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  Classes of Kristo Vaher  >  Wave Framework  >  engine/handler.appcache.php  >  Download  
File: engine/handler.appcache.php
Role: Application script
Content type: text/plain
Description: Handler for serving Appcache files
Class: Wave Framework
MVC framework for building Web sites and APIs
Author: By
Last change: Re-implemented system version number and updated versioning documentation. You can also limit API version numbers with API profiles now.
Date: 1 year ago
Size: 5,889 bytes
 

Contents

Class file image Download
<?php
/**
 * Wave Framework <http://www.waveframework.com>
 * 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();
    }
?>