Subversion-Projekte lars-tiefland.php_share

<?php

/**

 * Container for all PDO-based cache methods. Inherits additional methods from <CacheCore>. Adheres

 * to the ICacheCore interface.

 *

 * @version 2012.01.28

 * @copyright 2006-2012 Ryan Parman

 * @copyright 2006-2010 Foleeo, Inc.

 * @copyright 2012 Amazon.com, Inc. or its affiliates.

 * @copyright 2008-2010 Contributors

 * @license http://opensource.org/licenses/bsd-license.php Simplified BSD License

 * @link http://github.com/skyzyx/cachecore CacheCore

 * @link http://getcloudfusion.com CloudFusion

 * @link http://php.net/pdo PDO

 */

class CachePDO extends CacheCore implements ICacheCore

{

	/**

	 * Reference to the PDO connection object.

	 */

	var $pdo = null;

	/**

	 * Holds the parsed URL components.

	 */

	var $dsn = null;

	/**

	 * Holds the PDO-friendly version of the connection string.

	 */

	var $dsn_string = null;

	/**

	 * Holds the prepared statement for creating an entry.

	 */

	var $create = null;

	/**

	 * Holds the prepared statement for reading an entry.

	 */

	var $read = null;

	/**

	 * Holds the prepared statement for updating an entry.

	 */

	var $update = null;

	/**

	 * Holds the prepared statement for resetting the expiry of an entry.

	 */

	var $reset = null;

	/**

	 * Holds the prepared statement for deleting an entry.

	 */

	var $delete = null;

	/**

	 * Holds the response of the read so we only need to fetch it once instead of doing

	 * multiple queries.

	 */

	var $store_read = null;

	/*%******************************************************************************************%*/

	// CONSTRUCTOR

	/**

	 * Constructs a new instance of this class.

	 *

	 * Tested with [MySQL 5.0.x](http://mysql.com), [PostgreSQL](http://postgresql.com), and

	 * [SQLite 3.x](http://sqlite.org). SQLite 2.x is assumed to work. No other PDO-supported databases have

	 * been tested (e.g. Oracle, Microsoft SQL Server, IBM DB2, ODBC, Sybase, Firebird). Feel free to send

	 * patches for additional database support.

	 *

	 * See <http://php.net/pdo> for more information.

	 *

	 * @param string $name (Required) A name to uniquely identify the cache object.

	 * @param string $location (Required) The location to store the cache object in. This may vary by cache method.

	 * @param integer $expires (Required) The number of seconds until a cache object is considered stale.

	 * @param boolean $gzip (Optional) Whether data should be gzipped before being stored. Defaults to true.

	 * @return object Reference to the cache object.

	 */

	public function __construct($name, $location, $expires, $gzip = true)

	{

		// Make sure the name is no longer than 40 characters.

		$name = sha1($name);

		// Call parent constructor and set id.

		parent::__construct($name, $location, $expires, $gzip);

		$this->id = $this->name;

		$options = array();

		// Check if the location contains :// (e.g. mysql://user:pass@hostname:port/table)

		if (stripos($location, '://') === false)

		{

			// No? Just pass it through.

			$this->dsn = parse_url($location);

			$this->dsn_string = $location;

		}

		else

		{

			// Yes? Parse and set the DSN

			$this->dsn = parse_url($location);

			$this->dsn_string = $this->dsn['scheme'] . ':host=' . $this->dsn['host'] . ((isset($this->dsn['port'])) ? ';port=' . $this->dsn['port'] : '') . ';dbname=' . substr($this->dsn['path'], 1);

		}

		// Make sure that user/pass are defined.

		$user = isset($this->dsn['user']) ? $this->dsn['user'] : null;

		$pass = isset($this->dsn['pass']) ? $this->dsn['pass'] : null;

		// Set persistence for databases that support it.

		switch ($this->dsn['scheme'])

		{

			case 'mysql': // MySQL

			case 'pgsql': // PostgreSQL

				$options[PDO::ATTR_PERSISTENT] = true;

				break;

		}

		// Instantiate a new PDO object with a persistent connection.

		$this->pdo = new PDO($this->dsn_string, $user, $pass, $options);

		// Define prepared statements for improved performance.

		$this->create = $this->pdo->prepare("INSERT INTO cache (id, expires, data) VALUES (:id, :expires, :data)");

		$this->read = $this->pdo->prepare("SELECT id, expires, data FROM cache WHERE id = :id");

		$this->reset = $this->pdo->prepare("UPDATE cache SET expires = :expires WHERE id = :id");

		$this->delete = $this->pdo->prepare("DELETE FROM cache WHERE id = :id");

	}

	/**

	 * Creates a new cache.

	 *

	 * @param mixed $data (Required) The data to cache.

	 * @return boolean Whether the operation was successful.

	 */

	public function create($data)

	{

		$data = serialize($data);

		$data = $this->gzip ? gzcompress($data) : $data;

		$this->create->bindParam(':id', $this->id);

		$this->create->bindParam(':data', $data);

		$this->create->bindParam(':expires', $this->generate_timestamp());

		return (bool) $this->create->execute();

	}

	/**

	 * Reads a cache.

	 *

	 * @return mixed Either the content of the cache object, or boolean `false`.

	 */

	public function read()

	{

		if (!$this->store_read)

		{

			$this->read->bindParam(':id', $this->id);

			$this->read->execute();

			$this->store_read = $this->read->fetch(PDO::FETCH_ASSOC);

		}

		if ($this->store_read)

		{

			$data = $this->store_read['data'];

			$data = $this->gzip ? gzuncompress($data) : $data;

			return unserialize($data);

		}

		return false;

	}

	/**

	 * Updates an existing cache.

	 *

	 * @param mixed $data (Required) The data to cache.

	 * @return boolean Whether the operation was successful.

	 */

	public function update($data)

	{

		$this->delete();

		return $this->create($data);

	}

	/**

	 * Deletes a cache.

	 *

	 * @return boolean Whether the operation was successful.

	 */

	public function delete()

	{

		$this->delete->bindParam(':id', $this->id);

		return $this->delete->execute();

	}

	/**

	 * Checks whether the cache object is expired or not.

	 *

	 * @return boolean Whether the cache is expired or not.

	 */

	public function is_expired()

	{

		if ($this->timestamp() + $this->expires < time())

		{

			return true;

		}

		return false;

	}

	/**

	 * Retrieves the timestamp of the cache.

	 *

	 * @return mixed Either the Unix time stamp of the cache creation, or boolean `false`.

	 */

	public function timestamp()

	{

		if (!$this->store_read)

		{

			$this->read->bindParam(':id', $this->id);

			$this->read->execute();

			$this->store_read = $this->read->fetch(PDO::FETCH_ASSOC);

		}

		if ($this->store_read)

		{

			$value = $this->store_read['expires'];

			// If 'expires' isn't yet an integer, convert it into one.

			if (!is_numeric($value))

			{

				$value = strtotime($value);

			}

			$this->timestamp = date('U', $value);

			return $this->timestamp;

		}

		return false;

	}

	/**

	 * Resets the freshness of the cache.

	 *

	 * @return boolean Whether the operation was successful.

	 */

	public function reset()

	{

		$this->reset->bindParam(':id', $this->id);

		$this->reset->bindParam(':expires', $this->generate_timestamp());

		return (bool) $this->reset->execute();

	}

	/**

	 * Returns a list of supported PDO database drivers. Identical to <PDO::getAvailableDrivers()>.

	 *

	 * @return array The list of supported database drivers.

	 * @link http://php.net/pdo.getavailabledrivers PHP Method

	 */

	public function get_drivers()

	{

		return PDO::getAvailableDrivers();

	}

	/**

	 * Returns a timestamp value apropriate to the current database type.

	 *

	 * @return mixed Timestamp for MySQL and PostgreSQL, integer value for SQLite.

	 */

	protected function generate_timestamp()

	{

		// Define 'expires' settings differently.

		switch ($this->dsn['scheme'])

		{

			// These support timestamps.

			case 'mysql': // MySQL

			case 'pgsql': // PostgreSQL

				$expires = date(DATE_FORMAT_MYSQL, time());

				break;

			// These support integers.

			case 'sqlite': // SQLite 3

			case 'sqlite2': // SQLite 2

				$expires = time();

				break;

		}

		return $expires;

	}

}

/*%******************************************************************************************%*/

// EXCEPTIONS

class CachePDO_Exception extends CacheCore_Exception {}