From af9e4d0c99d9121e63097dca91900c2ad6fc977e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tobias=20Ho=CC=88=C3=9Fl?= <tobias@hoessl.eu>
Date: Sat, 21 Dec 2024 18:41:24 +0100
Subject: [PATCH] Begin background cache rebuild

---
 components/HashedStaticCache.php | 51 +++++++++++++++++++++++++++-----
 1 file changed, 44 insertions(+), 7 deletions(-)

diff --git a/components/HashedStaticCache.php b/components/HashedStaticCache.php
index dc2efe442f..1e6afe7d31 100644
--- a/components/HashedStaticCache.php
+++ b/components/HashedStaticCache.php
@@ -4,6 +4,7 @@
 
 namespace app\components;
 
+use app\models\backgroundJobs\IBackgroundJob;
 use app\models\settings\AntragsgruenApp;
 
 class HashedStaticCache
@@ -17,6 +18,8 @@ class HashedStaticCache
     private bool $skipCache = false;
     private ?int $timeout = null;
 
+    private ?IBackgroundJob $rebuildBackgroundJob = null;
+
     public function __construct(string $functionName, ?array $dependencies)
     {
         $this->functionName = $functionName;
@@ -53,6 +56,13 @@ public function setIsBulky(bool $isBulky): self
         return $this;
     }
 
+    public function setRebuildBackgroundJob(IBackgroundJob $rebuildBackgroundJob): self
+    {
+        $this->rebuildBackgroundJob = $rebuildBackgroundJob;
+
+        return $this;
+    }
+
     /**
      * Setting a cache to synchronized prevents the system from generating the same cache in parallel.
      * This does come with some performance impact due to the communication with Redis / File system,
@@ -84,13 +94,13 @@ public function getCacheKey(): string
         return $this->cacheKey;
     }
 
-    public function getCached(callable $method): mixed
+    public function getCached(callable $method, ?callable $cacheOutdatedDecorator = null): mixed
     {
         if (!$this->skipCache) {
             // Hint: don't even try to aquire a lock if a cache item already exists
             $cached = $this->getCache();
             if ($cached !== false) {
-                return $cached;
+                return $this->returnDecoratedCache($cached, $cacheOutdatedDecorator);
             }
         }
 
@@ -101,9 +111,11 @@ public function getCached(callable $method): mixed
             $cached = $this->getCache();
             if ($cached !== false) {
                 ResourceLock::unlockCache($this);
-                return $cached;
+                return $this->returnDecoratedCache($cached, $cacheOutdatedDecorator);
             }
 
+            // @TODO call backgroundjob if set
+
             $result = $method();
             ResourceLock::unlockCache($this);
         } else {
@@ -122,19 +134,43 @@ private static function getDirectory(string $key): string {
     }
 
     /**
-     * @return mixed|false
+     * @param array{content: mixed, createdAtTs: int|null} $cache
+     */
+    private function returnDecoratedCache(array $cache, ?callable $cacheOutdatedDecorator): mixed
+    {
+        $content = $cache['content'];
+        if ($cacheOutdatedDecorator) {
+            $content = $cacheOutdatedDecorator($cache['content'], $cache['createdAtTs']);
+        }
+        return $content;
+    }
+
+    /**
+     * @return array{content: mixed, createdAtTs: int|null}|false
      */
-    private function getCache(): mixed
+    private function getCache(): array|false
     {
         if ($this->isBulky && AntragsgruenApp::getInstance()->viewCacheFilePath) {
             $directory = self::getDirectory($this->cacheKey);
             if (file_exists($directory . '/' . $this->cacheKey)) {
-                return (string)file_get_contents($directory . '/' . $this->cacheKey);
+                $mtime = filemtime($directory . '/' . $this->cacheKey);
+                return [
+                    'content' => (string)file_get_contents($directory . '/' . $this->cacheKey),
+                    'createdAtTs' => ($mtime ? $mtime : null),
+                ];
             } else {
                 return false;
             }
         } else {
-            return \Yii::$app->cache->get($this->cacheKey);
+            $content = \Yii::$app->cache->get($this->cacheKey);
+            if ($content === false) {
+                return false;
+            } else {
+                return [
+                    'content' => $content,
+                    'createdAtTs' => null,
+                ];
+            }
         }
     }
 
@@ -165,6 +201,7 @@ public function setCache(mixed $data): void
     public function flushCache(): void
     {
         if ($this->isBulky && AntragsgruenApp::getInstance()->viewCacheFilePath) {
+            // @TODO Trigger backgroundjob instead if set
             $directory = self::getDirectory($this->cacheKey);
             if (file_exists($directory . '/' . $this->cacheKey)) {
                 unlink($directory . '/' . $this->cacheKey);