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<?php
// +----------------------------------------------------------------------+
// | PEAR :: Cache |
// +----------------------------------------------------------------------+
// | Copyright (c) 1997-2003 The PHP Group |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2.0 of the PHP license, |
// | that is bundled with this package in the file LICENSE, and is |
// | available at through the world-wide-web at |
// | http://www.php.net/license/2_02.txt. |
// | If you did not receive a copy of the PHP license and are unable to |
// | obtain it through the world-wide-web, please send a note to |
// | license@php.net so we can mail you a copy immediately. |
// +----------------------------------------------------------------------+
// | Authors: Ulf Wendel <ulf.wendel@phpdoc.de> |
// | Christian Stocker <chregu@phant.ch> |
// | Vinai Kopp <kopp@netzarbeiter.de> |
// +----------------------------------------------------------------------+
//
// $Id: Output.php 178289 2005-01-26 09:47:28Z dufuz $
require_once 'Cache.php';
/**
* Class to cache the output of a script using the output buffering functions
*
* Simple output cache. Some pages require lots of time to compute. Caching the
* output can increase the overall speed dramatically, especially if you use
* a Shared Memory storage container.
*
* As you can see in the example the usage is extemely simple. To cache a script
* simple put some few lines of code in front of your script and some at the end.
* A preferrable place for this are the auto_prepend and auto_append files (=> php.ini).
*
* Usage example:
*
* // place this somewhere in a central config file
* define(CACHE_STORAGE_CLASS, 'file');
* // file storage needs a dir to put the cache files
* define(CACHE_DIR, '/var/tmp/');
*
* // get a cache object
* $cache = new Cache_Output(CACHE_STORAGE_CLASS, array('cache_dir' => CACHE_DIR));
*
* // compute the unique handle.
* // if your script depends on Cookie and HTTP Post data as well
* // you should use:
* // $cache_handle = array(
* // 'file' => $REQUEST_URI,
* // 'post' => $HTTP_POST_VARS,
* // 'cookie' => $HTTP_COOKIE_VARS
* // );
* // But be warned, using all GET or POST Variables as a seed
* // can be used for a DOS attack. Calling http://www.example.com/example.php?whatever
* // where whatever is a random text might be used to flood your cache.
* $cache_handle = $cache->generateID($REQUEST_URI);
*
* // now the magic happens: if cached call die()
* // to end the time consumptiong script script execution and use the cached value!
* if ($content = $cache->start($cache_handle)) {
* print $content;
* print '<p>Cache hit</p>';
* die();
* }
*
* // time consumption script goes here.
*
* // store the output of the cache into the cache and print the output.
* print $cache->end();
* print "<p>Cache miss, stored using the ID '$id'.</p>";
*
* If you do not want to cache a whole page - no problem:
*
* if (!($content = $cache->start($cache_handle))) {
* // do the computation here
* print $cache->end()
* } else {
* print $content;
* }
*
* If you need an example script check the (auto_)prepend and (auto_)append
* files of my homepage:
*
* http://www.ulf-wendel.de/php/show_source.php?file=prepend
* http://www.ulf-wendel.de/php/show_source.php?file=append
*
* Don't know how to use it or you need profiling informations?`
* Ask Christian he was patient with me and he'll be so with your questions ;).
*
* Have fun!
*
* @authors Ulf Wendel <ulf.wendel@phpdoc.de>
* @version $ID: $
* @package Cache
* @access public
*/
class Cache_Output extends Cache
{
/**
* ID passed to start()
*
* @var string
* @see start(), end()
*/
var $output_id = '';
/**
* Group passed to start()
*
* @var string
* @see start(), end()
*/
var $output_group = '';
/**
* PEAR-Deconstructor
* Call deconstructor of parent
*/
function _Cache_Output()
{
$this->_Cache();
}
/**
* starts the output buffering and returns an empty string or returns the cached output from the cache.
*
* @param string dataset ID
* @param string cache group
* @return string
* @access public
*/
function start($id, $group = 'default')
{
if (!$this->caching) {
return '';
}
// this is already cached return it from the cache so that the user
// can use the cache content and stop script execution
if ($content = $this->get($id, $group)) {
return $content;
}
// remember some data to be able to fill the cache on calling end()
$this->output_id = $id;
$this->output_group = $group;
// WARNING: we need the output buffer - possible clashes
ob_start();
ob_implicit_flush(false);
return '';
} // end func start
/*
* Stores the content of the output buffer into the cache and returns the content.
*
* @param mixed lifetime of the cached data in seconds - 0 for endless. More formats available. see Container::getExpiresAbsolute()
* @param string additional userdefined data
* @return string cached output
* @access public
* @see endPrint(), endGet(), Container::getExpiresAbsolute()
*/
function end($expire = 0, $userdata = '')
{
$content = ob_get_contents();
ob_end_clean();
// store in the cache
if ($this->caching) {
$this->container->save($this->output_id, $content, $expire, $this->output_group, $userdata);
}
return $content;
} // end func end()
/**
* Stores the content of the output buffer into the cache and prints the content.
*
* @brother end()
*/
function endPrint($expire = 0, $userdata = '')
{
$this->printContent($this->end($expire, $userdata));
} // end func endPrint
/**
* Sends the data to the user.
* This is for compatibility with OutputCompression
*
* @param string
* @access public
*/
function printContent($content = '')
{
if ($content == '') {
$content = &$this->container->cachedata;
}
print $content;
}
/**
* Returns the content of the output buffer but does not store it into the cache.
*
* Use this method if the content of your script is markup (XML)
* that has to be parsed/converted (XSLT) before you can output
* and store it into the cache using save().
*
* @return string
* @access public
* @see endPrint(), end()
*/
function endGet()
{
$content = ob_get_contents();
ob_end_clean();
$this->output_id = '';
$this->output_group = '';
return $content;
} // end func endGet
} // end class output
?>
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