：这意味着，
/project/:id
提供一个项目及其映像：
{“id”：“1”，“title”：“foo”，“_embedded”：{“images”：[{image1}，{image2}，{image3}}
。（这对我来说意味着：
Paginator
作为集合父类的变体可以工作。）但它不适用于
/project
——当我请求项目列表时，它的项不包含嵌入的图像列表（请参见编辑）。你知道，如何让它也工作吗？为了避免误解，我将我的评论部分编号：1<代码>你想写什么就写什么。。。但是你真正的目标是…
——确切地说，我指的是嵌入
\u的正确
HAL
格式。2.“您在元数据映射中注册了水合器了吗？”--是的，我正在使用
Zend\\Stdlib\\hydrator\\ClassMethods
。3.“如何提取对象？”--请查看我的编辑。4.您的收藏建议：问题是，我无法遍历
ZF\Hal\collection
并修改其项目。您好，我面临着同样的问题，到目前为止，您是否找到了合适的解决方案？您好@JimitShah，这对我来说是一个合适的解决方案。我仍然不知道是否有更好/更优雅的，但至少这一个有效。