<?php
/**
* Wave Framework <http://github.com/kristovaher/Wave-Framework>
* Appcache Handler
*
* Appcache Handler is used to return an appcache manifest to the browser for pages that use
* Appcache. If this appcache file already exists in project root folder, then it is returned
* directly from that source. Otherwise the file will be generated.
*
* @package Index Gateway
* @author Kristo Vaher <kristo@waher.net>
* @copyright Copyright (c) 2012, Kristo Vaher
* @license GNU Lesser General Public License Version 3
* @tutorial /doc/pages/handler_appcache.htm
* @since 3.4.1
* @version 3.5.0
*/
// INITIALIZATION
// Stopping all requests that did not come from Index Gateway
if(!isset($resourceAddress)){
header('HTTP/1.1 403 Forbidden');
die();
}
// Appcache manifest file requires this header
header('Content-Type: text/cache-manifest;');
// This flag stores whether cache was used
$cacheUsed=false;
// GENERATING APPCACHE MANIFEST FILE
// Manifest file is generated only if it does not exist in root
if(!file_exists(__ROOT__.$resourceFile)){
// Finding data about the request
// Looking for cache
$cacheFilename=md5($resourceFile.'&'.$config['version-system'].'&'.$config['version-api'].'&'.$resourceRequest).'.tmp';
$cacheDirectory=__ROOT__.'filesystem'.DIRECTORY_SEPARATOR.'cache'.DIRECTORY_SEPARATOR.'resources'.DIRECTORY_SEPARATOR.substr($cacheFilename,0,2).DIRECTORY_SEPARATOR;
// If cache file exists then cache modified is considered that time
if(file_exists($cacheDirectory.$cacheFilename)){
$lastModified=filemtime($cacheDirectory.$cacheFilename);
} else {
// Otherwise it is server request time
$lastModified=$_SERVER['REQUEST_TIME'];
}
// GENERATING NEW MANIFEST FILE OR LOADING FROM CACHE
// If a new manifest file is requested
if($lastModified==$_SERVER['REQUEST_TIME']){
// STATE AND DATABASE
// State stores a lot of settings that are taken into account during Sitemap generation
require(__ROOT__.'engine'.DIRECTORY_SEPARATOR.'class.www-state.php');
$state=new WWW_State($config);
// Connecting to database, if configuration is set
// Uncomment this if you actually need to use database connection for manifest file
// if(isset($config['database-name']) && $config['database-name']!='' && isset($config['database-type']) && isset($config['database-host']) && isset($config['database-username']) && isset($config['database-password'])){
// require(__ROOT__.'engine'.DIRECTORY_SEPARATOR.'class.www-database.php');
// $databaseConnection=new WWW_Database($config['database-type'],$config['database-host'],$config['database-name'],$config['database-username'],$config['database-password'],((isset($config['database-errors']))?$config['database-errors']:false),((isset($config['database-persistent']))?$config['database-persistent']:false));
// }
// GENERATING APPCACHE MANIFEST
// This finds the web root, if set
if(!$config['url-web']){
$config['url-web']=str_replace('index.php','',$_SERVER['SCRIPT_NAME']);
}
$appcache='CACHE MANIFEST'."\n";
$appcache.='# System version '.$config['version-system']."\n";
$appcache.='NETWORK:'."\n";
$appcache.='*'."\n";
$appcache.='CACHE:'."\n";
$appcache.=$config['url-web'].'resources/styles/reset.css&style.css'."\n";
$appcache.='FALLBACK:'."\n";
$appcache.='/ '.$config['url-web'].'resources/offline.htm'."\n";
// WRITING TO CACHE
// Resource cache is cached in subdirectories, if directory does not exist then it is created
if(!is_dir($cacheDirectory)){
if(!mkdir($cacheDirectory,0755)){
trigger_error('Cannot create cache folder',E_USER_ERROR);
}
}
// Data is written to cache file
if(!file_put_contents($cacheDirectory.$cacheFilename,$appcache)){
trigger_error('Cannot create resource cache',E_USER_ERROR);
}
} else {
// Setting the flag for logger
$cacheUsed=true;
}
// HEADERS
// Appcache is technically never cached
header('Cache-Control: public,max-age=0');
header('Expires: '.gmdate('D, d M Y H:i:s',$_SERVER['REQUEST_TIME']).' GMT');
header('Last-Modified: '.gmdate('D, d M Y H:i:s',$lastModified).' GMT');
// Content length of the file
$contentLength=filesize($cacheDirectory.$cacheFilename);
// Content length is defined that can speed up website requests, letting user agent to determine file size
header('Content-Length: '.$contentLength);
// OUTPUT
// Returning the file to user agent
readfile($cacheDirectory.$cacheFilename);
} else {
// RETURNING EXISTING MANIFEST FILE
// This is technically considered as using cache
$cacheUsed=true;
// Appcache is technically never cached
header('Cache-Control: public,max-age=0');
header('Expires: '.gmdate('D, d M Y H:i:s',$_SERVER['REQUEST_TIME']).' GMT');
// Last modified header
header('Last-Modified: '.gmdate('D, d M Y H:i:s',filemtime(__ROOT__.$resourceFile)).' GMT');
// Content length of the file
$contentLength=filesize(__ROOT__.$resourceFile);
// Content length is defined that can speed up website requests, letting user agent to determine file size
header('Content-Length: '.$contentLength);
// Since the manifest did exist in root, it is simply returned
readfile(__ROOT__.$resourceFile);
}
// WRITING TO LOG
// If Logger is defined then request is logged and can be used for performance review later
if(isset($logger)){
// Assigning custom log data to logger
$logger->setCustomLogData(array('category'=>'appcache','cache-used'=>$cacheUsed,'content-length-used'=>$contentLength,'database-query-count'=>((isset($databaseConnection))?$databaseConnection->queryCounter:0)));
// Writing log entry
$logger->writeLog();
}
?>
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