[RFC] Redirect to last available page strategy

[Koc]

This is follow up of #60.

I want create redirect to last available page when trying open non-existent page (OutOfRangeCurrentPageException). Currently I've code like this

<?php

namespace Metal\ProjectBundle\Pagerfanta\EventListener;

use Pagerfanta\Exception\NotValidCurrentPageException;
use Pagerfanta\Exception\OutOfRangeCurrentPageException;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\Routing\Generator\UrlGeneratorInterface;

class HandleOutOfRangeCurrentPage implements EventSubscriberInterface
{
    private $router;

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

    /**
     * @param GetResponseForExceptionEvent $event
     */
    public function onException(GetResponseForExceptionEvent $event)
    {
        $rootException = $exception = $event->getException();

        do {
            if ($exception instanceof OutOfRangeCurrentPageException) {
                preg_match('/"(\d+)"$/', $exception->getMessage(), $matches); // this hack can be easy removed: create field "maxAvailablePage" in exception class
                $maxPage = $matches[1];
                $request = $event->getRequest();
                $url = $this->router->generate(
                    $request->attributes->get('_route'),
                    array_merge(
                        $request->attributes->get('_route_params'),
                        $request->query->all(),
                        array('page' => $maxPage) // we have hardcoded page parameter name here
                    ),
                    true
                );

                $event->setResponse(RedirectResponse::create($url, 301));

                return;
            }

            if ($exception instanceof NotValidCurrentPageException) {
                $event->setException(new NotFoundHttpException('Page Not Found', $rootException));
                return;
            }
        } while ($exception = $exception->getPrevious()); // Twig wraps actual exception into his own
    }

    /**
     * {@inheritDoc}
     */
    public static function getSubscribedEvents()
    {
        return array(
            KernelEvents::EXCEPTION => array('onException', 512)
        );
    }
}

As you can see from code above, main problem is that we cann't dehardcode parameter for page name. Has anybody any suggestions for how to deal with it?

I think, that we can create method like Form::handleRequest, something like $pagerfanta->handleRequest($request, 'nameOfPageParameter') and then use this parameter on route generation.

[pablodip]

A good solution could be setting the max available page to the exception, which should be done on Pagerfanta itself. Would you like to create a PR? :)

[Koc]

I'm can create PR but max available page is not enough. We should to know whan route or query parameter used for page generation.

[pablodip]

Aren't they on the request?

[Koc]

As you see it can be customized https://github.com/whiteoctober/WhiteOctoberPagerfantaBundle/blob/master/Twig/PagerfantaExtension.php#L105