freenetis-github/system/libraries/drivers/Cache/File.php @ cd149dd5
| 8baed187 | Michal Kliment | <?php defined('SYSPATH') or die('No direct script access.');
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/**
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* File-based Cache driver.
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*
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* @package Cache
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* @author Kohana Team
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* @copyright (c) 2007 Kohana Team
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* @license http://kohanaphp.com/license.html
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*/
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class Cache_File_Driver implements Cache_Driver {
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protected $directory = '';
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/**
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* Tests that the storage location is a directory and is writable.
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*/
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public function __construct($directory)
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{
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// Find the real path to the directory
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$directory = str_replace('\\', '/', realpath($directory)).'/';
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// Make sure the cache directory is writable
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if ( ! is_dir($directory) OR ! is_writable($directory))
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throw new Kohana_Exception('cache.unwritable', $directory);
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// Directory is valid
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$this->directory = $directory;
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}
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/**
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* Finds an array of files matching the given id or tag.
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*
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* @param string cache id or tag
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* @param bool search for tags
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* @return array of filenames matching the id or tag
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* @return void if no matching files are found
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*/
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public function exists($id, $tag = FALSE)
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{
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if ($id === TRUE)
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{
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// Find all the files
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$files = glob($this->directory.'*~*~*');
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}
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elseif ($tag == TRUE)
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{
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// Find all the files that have the tag name
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$files = glob($this->directory.'*~*'.$id.'*~*');
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// Find all tags matching the given tag
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foreach($files as $i => $file)
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{
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// Split the files
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$tags = explode('~', $file);
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// Find valid tags
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if (count($tags) !== 3 OR empty($tags[1]))
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continue;
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// Split the tags by plus signs, used to separate tags
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$tags = explode('+', $tags[1]);
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if ( ! in_array($tag, $tags))
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{
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// This entry does not match the tag
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unset($files[$i]);
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}
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}
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}
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else
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{
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// Find all the files matching the given id
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$files = glob($this->directory.$id.'~*');
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}
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return empty($files) ? NULL : $files;
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}
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/**
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* Sets a cache item to the given data, tags, and expiration.
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*
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* @param string cache id to set
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* @param string data in the cache
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* @param array cache tags
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* @param integer timestamp
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* @return bool
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*/
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public function set($id, $data, $tags, $expiration)
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{
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// Remove old cache files
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$this->delete($id);
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// Construct the filename
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$filename = $id.'~'.implode('+', $tags).'~'.$expiration;
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// Write the file, appending the sha1 signature to the beginning of the data
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return (bool) file_put_contents($this->directory.$filename, sha1($data).$data);
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}
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/**
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* Finds an array of ids for a given tag.
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*
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* @param string tag name
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* @return array of ids that match the tag
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*/
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public function find($tag)
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{
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if ($files = $this->exists($tag, TRUE))
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{
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// Length of directory name
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$offset = strlen($this->directory);
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// Find all the files with the given tag
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$array = array();
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foreach($files as $file)
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{
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// Get the id from the filename
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$array[] = substr(current(explode('~', $file)), $offset);
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}
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return $array;
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}
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return FALSE;
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}
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/**
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* Fetches a cache item. This will delete the item if it is expired or if
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* the hash does not match the stored hash.
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*
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* @param string cache id
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* @return mixed|NULL
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*/
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public function get($id)
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{
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if ($file = $this->exists($id))
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{
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// Always process the first result
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$file = current($file);
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// Validate that the cache has not expired
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if ($this->expired($file))
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{
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// Remove this cache, it has expired
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$this->delete($id);
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}
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else
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{
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$data = file_get_contents($file);
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// Find the hash of the data
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$hash = substr($data, 0, 40);
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// Remove the hash from the data
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$data = substr($data, 40);
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if ($hash !== sha1($data))
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{
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// Remove this cache, it doesn't validate
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$this->delete($id);
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// Unset data to prevent it from being returned
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unset($data);
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}
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}
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}
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// Return NULL if there is no data
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return isset($data) ? $data : NULL;
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}
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/**
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* Deletes a cache item by id or tag
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*
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* @param string cache id or tag, or TRUE for "all items"
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* @param bool use tags
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* @return bool
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*/
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public function delete($id, $tag = FALSE)
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{
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$files = $this->exists($id, $tag);
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if (empty($files))
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return FALSE;
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// Disable all error reporting while deleting
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$ER = error_reporting(0);
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foreach($files as $file)
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{
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// Remove the cache file
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if ( ! unlink($file))
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Log::add('error', 'Cache: Unable to delete cache file: '.$file);
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}
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// Turn on error reporting again
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error_reporting($ER);
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return TRUE;
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}
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/**
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* Deletes all cache files that are older than the current time.
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*/
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public function delete_expired()
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{
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if ($files = $this->exists(TRUE))
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{
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foreach($files as $file)
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{
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if ($this->expired($file))
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{
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// The cache file has already expired, delete it
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@unlink($file) or Log::add('error', 'Cache: Unable to delete cache file: '.$file);
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}
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}
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}
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}
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/**
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* Check if a cache file has expired by filename.
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*/
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protected function expired($file)
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{
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// Get the expiration time
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$expires = (int) end(explode('~', $file));
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// Expirations of 0 are "never expire"
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return ($expires !== 0 AND $expires <= time());
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}
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} // End Cache File Driver
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