Files
THOS-Server/api/getid3/extension.cache.dbm.php

271 lines
8.2 KiB
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/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;
/**
* @var string
*/
private $lock_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.');
}
// Store lock filename for cleanup operations
$this->lock_filename = $lock_filename;
// Create lock file if needed
if (!file_exists($this->lock_filename)) {
if (!touch($this->lock_filename)) {
throw new Exception('failed to create lock file: '.$this->lock_filename);
}
}
// Open lock file for writing with read/write mode (w+) to prevent truncation on BSD systems
$this->lock = fopen($this->lock_filename, 'w+');
if (!$this->lock) {
throw new Exception('Cannot open lock file: '.$this->lock_filename);
}
// Acquire exclusive write lock to lock file
if (!flock($this->lock, LOCK_EX)) {
fclose($this->lock);
throw new Exception('Cannot acquire lock: '.$this->lock_filename);
}
// Store connection parameters
$this->cache_type = $cache_type;
$this->dbm_filename = $dbm_filename;
try {
// Try to open existing DBM file
$this->dba = dba_open($this->dbm_filename, 'w', $this->cache_type);
// Create new DBM file if it didn't exist
if (!$this->dba) {
$this->dba = dba_open($this->dbm_filename, 'n', $this->cache_type);
if (!$this->dba) {
throw new Exception('failed to create dbm file: '.$this->dbm_filename);
}
// Insert getID3 version number
dba_insert(getID3::VERSION, getID3::VERSION, $this->dba);
}
// Check version number and clear cache if changed
if (dba_fetch(getID3::VERSION, $this->dba) != getID3::VERSION) {
$this->clear_cache();
}
} catch (Exception $e) {
$this->safe_close();
throw $e;
}
// Register destructor
register_shutdown_function(array($this, '__destruct'));
parent::__construct();
}
/**
* Destructor - ensure proper cleanup of resources
*/
public function __destruct() {
$this->safe_close();
}
/**
* Safely close all resources with error handling
*/
private function safe_close() {
try {
// Close DBM connection if open
if (is_resource($this->dba)) {
dba_close($this->dba);
$this->dba = null;
}
// Release lock if acquired
if (is_resource($this->lock)) {
flock($this->lock, LOCK_UN);
fclose($this->lock);
$this->lock = null;
}
} catch (Exception $e) {
error_log('getID3_cached_dbm cleanup error: ' . $e->getMessage());
}
}
/**
* Clear cache and recreate DBM file
*
* @throws Exception
*/
public function clear_cache() {
$this->safe_close();
// 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'));
}
/**
* Analyze file and cache results
*
* @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) {
try {
$key = null;
if (file_exists($filename)) {
// Calc key: filename::mod_time::size - should be unique
$key = $filename.'::'.filemtime($filename).'::'.filesize($filename);
// Lookup key in cache
$result = dba_fetch($key, $this->dba);
// Cache hit
if ($result !== false) {
return unserialize($result);
}
}
// Cache miss - perform actual analysis
$result = parent::analyze($filename, $filesize, $original_filename, $fp);
// Store result in cache if key was generated
if ($key !== null) {
dba_replace($key, serialize($result), $this->dba);
}
return $result;
} catch (Exception $e) {
$this->safe_close();
throw $e;
}
}
}