The various Laravel snippets I used in my Laracon EU 2022 Amsterdam presentation on how to improve the cacheability of Laravel projects. I'd like to see this end up in a larger caching or edge package and I'd like some of the code to be optimized.

EsiServiceProvider.php

<?php
//An ESI service provider that defines a custom @esi(/header) directive that can be used to render ESI tags

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Support\Facades\Blade;
class EsiServiceProvider extends ServiceProvider
{
    /**
     * @return void
     */
    public function boot(): void
    {
        Blade::directive('esi', function (string $url) {
            if(str_contains($this->app->request->headers->get('Surrogate-Capability'), 'ESI/1.0')) {
                return "<?php echo '<esi:include src=\"$url\" />'; ?>";
            } else {
                return "<?php echo subrequest('GET','$url')->getContent(); ?>";
            }
        });
    }    
}

NotModified.php

<?php
 //Middleware that matches the If-None-Match value to a cached ETag and exists quickly with a 304 Not Modified status

namespace App\Http\Middleware;

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Cache;
use Closure;
use Symfony\Component\HttpFoundation\Response;

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

        $etag = Cache::get('etag:'.md5($request->getUri()));
        $cacheControl = Cache::get('etag-cache-control:'.md5($request->getUri()));
        $response = new Response('',304,['ETag' => $etag, 'Cache-Control' => $cacheControl]);
        if($response->isNotModified(($request))) {
            return $response;
        }

        $response = $next($request);
        Cache::put('etag:'.md5($request->getUri()), $response->headers->get('ETag'),10);
        Cache::put('etag-cache-control:'.md5($request->getUri()),$response->headers->get('Cache-Control'),10);        
        return $response;
    }
}

Surrogate.php

<?php
//Middleware that sets a Surrogate-Controler header if the proper Surrogate-Capability is sent by the client

namespace App\Http\Middleware;

use Illuminate\Http\Request;
use Closure;

class Surrogate
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle(Request $request, Closure $next)
    {
        $response = $next($request);
        if(str_contains($request->headers->get('Surrogate-Capability'), 'ESI/1.0')) {
            $response->headers->set('Surrogate-Control', 'content="ESI/1.0"');
        }
        return $response;
    }
}