includes/api/ApiQuery.php

   1 <?php
   2 /**
   3  *
   4  *
   5  * Created on Sep 7, 2006
   6  *
   7  * Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  22  * http://www.gnu.org/copyleft/gpl.html
  23  *
  24  * @file
  25  */
  26
  27 /**
  28  * This is the main query class. It behaves similar to ApiMain: based on the
  29  * parameters given, it will create a list of titles to work on (an ApiPageSet
  30  * object), instantiate and execute various property/list/meta modules, and
  31  * assemble all resulting data into a single ApiResult object.
  32  *
  33  * In generator mode, a generator will be executed first to populate a second
  34  * ApiPageSet object, and that object will be used for all subsequent modules.
  35  *
  36  * @ingroup API
  37  */
  38 class ApiQuery extends ApiBase {
  39
  40         private $mPropModuleNames, $mListModuleNames, $mMetaModuleNames;
  41
  42         /**
  43          * @var ApiPageSet
  44          */
  45         private $mPageSet;
  46
  47         private $params, $redirects, $convertTitles, $iwUrl;
  48
  49         /**
  50          * List of Api Query prop modules
  51          * @var array
  52          */
  53         private $mQueryPropModules = array(
  54                 'categories' => 'ApiQueryCategories',
  55                 'categoryinfo' => 'ApiQueryCategoryInfo',
  56                 'duplicatefiles' => 'ApiQueryDuplicateFiles',
  57                 'extlinks' => 'ApiQueryExternalLinks',
  58                 'images' => 'ApiQueryImages',
  59                 'imageinfo' => 'ApiQueryImageInfo',
  60                 'info' => 'ApiQueryInfo',
  61                 'links' => 'ApiQueryLinks',
  62                 'iwlinks' => 'ApiQueryIWLinks',
  63                 'langlinks' => 'ApiQueryLangLinks',
  64                 'pageprops' => 'ApiQueryPageProps',
  65                 'revisions' => 'ApiQueryRevisions',
  66                 'stashimageinfo' => 'ApiQueryStashImageInfo',
  67                 'templates' => 'ApiQueryLinks',
  68         );
  69
  70         /**
  71          * List of Api Query list modules
  72          * @var array
  73          */
  74         private $mQueryListModules = array(
  75                 'allcategories' => 'ApiQueryAllCategories',
  76                 'allimages' => 'ApiQueryAllImages',
  77                 'alllinks' => 'ApiQueryAllLinks',
  78                 'allpages' => 'ApiQueryAllPages',
  79                 'alltransclusions' => 'ApiQueryAllLinks',
  80                 'allusers' => 'ApiQueryAllUsers',
  81                 'backlinks' => 'ApiQueryBacklinks',
  82                 'blocks' => 'ApiQueryBlocks',
  83                 'categorymembers' => 'ApiQueryCategoryMembers',
  84                 'deletedrevs' => 'ApiQueryDeletedrevs',
  85                 'embeddedin' => 'ApiQueryBacklinks',
  86                 'exturlusage' => 'ApiQueryExtLinksUsage',
  87                 'filearchive' => 'ApiQueryFilearchive',
  88                 'imageusage' => 'ApiQueryBacklinks',
  89                 'iwbacklinks' => 'ApiQueryIWBacklinks',
  90                 'langbacklinks' => 'ApiQueryLangBacklinks',
  91                 'logevents' => 'ApiQueryLogEvents',
  92                 'protectedtitles' => 'ApiQueryProtectedTitles',
  93                 'querypage' => 'ApiQueryQueryPage',
  94                 'random' => 'ApiQueryRandom',
  95                 'recentchanges' => 'ApiQueryRecentChanges',
  96                 'search' => 'ApiQuerySearch',
  97                 'tags' => 'ApiQueryTags',
  98                 'usercontribs' => 'ApiQueryContributions',
  99                 'users' => 'ApiQueryUsers',
 100                 'watchlist' => 'ApiQueryWatchlist',
 101                 'watchlistraw' => 'ApiQueryWatchlistRaw',
 102         );
 103
 104         /**
 105          * List of Api Query meta modules
 106          * @var array
 107          */
 108         private $mQueryMetaModules = array(
 109                 'allmessages' => 'ApiQueryAllMessages',
 110                 'siteinfo' => 'ApiQuerySiteinfo',
 111                 'userinfo' => 'ApiQueryUserInfo',
 112         );
 113
 114         /**
 115          * List of Api Query generator modules
 116          * Defined in code, rather than being derived at runtime,
 117          * due to performance reasons
 118          * @var array
 119          */
 120         private $mQueryGenerators = array(
 121                 'allcategories' => 'ApiQueryAllCategories',
 122                 'allimages' => 'ApiQueryAllImages',
 123                 'alllinks' => 'ApiQueryAllLinks',
 124                 'allpages' => 'ApiQueryAllPages',
 125                 'alltransclusions' => 'ApiQueryAllLinks',
 126                 'backlinks' => 'ApiQueryBacklinks',
 127                 'categories' => 'ApiQueryCategories',
 128                 'categorymembers' => 'ApiQueryCategoryMembers',
 129                 'duplicatefiles' => 'ApiQueryDuplicateFiles',
 130                 'embeddedin' => 'ApiQueryBacklinks',
 131                 'exturlusage' => 'ApiQueryExtLinksUsage',
 132                 'images' => 'ApiQueryImages',
 133                 'imageusage' => 'ApiQueryBacklinks',
 134                 'iwbacklinks' => 'ApiQueryIWBacklinks',
 135                 'langbacklinks' => 'ApiQueryLangBacklinks',
 136                 'links' => 'ApiQueryLinks',
 137                 'protectedtitles' => 'ApiQueryProtectedTitles',
 138                 'querypage' => 'ApiQueryQueryPage',
 139                 'random' => 'ApiQueryRandom',
 140                 'recentchanges' => 'ApiQueryRecentChanges',
 141                 'search' => 'ApiQuerySearch',
 142                 'templates' => 'ApiQueryLinks',
 143                 'watchlist' => 'ApiQueryWatchlist',
 144                 'watchlistraw' => 'ApiQueryWatchlistRaw',
 145         );
 146
 147         private $mSlaveDB = null;
 148         private $mNamedDB = array();
 149
 150         protected $mAllowedGenerators;
 151
 152         /**
 153          * @param $main ApiMain
 154          * @param $action string
 155          */
 156         public function __construct( $main, $action ) {
 157                 parent::__construct( $main, $action );
 158
 159                 // Allow custom modules to be added in LocalSettings.php
 160                 global $wgAPIPropModules, $wgAPIListModules, $wgAPIMetaModules, $wgAPIGeneratorModules;
 161                 self::appendUserModules( $this->mQueryPropModules, $wgAPIPropModules );
 162                 self::appendUserModules( $this->mQueryListModules, $wgAPIListModules );
 163                 self::appendUserModules( $this->mQueryMetaModules, $wgAPIMetaModules );
 164                 self::appendUserModules( $this->mQueryGenerators, $wgAPIGeneratorModules );
 165
 166                 $this->mPropModuleNames = array_keys( $this->mQueryPropModules );
 167                 $this->mListModuleNames = array_keys( $this->mQueryListModules );
 168                 $this->mMetaModuleNames = array_keys( $this->mQueryMetaModules );
 169                 $this->mAllowedGenerators = array_keys( $this->mQueryGenerators );
 170         }
 171
 172         /**
 173          * Helper function to append any add-in modules to the list
 174          * @param $modules array Module array
 175          * @param $newModules array Module array to add to $modules
 176          */
 177         private static function appendUserModules( &$modules, $newModules ) {
 178                 if ( is_array( $newModules ) ) {
 179                         foreach ( $newModules as $moduleName => $moduleClass ) {
 180                                 $modules[$moduleName] = $moduleClass;
 181                         }
 182                 }
 183         }
 184
 185         /**
 186          * Gets a default slave database connection object
 187          * @return DatabaseBase
 188          */
 189         public function getDB() {
 190                 if ( !isset( $this->mSlaveDB ) ) {
 191                         $this->profileDBIn();
 192                         $this->mSlaveDB = wfGetDB( DB_SLAVE, 'api' );
 193                         $this->profileDBOut();
 194                 }
 195                 return $this->mSlaveDB;
 196         }
 197
 198         /**
 199          * Get the query database connection with the given name.
 200          * If no such connection has been requested before, it will be created.
 201          * Subsequent calls with the same $name will return the same connection
 202          * as the first, regardless of the values of $db and $groups
 203          * @param $name string Name to assign to the database connection
 204          * @param $db int One of the DB_* constants
 205          * @param $groups array Query groups
 206          * @return DatabaseBase
 207          */
 208         public function getNamedDB( $name, $db, $groups ) {
 209                 if ( !array_key_exists( $name, $this->mNamedDB ) ) {
 210                         $this->profileDBIn();
 211                         $this->mNamedDB[$name] = wfGetDB( $db, $groups );
 212                         $this->profileDBOut();
 213                 }
 214                 return $this->mNamedDB[$name];
 215         }
 216
 217         /**
 218          * Gets the set of pages the user has requested (or generated)
 219          * @return ApiPageSet
 220          */
 221         public function getPageSet() {
 222                 return $this->mPageSet;
 223         }
 224
 225         /**
 226          * Get the array mapping module names to class names
 227          * @return array array(modulename => classname)
 228          */
 229         public function getModules() {
 230                 return array_merge( $this->mQueryPropModules, $this->mQueryListModules, $this->mQueryMetaModules );
 231         }
 232
 233         /**
 234          * Get the generators array mapping module names to class names
 235          * @return array array(modulename => classname)
 236          */
 237         public function getGenerators() {
 238                 return $this->mQueryGenerators;
 239         }
 240
 241         /**
 242          * Get whether the specified module is a prop, list or a meta query module
 243          * @param $moduleName string Name of the module to find type for
 244          * @return mixed string or null
 245          */
 246         function getModuleType( $moduleName ) {
 247                 if ( isset( $this->mQueryPropModules[$moduleName] ) ) {
 248                         return 'prop';
 249                 }
 250
 251                 if ( isset( $this->mQueryListModules[$moduleName] ) ) {
 252                         return 'list';
 253                 }
 254
 255                 if ( isset( $this->mQueryMetaModules[$moduleName] ) ) {
 256                         return 'meta';
 257                 }
 258
 259                 return null;
 260         }
 261
 262         /**
 263          * @return ApiFormatRaw|null
 264          */
 265         public function getCustomPrinter() {
 266                 // If &exportnowrap is set, use the raw formatter
 267                 if ( $this->getParameter( 'export' ) &&
 268                                 $this->getParameter( 'exportnowrap' ) )
 269                 {
 270                         return new ApiFormatRaw( $this->getMain(),
 271                                 $this->getMain()->createPrinterByName( 'xml' ) );
 272                 } else {
 273                         return null;
 274                 }
 275         }
 276
 277         /**
 278          * Query execution happens in the following steps:
 279          * #1 Create a PageSet object with any pages requested by the user
 280          * #2 If using a generator, execute it to get a new ApiPageSet object
 281          * #3 Instantiate all requested modules.
 282          *    This way the PageSet object will know what shared data is required,
 283          *    and minimize DB calls.
 284          * #4 Output all normalization and redirect resolution information
 285          * #5 Execute all requested modules
 286          */
 287         public function execute() {
 288                 $this->params = $this->extractRequestParams();
 289                 $this->redirects = $this->params['redirects'];
 290                 $this->convertTitles = $this->params['converttitles'];
 291                 $this->iwUrl = $this->params['iwurl'];
 292
 293                 // Create PageSet
 294                 $this->mPageSet = new ApiPageSet( $this, $this->redirects, $this->convertTitles );
 295
 296                 // Instantiate requested modules
 297                 $modules = array();
 298                 $this->instantiateModules( $modules, 'prop', $this->mQueryPropModules );
 299                 $this->instantiateModules( $modules, 'list', $this->mQueryListModules );
 300                 $this->instantiateModules( $modules, 'meta', $this->mQueryMetaModules );
 301
 302                 $cacheMode = 'public';
 303
 304                 // If given, execute generator to substitute user supplied data with generated data.
 305                 if ( isset( $this->params['generator'] ) ) {
 306                         $generator = $this->newGenerator( $this->params['generator'] );
 307                         $params = $generator->extractRequestParams();
 308                         $cacheMode = $this->mergeCacheMode( $cacheMode,
 309                                 $generator->getCacheMode( $params ) );
 310                         $this->executeGeneratorModule( $generator, $modules );
 311                 } else {
 312                         // Append custom fields and populate page/revision information
 313                         $this->addCustomFldsToPageSet( $modules, $this->mPageSet );
 314                         $this->mPageSet->execute();
 315                 }
 316
 317                 // Record page information (title, namespace, if exists, etc)
 318                 $this->outputGeneralPageInfo();
 319
 320                 // Execute all requested modules.
 321                 /**
 322                  * @var $module ApiQueryBase
 323                  */
 324                 foreach ( $modules as $module ) {
 325                         $params = $module->extractRequestParams();
 326                         $cacheMode = $this->mergeCacheMode(
 327                                 $cacheMode, $module->getCacheMode( $params ) );
 328                         $module->profileIn();
 329                         $module->execute();
 330                         wfRunHooks( 'APIQueryAfterExecute', array( &$module ) );
 331                         $module->profileOut();
 332                 }
 333
 334                 // Set the cache mode
 335                 $this->getMain()->setCacheMode( $cacheMode );
 336         }
 337
 338         /**
 339          * Update a cache mode string, applying the cache mode of a new module to it.
 340          * The cache mode may increase in the level of privacy, but public modules
 341          * added to private data do not decrease the level of privacy.
 342          *
 343          * @param $cacheMode string
 344          * @param $modCacheMode string
 345          * @return string
 346          */
 347         protected function mergeCacheMode( $cacheMode, $modCacheMode ) {
 348                 if ( $modCacheMode === 'anon-public-user-private' ) {
 349                         if ( $cacheMode !== 'private' ) {
 350                                 $cacheMode = 'anon-public-user-private';
 351                         }
 352                 } elseif ( $modCacheMode === 'public' ) {
 353                         // do nothing, if it's public already it will stay public
 354                 } else { // private
 355                         $cacheMode = 'private';
 356                 }
 357                 return $cacheMode;
 358         }
 359
 360         /**
 361          * Query modules may optimize data requests through the $this->getPageSet() object
 362          * by adding extra fields from the page table.
 363          * This function will gather all the extra request fields from the modules.
 364          * @param $modules array of module objects
 365          * @param $pageSet ApiPageSet
 366          */
 367         private function addCustomFldsToPageSet( $modules, $pageSet ) {
 368                 // Query all requested modules.
 369                 /**
 370                  * @var $module ApiQueryBase
 371                  */
 372                 foreach ( $modules as $module ) {
 373                         $module->requestExtraData( $pageSet );
 374                 }
 375         }
 376
 377         /**
 378          * Create instances of all modules requested by the client
 379          * @param $modules Array to append instantiated modules to
 380          * @param $param string Parameter name to read modules from
 381          * @param $moduleList Array array(modulename => classname)
 382          */
 383         private function instantiateModules( &$modules, $param, $moduleList ) {
 384                 if ( isset( $this->params[$param] ) ) {
 385                         foreach ( $this->params[$param] as $moduleName ) {
 386                                 $modules[] = new $moduleList[$moduleName] ( $this, $moduleName );
 387                         }
 388                 }
 389         }
 390
 391         /**
 392          * Appends an element for each page in the current pageSet with the
 393          * most general information (id, title), plus any title normalizations
 394          * and missing or invalid title/pageids/revids.
 395          */
 396         private function outputGeneralPageInfo() {
 397                 $pageSet = $this->getPageSet();
 398                 $result = $this->getResult();
 399
 400                 // We don't check for a full result set here because we can't be adding
 401                 // more than 380K. The maximum revision size is in the megabyte range,
 402                 // and the maximum result size must be even higher than that.
 403
 404                 // Title normalizations
 405                 $normValues = array();
 406                 foreach ( $pageSet->getNormalizedTitles() as $rawTitleStr => $titleStr ) {
 407                         $normValues[] = array(
 408                                 'from' => $rawTitleStr,
 409                                 'to' => $titleStr
 410                         );
 411                 }
 412
 413                 if ( count( $normValues ) ) {
 414                         $result->setIndexedTagName( $normValues, 'n' );
 415                         $result->addValue( 'query', 'normalized', $normValues );
 416                 }
 417
 418                 // Title conversions
 419                 $convValues = array();
 420                 foreach ( $pageSet->getConvertedTitles() as $rawTitleStr => $titleStr ) {
 421                         $convValues[] = array(
 422                                 'from' => $rawTitleStr,
 423                                 'to' => $titleStr
 424                         );
 425                 }
 426
 427                 if ( count( $convValues ) ) {
 428                         $result->setIndexedTagName( $convValues, 'c' );
 429                         $result->addValue( 'query', 'converted', $convValues );
 430                 }
 431
 432                 // Interwiki titles
 433                 $intrwValues = array();
 434                 foreach ( $pageSet->getInterwikiTitles() as $rawTitleStr => $interwikiStr ) {
 435                         $item = array(
 436                                 'title' => $rawTitleStr,
 437                                 'iw' => $interwikiStr,
 438                         );
 439                         if ( $this->iwUrl ) {
 440                                 $title = Title::newFromText( $rawTitleStr );
 441                                 $item['url'] = wfExpandUrl( $title->getFullURL(), PROTO_CURRENT );
 442                         }
 443                         $intrwValues[] = $item;
 444                 }
 445
 446                 if ( count( $intrwValues ) ) {
 447                         $result->setIndexedTagName( $intrwValues, 'i' );
 448                         $result->addValue( 'query', 'interwiki', $intrwValues );
 449                 }
 450
 451                 // Show redirect information
 452                 $redirValues = array();
 453                 /**
 454                  * @var $titleTo Title
 455                  */
 456                 foreach ( $pageSet->getRedirectTitles() as $titleStrFrom => $titleTo ) {
 457                         $r = array(
 458                                 'from' => strval( $titleStrFrom ),
 459                                 'to' => $titleTo->getPrefixedText(),
 460                         );
 461                         if ( $titleTo->getFragment() !== '' ) {
 462                                 $r['tofragment'] = $titleTo->getFragment();
 463                         }
 464                         $redirValues[] = $r;
 465                 }
 466
 467                 if ( count( $redirValues ) ) {
 468                         $result->setIndexedTagName( $redirValues, 'r' );
 469                         $result->addValue( 'query', 'redirects', $redirValues );
 470                 }
 471
 472                 // Missing revision elements
 473                 $missingRevIDs = $pageSet->getMissingRevisionIDs();
 474                 if ( count( $missingRevIDs ) ) {
 475                         $revids = array();
 476                         foreach ( $missingRevIDs as $revid ) {
 477                                 $revids[$revid] = array(
 478                                         'revid' => $revid
 479                                 );
 480                         }
 481                         $result->setIndexedTagName( $revids, 'rev' );
 482                         $result->addValue( 'query', 'badrevids', $revids );
 483                 }
 484
 485                 // Page elements
 486                 $pages = array();
 487
 488                 // Report any missing titles
 489                 foreach ( $pageSet->getMissingTitles() as $fakeId => $title ) {
 490                         $vals = array();
 491                         ApiQueryBase::addTitleInfo( $vals, $title );
 492                         $vals['missing'] = '';
 493                         $pages[$fakeId] = $vals;
 494                 }
 495                 // Report any invalid titles
 496                 foreach ( $pageSet->getInvalidTitles() as $fakeId => $title ) {
 497                         $pages[$fakeId] = array( 'title' => $title, 'invalid' => '' );
 498                 }
 499                 // Report any missing page ids
 500                 foreach ( $pageSet->getMissingPageIDs() as $pageid ) {
 501                         $pages[$pageid] = array(
 502                                 'pageid' => $pageid,
 503                                 'missing' => ''
 504                         );
 505                 }
 506                 // Report special pages
 507                 foreach ( $pageSet->getSpecialTitles() as $fakeId => $title ) {
 508                         $vals = array();
 509                         ApiQueryBase::addTitleInfo( $vals, $title );
 510                         $vals['special'] = '';
 511                         if ( $title->isSpecialPage() &&
 512                                         !SpecialPageFactory::exists( $title->getDbKey() ) ) {
 513                                 $vals['missing'] = '';
 514                         } elseif ( $title->getNamespace() == NS_MEDIA &&
 515                                         !wfFindFile( $title ) ) {
 516                                 $vals['missing'] = '';
 517                         }
 518                         $pages[$fakeId] = $vals;
 519                 }
 520
 521                 // Output general page information for found titles
 522                 foreach ( $pageSet->getGoodTitles() as $pageid => $title ) {
 523                         $vals = array();
 524                         $vals['pageid'] = $pageid;
 525                         ApiQueryBase::addTitleInfo( $vals, $title );
 526                         $pages[$pageid] = $vals;
 527                 }
 528
 529                 if ( count( $pages ) ) {
 530                         if ( $this->params['indexpageids'] ) {
 531                                 $pageIDs = array_keys( $pages );
 532                                 // json treats all map keys as strings - converting to match
 533                                 $pageIDs = array_map( 'strval', $pageIDs );
 534                                 $result->setIndexedTagName( $pageIDs, 'id' );
 535                                 $result->addValue( 'query', 'pageids', $pageIDs );
 536                         }
 537
 538                         $result->setIndexedTagName( $pages, 'page' );
 539                         $result->addValue( 'query', 'pages', $pages );
 540                 }
 541                 if ( $this->params['export'] ) {
 542                         $this->doExport( $pageSet, $result );
 543                 }
 544         }
 545
 546         /**
 547          * @param  $pageSet ApiPageSet Pages to be exported
 548          * @param  $result ApiResult Result to output to
 549          */
 550         private function doExport( $pageSet, $result ) {
 551                 $exportTitles = array();
 552                 $titles = $pageSet->getGoodTitles();
 553                 if ( count( $titles ) ) {
 554                         $user = $this->getUser();
 555                         foreach ( $titles as $title ) {
 556                                 if ( $title->userCan( 'read', $user ) ) {
 557                                         $exportTitles[] = $title;
 558                                 }
 559                         }
 560                 }
 561
 562                 $exporter = new WikiExporter( $this->getDB() );
 563                 // WikiExporter writes to stdout, so catch its
 564                 // output with an ob
 565                 ob_start();
 566                 $exporter->openStream();
 567                 foreach ( $exportTitles as $title ) {
 568                         $exporter->pageByTitle( $title );
 569                 }
 570                 $exporter->closeStream();
 571                 $exportxml = ob_get_contents();
 572                 ob_end_clean();
 573
 574                 // Don't check the size of exported stuff
 575                 // It's not continuable, so it would cause more
 576                 // problems than it'd solve
 577                 $result->disableSizeCheck();
 578                 if ( $this->params['exportnowrap'] ) {
 579                         $result->reset();
 580                         // Raw formatter will handle this
 581                         $result->addValue( null, 'text', $exportxml );
 582                         $result->addValue( null, 'mime', 'text/xml' );
 583                 } else {
 584                         $r = array();
 585                         ApiResult::setContent( $r, $exportxml );
 586                         $result->addValue( 'query', 'export', $r );
 587                 }
 588                 $result->enableSizeCheck();
 589         }
 590
 591         /**
 592          * Create a generator object of the given type and return it
 593          * @param $generatorName string Module name
 594          * @return ApiQueryGeneratorBase
 595          */
 596         public function newGenerator( $generatorName ) {
 597                 // Find class that implements requested generator
 598                 if ( isset( $this->mQueryListModules[$generatorName] ) ) {
 599                         $className = $this->mQueryListModules[$generatorName];
 600                 } elseif ( isset( $this->mQueryPropModules[$generatorName] ) ) {
 601                         $className = $this->mQueryPropModules[$generatorName];
 602                 } else {
 603                         ApiBase::dieDebug( __METHOD__, "Unknown generator=$generatorName" );
 604                 }
 605                 $generator = new $className ( $this, $generatorName );
 606                 if ( !$generator instanceof ApiQueryGeneratorBase ) {
 607                         $this->dieUsage( "Module $generatorName cannot be used as a generator", 'badgenerator' );
 608                 }
 609                 $generator->setGeneratorMode();
 610                 return $generator;
 611         }
 612
 613         /**
 614          * For generator mode, execute generator, and use its output as new
 615          * ApiPageSet
 616          * @param $generator ApiQueryGeneratorBase Generator Module
 617          * @param $modules array of module objects
 618          */
 619         protected function executeGeneratorModule( $generator, $modules ) {
 620                 // Generator results
 621                 $resultPageSet = new ApiPageSet( $this, $this->redirects, $this->convertTitles );
 622
 623                 // Add any additional fields modules may need
 624                 $generator->requestExtraData( $this->mPageSet );
 625                 $this->addCustomFldsToPageSet( $modules, $resultPageSet );
 626
 627                 // Populate page information with the original user input
 628                 $this->mPageSet->execute();
 629
 630                 // populate resultPageSet with the generator output
 631                 $generator->profileIn();
 632                 $generator->executeGenerator( $resultPageSet );
 633                 wfRunHooks( 'APIQueryGeneratorAfterExecute', array( &$generator, &$resultPageSet ) );
 634                 $resultPageSet->finishPageSetGeneration();
 635                 $generator->profileOut();
 636
 637                 // Swap the resulting pageset back in
 638                 $this->mPageSet = $resultPageSet;
 639         }
 640
 641         public function getAllowedParams() {
 642                 return array(
 643                         'prop' => array(
 644                                 ApiBase::PARAM_ISMULTI => true,
 645                                 ApiBase::PARAM_TYPE => $this->mPropModuleNames
 646                         ),
 647                         'list' => array(
 648                                 ApiBase::PARAM_ISMULTI => true,
 649                                 ApiBase::PARAM_TYPE => $this->mListModuleNames
 650                         ),
 651                         'meta' => array(
 652                                 ApiBase::PARAM_ISMULTI => true,
 653                                 ApiBase::PARAM_TYPE => $this->mMetaModuleNames
 654                         ),
 655                         'generator' => array(
 656                                 ApiBase::PARAM_TYPE => $this->mAllowedGenerators
 657                         ),
 658                         'redirects' => false,
 659                         'converttitles' => false,
 660                         'indexpageids' => false,
 661                         'export' => false,
 662                         'exportnowrap' => false,
 663                         'iwurl' => false,
 664                 );
 665         }
 666
 667         /**
 668          * Override the parent to generate help messages for all available query modules.
 669          * @return string
 670          */
 671         public function makeHelpMsg() {
 672                 // Make sure the internal object is empty
 673                 // (just in case a sub-module decides to optimize during instantiation)
 674                 $this->mPageSet = null;
 675
 676                 $querySeparator = str_repeat( '--- ', 12 );
 677                 $moduleSeparator = str_repeat( '*** ', 14 );
 678                 $msg = "\n$querySeparator Query: Prop  $querySeparator\n\n";
 679                 $msg .= $this->makeHelpMsgHelper( $this->mQueryPropModules, 'prop' );
 680                 $msg .= "\n$querySeparator Query: List  $querySeparator\n\n";
 681                 $msg .= $this->makeHelpMsgHelper( $this->mQueryListModules, 'list' );
 682                 $msg .= "\n$querySeparator Query: Meta  $querySeparator\n\n";
 683                 $msg .= $this->makeHelpMsgHelper( $this->mQueryMetaModules, 'meta' );
 684                 $msg .= "\n\n$moduleSeparator Modules: continuation  $moduleSeparator\n\n";
 685
 686                 // Use parent to make default message for the query module
 687                 $msg = parent::makeHelpMsg() . $msg;
 688
 689                 return $msg;
 690         }
 691
 692         /**
 693          * For all modules in $moduleList, generate help messages and join them together
 694          * @param $moduleList Array array(modulename => classname)
 695          * @param $paramName string Parameter name
 696          * @return string
 697          */
 698         private function makeHelpMsgHelper( $moduleList, $paramName ) {
 699                 $moduleDescriptions = array();
 700
 701                 foreach ( $moduleList as $moduleName => $moduleClass ) {
 702                         /**
 703                          * @var $module ApiQueryBase
 704                          */
 705                         $module = new $moduleClass( $this, $moduleName, null );
 706
 707                         $msg = ApiMain::makeHelpMsgHeader( $module, $paramName );
 708                         $msg2 = $module->makeHelpMsg();
 709                         if ( $msg2 !== false ) {
 710                                 $msg .= $msg2;
 711                         }
 712                         if ( $module instanceof ApiQueryGeneratorBase ) {
 713                                 $msg .= "Generator:\n  This module may be used as a generator\n";
 714                         }
 715                         $moduleDescriptions[] = $msg;
 716                 }
 717
 718                 return implode( "\n", $moduleDescriptions );
 719         }
 720
 721         /**
 722          * Override to add extra parameters from PageSet
 723          * @return string
 724          */
 725         public function makeHelpMsgParameters() {
 726                 $psModule = new ApiPageSet( $this );
 727                 return $psModule->makeHelpMsgParameters() . parent::makeHelpMsgParameters();
 728         }
 729
 730         public function shouldCheckMaxlag() {
 731                 return true;
 732         }
 733
 734         public function getParamDescription() {
 735                 return array(
 736                         'prop' => 'Which properties to get for the titles/revisions/pageids. Module help is available below',
 737                         'list' => 'Which lists to get. Module help is available below',
 738                         'meta' => 'Which metadata to get about the site. Module help is available below',
 739                         'generator' => array( 'Use the output of a list as the input for other prop/list/meta items',
 740                                         'NOTE: generator parameter names must be prefixed with a \'g\', see examples' ),
 741                         'redirects' => 'Automatically resolve redirects',
 742                         'converttitles' => array( "Convert titles to other variants if necessary. Only works if the wiki's content language supports variant conversion.",
 743                                         'Languages that support variant conversion include ' . implode( ', ', LanguageConverter::$languagesWithVariants ) ),
 744                         'indexpageids' => 'Include an additional pageids section listing all returned page IDs',
 745                         'export' => 'Export the current revisions of all given or generated pages',
 746                         'exportnowrap' => 'Return the export XML without wrapping it in an XML result (same format as Special:Export). Can only be used with export',
 747                         'iwurl' => 'Whether to get the full URL if the title is an interwiki link',
 748                 );
 749         }
 750
 751         public function getDescription() {
 752                 return array(
 753                         'Query API module allows applications to get needed pieces of data from the MediaWiki databases,',
 754                         'and is loosely based on the old query.php interface.',
 755                         'All data modifications will first have to use query to acquire a token to prevent abuse from malicious sites'
 756                 );
 757         }
 758
 759         public function getPossibleErrors() {
 760                 return array_merge( parent::getPossibleErrors(), array(
 761                         array( 'code' => 'badgenerator', 'info' => 'Module $generatorName cannot be used as a generator' ),
 762                 ) );
 763         }
 764
 765         public function getExamples() {
 766                 return array(
 767                         'api.php?action=query&prop=revisions&meta=siteinfo&titles=Main%20Page&rvprop=user|comment',
 768                         'api.php?action=query&generator=allpages&gapprefix=API/&prop=revisions',
 769                 );
 770         }
 771
 772         public function getHelpUrls() {
 773                 return array(
 774                         'https://www.mediawiki.org/wiki/API:Meta',
 775                         'https://www.mediawiki.org/wiki/API:Properties',
 776                         'https://www.mediawiki.org/wiki/API:Lists',
 777                 );
 778         }
 779 }