includes/interwiki/ClassicInterwikiLookup.php

   1 <?php
   2 /**
   3  * InterwikiLookup implementing the "classic" interwiki storage (hardcoded up to MW 1.26).
   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  */
  22
  23 namespace MediaWiki\Interwiki;
  24
  25 use Cdb\Exception as CdbException;
  26 use Cdb\Reader as CdbReader;
  27 use Hooks;
  28 use Interwiki;
  29 use Language;
  30 use MapCacheLRU;
  31 use WANObjectCache;
  32 use Wikimedia\Rdbms\Database;
  33
  34 /**
  35  * InterwikiLookup implementing the "classic" interwiki storage (hardcoded up to MW 1.26).
  36  *
  37  * This implements two levels of caching (in-process array and a WANObjectCache)
  38  * and tree storage backends (SQL, CDB, and plain PHP arrays).
  39  *
  40  * All information is loaded on creation when called by $this->fetch( $prefix ).
  41  * All work is done on replica DB, because this should *never* change (except during
  42  * schema updates etc, which aren't wiki-related)
  43  *
  44  * @since 1.28
  45  */
  46 class ClassicInterwikiLookup implements InterwikiLookup {
  47
  48         /**
  49          * @var MapCacheLRU
  50          */
  51         private $localCache;
  52
  53         /**
  54          * @var Language
  55          */
  56         private $contLang;
  57
  58         /**
  59          * @var WANObjectCache
  60          */
  61         private $objectCache;
  62
  63         /**
  64          * @var int
  65          */
  66         private $objectCacheExpiry;
  67
  68         /**
  69          * @var bool|array|string
  70          */
  71         private $cdbData;
  72
  73         /**
  74          * @var int
  75          */
  76         private $interwikiScopes;
  77
  78         /**
  79          * @var string
  80          */
  81         private $fallbackSite;
  82
  83         /**
  84          * @var CdbReader|null
  85          */
  86         private $cdbReader = null;
  87
  88         /**
  89          * @var string|null
  90          */
  91         private $thisSite = null;
  92
  93         /**
  94          * @param Language $contLang Language object used to convert prefixes to lower case
  95          * @param WANObjectCache $objectCache Cache for interwiki info retrieved from the database
  96          * @param int $objectCacheExpiry Expiry time for $objectCache, in seconds
  97          * @param bool|array|string $cdbData The path of a CDB file, or
  98          *        an array resembling the contents of a CDB file,
  99          *        or false to use the database.
 100          * @param int $interwikiScopes Specify number of domains to check for messages:
 101          *    - 1: Just local wiki level
 102          *    - 2: wiki and global levels
 103          *    - 3: site level as well as wiki and global levels
 104          * @param string $fallbackSite The code to assume for the local site,
 105          */
 106         function __construct(
 107                 Language $contLang,
 108                 WANObjectCache $objectCache,
 109                 $objectCacheExpiry,
 110                 $cdbData,
 111                 $interwikiScopes,
 112                 $fallbackSite
 113         ) {
 114                 $this->localCache = new MapCacheLRU( 100 );
 115
 116                 $this->contLang = $contLang;
 117                 $this->objectCache = $objectCache;
 118                 $this->objectCacheExpiry = $objectCacheExpiry;
 119                 $this->cdbData = $cdbData;
 120                 $this->interwikiScopes = $interwikiScopes;
 121                 $this->fallbackSite = $fallbackSite;
 122         }
 123
 124         /**
 125          * Check whether an interwiki prefix exists
 126          *
 127          * @param string $prefix Interwiki prefix to use
 128          * @return bool Whether it exists
 129          */
 130         public function isValidInterwiki( $prefix ) {
 131                 $result = $this->fetch( $prefix );
 132
 133                 return (bool)$result;
 134         }
 135
 136         /**
 137          * Fetch an Interwiki object
 138          *
 139          * @param string $prefix Interwiki prefix to use
 140          * @return Interwiki|null|bool
 141          */
 142         public function fetch( $prefix ) {
 143                 if ( $prefix == '' ) {
 144                         return null;
 145                 }
 146
 147                 $prefix = $this->contLang->lc( $prefix );
 148                 if ( $this->localCache->has( $prefix ) ) {
 149                         return $this->localCache->get( $prefix );
 150                 }
 151
 152                 if ( $this->cdbData ) {
 153                         $iw = $this->getInterwikiCached( $prefix );
 154                 } else {
 155                         $iw = $this->load( $prefix );
 156                         if ( !$iw ) {
 157                                 $iw = false;
 158                         }
 159                 }
 160                 $this->localCache->set( $prefix, $iw );
 161
 162                 return $iw;
 163         }
 164
 165         /**
 166          * Resets locally cached Interwiki objects. This is intended for use during testing only.
 167          * This does not invalidate entries in the persistent cache, as invalidateCache() does.
 168          * @since 1.27
 169          */
 170         public function resetLocalCache() {
 171                 $this->localCache->clear();
 172         }
 173
 174         /**
 175          * Purge the in-process and object cache for an interwiki prefix
 176          * @param string $prefix
 177          */
 178         public function invalidateCache( $prefix ) {
 179                 $this->localCache->clear( $prefix );
 180
 181                 $key = $this->objectCache->makeKey( 'interwiki', $prefix );
 182                 $this->objectCache->delete( $key );
 183         }
 184
 185         /**
 186          * Fetch interwiki prefix data from local cache in constant database.
 187          *
 188          * @note More logic is explained in DefaultSettings.
 189          *
 190          * @param string $prefix Interwiki prefix
 191          * @return Interwiki|false
 192          */
 193         private function getInterwikiCached( $prefix ) {
 194                 $value = $this->getInterwikiCacheEntry( $prefix );
 195
 196                 if ( $value ) {
 197                         // Split values
 198                         list( $local, $url ) = explode( ' ', $value, 2 );
 199                         return new Interwiki( $prefix, $url, '', '', (int)$local );
 200                 } else {
 201                         return false;
 202                 }
 203         }
 204
 205         /**
 206          * Get entry from interwiki cache
 207          *
 208          * @note More logic is explained in DefaultSettings.
 209          *
 210          * @param string $prefix Database key
 211          * @return bool|string The interwiki entry or false if not found
 212          */
 213         private function getInterwikiCacheEntry( $prefix ) {
 214                 wfDebug( __METHOD__ . "( $prefix )\n" );
 215                 $value = false;
 216                 try {
 217                         // Resolve site name
 218                         if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
 219                                 $this->thisSite = $this->getCacheValue( '__sites:' . wfWikiID() );
 220                                 if ( $this->thisSite == '' ) {
 221                                         $this->thisSite = $this->fallbackSite;
 222                                 }
 223                         }
 224
 225                         $value = $this->getCacheValue( wfWikiID() . ':' . $prefix );
 226                         // Site level
 227                         if ( $value == '' && $this->interwikiScopes >= 3 ) {
 228                                 $value = $this->getCacheValue( "_{$this->thisSite}:{$prefix}" );
 229                         }
 230                         // Global Level
 231                         if ( $value == '' && $this->interwikiScopes >= 2 ) {
 232                                 $value = $this->getCacheValue( "__global:{$prefix}" );
 233                         }
 234                         if ( $value == 'undef' ) {
 235                                 $value = '';
 236                         }
 237                 } catch ( CdbException $e ) {
 238                         wfDebug( __METHOD__ . ": CdbException caught, error message was "
 239                                 . $e->getMessage() );
 240                 }
 241
 242                 return $value;
 243         }
 244
 245         private function getCacheValue( $key ) {
 246                 if ( $this->cdbReader === null ) {
 247                         if ( is_string( $this->cdbData ) ) {
 248                                 $this->cdbReader = \Cdb\Reader::open( $this->cdbData );
 249                         } elseif ( is_array( $this->cdbData ) ) {
 250                                 $this->cdbReader = new \Cdb\Reader\Hash( $this->cdbData );
 251                         } else {
 252                                 $this->cdbReader = false;
 253                         }
 254                 }
 255
 256                 if ( $this->cdbReader ) {
 257                         return $this->cdbReader->get( $key );
 258                 } else {
 259                         return false;
 260                 }
 261         }
 262
 263         /**
 264          * Load the interwiki, trying first memcached then the DB
 265          *
 266          * @param string $prefix The interwiki prefix
 267          * @return Interwiki|bool Interwiki if $prefix is valid, otherwise false
 268          */
 269         private function load( $prefix ) {
 270                 $iwData = [];
 271                 if ( !Hooks::run( 'InterwikiLoadPrefix', [ $prefix, &$iwData ] ) ) {
 272                         return $this->loadFromArray( $iwData );
 273                 }
 274
 275                 if ( is_array( $iwData ) ) {
 276                         $iw = $this->loadFromArray( $iwData );
 277                         if ( $iw ) {
 278                                 return $iw; // handled by hook
 279                         }
 280                 }
 281
 282                 $fname = __METHOD__;
 283                 $iwData = $this->objectCache->getWithSetCallback(
 284                         $this->objectCache->makeKey( 'interwiki', $prefix ),
 285                         $this->objectCacheExpiry,
 286                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $prefix, $fname ) {
 287                                 $dbr = wfGetDB( DB_REPLICA ); // TODO: inject LoadBalancer
 288
 289                                 $setOpts += Database::getCacheSetOptions( $dbr );
 290
 291                                 $row = $dbr->selectRow(
 292                                         'interwiki',
 293                                         self::selectFields(),
 294                                         [ 'iw_prefix' => $prefix ],
 295                                         $fname
 296                                 );
 297
 298                                 return $row ? (array)$row : '!NONEXISTENT';
 299                         }
 300                 );
 301
 302                 if ( is_array( $iwData ) ) {
 303                         return $this->loadFromArray( $iwData ) ?: false;
 304                 }
 305
 306                 return false;
 307         }
 308
 309         /**
 310          * Fill in member variables from an array (e.g. memcached result, Database::fetchRow, etc)
 311          *
 312          * @param array $mc Associative array: row from the interwiki table
 313          * @return Interwiki|bool Interwiki object or false if $mc['iw_url'] is not set
 314          */
 315         private function loadFromArray( $mc ) {
 316                 if ( isset( $mc['iw_url'] ) ) {
 317                         $url = $mc['iw_url'];
 318                         $local = $mc['iw_local'] ?? 0;
 319                         $trans = $mc['iw_trans'] ?? 0;
 320                         $api = $mc['iw_api'] ?? '';
 321                         $wikiId = $mc['iw_wikiid'] ?? '';
 322
 323                         return new Interwiki( null, $url, $api, $wikiId, $local, $trans );
 324                 }
 325
 326                 return false;
 327         }
 328
 329         /**
 330          * Fetch all interwiki prefixes from interwiki cache
 331          *
 332          * @param null|string $local If not null, limits output to local/non-local interwikis
 333          * @return array List of prefixes, where each row is an associative array
 334          */
 335         private function getAllPrefixesCached( $local ) {
 336                 wfDebug( __METHOD__ . "()\n" );
 337                 $data = [];
 338                 try {
 339                         /* Resolve site name */
 340                         if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
 341                                 $site = $this->getCacheValue( '__sites:' . wfWikiID() );
 342
 343                                 if ( $site == '' ) {
 344                                         $this->thisSite = $this->fallbackSite;
 345                                 } else {
 346                                         $this->thisSite = $site;
 347                                 }
 348                         }
 349
 350                         // List of interwiki sources
 351                         $sources = [];
 352                         // Global Level
 353                         if ( $this->interwikiScopes >= 2 ) {
 354                                 $sources[] = '__global';
 355                         }
 356                         // Site level
 357                         if ( $this->interwikiScopes >= 3 ) {
 358                                 $sources[] = '_' . $this->thisSite;
 359                         }
 360                         $sources[] = wfWikiID();
 361
 362                         foreach ( $sources as $source ) {
 363                                 $list = $this->getCacheValue( '__list:' . $source );
 364                                 foreach ( explode( ' ', $list ) as $iw_prefix ) {
 365                                         $row = $this->getCacheValue( "{$source}:{$iw_prefix}" );
 366                                         if ( !$row ) {
 367                                                 continue;
 368                                         }
 369
 370                                         list( $iw_local, $iw_url ) = explode( ' ', $row );
 371
 372                                         if ( $local !== null && $local != $iw_local ) {
 373                                                 continue;
 374                                         }
 375
 376                                         $data[$iw_prefix] = [
 377                                                 'iw_prefix' => $iw_prefix,
 378                                                 'iw_url' => $iw_url,
 379                                                 'iw_local' => $iw_local,
 380                                         ];
 381                                 }
 382                         }
 383                 } catch ( CdbException $e ) {
 384                         wfDebug( __METHOD__ . ": CdbException caught, error message was "
 385                                 . $e->getMessage() );
 386                 }
 387
 388                 return array_values( $data );
 389         }
 390
 391         /**
 392          * Fetch all interwiki prefixes from DB
 393          *
 394          * @param string|null $local If not null, limits output to local/non-local interwikis
 395          * @return array[] Interwiki rows
 396          */
 397         private function getAllPrefixesDB( $local ) {
 398                 $db = wfGetDB( DB_REPLICA ); // TODO: inject DB LoadBalancer
 399
 400                 $where = [];
 401
 402                 if ( $local !== null ) {
 403                         if ( $local == 1 ) {
 404                                 $where['iw_local'] = 1;
 405                         } elseif ( $local == 0 ) {
 406                                 $where['iw_local'] = 0;
 407                         }
 408                 }
 409
 410                 $res = $db->select( 'interwiki',
 411                         self::selectFields(),
 412                         $where, __METHOD__, [ 'ORDER BY' => 'iw_prefix' ]
 413                 );
 414
 415                 $retval = [];
 416                 foreach ( $res as $row ) {
 417                         $retval[] = (array)$row;
 418                 }
 419
 420                 return $retval;
 421         }
 422
 423         /**
 424          * Returns all interwiki prefixes
 425          *
 426          * @param string|null $local If set, limits output to local/non-local interwikis
 427          * @return array[] Interwiki rows, where each row is an associative array
 428          */
 429         public function getAllPrefixes( $local = null ) {
 430                 if ( $this->cdbData ) {
 431                         return $this->getAllPrefixesCached( $local );
 432                 }
 433
 434                 return $this->getAllPrefixesDB( $local );
 435         }
 436
 437         /**
 438          * Return the list of interwiki fields that should be selected to create
 439          * a new Interwiki object.
 440          * @return string[]
 441          */
 442         private static function selectFields() {
 443                 return [
 444                         'iw_prefix',
 445                         'iw_url',
 446                         'iw_api',
 447                         'iw_wikiid',
 448                         'iw_local',
 449                         'iw_trans'
 450                 ];
 451         }
 452
 453 }