Current File : //www/varak.net/wiki.varak.net/includes/cache/FileCacheBase.php
<?php
/**
* Data storage in the file system.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup Cache
*/
/**
* Base class for data storage in the file system.
*
* @ingroup Cache
*/
abstract class FileCacheBase {
protected $mKey;
protected $mType = 'object';
protected $mExt = 'cache';
protected $mFilePath;
protected $mUseGzip;
/* lazy loaded */
protected $mCached;
/* @todo configurable? */
const MISS_FACTOR = 15; // log 1 every MISS_FACTOR cache misses
const MISS_TTL_SEC = 3600; // how many seconds ago is "recent"
protected function __construct() {
global $wgUseGzip;
$this->mUseGzip = (bool)$wgUseGzip;
}
/**
* Get the base file cache directory
* @return string
*/
final protected function baseCacheDirectory() {
global $wgFileCacheDirectory;
return $wgFileCacheDirectory;
}
/**
* Get the base cache directory (not specific to this file)
* @return string
*/
abstract protected function cacheDirectory();
/**
* Get the path to the cache file
* @return string
*/
protected function cachePath() {
if ( $this->mFilePath !== null ) {
return $this->mFilePath;
}
$dir = $this->cacheDirectory();
# Build directories (methods include the trailing "/")
$subDirs = $this->typeSubdirectory() . $this->hashSubdirectory();
# Avoid extension confusion
$key = str_replace( '.', '%2E', urlencode( $this->mKey ) );
# Build the full file path
$this->mFilePath = "{$dir}/{$subDirs}{$key}.{$this->mExt}";
if ( $this->useGzip() ) {
$this->mFilePath .= '.gz';
}
return $this->mFilePath;
}
/**
* Check if the cache file exists
* @return bool
*/
public function isCached() {
if ( $this->mCached === null ) {
$this->mCached = file_exists( $this->cachePath() );
}
return $this->mCached;
}
/**
* Get the last-modified timestamp of the cache file
* @return string|bool TS_MW timestamp
*/
public function cacheTimestamp() {
$timestamp = filemtime( $this->cachePath() );
return ( $timestamp !== false )
? wfTimestamp( TS_MW, $timestamp )
: false;
}
/**
* Check if up to date cache file exists
* @param string $timestamp MW_TS timestamp
*
* @return bool
*/
public function isCacheGood( $timestamp = '' ) {
global $wgCacheEpoch;
if ( !$this->isCached() ) {
return false;
}
$cachetime = $this->cacheTimestamp();
$good = ( $timestamp <= $cachetime && $wgCacheEpoch <= $cachetime );
wfDebug( __METHOD__ .
": cachetime $cachetime, touched '{$timestamp}' epoch {$wgCacheEpoch}, good $good\n" );
return $good;
}
/**
* Check if the cache is gzipped
* @return bool
*/
protected function useGzip() {
return $this->mUseGzip;
}
/**
* Get the uncompressed text from the cache
* @return string
*/
public function fetchText() {
if ( $this->useGzip() ) {
$fh = gzopen( $this->cachePath(), 'rb' );
return stream_get_contents( $fh );
} else {
return file_get_contents( $this->cachePath() );
}
}
/**
* Save and compress text to the cache
* @param string $text
* @return string|false Compressed text
*/
public function saveText( $text ) {
if ( $this->useGzip() ) {
$text = gzencode( $text );
}
$this->checkCacheDirs(); // build parent dir
if ( !file_put_contents( $this->cachePath(), $text, LOCK_EX ) ) {
wfDebug( __METHOD__ . "() failed saving " . $this->cachePath() . "\n" );
$this->mCached = null;
return false;
}
$this->mCached = true;
return $text;
}
/**
* Clear the cache for this page
* @return void
*/
public function clearCache() {
Wikimedia\suppressWarnings();
unlink( $this->cachePath() );
Wikimedia\restoreWarnings();
$this->mCached = false;
}
/**
* Create parent directors of $this->cachePath()
* @return void
*/
protected function checkCacheDirs() {
wfMkdirParents( dirname( $this->cachePath() ), null, __METHOD__ );
}
/**
* Get the cache type subdirectory (with trailing slash)
* An extending class could use that method to alter the type -> directory
* mapping. @see HTMLFileCache::typeSubdirectory() for an example.
*
* @return string
*/
protected function typeSubdirectory() {
return $this->mType . '/';
}
/**
* Return relative multi-level hash subdirectory (with trailing slash)
* or the empty string if not $wgFileCacheDepth
* @return string
*/
protected function hashSubdirectory() {
global $wgFileCacheDepth;
$subdir = '';
if ( $wgFileCacheDepth > 0 ) {
$hash = md5( $this->mKey );
for ( $i = 1; $i <= $wgFileCacheDepth; $i++ ) {
$subdir .= substr( $hash, 0, $i ) . '/';
}
}
return $subdir;
}
/**
* Roughly increments the cache misses in the last hour by unique visitors
* @param WebRequest $request
* @return void
*/
public function incrMissesRecent( WebRequest $request ) {
if ( mt_rand( 0, self::MISS_FACTOR - 1 ) == 0 ) {
$cache = ObjectCache::getLocalClusterInstance();
# Get a large IP range that should include the user even if that
# person's IP address changes
$ip = $request->getIP();
if ( !IP::isValid( $ip ) ) {
return;
}
$ip = IP::isIPv6( $ip )
? IP::sanitizeRange( "$ip/32" )
: IP::sanitizeRange( "$ip/16" );
# Bail out if a request already came from this range...
$key = $cache->makeKey( static::class, 'attempt', $this->mType, $this->mKey, $ip );
if ( $cache->get( $key ) ) {
return; // possibly the same user
}
$cache->set( $key, 1, self::MISS_TTL_SEC );
# Increment the number of cache misses...
$key = $this->cacheMissKey( $cache );
if ( $cache->get( $key ) === false ) {
$cache->set( $key, 1, self::MISS_TTL_SEC );
} else {
$cache->incr( $key );
}
}
}
/**
* Roughly gets the cache misses in the last hour by unique visitors
* @return int
*/
public function getMissesRecent() {
$cache = ObjectCache::getLocalClusterInstance();
return self::MISS_FACTOR * $cache->get( $this->cacheMissKey( $cache ) );
}
/**
* @param BagOStuff $cache Instance that the key will be used with
* @return string
*/
protected function cacheMissKey( BagOStuff $cache ) {
return $cache->makeKey( static::class, 'misses', $this->mType, $this->mKey );
}
}
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