boinc/html/inc/cache.inc

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<?php
// This file is part of BOINC.
// http://boinc.berkeley.edu
// Copyright (C) 2008 University of California
//
// BOINC is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// BOINC is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with BOINC. If not, see <http://www.gnu.org/licenses/>.
require_once("../project/cache_parameters.inc");
// If we can't see request headers, don't do caching
//
$no_cache = false;
if (!function_exists("apache_request_headers")) {
$no_cache = true;
}
// mechanism for caching commonly-accessed pages
function make_cache_dirs() {
if (!@filemtime("../cache")) {
mkdir("../cache", 0770);
chmod("../cache", 0770);
}
for ($i=0;$i<256;$i++) {
$j=sprintf("%02x",$i);
if (!@filemtime("../cache/$j")) {
mkdir("../cache/$j", 0770);
chmod("../cache/$j", 0770);
}
}
}
function get_path($params, $phpfile=null) {
if (!@filemtime("../cache/00")) make_cache_dirs();
if ($phpfile) {
$z = $phpfile;
} else {
$y = pathinfo($_SERVER["PHP_SELF"]);
$z = $y["basename"];
}
// add a layer of subdirectories for reducing file lookup time
$sz = substr(md5($z."_".urlencode($params)),1,2);
$path = "../cache/".$sz."/".$z;
if ($params) {
$path = $path."_".urlencode($params);
}
return $path;
}
function disk_usage($dir) {
$usage=0;
if ($handle=@opendir($dir)) {
while ($file=readdir($handle)) {
if (($file != ".") && ($file != "..")) {
if (@is_dir($dir."/".$file)) {
$usage+=disk_usage($dir."/".$file);
} else {
$usage+=@filesize($dir."/".$file);
}
}
}
@closedir($handle);
}
return $usage;
}
function clean_cache($max_age, $dir) {
$start_dir = getcwd();
if (!chdir($dir)) {
return;
}
if ($handle=@opendir(".")) {
while ($file=readdir($handle)) {
if ($file == ".") continue;
if ($file == "..") continue;
// don't let hackers trick us into deleting other files!
if (strstr($file, "..")) {
continue;
}
if (@is_dir($file)) {
clean_cache($max_age, $file);
} else {
if ((time()-@filemtime($file))>$max_age) {
//echo "unlinking ".getcwd()."/$file\n";
@unlink($file);
}
}
}
@closedir($handle);
}
chdir($start_dir);
}
// check free disk space every once in a while
function cache_check_diskspace(){
if (!(rand() % CACHE_SIZE_CHECK_FREQ)) {
set_time_limit(0); // this may take a while
$max_age = 86400;
while ((disk_free_space("../cache") < MIN_FREE_SPACE) ||
(disk_usage("../cache") > MAX_CACHE_USAGE)
) {
clean_cache($max_age, "../cache");
$max_age/=2;
}
}
}
function cache_need_to_regenerate($path, $max_age){
$regenerate = false;
$request = apache_request_headers();
clearstatcache();
$lastmodified = @filemtime($path);
if ($lastmodified) {
// Check to see if this is a conditional fetch.
//
$if_modified_since = isset($request['If-Modified-Since']) ?
(explode(';',$request['If-Modified-Since'])) : false;
if ($if_modified_since) {
$if_modified_since=strtotime($if_modified_since[0]);
}
if ($if_modified_since && ($if_modified_since == $lastmodified)) {
Header("Last-Modified: " . gmdate("D, d M Y H:i:s",$lastmodified) . " GMT");
Header('HTTP/1.0 304 Not Modified');
exit;
}
// See if cached copy is too old.
// If so regenerate,
// and touch the cached copy so other processes
// don't regenerate at the same time
//
if ($lastmodified<time()-$max_age) {
$regenerate = true;
@touch($path);
}
} else {
$regenerate = true;
}
return $regenerate;
}
// Returns cached data or false if nothing was found
function get_cached_data($max_age, $params=""){
global $no_cache;
if ($no_cache) return;
$path = get_path($params);
if ($max_age) {
if (defined('MEMCACHE_SERVERS')) {
$cache = BoincMemcache::get()->get($path);
if ($cache['content']) {
return $cache['content'];
} else {
return $cache;
}
} else {
cache_check_diskspace();
$regenerate=cache_need_to_regenerate($path, $max_age);
if (!$regenerate) {
return file_get_contents($path);
}
}
}
return false; //No data was cached, just return
}
// DEPRECATED
function start_cache($max_age, $params=""){
global $no_cache, $caching, $memcache;
if ($no_cache) return;
$caching = true;
if ($max_age) {
$path = get_path($params);
if (defined('MEMCACHE_SERVERS')) {
$cache = BoincMemcache::get()->get($path);
if ($cache) {
$regenerate = false;
$lastmodified = abs($cache->timestamp);
} else {
$regenerate = true;
}
} else {
$lastmodified = @filemtime($path);
cache_check_diskspace(); //Check free disk space once in a while
$regenerate = cache_need_to_regenerate($path, $max_age);
}
//Is the stored version too old, do we need to regenerate it?
if ($regenerate){
// If cached version is too old (or non-existent)
// generate the page and write to cache
//
ob_start();
ob_implicit_flush(0);
Header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
Header("Expires: " . gmdate("D, d M Y H:i:s",time()+$max_age) . " GMT");
Header("Cache-Control: public, max-age=" . $max_age);
// allow the calling page to see cache period
//
global $cached_max_age;
$cached_max_age = $max_age;
} else {
// Otherwise serve the cached version and exit
//
if (strstr($params, "format=xml")) {
header('Content-type: text/xml');
}
Header("Last-Modified: " . gmdate("D, d M Y H:i:s",$lastmodified) . " GMT");
Header("Expires: " . gmdate("D, d M Y H:i:s",$lastmodified+$max_age) . " GMT");
Header("Cache-Control: public, max-age=" . $max_age );
if ($cache->content) {
echo $cache->content;
exit;
}
if (!@readfile($path)) {
//echo "can't read $path; lastmod $lastmodified\n";
@unlink($path);
//Proceed to regenerate content
} else {
exit;
}
}
}
}
// write output buffer both to client and to cache
// DEPRECATED
function end_cache($max_age,$params=""){
global $no_cache;
if ($no_cache) return;
// for the benefit of hackers
if (strstr($params, "..")) {
return;
}
if ($max_age) {
$path = get_path($params);
if (defined('MEMCACHE_SERVERS')) {
$cache = array('content' => ob_get_contents(), 'timestamp' => time());
ob_end_flush();
$cache = BoincMemcache::get()->set($path, $cache, $max_age);
} else {
$fhandle=fopen($path, "w");
$page=ob_get_contents();
ob_end_flush();
fwrite($fhandle, $page);
fclose($fhandle);
}
}
}
function set_cached_data($max_age, $data, $params=""){
// for the benefit of hackers
if (strstr($params, "..")) {
return;
}
$path = get_path($params);
if (defined('MEMCACHE_SERVERS')) {
$cache = array('content' => $data, 'timestamp' => time());
BoincMemcache::get()->set($path, $cache, $max_age);
} else {
$fhandle = fopen($path, "w");
fwrite($fhandle, $data);
fclose($fhandle);
}
}
function clear_cache_entry($phpfile, $params) {
if (strstr($phpfile, "..")) {
return;
}
if (strstr($params, "..")) {
return;
}
$path = get_path($params, $phpfile);
@unlink($path);
}
// Memcached class
class BoincMemcache {
static $instance;
static function get() {
self::$instance = new Memcached;
if (defined('MEMCACHE_PREFIX')) {
self::$instance->setOption(Memcached::OPT_PREFIX_KEY, MEMCACHE_PREFIX);
}
$servers = explode('|', MEMCACHE_SERVERS);
foreach($servers as &$server) {
list($ip, $port) = explode(':', $server);
if (!$port) { $port = 11211; }
$server = array($ip, $port);
}
self::$instance->addServers($servers);
return self::$instance;
}
}
?>