Error using browser back to ACS url

[tmilos]

@moltedopablo reported issue in aerialship/lightsaml#45

This error happens when the user goes back in the browser and ends up in app_dev.php/saml/sp/acs. Apparently a simple request to the acs throws a 500 error and that it's not the desired behavior. Ideally the user has to be redirected to the application again.

Here is my trace:

[1] RuntimeException: Expected Protocol/Response type but got nothing
    at n/a
        in /srv/qcm/wwwroot/vendor/aerialship/saml-sp-bundle/src/AerialShip/SamlSPBundle/Bridge/AssertionConsumer.php line 99

    at AerialShip\SamlSPBundle\Bridge\AssertionConsumer->getSamlResponse(object(Request))
        in /srv/qcm/wwwroot/vendor/aerialship/saml-sp-bundle/src/AerialShip/SamlSPBundle/Bridge/AssertionConsumer.php line 72

    at AerialShip\SamlSPBundle\Bridge\AssertionConsumer->manage(object(Request))
        in /srv/qcm/wwwroot/vendor/aerialship/saml-sp-bundle/src/AerialShip/SamlSPBundle/RelyingParty/RelyingPartyCollection.php line 41

    at AerialShip\SamlSPBundle\RelyingParty\RelyingPartyCollection->manage(object(Request))
        in /srv/qcm/wwwroot/vendor/aerialship/saml-sp-bundle/src/AerialShip/SamlSPBundle/Security/Http/Firewall/SamlSpAuthenticationListener.php line 64

    at AerialShip\SamlSPBundle\Security\Http\Firewall\SamlSpAuthenticationListener->attemptAuthentication(object(Request))
        in /srv/qcm/wwwroot/vendor/symfony/symfony/src/Symfony/Component/Security/Http/Firewall/AbstractAuthenticationListener.php line 145

    at Symfony\Component\Security\Http\Firewall\AbstractAuthenticationListener->handle(object(GetResponseEvent))
        in /srv/qcm/wwwroot/app/cache/dev/classes.php line 2454

    at Symfony\Component\Security\Http\Firewall->onKernelRequest(object(GetResponseEvent), 'kernel.request', object(TraceableEventDispatcher))
        in  line 

    at call_user_func(array(object(Firewall), 'onKernelRequest'), object(GetResponseEvent), 'kernel.request', object(TraceableEventDispatcher))
        in /srv/qcm/wwwroot/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/Debug/TraceableEventDispatcher.php line 392

    at Symfony\Component\HttpKernel\Debug\TraceableEventDispatcher->Symfony\Component\HttpKernel\Debug\{closure}(object(GetResponseEvent), 'kernel.request', object(ContainerAwareEventDispatcher))
        in  line 

    at call_user_func(object(Closure), object(GetResponseEvent), 'kernel.request', object(ContainerAwareEventDispatcher))
        in /srv/qcm/wwwroot/app/cache/dev/classes.php line 1747

    at Symfony\Component\EventDispatcher\EventDispatcher->doDispatch(array(object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure), object(Closure)), 'kernel.request', object(GetResponseEvent))
        in /srv/qcm/wwwroot/app/cache/dev/classes.php line 1680

    at Symfony\Component\EventDispatcher\EventDispatcher->dispatch('kernel.request', object(GetResponseEvent))
        in /srv/qcm/wwwroot/app/cache/dev/classes.php line 1844

    at Symfony\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.request', object(GetResponseEvent))
        in /srv/qcm/wwwroot/vendor/symfony/symfony/src/Symfony/Component/HttpKernel/Debug/TraceableEventDispatcher.php line 139

    at Symfony\Component\HttpKernel\Debug\TraceableEventDispatcher->dispatch('kernel.request', object(GetResponseEvent))
        in /srv/qcm/wwwroot/app/bootstrap.php.cache line 2900

    at Symfony\Component\HttpKernel\HttpKernel->handleRaw(object(Request), '1')
        in /srv/qcm/wwwroot/app/bootstrap.php.cache line 2883

    at Symfony\Component\HttpKernel\HttpKernel->handle(object(Request), '1', true)
        in /srv/qcm/wwwroot/app/bootstrap.php.cache line 3022

    at Symfony\Component\HttpKernel\DependencyInjection\ContainerAwareHttpKernel->handle(object(Request), '1', true)
        in /srv/qcm/wwwroot/app/bootstrap.php.cache line 2303

    at Symfony\Component\HttpKernel\Kernel->handle(object(Request))
        in /srv/qcm/wwwroot/web/app_dev.php line 28

Thanks a lot for your help
Regards