Location: PHPKode > projects > Taxonomic Search Engine > lib/class.wsdlcache.php
<?php







/**

* caches instances of the wsdl class

* 

* @author   Scott Nichol <hide@address.com>

* @author	Ingo Fischer <hide@address.com>

* @version  $Id: class.wsdlcache.php,v 1.1.1.1 2005/05/19 10:31:11 rdmpage Exp $

* @access public 

*/

class wsdlcache {

	var $fplock;

	var $cache_lifetime;

	var $cache_dir;

	var $debug_str = '';



	/*

	* constructor

	*

	* @param string $cache_dir directory for cache-files

	* @param integer $cache_lifetime lifetime for caching-files in seconds or 0 for unlimited

	* @access public

	*/

	function wsdlcache($cache_dir='.', $cache_lifetime=0) {

		$this->fplock = array();

		$this->cache_dir = $cache_dir != '' ? $cache_dir : '.';

		$this->cache_lifetime = $cache_lifetime;

	}



	/**

	* creates the filename used to cache a wsdl instance

	*

	* @param string $wsdl The URL of the wsdl instance

	* @return string The filename used to cache the instance

	* @access protected

	*/

	function createFilename($wsdl) {

		return $this->cache_dir.'/wsdlcache-' . md5($wsdl);

	}



	/**

	* adds debug data to the class level debug string

	*

	* @param    string $string debug data

	* @access   private

	*/

	function debug($string){

		$this->debug_str .= get_class($this).": $string\n";

	}



	/**

	* gets a wsdl instance from the cache

	*

	* @param string $wsdl The URL of the wsdl instance

	* @return object The cached wsdl instance, null if the instance is not in the cache

	* @access public

	*/

	function get($wsdl) {

		$filename = $this->createFilename($wsdl);

		if ($this->obtainMutex($filename, "r")) {

			// check for expired WSDL that must be removed from the cache

 			if ($this->cache_lifetime > 0) {

				if (file_exists($filename) && (time() - filemtime($filename) > $this->cache_lifetime)) {

					unlink($filename);

					$this->debug("Expired $wsdl ($filename) from cache");

					$this->releaseMutex($filename);

					return null;

  				}

			}

			// see what there is to return

			$fp = @fopen($filename, "r");

			if ($fp) {

				$s = implode("", @file($filename));

				fclose($fp);

				$this->debug("Got $wsdl ($filename) from cache");

			} else {

				$s = null;

				$this->debug("$wsdl ($filename) not in cache");

			}

			$this->releaseMutex($filename);

			return (!is_null($s)) ? unserialize($s) : null;

		}

		return null;

	}



	/**

	* obtains the local mutex

	*

	* @param string $filename The Filename of the Cache to lock

	* @param string $mode The open-mode ("r" or "w") or the file - affects lock-mode

	* @return boolean Lock successfully obtained ?!

	* @access protected

	*/

	function obtainMutex($filename, $mode) {

		if (isset($this->fplock[md5($filename)])) {

			$this->debug("Lock for $filename already exists");

			return false;

		}

		$this->fplock[md5($filename)] = fopen($filename.".lock", "w");

		if ($mode == "r") {

			return flock($this->fplock[md5($filename)], LOCK_SH);

		} else {

			return flock($this->fplock[md5($filename)], LOCK_EX);

		}

	}



	/*

	* adds a wsdl instance to the cache

	*

	* @param object $wsdl_instance The wsdl instance to add

	* @return boolean WSDL successfully cached

	* @access public

	*/

	function put($wsdl_instance) {

		$filename = $this->createFilename($wsdl_instance->wsdl);

		$s = serialize($wsdl_instance);

		if ($this->obtainMutex($filename, "w")) {

			$fp = fopen($filename, "w");

			fputs($fp, $s);

			fclose($fp);

			$this->debug("Put $wsdl_instance->wsdl ($filename) in cache");

			$this->releaseMutex($filename);

			return true;

		}

		return false;

	}



	/**

	* releases the local mutex

	*

	* @param string $filename The Filename of the Cache to lock

	* @return boolean Lock successfully released

	* @access protected

	*/

	function releaseMutex($filename) {

		$ret = flock($this->fplock[md5($filename)], LOCK_UN);

		fclose($this->fplock[md5($filename)]);

		unset($this->fplock[md5($filename)]);

		return $ret;

	}



	/**

	* removes a wsdl instance from the cache

	*

	* @param string $wsdl The URL of the wsdl instance

	* @return boolean Whether there was an instance to remove

	* @access public

	*/

	function remove($wsdl) {

		$filename = $this->createFilename($wsdl);

		$this->obtainMutex($filename, "w");

		$ret = unlink($filename);

		$this->debug("Removed $wsdl ($filename) from cache");

		$this->releaseMutex($filename);

		return $ret;

	}

}

?>

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