Quick and dirty Fractal HAL serializer

HalSerializer.php

<?php

/**
 * The MIT License (MIT)
 * Copyright (c) 2016 Alegion (http://www.alegion.com)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

namespace Alegion\Fractal\Serializer;

use League\Fractal\Pagination\CursorInterface;
use League\Fractal\Pagination\PaginatorInterface;
use League\Fractal\Resource\ResourceInterface;
use League\Fractal\Serializer\ArraySerializer;
use Nocarrier\Hal;

/**
 * HalSerializer for use with Fractal.
 */
class HalSerializer extends ArraySerializer
{
    /**
     * @var Hal
     */
    private $hal;

    /**
     * HalSerializer constructor.
     *
     * @param Hal $hal Used for "top level" resources in collections only
     */
    public function __construct(Hal $hal)
    {
        $this->hal = $hal;
    }

    /**
     * Serialize a collection.
     *
     * @param string $resourceKey
     * @param array  $data
     *
     * @return array
     */
    public function collection($resourceKey, array $data)
    {
        \Functional\each($data, function (array $resource) use ($resourceKey) {
            $embedded = new Hal(null, $this->item(null, $resource));
            $this->hal->addResource($resourceKey, $embedded);
        });

        return $this->getHalAsArray($this->hal);
    }

    /**
     * Serialize an item.
     *
     * @param string $resourceKey Not used in this implementation
     * @param array  $data
     *
     * @return array
     */
    public function item($resourceKey, array $data): array
    {
        $hal = new Hal();

        if (array_key_exists('links', $data)) {
            \Functional\each($data['links'], function ($link) use ($hal, $resourceKey) {
                $rel = $resourceKey ?? $link['rel'];
                $attributes = $link['attributes'] ?? [];
                $hal->addLink($link['rel'], $link['uri'], $attributes);
            });

            unset($data['links']);
        }

        $hal->setData($data);

        return $this->getHalAsArray($hal);
    }

    /**
     * Serialize null resource.
     *
     * @return array
     */
    public function null()
    {
        // TODO: Implement null() method.
        return [];
    }

    /**
     * Serialize the included data.
     *
     * @param ResourceInterface $resource
     * @param array             $data
     *
     * @return array
     *
     * @throws \RuntimeException
     */
    public function includedData(ResourceInterface $resource, array $data)
    {
        throw new \RuntimeException('HalSerializer::includedData NOT IMPLEMENTED');
    }

    /**
     * Serialize the meta.
     *
     * @param array $meta
     *
     * @return array
     */
    public function meta(array $meta)
    {
        $this->hal->setData(array_merge($this->hal->getData(), $meta));

        return $this->getHalAsArray($this->hal);
    }

    /**
     * Serialize the paginator.
     *
     * @param PaginatorInterface $paginator
     *
     * @return array
     */
    public function paginator(PaginatorInterface $paginator)
    {
        $currentPage = (int) $paginator->getCurrentPage();
        $lastPage = (int) $paginator->getLastPage();

        $data = [
            'total' => (int) $paginator->getTotal(),
            'count' => (int) $paginator->getCount(),
            'per_page' => (int) $paginator->getPerPage(),
            'current_page' => $currentPage,
            'total_pages' => $lastPage,
        ];

        $links = [];

        $links['self'] = $paginator->getUrl($currentPage);

        if ($currentPage > 1) {
            $links['first'] = $paginator->getUrl(1);
            $links['previous'] = $paginator->getUrl($currentPage - 1);
        }

        if ($currentPage < $lastPage) {
            $links['next'] = $paginator->getUrl($currentPage + 1);
            $links['last'] = $paginator->getUrl($lastPage);
        }

        foreach ($links as $rel => $uri) {
            $this->hal->addLink($rel, $uri);
        }

        $this->hal->setData(array_merge($this->hal->getData(), $data));

        // Return empty array so Scope doesn't set pagination data and links
        // in a pagination key
        return [];
    }

    /**
     * Serialize the cursor.
     *
     * @param CursorInterface $cursor
     *
     * @return array
     */
    public function cursor(CursorInterface $cursor)
    {
        // TODO: Implement cursor() method.
        return [];
    }

    /**
     * Returns an array representation of the Hal entity.
     *
     * @param Hal $hal
     *
     * @return array
     */
    private function getHalAsArray(Hal $hal)
    {
        $pretty = false;
        $encode = false;

        return $hal->asJson($pretty, $encode);
    }
}