1 files changed, 113 insertions, 0 deletions
diff --git a/include/MyCache.class.php b/include/MyCache.class.php
new file mode 100644
index 0000000..e074a3b
--- /dev/null
+++ b/include/MyCache.class.php
@@ -0,0 +1,113 @@
+<?php
+/**
+ * Simple on-disk variable caching class. Implements file caching logic.
+ */
+class MyCache {
+
+    private function __construct() {}
+
+    private function __clone() {}
+
+
+    /**
+     * Sets given cache line to given value
+     *
+     * @param id string cache line name. It should follow file naming conventions.
+     * @param value object - any serializable variable
+     *
+     * @return its second argument
+     */
+    static function set($id, $value) {
+        file_put_contents(BASEPATH.'/caches/MyCache/'.$id, serialize($value));
+        return $value;
+    }
+
+
+    /**
+     * fetches cached value from disk
+     *
+     * @param id string - cache line identifier to fetch. It should follow file naming conventions.
+     * @param valid int - if exists and non zero, method throws ExceptionCacheLineExpired if cache line
+     * is older than given time in seconds
+     *
+     * @return restored variable contents
+     */
+    static function get($id, $valid=0, $callback=null, $passexception=true) {
+        $isValid = self::valid($id, $valid);
+        if ($valid != 0 && !$isValid && $callback===null) {
+            throw new CacheLineExpiredException();
+        }
+        if ($isValid) {
+            return unserialize(file_get_contents(BASEPATH.'/caches/MyCache/'.$id));
+        }
+        elseif ($callback===null) {
+            if (file_exists(BASEPATH.'/caches/MyCache/'.$id)) {
+                throw new CacheLineExpiredException();
+            }
+            else {
+                throw new CacheLineNotFoundException($id);
+            }
+        }
+        else {
+            try {
+                $value = call_user_func($callback);
+                self::set($id,$value);
+                return $value;
+            }
+            catch (Exception $e) {
+                if ($passexception) {
+                    throw $e;
+                }
+                return self::get($id);
+            }
+        }
+    }
+
+
+    /**
+     * Removes given cache line from disk
+     *
+     * @param id string cache line name
+     *
+     * @return void
+     */
+    static function delete($id) {
+        if (file_exists(BASEPATH.'/caches/MyCache/'.$id)) {
+            unlink(BASEPATH.'/caches/MyCache/'.$id);
+        }
+    }
+
+    /**
+     * validates if cache line is not older than given time in seconds
+     *
+     * @param id string cache line name.
+     * @param cacheLifeTime int cache line age limit (default 300 seconds)
+     *
+     * @return true if cache is stil valid, false otherwise
+     */
+    static function valid($id, $cacheLifeTime=null) {
+
+        $cacheLifeTime = (int)$cacheLifeTime; //seconds
+
+        if ($cacheLifeTime==null) {
+            return is_readable(BASEPATH.'/caches/MyCache/'.$id);
+        }
+
+        if (!is_readable(BASEPATH.'/caches/MyCache/'.$id)) {
+            return false;
+        }
+        return (time()-filemtime(BASEPATH.'/caches/MyCache/'.$id)) <= $cacheLifeTime;
+    }
+
+
+    /**
+     * checks if cache line exists without validating its age
+     *
+     * @param id sting cache line name
+     *
+     * @return boolean true if cache line is found
+     */
+    static function exist($id) {
+        return is_readable(BASEPATH .'/caches/MyCache/'.$id);
+    }
+}