JsonHandler for KnpPaginatiorBundle

JsonHandler.php

<?php

namespace Serializer\Handler;

use FOS\RestBundle\View\ViewHandler;
use FOS\RestBundle\View\View;
use Knp\Bundle\PaginatorBundle\Pagination\SlidingPagination;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\RouterInterface;

/**
* @author kibao
*/
class JsonHandler
{
    protected $router;

    public function __construct(RouterInterface $router)
    {
        $this->router = $router;
    }

    public function createResponse(ViewHandler $handler, View $view, Request $request, $format)
    {
        $data = $view->getData();

        if ($data instanceof SlidingPagination) {
            $view->setHeader('Link', $this->getPageLinksHeader($data));
            $view->setData($data->getItems());
        }

        return $handler->createResponse($view, $request, $format);
    }

    protected function getPageLinksHeader(SlidingPagination $pagination)
    {
        $pages = $this->getPages($pagination);
        $page_links = array();
        foreach ($pages as $page => $path) {
            $page_links[$page] = sprintf('<%s>; rel="%s"', $path, $page);
        }

        return implode(', ', $page_links);
    }

    protected function getPages(SlidingPagination $pagination)
    {
        $current = $pagination->getCurrentPageNumber();
        $pagination_data = $pagination->getPaginationData();

        $first = isset($pagination_data['first']) ? $pagination_data['first'] : null;
        $previous = isset($pagination_data['previous']) ? $pagination_data['previous'] : null;
        $next = isset($pagination_data['next']) ? $pagination_data['next'] : null;
        $last = isset($pagination_data['last']) && $pagination_data['last'] != 0 ? $pagination_data['last'] : null;

        $pages = array();
        if (null !== $first && $current != $first) {
            $pages["first"] = $this->generatePath($pagination, $first);
        }
        if (null !== $previous) {
            $pages["previous"] = $this->generatePath($pagination, $previous);
        }
        if (null !== $next) {
            $pages["next"] = $this->generatePath($pagination, $next);
        }
        if (null !== $last && $current != $last) {
            $pages["last"] = $this->generatePath($pagination, $last);
        }

        return $pages;
    }

    protected function generatePath(SlidingPagination $pagination, $page, $absolute = true)
    {
        $params = $pagination->getQuery(
                array(
                    $pagination->getPaginatorOption('pageParameterName') => $page
                )
        );

        return $this->router->generate($pagination->getRoute(), $params, $absolute);
    }
}