Implement central caching class

shared/cache.php

@@ -0,0 +1,68 @@
+<?php
+/*
+Copyright 2022 eraseyourknees
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+class UupDumpCache {
+    private $cacheFile;
+
+    public function __construct($resource, $compressed = true) {
+        $cacheHash = hash('sha256', strtolower($resource));
+        $ext = $compressed ? '.json.gz' : '.json';
+        $this->cacheFile = 'cache/'.$cacheHash.$ext;
+    }
+
+    public function getFileName() {
+        return $this->cacheFile;
+    }
+
+    public function delete() {
+        @unlink($this->cacheFile);
+    }
+
+    public function get() {
+        $cacheFile = $this->cacheFile;
+
+        if(!file_exists($cacheFile)) {
+            return false;
+        }
+
+        $cache = @gzdecode(@file_get_contents($cacheFile));
+        $cache = json_decode($cache, 1);
+
+        $expires = $cache['expires'];
+        $isExpired = ($expires !== false) && (time() > $expires);
+
+        if(empty($cache['content']) && $isExpired) {
+            $this->deleteCache();
+            return false;
+        }
+
+        return $cache['content'];
+    }
+
+    public function put($content, $validity) {
+        $cacheFile = $this->cacheFile;
+        $expires = $validity ? time() + $validity : false;
+
+        $cache = array(
+            'expires' => $expires,
+            'content' => $content,
+        );
+    
+        if(!file_exists('cache')) mkdir('cache');
+        @file_put_contents($cacheFile, gzencode(json_encode($cache)."\n"));
+    }
+}