includes/cache/FileCacheBase.php

   1 <?php
   2 /**
   3  * Data storage in the file system.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Cache
  22  */
  23
  24 namespace MediaWiki\Cache;
  25
  26 use MediaWiki\Config\ServiceOptions;
  27 use MediaWiki\MainConfigNames;
  28 use MediaWiki\MediaWikiServices;
  29 use MediaWiki\Request\WebRequest;
  30 use Wikimedia\AtEase\AtEase;
  31 use Wikimedia\IPUtils;
  32 use Wikimedia\ObjectCache\BagOStuff;
  33
  34 /**
  35  * Base class for data storage in the file system.
  36  *
  37  * @ingroup Cache
  38  */
  39 abstract class FileCacheBase {
  40
  41         private const CONSTRUCTOR_OPTIONS = [
  42                 MainConfigNames::CacheEpoch,
  43                 MainConfigNames::FileCacheDepth,
  44                 MainConfigNames::FileCacheDirectory,
  45                 MainConfigNames::MimeType,
  46                 MainConfigNames::UseGzip,
  47         ];
  48
  49         /** @var string */
  50         protected $mKey;
  51         /** @var string */
  52         protected $mType = 'object';
  53         /** @var string */
  54         protected $mExt = 'cache';
  55         /** @var string|null */
  56         protected $mFilePath;
  57         /** @var bool */
  58         protected $mUseGzip;
  59         /** @var bool|null lazy loaded */
  60         protected $mCached;
  61         /** @var ServiceOptions */
  62         protected $options;
  63
  64         /* @todo configurable? */
  65         private const MISS_FACTOR = 15; // log 1 every MISS_FACTOR cache misses
  66         private const MISS_TTL_SEC = 3600; // how many seconds ago is "recent"
  67
  68         protected function __construct() {
  69                 $this->options = new ServiceOptions(
  70                         self::CONSTRUCTOR_OPTIONS,
  71                         MediaWikiServices::getInstance()->getMainConfig()
  72                 );
  73                 $this->mUseGzip = (bool)$this->options->get( MainConfigNames::UseGzip );
  74         }
  75
  76         /**
  77          * Get the base file cache directory
  78          * @return string
  79          */
  80         final protected function baseCacheDirectory() {
  81                 return $this->options->get( MainConfigNames::FileCacheDirectory );
  82         }
  83
  84         /**
  85          * Get the base cache directory (not specific to this file)
  86          * @return string
  87          */
  88         abstract protected function cacheDirectory();
  89
  90         /**
  91          * Get the path to the cache file
  92          * @return string
  93          */
  94         protected function cachePath() {
  95                 if ( $this->mFilePath !== null ) {
  96                         return $this->mFilePath;
  97                 }
  98
  99                 $dir = $this->cacheDirectory();
 100                 # Build directories (methods include the trailing "/")
 101                 $subDirs = $this->typeSubdirectory() . $this->hashSubdirectory();
 102                 # Avoid extension confusion
 103                 $key = str_replace( '.', '%2E', urlencode( $this->mKey ) );
 104                 # Build the full file path
 105                 $this->mFilePath = "{$dir}/{$subDirs}{$key}.{$this->mExt}";
 106                 if ( $this->useGzip() ) {
 107                         $this->mFilePath .= '.gz';
 108                 }
 109
 110                 return $this->mFilePath;
 111         }
 112
 113         /**
 114          * Check if the cache file exists
 115          * @return bool
 116          */
 117         public function isCached() {
 118                 $this->mCached ??= is_file( $this->cachePath() );
 119
 120                 return $this->mCached;
 121         }
 122
 123         /**
 124          * Get the last-modified timestamp of the cache file
 125          * @return string|bool TS_MW timestamp
 126          */
 127         public function cacheTimestamp() {
 128                 $timestamp = filemtime( $this->cachePath() );
 129
 130                 return ( $timestamp !== false )
 131                         ? wfTimestamp( TS_MW, $timestamp )
 132                         : false;
 133         }
 134
 135         /**
 136          * Check if up to date cache file exists
 137          * @param string $timestamp MW_TS timestamp
 138          *
 139          * @return bool
 140          */
 141         public function isCacheGood( $timestamp = '' ) {
 142                 $cacheEpoch = $this->options->get( MainConfigNames::CacheEpoch );
 143
 144                 if ( !$this->isCached() ) {
 145                         return false;
 146                 }
 147
 148                 $cachetime = $this->cacheTimestamp();
 149                 $good = ( $timestamp <= $cachetime && $cacheEpoch <= $cachetime );
 150                 wfDebug( __METHOD__ .
 151                         ": cachetime $cachetime, touched '{$timestamp}' epoch {$cacheEpoch}, good " . wfBoolToStr( $good ) );
 152
 153                 return $good;
 154         }
 155
 156         /**
 157          * Check if the cache is gzipped
 158          * @return bool
 159          */
 160         protected function useGzip() {
 161                 return $this->mUseGzip;
 162         }
 163
 164         /**
 165          * Get the uncompressed text from the cache
 166          * @return string
 167          */
 168         public function fetchText() {
 169                 if ( $this->useGzip() ) {
 170                         $fh = gzopen( $this->cachePath(), 'rb' );
 171
 172                         return stream_get_contents( $fh );
 173                 } else {
 174                         return file_get_contents( $this->cachePath() );
 175                 }
 176         }
 177
 178         /**
 179          * Save and compress text to the cache
 180          * @param string $text
 181          * @return string|false Compressed text
 182          */
 183         public function saveText( $text ) {
 184                 if ( $this->useGzip() ) {
 185                         $text = gzencode( $text );
 186                 }
 187
 188                 $this->checkCacheDirs(); // build parent dir
 189                 if ( !file_put_contents( $this->cachePath(), $text, LOCK_EX ) ) {
 190                         wfDebug( __METHOD__ . "() failed saving " . $this->cachePath() );
 191                         $this->mCached = null;
 192
 193                         return false;
 194                 }
 195
 196                 $this->mCached = true;
 197
 198                 return $text;
 199         }
 200
 201         /**
 202          * Clear the cache for this page
 203          * @return void
 204          */
 205         public function clearCache() {
 206                 AtEase::suppressWarnings();
 207                 unlink( $this->cachePath() );
 208                 AtEase::restoreWarnings();
 209                 $this->mCached = false;
 210         }
 211
 212         /**
 213          * Create parent directors of $this->cachePath()
 214          * @return void
 215          */
 216         protected function checkCacheDirs() {
 217                 wfMkdirParents( dirname( $this->cachePath() ), null, __METHOD__ );
 218         }
 219
 220         /**
 221          * Get the cache type subdirectory (with trailing slash)
 222          * An extending class could use that method to alter the type -> directory
 223          * mapping. @see HTMLFileCache::typeSubdirectory() for an example.
 224          *
 225          * @return string
 226          */
 227         protected function typeSubdirectory() {
 228                 return $this->mType . '/';
 229         }
 230
 231         /**
 232          * Return relative multi-level hash subdirectory (with trailing slash)
 233          * or the empty string if not $wgFileCacheDepth
 234          * @return string
 235          */
 236         protected function hashSubdirectory() {
 237                 $fileCacheDepth = $this->options->get( MainConfigNames::FileCacheDepth );
 238
 239                 $subdir = '';
 240                 if ( $fileCacheDepth > 0 ) {
 241                         $hash = md5( $this->mKey );
 242                         for ( $i = 1; $i <= $fileCacheDepth; $i++ ) {
 243                                 $subdir .= substr( $hash, 0, $i ) . '/';
 244                         }
 245                 }
 246
 247                 return $subdir;
 248         }
 249
 250         /**
 251          * Roughly increments the cache misses in the last hour by unique visitors
 252          * @param WebRequest $request
 253          * @return void
 254          */
 255         public function incrMissesRecent( WebRequest $request ) {
 256                 if ( mt_rand( 1, self::MISS_FACTOR ) == 1 ) {
 257                         # Get a large IP range that should include the user  even if that
 258                         # person's IP address changes
 259                         $ip = $request->getIP();
 260                         if ( !IPUtils::isValid( $ip ) ) {
 261                                 return;
 262                         }
 263
 264                         $ip = IPUtils::isIPv6( $ip )
 265                                 ? IPUtils::sanitizeRange( "$ip/32" )
 266                                 : IPUtils::sanitizeRange( "$ip/16" );
 267
 268                         # Bail out if a request already came from this range...
 269                         $cache = MediaWikiServices::getInstance()->getObjectCacheFactory()
 270                                 ->getLocalClusterInstance();
 271                         $key = $cache->makeKey( static::class, 'attempt', $this->mType, $this->mKey, $ip );
 272                         if ( !$cache->add( $key, 1, self::MISS_TTL_SEC ) ) {
 273                                 return; // possibly the same user
 274                         }
 275
 276                         # Increment the number of cache misses...
 277                         $cache->incrWithInit( $this->cacheMissKey( $cache ), self::MISS_TTL_SEC );
 278                 }
 279         }
 280
 281         /**
 282          * Roughly gets the cache misses in the last hour by unique visitors
 283          * @return int
 284          */
 285         public function getMissesRecent() {
 286                 $cache = MediaWikiServices::getInstance()->getObjectCacheFactory()
 287                         ->getLocalClusterInstance();
 288
 289                 return self::MISS_FACTOR * $cache->get( $this->cacheMissKey( $cache ) );
 290         }
 291
 292         /**
 293          * @param BagOStuff $cache Instance that the key will be used with
 294          * @return string
 295          */
 296         protected function cacheMissKey( BagOStuff $cache ) {
 297                 return $cache->makeKey( static::class, 'misses', $this->mType, $this->mKey );
 298         }
 299 }
 300
 301 /** @deprecated class alias since 1.42 */
 302 class_alias( FileCacheBase::class, 'FileCacheBase' );