name : extension.cache.dbm.php <?php ///////////////////////////////////////////////////////////////// /// getID3() by James Heinrich <info@getid3.org> // // available at https://github.com/JamesHeinrich/getID3 // // or https://www.getid3.org // // or http://getid3.sourceforge.net // // // // extension.cache.dbm.php - part of getID3() // // Please see readme.txt for more information // // /// ///////////////////////////////////////////////////////////////// // // // This extension written by Allan Hansen <ahØartemis*dk> // // /// ///////////////////////////////////////////////////////////////// /** * This is a caching extension for getID3(). It works the exact same * way as the getID3 class, but return cached information very fast * * Example: * * Normal getID3 usage (example): * * require_once 'getid3/getid3.php'; * $getID3 = new getID3; * $getID3->encoding = 'UTF-8'; * $info1 = $getID3->analyze('file1.flac'); * $info2 = $getID3->analyze('file2.wv'); * * getID3_cached usage: * * require_once 'getid3/getid3.php'; * require_once 'getid3/getid3/extension.cache.dbm.php'; * $getID3 = new getID3_cached('db3', '/tmp/getid3_cache.dbm', * '/tmp/getid3_cache.lock'); * $getID3->encoding = 'UTF-8'; * $info1 = $getID3->analyze('file1.flac'); * $info2 = $getID3->analyze('file2.wv'); * * * Supported Cache Types * * SQL Databases: (use extension.cache.mysql) * * cache_type cache_options * ------------------------------------------------------------------- * mysql host, database, username, password * * * DBM-Style Databases: (this extension) * * cache_type cache_options * ------------------------------------------------------------------- * gdbm dbm_filename, lock_filename * ndbm dbm_filename, lock_filename * db2 dbm_filename, lock_filename * db3 dbm_filename, lock_filename * db4 dbm_filename, lock_filename (PHP5 required) * * PHP must have write access to both dbm_filename and lock_filename. * * * Recommended Cache Types * * Infrequent updates, many reads any DBM * Frequent updates mysql */ class getID3_cached_dbm extends getID3 { /** * @var resource */ private $dba; /** * @var resource|bool */ private $lock; /** * @var string */ private $cache_type; /** * @var string */ private $dbm_filename; /** * constructor - see top of this file for cache type and cache_options * * @param string $cache_type * @param string $dbm_filename * @param string $lock_filename * * @throws Exception * @throws getid3_exception */ public function __construct($cache_type, $dbm_filename, $lock_filename) { // Check for dba extension if (!extension_loaded('dba')) { throw new Exception('PHP is not compiled with dba support, required to use DBM style cache.'); } // Check for specific dba driver if (!function_exists('dba_handlers') || !in_array($cache_type, dba_handlers())) { throw new Exception('PHP is not compiled --with '.$cache_type.' support, required to use DBM style cache.'); } // Create lock file if needed if (!file_exists($lock_filename)) { if (!touch($lock_filename)) { throw new Exception('failed to create lock file: '.$lock_filename); } } // Open lock file for writing if (!is_writeable($lock_filename)) { throw new Exception('lock file: '.$lock_filename.' is not writable'); } $this->lock = fopen($lock_filename, 'w'); // Acquire exclusive write lock to lock file flock($this->lock, LOCK_EX); // Create dbm-file if needed if (!file_exists($dbm_filename)) { if (!touch($dbm_filename)) { throw new Exception('failed to create dbm file: '.$dbm_filename); } } // Try to open dbm file for writing $this->dba = dba_open($dbm_filename, 'w', $cache_type); if (!$this->dba) { // Failed - create new dbm file $this->dba = dba_open($dbm_filename, 'n', $cache_type); if (!$this->dba) { throw new Exception('failed to create dbm file: '.$dbm_filename); } // Insert getID3 version number dba_insert(getID3::VERSION, getID3::VERSION, $this->dba); } // Init misc values $this->cache_type = $cache_type; $this->dbm_filename = $dbm_filename; // Register destructor register_shutdown_function(array($this, '__destruct')); // Check version number and clear cache if changed if (dba_fetch(getID3::VERSION, $this->dba) != getID3::VERSION) { $this->clear_cache(); } parent::__construct(); } /** * destructor */ public function __destruct() { // Close dbm file dba_close($this->dba); // Release exclusive lock flock($this->lock, LOCK_UN); // Close lock file fclose($this->lock); } /** * clear cache * * @throws Exception */ public function clear_cache() { // Close dbm file dba_close($this->dba); // Create new dbm file $this->dba = dba_open($this->dbm_filename, 'n', $this->cache_type); if (!$this->dba) { throw new Exception('failed to clear cache/recreate dbm file: '.$this->dbm_filename); } // Insert getID3 version number dba_insert(getID3::VERSION, getID3::VERSION, $this->dba); // Re-register shutdown function register_shutdown_function(array($this, '__destruct')); } /** * clear cache * * @param string $filename * @param int $filesize * @param string $original_filename * @param resource $fp * * @return mixed */ public function analyze($filename, $filesize=null, $original_filename='', $fp=null) { $key = null; if (file_exists($filename)) { // Calc key filename::mod_time::size - should be unique $key = $filename.'::'.filemtime($filename).'::'.filesize($filename); // Loopup key $result = dba_fetch($key, $this->dba); // Hit if ($result !== false) { return unserialize($result); } } // Miss $result = parent::analyze($filename, $filesize, $original_filename, $fp); // Save result if (isset($key) && file_exists($filename)) { dba_insert($key, serialize($result), $this->dba); } return $result; } }