From 6c86721bbbdfd78105b2e08f2d05aef2ffd14cab Mon Sep 17 00:00:00 2001
From: Dariush  Hasanpoor <b.g.dariush@gmail.com>
Date: Fri, 6 Sep 2013 00:42:15 +0430
Subject: [PATCH] an internal cache system && a security upgrade

to preventing unnecessary IO i added an internal cache `private static $_soft_cache = NULL;` and for security reasons [which we should ever encounter to this] i put general hash sum to cache file's content
---
 cache.class.php | 554 +++++++++++++++++++++++++-----------------------
 1 file changed, 289 insertions(+), 265 deletions(-)

diff --git a/cache.class.php b/cache.class.php
index 9969671..948abcd 100644
--- a/cache.class.php
+++ b/cache.class.php
@@ -1,5 +1,4 @@
 <?php
-
 /**
  * Simple Cache class
  * API Documentation: https://github.com/cosenary/Simple-PHP-Cache
@@ -13,300 +12,325 @@
 
 class Cache {
 
-  /**
-   * The path to the cache file folder
-   *
-   * @var string
-   */
-  private $_cachepath = 'cache/';
+    /**
+     * The path to the cache file folder
+     *
+     * @var string
+     */
+    private $_cachepath = 'cache/';
 
-  /**
-   * The name of the default cache file
-   *
-   * @var string
-   */
-  private $_cachename = 'default';
+    /**
+     * The name of the default cache file
+     *
+     * @var string
+     */
+    private $_cachename = 'default';
 
-  /**
-   * The cache file extension
-   *
-   * @var string
-   */
-  private $_extension = '.cache';
+    /**
+     * The cache file extension
+     *
+     * @var string
+     */
+    private $_extension = '.cache';
+    /**
+     * uses for internal cache upgrading
+     * @var type 
+     */
+    private static $_soft_cache = NULL;
 
-  /**
-   * Default constructor
-   *
-   * @param string|array [optional] $config
-   * @return void
-   */
-  public function __construct($config = null) {
-    if (true === isset($config)) {
-      if (is_string($config)) {
-        $this->setCache($config);
-      } else if (is_array($config)) {
-        $this->setCache($config['name']);
-        $this->setCachePath($config['path']);
-        $this->setExtension($config['extension']);
-      }
+    /**
+     * Default constructor
+     *
+     * @param string|array [optional] $config
+     * @return void
+     */
+    public function __construct($config = null) {
+        if (true === isset($config)) {
+            if (is_string($config)) {
+                $this->setCache($config);
+            } else if (is_array($config)) {
+                $this->setCache($config['name']);
+                $this->setCachePath($config['path']);
+                $this->setExtension($config['extension']);
+            }
+        }
     }
-  }
 
-  /**
-   * Check whether data accociated with a key
-   *
-   * @param string $key
-   * @return boolean
-   */
-  public function isCached($key) {
-    if (false != $this->_loadCache()) {
-      $cachedData = $this->_loadCache();
-      return isset($cachedData[$key]['data']);
+    /**
+     * Check whether data accociated with a key
+     *
+     * @param string $key
+     * @return boolean
+     */
+    public function isCached($key) {
+        $cachedData = $this->_loadCache();
+        if (!$cachedData) {
+            return isset($cachedData[$key]['data']);
+        }
     }
-  }
 
-  /**
-   * Store data in the cache
-   *
-   * @param string $key
-   * @param mixed $data
-   * @param integer [optional] $expiration
-   * @return object
-   */
-  public function store($key, $data, $expiration = 0) {
-    $storeData = array(
-      'time'   => time(),
-      'expire' => $expiration,
-      'data'   => $data
-    );
-    if (true === is_array($this->_loadCache())) {
-      $dataArray = $this->_loadCache();
-      $dataArray[$key] = $storeData;
-    } else {
-      $dataArray = array($key => $storeData);
+    /**
+     * Store data in the cache
+     *
+     * @param string $key
+     * @param mixed $data
+     * @param integer [optional] $expiration
+     * @return object
+     */
+    public function store($key, $data, $expiration = 0) {
+        $storeData = array(
+            'time'   => time(),
+            'expire' => $expiration,
+            'data'   => $data
+        );
+        $dataArray = $this->_loadCache();
+        if (true === is_array($dataArray)) {
+            $dataArray[$key] = $storeData;
+        } else {
+            $dataArray = array($key => $storeData);
+        }
+        $this->_saveData($dataArray);
+        return $this;
+    }
+    protected function _saveData(array $cacheData)
+    {
+          self::$_soft_cache = $cacheData;
+          $cacheData['hash-sum'] = $this->_getHash(serialize($cacheData));
+          $cacheData = serialize($cacheData);
+          file_put_contents($this->getCacheDir(), $cacheData);
+    }
+    /**
+     * Retrieve cached data by its key
+     * 
+     * @param string $key
+     * @param boolean [optional] $timestamp
+     * @return string
+     */
+    public function retrieve($key, $timestamp = false) {
+        $cachedData = $this->_loadCache();
+        (false === $timestamp) ? $type = 'data' : $type = 'time';
+        if(!isset($cachedData[$key][$type])) return NULL;
+        return $cachedData[$key][$type];
     }
-    $cacheData = json_encode($dataArray);
-    file_put_contents($this->getCacheDir(), $cacheData);
-    return $this;
-  }
-
-  /**
-   * Retrieve cached data by its key
-   * 
-   * @param string $key
-   * @param boolean [optional] $timestamp
-   * @return string
-   */
-  public function retrieve($key, $timestamp = false) {
-    $cachedData = $this->_loadCache();
-    (false === $timestamp) ? $type = 'data' : $type = 'time';
-    return $cachedData[$key][$type];
-  }
 
-  /**
-   * Retrieve all cached data
-   * 
-   * @param boolean [optional] $meta
-   * @return array
-   */
-  public function retrieveAll($meta = false) {
-    if ($meta === false) {
-      $results = array();
-      $cachedData = $this->_loadCache();
-      if ($cachedData) {
-        foreach ($cachedData as $k => $v) {
-          $results[$k] = $v['data'];
+    /**
+     * Retrieve all cached data
+     * 
+     * @param boolean [optional] $meta
+     * @return array
+     */
+    public function retrieveAll($meta = false) {
+        if ($meta === false) {
+            $results = array();
+            $cachedData = $this->_loadCache();
+            if ($cachedData) {
+                foreach ($cachedData as $k => $v) {
+                  $results[$k] = $v['data'];
+                }
+            }
+            return $results;
+        } else {
+            return $this->_loadCache();
         }
-      }
-      return $results;
-    } else {
-      return $this->_loadCache();
     }
-  }
 
-  /**
-   * Erase cached entry by its key
-   * 
-   * @param string $key
-   * @return object
-   */
-  public function erase($key) {
-    $cacheData = $this->_loadCache();
-    if (true === is_array($cacheData)) {
-      if (true === isset($cacheData[$key])) {
-        unset($cacheData[$key]);
-        $cacheData = json_encode($cacheData);
-        file_put_contents($this->getCacheDir(), $cacheData);
-      } else {
-        throw new Exception("Error: erase() - Key '{$key}' not found.");
-      }
+    /**
+     * Erase cached entry by its key
+     * 
+     * @param string $key
+     * @return object
+     */
+    public function erase($key) {
+        $cacheData = $this->_loadCache();
+        if (true === is_array($cacheData)) {
+            if (true === isset($cacheData[$key])) {
+                unset($cacheData[$key]);
+                $this->_saveData($cacheData);
+            } else {
+                throw new Exception("Error: erase() - Key '{$key}' not found.");
+            }
+        }
+        return $this;
     }
-    return $this;
-  }
 
-  /**
-   * Erase all expired entries
-   * 
-   * @return integer
-   */
-  public function eraseExpired() {
-    $cacheData = $this->_loadCache();
-    if (true === is_array($cacheData)) {
-      $counter = 0;
-      foreach ($cacheData as $key => $entry) {
-        if (true === $this->_checkExpired($entry['time'], $entry['expire'])) {
-          unset($cacheData[$key]);
-          $counter++;
+    /**
+     * Erase all expired entries
+     * 
+     * @return integer
+     */
+    public function eraseExpired() {
+        $cacheData = $this->_loadCache();
+        if (true === is_array($cacheData)) {
+            $counter = 0;
+            foreach ($cacheData as $key => $entry) {
+            if (true === $this->_checkExpired($entry['time'], $entry['expire'])) {
+                unset($cacheData[$key]);
+                $counter++;
+            }
+            }
+            if ($counter > 0) {
+                $this->_saveData($cacheData);
+            }
+            return $counter;
         }
-      }
-      if ($counter > 0) {
-        $cacheData = json_encode($cacheData);
-        file_put_contents($this->getCacheDir(), $cacheData);
-      }
-      return $counter;
     }
-  }
 
-  /**
-   * Erase all cached entries
-   * 
-   * @return object
-   */
-  public function eraseAll() {
-    $cacheDir = $this->getCacheDir();
-    if (true === file_exists($cacheDir)) {
-      $cacheFile = fopen($cacheDir, 'w');
-      fclose($cacheFile);
+    /**
+     * Erase all cached entries
+     * 
+     * @return object
+     */
+    public function eraseAll() {
+        $cacheDir = $this->getCacheDir();
+        if (true === file_exists($cacheDir)) {
+            $cacheFile = fopen($cacheDir, 'w');
+            fclose($cacheFile);
+        }
+        return $this;
     }
-    return $this;
-  }
 
-  /**
-   * Load appointed cache
-   * 
-   * @return mixed
-   */
-  private function _loadCache() {
-    if (true === file_exists($this->getCacheDir())) {
-      $file = file_get_contents($this->getCacheDir());
-      return json_decode($file, true);
-    } else {
-      return false;
-    }
-  }
+    /**
+     * Load appointed cache
+     * 
+     * @return mixed
+     */
+      private function _loadCache() {
+            if(self::$_soft_cache)
+                return self::$_soft_cache;
 
-  /**
-   * Get the cache directory path
-   * 
-   * @return string
-   */
-  public function getCacheDir() {
-    if (true === $this->_checkCacheDir()) {
-      $filename = $this->getCache();
-      $filename = preg_replace('/[^0-9a-z\.\_\-]/i', '', strtolower($filename));
-      return $this->getCachePath() . $this->_getHash($filename) . $this->getExtension();
+            if (true === file_exists($this->getCacheDir())) {
+                $file = file_get_contents($this->getCacheDir());
+                $u = unserialize($file);
+                if(!isset($u['hash-sum']))
+                {
+                    unlink($this->getCacheDir());
+                    die("cache data miss-hashed, cache file deleted...");
+                }
+                $h = $u['hash-sum'];
+                unset($u['hash-sum']);
+                if($h != $this->_getHash(serialize($u)))
+                {
+                    unlink($this->getCacheDir());
+                    die("cache data miss-hashed, cache file deleted...");
+                }  
+                return $u;
+              }
+              else {
+                return false;
+            }
     }
-  }
 
-  /**
-   * Get the filename hash
-   * 
-   * @return string
-   */
-  private function _getHash($filename) {
-    return sha1($filename);
-  }
+    /**
+     * Get the cache directory path
+     * 
+     * @return string
+     */
+    public function getCacheDir() {
+        if (true === $this->_checkCacheDir()) {
+            $filename = $this->getCache();
+            $filename = preg_replace('/[^0-9a-z\.\_\-]/i', '', strtolower($filename));
+            return $this->getCachePath() . $this->_getHash($filename) . $this->getExtension();
+        }
+    }
 
-  /**
-   * Check whether a timestamp is still in the duration 
-   * 
-   * @param integer $timestamp
-   * @param integer $expiration
-   * @return boolean
-   */
-  private function _checkExpired($timestamp, $expiration) {
-    $result = false;
-    if ($expiration !== 0) {
-      $timeDiff = time() - $timestamp;
-      ($timeDiff > $expiration) ? $result = true : $result = false;
+    /**
+     * Get the filename hash
+     * 
+     * @return string
+     */
+    private function _getHash($filename) {
+        return sha1($filename);
     }
-    return $result;
-  }
 
-  /**
-   * Check if a writable cache directory exists and if not create a new one
-   * 
-   * @return boolean
-   */
-  private function _checkCacheDir() {
-    if (!is_dir($this->getCachePath()) && !mkdir($this->getCachePath(), 0775, true)) {
-      throw new Exception('Unable to create cache directory ' . $this->getCachePath());
-    } elseif (!is_readable($this->getCachePath()) || !is_writable($this->getCachePath())) {
-      if (!chmod($this->getCachePath(), 0775)) {
-        throw new Exception($this->getCachePath() . ' must be readable and writeable');
-      }
+    /**
+     * Check whether a timestamp is still in the duration 
+     * 
+     * @param integer $timestamp
+     * @param integer $expiration
+     * @return boolean
+     */
+    private function _checkExpired($timestamp, $expiration) {
+        $result = false;
+        if ($expiration !== 0) {
+            $timeDiff = time() - $timestamp;
+            ($timeDiff > $expiration) ? $result = true : $result = false;
+        }
+        return $result;
     }
-    return true;
-  }
 
-  /**
-   * Cache path Setter
-   * 
-   * @param string $path
-   * @return object
-   */
-  public function setCachePath($path) {
-    $this->_cachepath = $path;
-    return $this;
-  }
+    /**
+     * Check if a writable cache directory exists and if not create a new one
+     * 
+     * @return boolean
+     */
+    private function _checkCacheDir() {
+        if (!is_dir($this->getCachePath()) && !mkdir($this->getCachePath(), 0775, true)) {
+            throw new Exception('Unable to create cache directory ' . $this->getCachePath());
+        } elseif (!is_readable($this->getCachePath()) || !is_writable($this->getCachePath())) {
+            if (!chmod($this->getCachePath(), 0775)) {
+                throw new Exception($this->getCachePath() . ' must be readable and writeable');
+            }
+        }
+        return true;
+    }
 
-  /**
-   * Cache path Getter
-   * 
-   * @return string
-   */
-  public function getCachePath() {
-    return $this->_cachepath;
-  }
+    /**
+     * Cache path Setter
+     * 
+     * @param string $path
+     * @return object
+     */
+    public function setCachePath($path) {
+        $this->_cachepath = $path;
+        return $this;
+    }
 
-  /**
-   * Cache name Setter
-   * 
-   * @param string $name
-   * @return object
-   */
-  public function setCache($name) {
-    $this->_cachename = $name;
-    return $this;
-  }
+    /**
+     * Cache path Getter
+     * 
+     * @return string
+     */
+    public function getCachePath() {
+        return $this->_cachepath;
+    }
 
-  /**
-   * Cache name Getter
-   * 
-   * @return void
-   */
-  public function getCache() {
-    return $this->_cachename;
-  }
+    /**
+     * Cache name Setter
+     * 
+     * @param string $name
+     * @return object
+     */
+    public function setCache($name) {
+        $this->_cachename = $name;
+        return $this;
+    }
 
-  /**
-   * Cache file extension Setter
-   * 
-   * @param string $ext
-   * @return object
-   */
-  public function setExtension($ext) {
-    $this->_extension = $ext;
-    return $this;
-  }
+    /**
+     * Cache name Getter
+     * 
+     * @return void
+     */
+    public function getCache() {
+        return $this->_cachename;
+    }
 
-  /**
-   * Cache file extension Getter
-   * 
-   * @return string
-   */
-  public function getExtension() {
-    return $this->_extension;
-  }
+    /**
+     * Cache file extension Setter
+     * 
+     * @param string $ext
+     * @return object
+     */
+    public function setExtension($ext) {
+        $this->_extension = $ext;
+        return $this;
+    }
 
-}
\ No newline at end of file
+    /**
+     * Cache file extension Getter
+     * 
+     * @return string
+     */
+    public function getExtension() {
+        return $this->_extension;
+    }
+}