OutputCache.php

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<?php
class Dataface_OutputCache {

        var $useGzipCompression = true;
        var $tableName = '__output_cache';
        var $ignoredTables=array();
        var $observedTables=array();
        var $exemptActions=array();
        var $stripKeys=array('-l','-lang');
        var $app;
        var $threshold = 0.1;
        var $tableModificationTimes;
        var $lifeTime = 360000;
        var $randomize = 0;
        var $_cacheTableExists=null;
        var $lastModified=null;
        var $headers=array();
        var $userId = null;
        
        var $usedTables=array();
        
        function Dataface_OutputCache($params=array()){
                if ( !extension_loaded('zlib') ){
                        $this->useGzipCompression = false;
                } else if ( isset($params['useGzipCompression']) ){
                        $this->useGzipCompression = $params['useGzipCompression'];
                }

                if ( isset($params['threshold']) ) $this->threshold = $params['threshold'];
                if ( isset($params['lifeTime']) ) $this->lifeTime = $params['lifeTime'];
                if ( isset($params['tableName']) ) $this->tableName = $params['tableName'];
                if ( isset($params['ignoredTables']) ) $this->ignoredTables = explode(',', $params['ignoredTables']);
                if ( isset($params['observedTables']) ) $this->observedTables = explode(',', $params['observedTables']);
                if ( isset($params['exemptActions']) ) $this->exemptActions = explode(',', $params['exemptActions']);
                if ( isset($params['stripKeys']) ) $this->stripKeys = explode(',', $params['stripKeys']);
                $this->app =& Dataface_Application::getInstance();
                
                if ( !$this->_cacheTableExists() ) $this->_createCacheTable();
        }
        
        function getUserId(){
                if ( !isset($this->userId) ){
                        $del = $this->app->getDelegate();

                        if ( $del and method_exists($del, 'getOutputCacheUserId') ){
                                $this->userId = $del->getOutputCacheUserId();
                        }
                        if ( !isset($this->userId) ){
                                
                                if ( class_exists('Dataface_AuthenticationTool') ){
                                        $this->userId = Dataface_AuthenticationTool::getInstance()->getLoggedInUsername();
                                }
                                
                        }
                        if ( !isset($this->userId) ) $this->userId = '';
                }
                return $this->userId;
        
        }
        
        function _buildPageSelect($params=array()){
                import('Dataface/AuthenticationTool.php');
                $query =& $this->app->getQuery();
                
                
                $PageID = $this->getPageID($params);
                $Language = ( isset($params['lang']) ? $params['lang'] : $this->app->_conf['lang']);
                $auth =& Dataface_AuthenticationTool::getInstance();
                //$UserID = ( isset($params['user']) ? $params['user'] : $auth->getLoggedInUsername());
                $UserID = $this->getUserId();
                $TimeStamp = ( isset($params['time']) ? $params['time'] : time()-$this->lifeTime);
                
                
                return "
                        where `PageID` = '".addslashes($PageID)."'
                        and `Language` = '".addslashes($Language)."'
                        and `UserID` = '".addslashes($UserID)."'
                        and `Expires` > NOW() 
                        ORDER BY RAND()";
        }
        
        function getPage($params=array()){
                
                $app =& Dataface_Application::getInstance();
                $query =& $app->getQuery();
                if ( in_array($query['-action'], $this->exemptActions) ) return null;
                
                if ( $this->gzipSupported() and $this->useGzipCompression ){
                        $DataColumn = 'Data_gz';
                } else {
                        $DataColumn = 'Data';
                }
                
                $res = mysql_query("select `".addslashes($DataColumn)."`, UNIX_TIMESTAMP(`LastModified`) as `TimeStamp`, `Dependencies`, `Headers` from `".addslashes($this->tableName)."` 
                        ".$this->_buildPageSelect($params)." LIMIT 1", $this->app->db());
                        
                if ( !$res ){
                         throw new Exception(mysql_error($this->app->db()), E_USER_ERROR);
                }
                
                if ( mysql_num_rows($res) == 0 ) return null;
                //echo "here";
                list($data, $lastModified, $dependencies, $headers) = mysql_fetch_row($res);
                $this->lastModified=$lastModified;
                $tables = explode(',',$dependencies);
                if ( $headers ) $this->headers = unserialize($headers);
                if ( count($tables) == 0 ) $tables = null;
                if ( $this->isModified($lastModified, $tables) ){
                        return null;
                }
                if ( is_resource($res) ) mysql_free_result($res);
                return $data;   
        }
        
        function numCurrentVersions($params=array()){
                $res = mysql_query("
                        SELECT COUNT(*) FROM `".addslashes($this->tableName)."` ".
                        $this->_buildPageSelect($params), $this->app->db());
                if ( !$res ){
                        throw new Exception(mysql_error($this->app->db()), E_USER_ERROR);
                }
                list($num) = mysql_fetch_row($res);
                mysql_free_result($res);
                return $num;
                        
        }
        
        function ob_start($params=array()){
                
                $app =& Dataface_Application::getInstance();
                $query =& $app->getQuery();
                if ( in_array($query['-action'], $this->exemptActions) ){
                        return true;
                }
                
                if ( floatval($this->threshold) * floatval(100) > rand(0,100) ){
                        register_shutdown_function(array(&$this, 'cleanCache'));
                }
        
                if ( isset($params['randomize']) and $params['randomize'] > 1 ){
                        $this->randomize = $params['randomize'];
                        $numVersions = $this->numCurrentVersions($params);
                        if ( $numVersions < $params['randomize'] ){
                                // We don't have enough versions yet to do a proper randomization.
                                if ( floatval(100)*floatval($numVersions)/floatval($params['randomize']) > rand(0,100) ){
                                        // We will use the cached version
                                        $useCache = true;
                                } else {
                                        $useCache = false;
                                }
                        } else {
                                $useCache = true;
                        }
                } else {
                        $useCache = true;
                }
                
                if ( $useCache ){
                        //echo "Trying to use cached version";
                        $output = $this->getPage($params);
                } else {
                        //echo "Not using cached version";
                        $output = null;
                }
                
                if ( isset($output) ){
                        //echo "Using cached version";
                        //$last_modified_time = filemtime($file);
                        $etag = md5($output);
                        
                        //echo "Session enabled: ".$this->app->sessionEnabled();exit;
                        if (!$this->app->sessionEnabled() and  @$_SERVER['REQUEST_URI'] and strpos($_SERVER['REQUEST_URI'], '?') === false ){
                                session_cache_limiter('public');
                                $expires = 60*60*24;
                                header('Cache-Control: public, max-age='.$expires.', s-maxage='.$expires);
                                header('Connection: close');
                                header("Last-Modified: ".gmdate("D, d M Y H:i:s", $this->lastModified)." GMT");
                                header('Pragma: public');
                                header('Content-Length: '.strlen($output));
                                //header('Expires: '.gmdate('D, d M Y H:i:s', time()+$expires) . ' GMT');
                
                        } else {
                                header("Last-Modified: ".gmdate("D, d M Y H:i:s", $this->lastModified)." GMT");
                                header("Etag: $etag");
                                if (@strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) == $this->lastModified ||
                                        @trim($_SERVER['HTTP_IF_NONE_MATCH']) == $etag) {
                                        header("HTTP/1.1 304 Not Modified");
                                        exit;
                                }
                        
                        }
                        
                        
                        // Send the necessary headers
                        if ( function_exists('headers_list')){
                                $hlist = headers_list();
                                $harr = array();
                                foreach ($hlist as $h){
                                        if ( preg_match( '/^(?:Content-Type|Content-Language|Content-Location|Content-Disposition|P3P):/i', $h ) ) {
                                                list($hname,$hval) = array_map('trim',explode(':',$h));
                                                $harr[$hname] = $hval;
                                        }
                                }
                                
                                foreach ( $this->headers as $h){
                                        list($hname,$hval) = array_map('trim',explode(':',$h));
                                        if ( !isset($harr[$hname]) ){
                                                header($hname.': '.$hval);
                                        }
                                }
                        }       
                                
                        
                        if ( $this->gzipSupported() and $this->useGzipCompression ){
                                header("Content-Encoding: gzip");
                                echo $output;
                        } else {
                                echo $output;
                        }
                        exit;
                }
                
                ob_start(array(&$this, 'ob_flush'));
                ob_implicit_flush(0);
                return true;
        }
        
        function ob_flush($data){
                if ( !$data ) return false;
                $params = array('randomize'=>$this->randomize, 'data'=>$data, 'tables'=>$this->app->tableNamesUsed);
                $res = $this->cachePage($params);
                
                $etag = md5($data);
                if ( !$this->app->sessionEnabled() and @$_SERVER['REQUEST_URI'] and strpos($_SERVER['REQUEST_URI'], '?') === false ){
                        //echo "here";exit;
                        $expires = 60*60*24;
                        session_cache_limiter('public');
                        header('Cache-Control: public, max-age='.$expires.', s-maxage='.$expires);
                        header('Connection: close');
                        header("Last-Modified: ".gmdate("D, d M Y H:i:s", time())." GMT");
                        header('Pragma: public');
                        header('Content-Length: '.strlen($data));
                } else {
                        header("Last-Modified: ".gmdate("D, d M Y H:i:s", time())." GMT");
                        header("Etag: $etag");
                        if (@strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) == time() ||
                                @trim($_SERVER['HTTP_IF_NONE_MATCH']) == $etag) {
                                header("HTTP/1.1 304 Not Modified");
                                exit;
                        }
                }
                
                
                return $data;
                
        }
        
        function getPageID($params=array()){
                $page_url = $_SERVER['REQUEST_URI'];
                foreach ($this->stripKeys as $key){
                        $page_url = preg_replace('/&?'.preg_quote($key, '/').'=[^&]*/','', $page_url);
                }
                //mail('steve@weblite.ca', 'Page URL', $page_url);
                $PageID = ( isset($params['id']) ? $params['id'] : md5($page_url));
                return $PageID;
        }
        
        function cachePage($params=array()){
                $PageID = $this->getPageID($params);
                
                if ( !isset($params['data']) ) throw new Exception('Missing parameter "data"', E_USER_ERROR);
                $Data = $params['data'];
                $Language = ( isset($params['lang']) ? $params['lang'] : $this->app->_conf['lang']);
                //if ( class_exists('Dataface_AuthenticationTool') ){$auth =& Dataface_AuthenticationTool::getInstance();
                //      $UserID = ( isset($params['user']) ? $params['user'] : $auth->getLoggedInUsername());
                //} else {
                //      $UserID = null;
                //}
                $UserID = $this->getUserId();
                
                $Expires = (isset($params['expires']) ? $params['expires'] : time() + $this->lifeTime);
                $tables = (isset($params['tables']) ? $params['tables'] : '');
                $Dependencies = (is_array($tables) ? implode(',',$tables) : $tables);
                
                if ( $this->useGzipCompression && extension_loaded('zlib') ){
                        // If we are using GZIP compression then we will use zlib library
                        // functions (gzcompress) to compress the data also for storage
                        // in the database.
                        // Apparently we have to play with the headers and footers of the 
                        // gzip file for it to work properly with the web browsers.
                        // see http://ca.php.net/gzcompress user comments.
                        
                        $size = strlen($Data);
                        $crc = crc32($Data);
                        /*
                        $Data_gz = "\x1f\x8b\x08\x00\x00\x00\x00\x00".
                                                substr(gzcompress($Data,9),0, $size-4).
                                                $this->_gzipGetFourChars($crc).
                                                $this->_gzipGetFourChars($size);
                        */
                        /* Fix for IE compatibility .. seems to work for mozilla too. */
                        $Data_gz = "\x1f\x8b\x08\x00\x00\x00\x00\x00".
                                                substr(gzcompress($Data,9),0, $size);
                        
                }
                
                
                if ( isset($params['randomize']) and $params['randomize'] ){
                        // We are keeping multiple versions of this page so that we can 
                        // show them on a random rotation.  This is to simulate dynamicism
                        // while still caching pages.
                        
                        // Basically the following query will delete existing cached versions
                        // of this page except for the most recent X versions - where X
                        // is the number specified in the $randomize parameter.  The 
                        // $randomize parameter is the number of versions of this page
                        // that should be used on random rotation.
                        $res = mysql_query("
                                DELETE FROM `".addslashes($this->tableName)."`
                                WHERE 
                                        `PageID`='".addslashes($PageID)."' AND
                                        `Language`='".addslashes($Language)."' AND
                                        `UserID`='".addslashes($UserID)."' AND
                                        `GenID` NOT IN (
                                                SELECT `GenID` FROM `".addslashes($this->tableName)."`
                                                WHERE 
                                                        `PageID`='".addslashes($PageID)."' AND
                                                        `Language`='".addslashes($Language)."' AND
                                                        `UserID`='".addslashes($UserID)."'
                                                ORDER BY
                                                        `LastModified` desc
                                                LIMIT ".(intval($params['randomize']) - 1)."
                                )", $this->app->db() );
                        
                        if ( !$res ){
                                throw new Exception(mysql_error($this->app->db()), E_USER_ERROR);
                        }
                } else {
                        // We are not randomizing.  We delete any existing pages.
                        /*
                        $res = mysql_query("
                                DELETE low_priority FROM `".addslashes($this->tableName)."`
                                WHERE
                                        `PageID`='".addslashes($PageID)."' AND
                                        `Language`='".addslashes($Language)."' AND
                                        `UserID`='".addslashes($UserID)."'", $this->app->db());
                        if ( !$res ){
                                throw new Exception(mysql_error($this->app->db()), E_USER_ERROR);
                        }
                        */
                }
                
                // Get the headers so we can reproduce them properly.
                if ( function_exists('headers_list') ){
                        //$headers = serialize(headers_list());
                        $headers = headers_list();
                        $hout = array();
                        foreach ( $headers as $h){
                                if ( preg_match( '/^(?:Content-Type|Content-Language|Content-Location|Content-Disposition|P3P):/i', $h ) ) {
                                        $hout[] = $h;
                                }
                        }
                        $headers = $hout;
                } else {
                        $headers = array();
                }
                
                
                // Now we can insert the cached page.
                $sql = "
                        replace delayed INTO `".addslashes($this->tableName)."`
                        (`PageID`,`Language`,`UserID`,`Dependencies`,`Expires`,`Data`,`Data_gz`, `Headers`)
                        VALUES
                        ('".addslashes($PageID)."',
                         '".addslashes($Language)."',
                         '".addslashes($UserID)."',
                         '".addslashes($Dependencies)."',
                         FROM_UNIXTIME('".addslashes($Expires)."'),
                         '".addslashes($Data)."',
                         '".addslashes($Data_gz)."',
                         '".addslashes(serialize($headers))."'
                        )";
                        //file_put_contents('/tmp/dump.sql',$sql);
                $res = mysql_query($sql, $this->app->db());
                
                if ( !$res ){
                        throw new Exception(mysql_error($this->app->db()), E_USER_ERROR);
                }
        
                if ( @$this->app->_conf['_output_cache']['cachedir'] ){
                        $filename =  DATAFACE_SITE_PATH.'/'.$this->app->_conf['_output_cache']['cachedir'];
                        $dir = $PageID{0};
                        $filename = $filename.'/'.$dir;
                        if ( !file_exists($filename)){
                                mkdir($filename, 0777);
                                
                        }
                        
                        $filename .= '/'.$PageID.'-'.md5($Language.'-'.$UserID);
                        if ( file_exists($filename) ){
                                @unlink($filename);
                        } 
                        //echo "Opening $filename";
                        $fh = fopen($filename, 'w');
                        if ( $fh ){ 
                                fwrite($fh, $Data);
                                fclose($fh);
                        }
                        
                        $fh = fopen($filename.'.gz', 'w');
                        if ( $fh ){
                                fwrite($fh, $Data_gz);
                                fclose($fh);
                        }
                        
                }
                
                
                
                
                
        
        }
        
        function _gzipGetFourChars($Val){
                $out = '';
                for ($i = 0; $i < 4; $i ++) { 
                   $out .= chr($Val % 256); 
                   $Val = floor($Val / 256); 
           } 
           return $out;
        
        }
        
        
        function _createCacheTable(){
                $res = mysql_query("create table IF NOT EXISTS `".addslashes($this->tableName)."`(
                        `GenID` INT(11) auto_increment,
                        `PageID` VARCHAR(64),
                        `Language` CHAR(2),
                        `UserID` VARCHAR(32),
                        `Dependencies` TEXT,
                        `LastModified` TIMESTAMP,
                        `Expires` DateTime,
                        `Data` LONGTEXT,
                        `Data_gz` LONGBLOB,
                        `Headers` TEXT,
                        PRIMARY KEY (`GenID`),
                        INDEX `LookupIndex` (`Language`,`UserID`,`PageID`)
                        )", $this->app->db());
                if ( !$res ){
                        return PEAR::raiseError('Could not create cache table: '.mysql_error($this->app->db()));
                }       
                
        }
        
        function _cacheTableExists(){
                if ( isset($this->_cacheTableExists) ) return $this->_cacheTableExists;
                $res = mysql_query("SHOW TABLES LIKE '".addslashes($this->tableName)."'", $this->app->db());
                if ( !$res ){
                        throw new Exception(mysql_error($this->app->db()), E_USER_ERROR);
                }
                return (mysql_num_rows($res) > 0);
        }
        
        function cleanCache(){
                $res = mysql_query("delete low_priority from `".addslashes($this->tableName)."` where `Expires` < NOW()", $this->app->db());
        }
        
        function gzipSupported(){
                return stristr(@$_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip');
        }
        
        function &getTableModificationTimes(){  
                $mod_times =&  Dataface_Table::getTableModificationTimes();
                $this->tableModificationTimes =& $mod_times;
                return $mod_times;
        }
        
        function isModified($time, $tables=null){
                $this->getTableModificationTimes();
                if ( !isset($tables) ) $tables = array_keys($this->tableModificationTimes);
                if ( !is_array($tables) ){
                        $tables = explode(',', $tables);
                }
                $tables = array_merge($this->observedTables, $tables);
                foreach ($tables as $table ){
                        if ( isset( $this->ignoredTables[$table] ) ) continue;
                        if ( !isset($this->tableModificationTimes[$table]) ) continue;
                        if ( $this->tableModificationTimes[$table] > $time ) return true;
                }
                return false;
        }

}