<?php
/**
* Wave Framework <http://github.com/kristovaher/Wave-Framework>
* Robots Handler
*
* Robots Handler is used to return robots.txt files, if a request is made to such a file. This
* handler either returns the existing /robots.txt file, or generates a new one that allows
* all-access to robots. Robot directives for search engines and other crawlers are actually
* stored on files and pages themselves, so it is not needed to specifically allow or deny
* anything through robots.txt file. Robots Handler also pinpoints to sitemap.xml file.
*
* @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_robots.htm
* @since 1.5.0
* @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();
}
// Robots.txt file is always returned in plain text format
header('Content-Type: text/plain;charset=utf-8;');
// This flag stores whether cache was used
$cacheUsed=false;
// Default cache timeout of one month, unless timeout is set
if(!isset($config['robots-cache-timeout'])){
$config['robots-cache-timeout']=14400; // Four hours
}
// GENERATING ROBOTS FILE
// Robots file is generated only if it does not exist in root
if(!file_exists(__ROOT__.'robots.txt')){
// ASSIGNING PARAMETERS FROM REQUEST
// If filename includes & symbol, then system assumes it should be dynamically generated
$parameters=array_unique(explode('&',$resourceFile));
// Looking for cache
$cacheFilename=md5('robots.txt&'.$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 ROBOTS FILE OR LOADING FROM CACHE
// If robots cannot be found from cache, it is generated
if(in_array('nocache',$parameters) || ($lastModified==$_SERVER['REQUEST_TIME'] || $lastModified<($_SERVER['REQUEST_TIME']-$config['robots-cache-timeout']))){
// 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 robots.txt 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 ROBOTS STRING
// Robots string is stored here
$robots='';
$robots.='User-agent: *'."\n";
$robots.='Disallow: '."\n";
$robots.='Sitemap: '.((isset($config['limiter-https']) && $config['limiter-https']==true)?'https://':'http://').$_SERVER['HTTP_HOST'].$state->data['url-web'].'sitemap.xml';
// WRITING TO CACHE
// Resource cache is cached in subdirectories, if directory does not exist then it is created
if(!is_dir($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.$cacheFilename,$robots)){
trigger_error('Cannot create resource cache',E_USER_ERROR);
}
} else {
// Setting the flag for logger
$cacheUsed=true;
}
// HEADERS
// If cache is used, then proper headers will be sent
if(in_array('nocache',$parameters)){
// user agent is told to cache these results for set duration
header('Cache-Control: no-cache,no-store');
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');
} else {
// user agent is told to cache these results for set duration
header('Cache-Control: public,max-age='.$config['robots-cache-timeout']);
header('Expires: '.gmdate('D, d M Y H:i:s',($_SERVER['REQUEST_TIME']+$config['robots-cache-timeout'])).' GMT');
header('Last-Modified: '.gmdate('D, d M Y H:i:s',$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);
// File is deleted if cache was requested to be off
if(in_array('nocache',$parameters)){
unlink($cacheDirectory.$cacheFilename);
}
} else {
// RETURNING EXISTING ROBOTS FILE
// This is technically considered as using cache
$cacheUsed=true;
// Cache headers
header('Cache-Control: public,max-age='.$config['robots-cache-timeout']);
header('Expires: '.gmdate('D, d M Y H:i:s',($_SERVER['REQUEST_TIME']+$config['robots-cache-timeout'])).' GMT');
// Last modified header
header('Last-Modified: '.gmdate('D, d M Y H:i:s',filemtime(__ROOT__.'robots.txt')).' GMT');
// Content length of the file
$contentLength=filesize(__ROOT__.'robots.txt');
// Content length is defined that can speed up website requests, letting user agent to determine file size
header('Content-Length: '.$contentLength);
// Since robots.txt did exist in root, it is simply returned
readfile(__ROOT__.'robots.txt');
}
// 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
$logger->setCustomLogData(array('category'=>'robots','cache-used'=>$cacheUsed,'content-length-used'=>$contentLength,'database-query-count'=>((isset($databaseConnection))?$databaseConnection->queryCounter:0)));
// Writing log entry
$logger->writeLog();
}
?>
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