Browse.php

<?php

namespace Sprocketbox\Quartermaster\Http\Actions;

use Illuminate\Contracts\Pagination\LengthAwarePaginator;
use Illuminate\Contracts\Pagination\Paginator;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Collection;
use Sprocketbox\Quartermaster\Contracts\Resource;

class Browse extends Action
{

    public function name(): string
    {
        return 'browse';
    }

    public function handle(Request $request, Resource $resource): JsonResponse
    {
        $handler = $resource->handler();

        if (! method_exists($handler, 'browse')) {
            throw new \RuntimeException('Resource handler does not support browse action');
        }

        $data = $handler->browse($request->query('limit'));

        if ($data instanceof Paginator) {
            return $this->handlePagination($resource, $data);
        }

        return $this->handleCollection($resource, $data);
    }

    private function handlePagination(Resource $resource, Paginator $paginator): JsonResponse
    {
        $format = '<%s>; rel="%s"';
        $links  = [];

        if (! \in_array($paginator->currentPage(), [0, 1], true)) {
            $links[] = sprintf($format, $paginator->url(1), 'first');
            $links[] = sprintf($format, $paginator->previousPageUrl(), 'prev');
        }

        if ($paginator->hasMorePages()) {
            $links[] = sprintf($format, $paginator->nextPageUrl(), 'next');
        }

        if ($paginator instanceof LengthAwarePaginator) {
            $links[] = sprintf($format, $paginator->url($paginator->lastPage()), 'last');
        }

        $headers = ['Links' => $links];
        return $this->quartermaster->buildResponse($resource, collect($paginator->items()), $headers, 200);
    }

    private function handleCollection(Resource $resource, $data): JsonResponse
    {
        $data = ! ($data instanceof Collection) ? collect($data) : $data;
        return $this->quartermaster->buildResponse($resource, $data, [], 200);
    }
}

Quartermaster.php

<?php

namespace Sprocketbox\Quartermaster;

use Illuminate\Http\JsonResponse;
use Illuminate\Support\Collection;
use Sprocketbox\Quartermaster\Contracts\Resource;

class Quartermaster
{
    /**
     * @var \Illuminate\Support\Collection
     */
    protected $resources;

    public function __construct()
    {
        $this->resources = new Collection;
    }

    public function registerResource(Resource $resource)
    {
        if (! $this->resources->has($resource->name())) {
            $this->resources->put($resource->name(), $resource);
            return $this;
        }

        throw new \InvalidArgumentException(sprintf('Resource %s is already registered', $resource->name()));
    }

    /**
     * @param string $name
     *
     * @return null|Resource
     */
    public function getResource(string $name): ?Resource
    {
        return $this->resources->get($name, null);
    }

    public function buildResponse(Resource $resource, $data, array $headers = [], int $status = 200): JsonResponse
    {
        $handler  = $resource->handler();
        $modified = $handler->lastModified($data);

        if ($data instanceof Collection) {
            $data = $data->map(function ($data) use ($handler) {
                return $handler->transform($data);
            });
        } else {
            $data = $handler->transform($data);
        }

        $content  = ['data' => $data];
        $response = response()->json($content, $status, $headers);

        return $response
            ->setEtag(md5($response->content()))
            ->setLastModified($modified);
    }
}