Zend Expressive injecting default variables into templates.

TemplateDefaultsMiddleware.php

<?php

declare(strict_types=1);

namespace Xtreamwayz\Expressive\TwigExtras\Middleware;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;
use Xtreamwayz\Expressive\Session\Authentication\UserInterface;
use Xtreamwayz\Expressive\Session\Flash\FlashMessagesInterface;
use Zend\Expressive\Router\RouteResult;
use Zend\Expressive\Template\TemplateRendererInterface;

class TemplateDefaultsMiddleware implements MiddlewareInterface
{
    /** @var TemplateRendererInterface */
    private $templateRenderer;

    public function __construct(TemplateRendererInterface $templateRenderer)
    {
        $this->templateRenderer = $templateRenderer;
    }

    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler) : ResponseInterface
    {
        $this->templateRenderer->addDefaultParam(
            TemplateRendererInterface::TEMPLATE_ALL,
            'security',
            $request->getAttribute(UserInterface::class)
        );

        $routeResult = $request->getAttribute(RouteResult::class);
        $this->templateRenderer->addDefaultParam(
            TemplateRendererInterface::TEMPLATE_ALL,
            'matchedRouteName',
            $routeResult ? $routeResult->getMatchedRouteName() : null
        );

        /** @var FlashMessagesInterface $flashMessages */
        $flashMessages = $request->getAttribute(FlashMessagesInterface::class);
        $this->templateRenderer->addDefaultParam(
            TemplateRendererInterface::TEMPLATE_ALL,
            'notifications',
            $flashMessages ? $flashMessages->getFlashes() : []
        );

        return $handler->handle($request);
    }
}