From 72fa7e562101547ae2af2b383ed04e5264c46e2e Mon Sep 17 00:00:00 2001
From: Chris Kankiewicz <Chris@ChrisKankiewicz.com>
Date: Sat, 19 Jun 2021 23:53:09 -0700
Subject: [PATCH] Implemented custom CacheMiddleware

---
 app/config/cache.php                    | 17 +++++++++++++
 app/config/container.php                |  1 +
 app/src/Middlewares/CacheMiddleware.php | 34 +++++++++++++++++++++++++
 3 files changed, 52 insertions(+)
 create mode 100644 app/src/Middlewares/CacheMiddleware.php

diff --git a/app/config/cache.php b/app/config/cache.php
index eb016ac..025a0de 100644
--- a/app/config/cache.php
+++ b/app/config/cache.php
@@ -96,4 +96,21 @@ return [
             $config->get('redis_port')
         );
     }),
+
+    /**
+     * HTTP cache values for controlling browser page cache durations.
+     *
+     * Possible values: An array of content types mapped to their cache duration
+     * in seconds
+     *
+     * Default value: [
+     *     'application/json' => '300',
+     *     'application/zip' => '300',
+     * ]
+     */
+    'http_cache' => [
+        'application/json' => '300',
+        'application/zip' => '300',
+    ],
+
 ];
diff --git a/app/config/container.php b/app/config/container.php
index ecb8843..ebb65ba 100644
--- a/app/config/container.php
+++ b/app/config/container.php
@@ -23,6 +23,7 @@ return [
     /** Array of application middlewares */
     'middlewares' => function (ContainerInterface $container): array {
         return [
+            Middlewares\CacheMiddleware::class,
             Middlewares\ThemeMiddleware::class,
             Middlewares\WhoopsMiddleware::class,
         ];
diff --git a/app/src/Middlewares/CacheMiddleware.php b/app/src/Middlewares/CacheMiddleware.php
new file mode 100644
index 0000000..8494d9b
--- /dev/null
+++ b/app/src/Middlewares/CacheMiddleware.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace App\Middlewares;
+
+use App\Config;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Psr\Http\Server\RequestHandlerInterface as RequestHandler;
+
+class CacheMiddleware
+{
+    /** @var Config The application configuration */
+    protected $config;
+
+    /** Create a new CacheMiddleware. */
+    public function __construct(Config $config)
+    {
+        $this->config = $config;
+    }
+
+    /** Invoke the CacheMiddleware class. */
+    public function __invoke(Request $request, RequestHandler $handler): ResponseInterface
+    {
+        $response = $handler->handle($request);
+
+        foreach ($this->config->get('http_cache') as $contentType => $age) {
+            if (in_array($contentType, $response->getHeader('Content-Type'))) {
+                return $response->withHeader('Cache-Control', sprintf('max-age=%d', $age));
+            }
+        }
+
+        return $response->withHeader('Cache-Control', 'max-age=0, must-revalidate');
+    }
+}