Add own storage backend to respect tags when caches are saved in fs

Classes/Cache/Backend/TaggableFileBackend.php

@@ -0,0 +1,84 @@
+<?php
+
+namespace DanielSiepmann\DsSite\Cache\Backend;
+
+/*
+ * Copyright (C) 2020 Daniel Siepmann <coding@daniel-siepmann.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+use TYPO3\CMS\Core\Cache\Backend\FileBackend as CoreFileBackend;
+use TYPO3\CMS\Core\Cache\Backend\TaggableBackendInterface;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+
+class TaggableFileBackend extends CoreFileBackend implements TaggableBackendInterface
+{
+    public function flushByTag($tag)
+    {
+        array_walk($this->findIdentifiersByTag($tag), [$this, 'remove']);
+    }
+
+    public function flushByTags(array $tags)
+    {
+        foreach ($tags as $tag) {
+            $this->flushByTag($tag);
+        }
+    }
+
+    public function findIdentifiersByTag($tag)
+    {
+        $files = GeneralUtility::getFilesInDir($this->getCacheDirectory() . 'tag-' . $tag);
+
+        if ($files === []) {
+            return [];
+        }
+
+        return array_values($files);
+    }
+
+    public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
+    {
+        parent::set($entryIdentifier, $data, $tags, $lifetime);
+
+        foreach ($tags as $tag) {
+            $folder = $this->getCacheDirectory() . 'tag-' . $tag;
+            if (!is_dir($folder)) {
+                GeneralUtility::mkdir_deep($folder);
+            }
+            touch($folder . DIRECTORY_SEPARATOR . $entryIdentifier);
+        }
+
+        file_put_contents(
+            $this->getCacheDirectory() . $entryIdentifier . '-tags',
+            serialize($tags)
+        );
+    }
+
+    public function remove($entryIdentifier)
+    {
+        $pathAndFilename = $this->getCacheDirectory() . $entryIdentifier . '-tags';
+        if (file_exists($pathAndFilename)) {
+            $tags = unserialize(file_get_contents($pathAndFilename));
+            foreach ($tags as $tag) {
+                $tagFile = $this->getCacheDirectory() . 'tag-' . $tag . DIRECTORY_SEPARATOR . $entryIdentifier;
+                file_exists($tagFile) && unlink($tagFile);
+            }
+        }
+
+        return parent::remove($entryIdentifier);
+    }
+}