StartSession.php

TLDR

This file, StartSession.php, is part of the Illuminate\Session\Middleware namespace in the Demo Projects project. It contains the StartSession class which is responsible for handling incoming requests and managing the session.

Methods

__construct(SessionManager $manager, callable $cacheFactoryResolver = null)

This method is the constructor of the StartSession class. It initializes the session manager and the cache factory resolver.

handle(Request $request, Closure $next)

This method handles an incoming request. It checks if the session is configured and then decides whether to handle the request in session state or handle the request while blocking.

handleRequestWhileBlocking(Request $request, $session, Closure $next)

This method handles the given request while blocking. It determines the lock duration and acquires a session lock. It then proceeds to handle the request in session state.

handleStatefulRequest(Request $request, $session, Closure $next)

This method handles the given request in session state. It starts the session, collects garbage, handles the request using the provided closure, stores the current URL, adds the session cookie to the response, and saves the session data.

startSession(Request $request, $session)

This method starts the session for the given request. It sets the request on the session handler and starts the session.

getSession(Request $request)

This method retrieves the session implementation from the session manager. It sets the session ID on the session object.

collectGarbage(Session $session)

This method removes garbage from the session if necessary. It checks if the configuration allows for garbage collection and calls the garbage collection handler.

configHitsLottery(array $config)

This method determines if the odds in the configuration allow for garbage collection.

storeCurrentUrl(Request $request, $session)

This method stores the current URL for the request if necessary. It checks if the request is a GET request, has a route instance, is not an AJAX request, is not a prefetch request, and is not a precognitive request. If these conditions are met, the previous URL is set in the session.

addCookieToResponse(Response $response, Session $session)

This method adds the session cookie to the application response. It checks if the session is persistent and sets the cookie with the appropriate attributes.

saveSession($request)

This method saves the session data to storage. It checks if the request is not a precognitive request and then calls the save method on the session driver.

getSessionLifetimeInSeconds()

This method returns the session lifetime in seconds.

getCookieExpirationDate()

This method returns the cookie expiration date for the session. It checks if the session should expire on close and calculates the expiration date based on the session lifetime.

sessionConfigured()

This method determines if a session driver has been configured.

sessionIsPersistent(array $config = null)

This method determines if the configured session driver is persistent. It checks if the driver value is not null.

cache($driver)

This method resolves the given cache driver. It calls the cache factory resolver to get the cache driver.

END

<?php

namespace Illuminate\Session\Middleware;

use Closure;
use Illuminate\Contracts\Session\Session;
use Illuminate\Http\Request;
use Illuminate\Routing\Route;
use Illuminate\Session\SessionManager;
use Illuminate\Support\Carbon;
use Illuminate\Support\Facades\Date;
use Symfony\Component\HttpFoundation\Cookie;
use Symfony\Component\HttpFoundation\Response;

class StartSession
{
    /**
     * The session manager.
     *
     * @var \Illuminate\Session\SessionManager
     */
    protected $manager;

    /**
     * The callback that can resolve an instance of the cache factory.
     *
     * @var callable|null
     */
    protected $cacheFactoryResolver;

    /**
     * Create a new session middleware.
     *
     * @param  \Illuminate\Session\SessionManager  $manager
     * @param  callable|null  $cacheFactoryResolver
     * @return void
     */
    public function __construct(SessionManager $manager, callable $cacheFactoryResolver = null)
    {
        $this->manager = $manager;
        $this->cacheFactoryResolver = $cacheFactoryResolver;
    }

    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        if (! $this->sessionConfigured()) {
            return $next($request);
        }

        $session = $this->getSession($request);

        if ($this->manager->shouldBlock() ||
            ($request->route() instanceof Route && $request->route()->locksFor())) {
            return $this->handleRequestWhileBlocking($request, $session, $next);
        }

        return $this->handleStatefulRequest($request, $session, $next);
    }

    /**
     * Handle the given request within session state.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Illuminate\Contracts\Session\Session  $session
     * @param  \Closure  $next
     * @return mixed
     */
    protected function handleRequestWhileBlocking(Request $request, $session, Closure $next)
    {
        if (! $request->route() instanceof Route) {
            return;
        }

        $lockFor = $request->route() && $request->route()->locksFor()
                        ? $request->route()->locksFor()
                        : $this->manager->defaultRouteBlockLockSeconds();

        $lock = $this->cache($this->manager->blockDriver())
                    ->lock('session:'.$session->getId(), $lockFor)
                    ->betweenBlockedAttemptsSleepFor(50);

        try {
            $lock->block(
                ! is_null($request->route()->waitsFor())
                        ? $request->route()->waitsFor()
                        : $this->manager->defaultRouteBlockWaitSeconds()
            );

            return $this->handleStatefulRequest($request, $session, $next);
        } finally {
            $lock?->release();
        }
    }

    /**
     * Handle the given request within session state.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Illuminate\Contracts\Session\Session  $session
     * @param  \Closure  $next
     * @return mixed
     */
    protected function handleStatefulRequest(Request $request, $session, Closure $next)
    {
        // If a session driver has been configured, we will need to start the session here
        // so that the data is ready for an application. Note that the Laravel sessions
        // do not make use of PHP "native" sessions in any way since they are crappy.
        $request->setLaravelSession(
            $this->startSession($request, $session)
        );

        $this->collectGarbage($session);

        $response = $next($request);

        $this->storeCurrentUrl($request, $session);

        $this->addCookieToResponse($response, $session);

        // Again, if the session has been configured we will need to close out the session
        // so that the attributes may be persisted to some storage medium. We will also
        // add the session identifier cookie to the application response headers now.
        $this->saveSession($request);

        return $response;
    }

    /**
     * Start the session for the given request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Illuminate\Contracts\Session\Session  $session
     * @return \Illuminate\Contracts\Session\Session
     */
    protected function startSession(Request $request, $session)
    {
        return tap($session, function ($session) use ($request) {
            $session->setRequestOnHandler($request);

            $session->start();
        });
    }

    /**
     * Get the session implementation from the manager.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Contracts\Session\Session
     */
    public function getSession(Request $request)
    {
        return tap($this->manager->driver(), function ($session) use ($request) {
            $session->setId($request->cookies->get($session->getName()));
        });
    }

    /**
     * Remove the garbage from the session if necessary.
     *
     * @param  \Illuminate\Contracts\Session\Session  $session
     * @return void
     */
    protected function collectGarbage(Session $session)
    {
        $config = $this->manager->getSessionConfig();

        // Here we will see if this request hits the garbage collection lottery by hitting
        // the odds needed to perform garbage collection on any given request. If we do
        // hit it, we'll call this handler to let it delete all the expired sessions.
        if ($this->configHitsLottery($config)) {
            $session->getHandler()->gc($this->getSessionLifetimeInSeconds());
        }
    }

    /**
     * Determine if the configuration odds hit the lottery.
     *
     * @param  array  $config
     * @return bool
     */
    protected function configHitsLottery(array $config)
    {
        return random_int(1, $config['lottery'][1]) <= $config['lottery'][0];
    }

    /**
     * Store the current URL for the request if necessary.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Illuminate\Contracts\Session\Session  $session
     * @return void
     */
    protected function storeCurrentUrl(Request $request, $session)
    {
        if ($request->isMethod('GET') &&
            $request->route() instanceof Route &&
            ! $request->ajax() &&
            ! $request->prefetch() &&
            ! $request->isPrecognitive()) {
            $session->setPreviousUrl($request->fullUrl());
        }
    }

    /**
     * Add the session cookie to the application response.
     *
     * @param  \Symfony\Component\HttpFoundation\Response  $response
     * @param  \Illuminate\Contracts\Session\Session  $session
     * @return void
     */
    protected function addCookieToResponse(Response $response, Session $session)
    {
        if ($this->sessionIsPersistent($config = $this->manager->getSessionConfig())) {
            $response->headers->setCookie(new Cookie(
                $session->getName(),
                $session->getId(),
                $this->getCookieExpirationDate(),
                $config['path'],
                $config['domain'],
                $config['secure'] ?? false,
                $config['http_only'] ?? true,
                false,
                $config['same_site'] ?? null,
                $config['partitioned'] ?? false
            ));
        }
    }

    /**
     * Save the session data to storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return void
     */
    protected function saveSession($request)
    {
        if (! $request->isPrecognitive()) {
            $this->manager->driver()->save();
        }
    }

    /**
     * Get the session lifetime in seconds.
     *
     * @return int
     */
    protected function getSessionLifetimeInSeconds()
    {
        return ($this->manager->getSessionConfig()['lifetime'] ?? null) * 60;
    }

    /**
     * Get the cookie lifetime in seconds.
     *
     * @return \DateTimeInterface|int
     */
    protected function getCookieExpirationDate()
    {
        $config = $this->manager->getSessionConfig();

        return $config['expire_on_close'] ? 0 : Date::instance(
            Carbon::now()->addRealMinutes($config['lifetime'])
        );
    }

    /**
     * Determine if a session driver has been configured.
     *
     * @return bool
     */
    protected function sessionConfigured()
    {
        return ! is_null($this->manager->getSessionConfig()['driver'] ?? null);
    }

    /**
     * Determine if the configured session driver is persistent.
     *
     * @param  array|null  $config
     * @return bool
     */
    protected function sessionIsPersistent(array $config = null)
    {
        $config = $config ?: $this->manager->getSessionConfig();

        return ! is_null($config['driver'] ?? null);
    }

    /**
     * Resolve the given cache driver.
     *
     * @param  string  $driver
     * @return \Illuminate\Cache\Store
     */
    protected function cache($driver)
    {
        return call_user_func($this->cacheFactoryResolver)->driver($driver);
    }
}