Using zend-expressive-session-cache as PSR-6 session persistence adapter in Expressive 3

zend-expressive-session-cache is a PSR-6 session persistence adapter for zend-expressive-session that can be used in Expressive 3. In current post, I will provide the use case of it with apcu for cache adapter with zend-cache for cache item pool.

Let’s start with create new project from skeleton with the following command:

➜ composer create-project \
    zendframework/zend-expressive-skeleton \
    expressive3-cache-tutorial

After the skeleton installed, we can require the zendframework/zend-expressive-session-cache and zend-cache with the following command:

➜ cd expressive3-cache-tutorial
➜ composer require \
    zendframework/zend-expressive-session-cache \
    zendframework/zend-cache

Now, ensure config/config.php has the following ConfigProviders registered:

<?php
// config/config.php
$aggregator = new ConfigAggregator([
    // ...
    \Zend\Cache\ConfigProvider::class,
    \Zend\Expressive\Session\Cache\ConfigProvider::class,
    \Zend\Expressive\Session\ConfigProvider::class,
    // ...
], $cacheConfig['config_cache_path']);

For apcu adapter, we need the apcu extension to be installed, we can install via pecl like the following:

➜ sudo pecl install apcu

After it installed, we need to set apc.use_request_time = 0 in php.ini like the following:

# your php.ini
apc.use_request_time = 0

For Cache Item Pool service, we can create a factory for it, for example, like the following:

<?php
// src/App/Cache/CacheItemPoolFactory.php

declare(strict_types=1);

namespace App\Cache;

use Psr\Cache\CacheItemPoolInterface;
use Psr\Container\ContainerInterface;
use Zend\Cache\Psr\CacheItemPool\CacheItemPoolDecorator;
use Zend\Cache\StorageFactory;

final class CacheItemPoolFactory
{
    public function __invoke(ContainerInterface $container) : CacheItemPoolInterface
    {
        $storage = StorageFactory::factory([
            'adapter' => [
                'name'    => 'apcu',
            ],
        ]);

        return new CacheItemPoolDecorator($storage);
    }
}

We can register then the cache pool service and make alias of SessionPersistenceInterface with CacheSessionPersistence:

<?php
// config/autoload/dependencies.global.php
use App\Cache\CacheItemPoolFactory;
use Psr\Cache\CacheItemPoolInterface;
use Zend\Expressive\Session\Cache\CacheSessionPersistence;
use Zend\Expressive\Session\SessionPersistenceInterface;

return [
    // ...
    'aliases' => [
        SessionPersistenceInterface::class => CacheSessionPersistence::class,
    ],
    'factories'  => [
        CacheItemPoolInterface::class => CacheItemPoolFactory::class,
    ],
    // ...
];

If we need a custom configuration for zend-expressive-session-cache, we can define at config/autoload/zend-expressive.global.php:

<?php
// config/autoload/zend-expressive.global.php
use Psr\Cache\CacheItemPoolInterface;

return [
    // ...
    'zend-expressive-session-cache' => [
        'cache_item_pool_service' => CacheItemPoolInterface::class,
        'cookie_name'             => 'PHPSESSION',
        'cookie_path'             => '/',
        'cache_limiter'           => 'nocache',
        'cache_expire'            => 10800,
        'last_modified'           => null,
    ],
    // ...
];

To start the session, we can apply Zend\Expressive\Session\SessionMiddleware into config/pipeline.php before Zend\Expressive\Router\Middleware\RouteMiddleware registration:

<?php
use Zend\Expressive\Router\Middleware\RouteMiddleware;
use Zend\Expressive\Session\SessionMiddleware;

// ...
    $app->pipe(SessionMiddleware::class);
    $app->pipe(RouteMiddleware::class);
// ...

The preparation done! Now, we can use it by consume it from via SessionMiddleware, for example, we need to generate “csrf” token when rendering the form, like I written at the CSRF usage in Expressive post, we can just use the session as is, and the cache will be used as session persistence:

<?php
// src/Handler/LoginPageHandler.php
use Zend\Expressive\Session\SessionInterface;
use Zend\Expressive\Csrf\SessionCsrfGuard;
use Zend\Expressive\Session\SessionMiddleware;
use Zend\Expressive\Csrf\CsrfMiddleware;

    // ...
    private function getToken(SessionInterface $session, SessionCsrfGuard $guard)
    {
        if (! $session->has('__csrf')) {
            return $guard->generateToken();
        }

        return $session->get('__csrf');
    }

    public function process(
         ServerRequestInterface $request,
         RequestHandlerInterface $handler
    ) : ResponseInterface
    {
        $guard     = $request->getAttribute(CsrfMiddleware::GUARD_ATTRIBUTE);
        $loginForm = new LoginForm($guard);

        $session = $request->getAttribute(SessionMiddleware::SESSION_ATTRIBUTE);
        $token   = $this->getToken($session, $guard);

        // ...
    }
    // ...

That’s it!