includes/api/ApiQuery.php

   1 <?php
   2
   3 /**
   4  * Created on Sep 7, 2006
   5  *
   6  * API for MediaWiki 1.8+
   7  *
   8  * Copyright © 2006 Yuri Astrakhan <Firstname><Lastname>@gmail.com
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with this program; if not, write to the Free Software Foundation, Inc.,
  22  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  23  * http://www.gnu.org/copyleft/gpl.html
  24  */
  25
  26 if ( !defined( 'MEDIAWIKI' ) ) {
  27         // Eclipse helper - will be ignored in production
  28         require_once( 'ApiBase.php' );
  29 }
  30
  31 /**
  32  * This is the main query class. It behaves similar to ApiMain: based on the
  33  * parameters given, it will create a list of titles to work on (an ApiPageSet
  34  * object), instantiate and execute various property/list/meta modules, and
  35  * assemble all resulting data into a single ApiResult object.
  36  *
  37  * In generator mode, a generator will be executed first to populate a second
  38  * ApiPageSet object, and that object will be used for all subsequent modules.
  39  *
  40  * @ingroup API
  41  */
  42 class ApiQuery extends ApiBase {
  43
  44         private $mPropModuleNames, $mListModuleNames, $mMetaModuleNames;
  45         private $mPageSet;
  46         private $params;
  47
  48         private $mQueryPropModules = array(
  49                 'info' => 'ApiQueryInfo',
  50                 'revisions' => 'ApiQueryRevisions',
  51                 'links' => 'ApiQueryLinks',
  52                 'iwlinks' => 'ApiQueryIWLinks',
  53                 'langlinks' => 'ApiQueryLangLinks',
  54                 'images' => 'ApiQueryImages',
  55                 'imageinfo' => 'ApiQueryImageInfo',
  56                 'templates' => 'ApiQueryLinks',
  57                 'categories' => 'ApiQueryCategories',
  58                 'extlinks' => 'ApiQueryExternalLinks',
  59                 'categoryinfo' => 'ApiQueryCategoryInfo',
  60                 'duplicatefiles' => 'ApiQueryDuplicateFiles',
  61                 'pageprops' => 'ApiQueryPageProps',
  62         );
  63
  64         private $mQueryListModules = array(
  65                 'allimages' => 'ApiQueryAllimages',
  66                 'allpages' => 'ApiQueryAllpages',
  67                 'alllinks' => 'ApiQueryAllLinks',
  68                 'allcategories' => 'ApiQueryAllCategories',
  69                 'allusers' => 'ApiQueryAllUsers',
  70                 'backlinks' => 'ApiQueryBacklinks',
  71                 'blocks' => 'ApiQueryBlocks',
  72                 'categorymembers' => 'ApiQueryCategoryMembers',
  73                 'deletedrevs' => 'ApiQueryDeletedrevs',
  74                 'embeddedin' => 'ApiQueryBacklinks',
  75                 'filearchive' => 'ApiQueryFilearchive',
  76                 'imageusage' => 'ApiQueryBacklinks',
  77                 'iwbacklinks' => 'ApiQueryIWBacklinks',
  78                 'logevents' => 'ApiQueryLogEvents',
  79                 'recentchanges' => 'ApiQueryRecentChanges',
  80                 'search' => 'ApiQuerySearch',
  81                 'tags' => 'ApiQueryTags',
  82                 'usercontribs' => 'ApiQueryContributions',
  83                 'watchlist' => 'ApiQueryWatchlist',
  84                 'watchlistraw' => 'ApiQueryWatchlistRaw',
  85                 'exturlusage' => 'ApiQueryExtLinksUsage',
  86                 'users' => 'ApiQueryUsers',
  87                 'random' => 'ApiQueryRandom',
  88                 'protectedtitles' => 'ApiQueryProtectedTitles',
  89         );
  90
  91         private $mQueryMetaModules = array(
  92                 'siteinfo' => 'ApiQuerySiteinfo',
  93                 'userinfo' => 'ApiQueryUserInfo',
  94                 'allmessages' => 'ApiQueryAllmessages',
  95         );
  96
  97         private $mSlaveDB = null;
  98         private $mNamedDB = array();
  99
 100         public function __construct( $main, $action ) {
 101                 parent::__construct( $main, $action );
 102
 103                 // Allow custom modules to be added in LocalSettings.php
 104                 global $wgAPIPropModules, $wgAPIListModules, $wgAPIMetaModules;
 105                 self::appendUserModules( $this->mQueryPropModules, $wgAPIPropModules );
 106                 self::appendUserModules( $this->mQueryListModules, $wgAPIListModules );
 107                 self::appendUserModules( $this->mQueryMetaModules, $wgAPIMetaModules );
 108
 109                 $this->mPropModuleNames = array_keys( $this->mQueryPropModules );
 110                 $this->mListModuleNames = array_keys( $this->mQueryListModules );
 111                 $this->mMetaModuleNames = array_keys( $this->mQueryMetaModules );
 112
 113                 // Allow the entire list of modules at first,
 114                 // but during module instantiation check if it can be used as a generator.
 115                 $this->mAllowedGenerators = array_merge( $this->mListModuleNames, $this->mPropModuleNames );
 116         }
 117
 118         /**
 119          * Helper function to append any add-in modules to the list
 120          * @param $modules array Module array
 121          * @param $newModules array Module array to add to $modules
 122          */
 123         private static function appendUserModules( &$modules, $newModules ) {
 124                 if ( is_array( $newModules ) ) {
 125                         foreach ( $newModules as $moduleName => $moduleClass ) {
 126                                 $modules[$moduleName] = $moduleClass;
 127                         }
 128                 }
 129         }
 130
 131         /**
 132          * Gets a default slave database connection object
 133          * @return Database
 134          */
 135         public function getDB() {
 136                 if ( !isset( $this->mSlaveDB ) ) {
 137                         $this->profileDBIn();
 138                         $this->mSlaveDB = wfGetDB( DB_SLAVE, 'api' );
 139                         $this->profileDBOut();
 140                 }
 141                 return $this->mSlaveDB;
 142         }
 143
 144         /**
 145          * Get the query database connection with the given name.
 146          * If no such connection has been requested before, it will be created.
 147          * Subsequent calls with the same $name will return the same connection
 148          * as the first, regardless of the values of $db and $groups
 149          * @param $name string Name to assign to the database connection
 150          * @param $db int One of the DB_* constants
 151          * @param $groups array Query groups
 152          * @return Database
 153          */
 154         public function getNamedDB( $name, $db, $groups ) {
 155                 if ( !array_key_exists( $name, $this->mNamedDB ) ) {
 156                         $this->profileDBIn();
 157                         $this->mNamedDB[$name] = wfGetDB( $db, $groups );
 158                         $this->profileDBOut();
 159                 }
 160                 return $this->mNamedDB[$name];
 161         }
 162
 163         /**
 164          * Gets the set of pages the user has requested (or generated)
 165          * @return ApiPageSet
 166          */
 167         public function getPageSet() {
 168                 return $this->mPageSet;
 169         }
 170
 171         /**
 172          * Get the array mapping module names to class names
 173          * @return array(modulename => classname)
 174          */
 175         function getModules() {
 176                 return array_merge( $this->mQueryPropModules, $this->mQueryListModules, $this->mQueryMetaModules );
 177         }
 178
 179         /**
 180          * Get whether the specified module is a prop, list or a meta query module
 181          * @param $moduleName string Name of the module to find type for
 182          * @return mixed string or null
 183          */
 184         function getModuleType( $moduleName ) {
 185                 if ( array_key_exists ( $moduleName, $this->mQueryPropModules ) ) {
 186                         return 'prop';
 187                 }
 188
 189                 if ( array_key_exists ( $moduleName, $this->mQueryListModules ) ) {
 190                         return 'list';
 191                 }
 192
 193                 if ( array_key_exists ( $moduleName, $this->mQueryMetaModules ) ) {
 194                         return 'meta';
 195                 }
 196
 197                 return null;
 198         }
 199
 200         public function getCustomPrinter() {
 201                 // If &exportnowrap is set, use the raw formatter
 202                 if ( $this->getParameter( 'export' ) &&
 203                                 $this->getParameter( 'exportnowrap' ) )
 204                 {
 205                         return new ApiFormatRaw( $this->getMain(),
 206                                 $this->getMain()->createPrinterByName( 'xml' ) );
 207                 } else {
 208                         return null;
 209                 }
 210         }
 211
 212         /**
 213          * Query execution happens in the following steps:
 214          * #1 Create a PageSet object with any pages requested by the user
 215          * #2 If using a generator, execute it to get a new ApiPageSet object
 216          * #3 Instantiate all requested modules.
 217          *    This way the PageSet object will know what shared data is required,
 218          *    and minimize DB calls.
 219          * #4 Output all normalization and redirect resolution information
 220          * #5 Execute all requested modules
 221          */
 222         public function execute() {
 223                 $this->params = $this->extractRequestParams();
 224                 $this->redirects = $this->params['redirects'];
 225                 $this->convertTitles = $this->params['converttitles'];
 226
 227                 // Create PageSet
 228                 $this->mPageSet = new ApiPageSet( $this, $this->redirects, $this->convertTitles );
 229
 230                 // Instantiate requested modules
 231                 $modules = array();
 232                 $this->instantiateModules( $modules, 'prop', $this->mQueryPropModules );
 233                 $this->instantiateModules( $modules, 'list', $this->mQueryListModules );
 234                 $this->instantiateModules( $modules, 'meta', $this->mQueryMetaModules );
 235
 236                 $cacheMode = 'public';
 237
 238                 // If given, execute generator to substitute user supplied data with generated data.
 239                 if ( isset( $this->params['generator'] ) ) {
 240                         $generator = $this->newGenerator( $this->params['generator'] );
 241                         $params = $generator->extractRequestParams();
 242                         $cacheMode = $this->mergeCacheMode( $cacheMode,
 243                                 $generator->getCacheMode( $params ) );
 244                         $this->executeGeneratorModule( $generator, $modules );
 245                 } else {
 246                         // Append custom fields and populate page/revision information
 247                         $this->addCustomFldsToPageSet( $modules, $this->mPageSet );
 248                         $this->mPageSet->execute();
 249                 }
 250
 251                 // Record page information (title, namespace, if exists, etc)
 252                 $this->outputGeneralPageInfo();
 253
 254                 // Execute all requested modules.
 255                 foreach ( $modules as $module ) {
 256                         $params = $module->extractRequestParams();
 257                         $cacheMode = $this->mergeCacheMode(
 258                                 $cacheMode, $module->getCacheMode( $params ) );
 259                         $module->profileIn();
 260                         $module->execute();
 261                         wfRunHooks( 'APIQueryAfterExecute', array( &$module ) );
 262                         $module->profileOut();
 263                 }
 264
 265                 // Set the cache mode
 266                 $this->getMain()->setCacheMode( $cacheMode );
 267         }
 268
 269         /**
 270          * Update a cache mode string, applying the cache mode of a new module to it.
 271          * The cache mode may increase in the level of privacy, but public modules
 272          * added to private data do not decrease the level of privacy.
 273          */
 274         protected function mergeCacheMode( $cacheMode, $modCacheMode ) {
 275                 if ( $modCacheMode === 'anon-public-user-private' ) {
 276                         if ( $cacheMode !== 'private' ) {
 277                                 $cacheMode = 'anon-public-user-private';
 278                         }
 279                 } elseif ( $modCacheMode === 'public' ) {
 280                         // do nothing, if it's public already it will stay public
 281                 } else { // private
 282                         $cacheMode = 'private';
 283                 }
 284                 return $cacheMode;
 285         }
 286
 287         /**
 288          * Query modules may optimize data requests through the $this->getPageSet() object
 289          * by adding extra fields from the page table.
 290          * This function will gather all the extra request fields from the modules.
 291          * @param $modules array of module objects
 292          * @param $pageSet ApiPageSet
 293          */
 294         private function addCustomFldsToPageSet( $modules, $pageSet ) {
 295                 // Query all requested modules.
 296                 foreach ( $modules as $module ) {
 297                         $module->requestExtraData( $pageSet );
 298                 }
 299         }
 300
 301         /**
 302          * Create instances of all modules requested by the client
 303          * @param $modules array to append instatiated modules to
 304          * @param $param string Parameter name to read modules from
 305          * @param $moduleList array(modulename => classname)
 306          */
 307         private function instantiateModules( &$modules, $param, $moduleList ) {
 308                 $list = @$this->params[$param];
 309                 if ( !is_null ( $list ) ) {
 310                         foreach ( $list as $moduleName ) {
 311                                 $modules[] = new $moduleList[$moduleName] ( $this, $moduleName );
 312                         }
 313                 }
 314         }
 315
 316         /**
 317          * Appends an element for each page in the current pageSet with the
 318          * most general information (id, title), plus any title normalizations
 319          * and missing or invalid title/pageids/revids.
 320          */
 321         private function outputGeneralPageInfo() {
 322                 $pageSet = $this->getPageSet();
 323                 $result = $this->getResult();
 324
 325                 // We don't check for a full result set here because we can't be adding
 326                 // more than 380K. The maximum revision size is in the megabyte range,
 327                 // and the maximum result size must be even higher than that.
 328
 329                 // Title normalizations
 330                 $normValues = array();
 331                 foreach ( $pageSet->getNormalizedTitles() as $rawTitleStr => $titleStr ) {
 332                         $normValues[] = array(
 333                                 'from' => $rawTitleStr,
 334                                 'to' => $titleStr
 335                         );
 336                 }
 337
 338                 if ( count( $normValues ) ) {
 339                         $result->setIndexedTagName( $normValues, 'n' );
 340                         $result->addValue( 'query', 'normalized', $normValues );
 341                 }
 342
 343                 // Title conversions
 344                 $convValues = array();
 345                 foreach ( $pageSet->getConvertedTitles() as $rawTitleStr => $titleStr ) {
 346                         $convValues[] = array(
 347                                 'from' => $rawTitleStr,
 348                                 'to' => $titleStr
 349                         );
 350                 }
 351
 352                 if ( count( $convValues ) ) {
 353                         $result->setIndexedTagName( $convValues, 'c' );
 354                         $result->addValue( 'query', 'converted', $convValues );
 355                 }
 356
 357                 // Interwiki titles
 358                 $intrwValues = array();
 359                 foreach ( $pageSet->getInterwikiTitles() as $rawTitleStr => $interwikiStr ) {
 360                         $intrwValues[] = array(
 361                                 'title' => $rawTitleStr,
 362                                 'iw' => $interwikiStr
 363                         );
 364                 }
 365
 366                 if ( count( $intrwValues ) ) {
 367                         $result->setIndexedTagName( $intrwValues, 'i' );
 368                         $result->addValue( 'query', 'interwiki', $intrwValues );
 369                 }
 370
 371                 // Show redirect information
 372                 $redirValues = array();
 373                 foreach ( $pageSet->getRedirectTitles() as $titleStrFrom => $titleStrTo ) {
 374                         $redirValues[] = array(
 375                                 'from' => strval( $titleStrFrom ),
 376                                 'to' => $titleStrTo
 377                         );
 378                 }
 379
 380                 if ( count( $redirValues ) ) {
 381                         $result->setIndexedTagName( $redirValues, 'r' );
 382                         $result->addValue( 'query', 'redirects', $redirValues );
 383                 }
 384
 385                 //
 386                 // Missing revision elements
 387                 //
 388                 $missingRevIDs = $pageSet->getMissingRevisionIDs();
 389                 if ( count( $missingRevIDs ) ) {
 390                         $revids = array();
 391                         foreach ( $missingRevIDs as $revid ) {
 392                                 $revids[$revid] = array(
 393                                         'revid' => $revid
 394                                 );
 395                         }
 396                         $result->setIndexedTagName( $revids, 'rev' );
 397                         $result->addValue( 'query', 'badrevids', $revids );
 398                 }
 399
 400                 //
 401                 // Page elements
 402                 //
 403                 $pages = array();
 404
 405                 // Report any missing titles
 406                 foreach ( $pageSet->getMissingTitles() as $fakeId => $title ) {
 407                         $vals = array();
 408                         ApiQueryBase::addTitleInfo( $vals, $title );
 409                         $vals['missing'] = '';
 410                         $pages[$fakeId] = $vals;
 411                 }
 412                 // Report any invalid titles
 413                 foreach ( $pageSet->getInvalidTitles() as $fakeId => $title ) {
 414                         $pages[$fakeId] = array( 'title' => $title, 'invalid' => '' );
 415                 }
 416                 // Report any missing page ids
 417                 foreach ( $pageSet->getMissingPageIDs() as $pageid ) {
 418                         $pages[$pageid] = array(
 419                                 'pageid' => $pageid,
 420                                 'missing' => ''
 421                         );
 422                 }
 423                 // Report special pages
 424                 foreach ( $pageSet->getSpecialTitles() as $fakeId => $title ) {
 425                         $vals = array();
 426                         ApiQueryBase::addTitleInfo( $vals, $title );
 427                         $vals['special'] = '';
 428                         if ( $title->getNamespace() == NS_SPECIAL &&
 429                                         !SpecialPage::exists( $title->getText() ) ) {
 430                                 $vals['missing'] = '';
 431                         } elseif ( $title->getNamespace() == NS_MEDIA &&
 432                                         !wfFindFile( $title ) ) {
 433                                 $vals['missing'] = '';
 434                         }
 435                         $pages[$fakeId] = $vals;
 436                 }
 437
 438                 // Output general page information for found titles
 439                 foreach ( $pageSet->getGoodTitles() as $pageid => $title ) {
 440                         $vals = array();
 441                         $vals['pageid'] = $pageid;
 442                         ApiQueryBase::addTitleInfo( $vals, $title );
 443                         $pages[$pageid] = $vals;
 444                 }
 445
 446                 if ( count( $pages ) ) {
 447                         if ( $this->params['indexpageids'] ) {
 448                                 $pageIDs = array_keys( $pages );
 449                                 // json treats all map keys as strings - converting to match
 450                                 $pageIDs = array_map( 'strval', $pageIDs );
 451                                 $result->setIndexedTagName( $pageIDs, 'id' );
 452                                 $result->addValue( 'query', 'pageids', $pageIDs );
 453                         }
 454
 455                         $result->setIndexedTagName( $pages, 'page' );
 456                         $result->addValue( 'query', 'pages', $pages );
 457                 }
 458                 if ( $this->params['export'] ) {
 459                         $exporter = new WikiExporter( $this->getDB() );
 460                         // WikiExporter writes to stdout, so catch its
 461                         // output with an ob
 462                         ob_start();
 463                         $exporter->openStream();
 464                         foreach ( @$pageSet->getGoodTitles() as $title ) {
 465                                 if ( $title->userCanRead() ) {
 466                                         $exporter->pageByTitle( $title );
 467                                 }
 468                         }
 469                         $exporter->closeStream();
 470                         $exportxml = ob_get_contents();
 471                         ob_end_clean();
 472
 473                         // Don't check the size of exported stuff
 474                         // It's not continuable, so it would cause more
 475                         // problems than it'd solve
 476                         $result->disableSizeCheck();
 477                         if ( $this->params['exportnowrap'] ) {
 478                                 $result->reset();
 479                                 // Raw formatter will handle this
 480                                 $result->addValue( null, 'text', $exportxml );
 481                                 $result->addValue( null, 'mime', 'text/xml' );
 482                         } else {
 483                                 $r = array();
 484                                 ApiResult::setContent( $r, $exportxml );
 485                                 $result->addValue( 'query', 'export', $r );
 486                         }
 487                         $result->enableSizeCheck();
 488                 }
 489         }
 490
 491         /**
 492          * Create a generator object of the given type and return it
 493          * @param $generatorName string Module name
 494          */
 495         public function newGenerator( $generatorName ) {
 496                 // Find class that implements requested generator
 497                 if ( isset( $this->mQueryListModules[$generatorName] ) ) {
 498                         $className = $this->mQueryListModules[$generatorName];
 499                 } elseif ( isset( $this->mQueryPropModules[$generatorName] ) ) {
 500                         $className = $this->mQueryPropModules[$generatorName];
 501                 } else {
 502                         ApiBase::dieDebug( __METHOD__, "Unknown generator=$generatorName" );
 503                 }
 504                 $generator = new $className ( $this, $generatorName );
 505                 if ( !$generator instanceof ApiQueryGeneratorBase ) {
 506                         $this->dieUsage( "Module $generatorName cannot be used as a generator", 'badgenerator' );
 507                 }
 508                 $generator->setGeneratorMode();
 509                 return $generator;
 510         }
 511
 512         /**
 513          * For generator mode, execute generator, and use its output as new
 514          * ApiPageSet
 515          * @param $generatorName string Module name
 516          * @param $modules array of module objects
 517          */
 518         protected function executeGeneratorModule( $generator, $modules ) {
 519                 // Generator results
 520                 $resultPageSet = new ApiPageSet( $this, $this->redirects, $this->convertTitles );
 521
 522                 // Add any additional fields modules may need
 523                 $generator->requestExtraData( $this->mPageSet );
 524                 $this->addCustomFldsToPageSet( $modules, $resultPageSet );
 525
 526                 // Populate page information with the original user input
 527                 $this->mPageSet->execute();
 528
 529                 // populate resultPageSet with the generator output
 530                 $generator->profileIn();
 531                 $generator->executeGenerator( $resultPageSet );
 532                 wfRunHooks( 'APIQueryGeneratorAfterExecute', array( &$generator, &$resultPageSet ) );
 533                 $resultPageSet->finishPageSetGeneration();
 534                 $generator->profileOut();
 535
 536                 // Swap the resulting pageset back in
 537                 $this->mPageSet = $resultPageSet;
 538         }
 539
 540         public function getAllowedParams() {
 541                 return array(
 542                         'prop' => array(
 543                                 ApiBase::PARAM_ISMULTI => true,
 544                                 ApiBase::PARAM_TYPE => $this->mPropModuleNames
 545                         ),
 546                         'list' => array(
 547                                 ApiBase::PARAM_ISMULTI => true,
 548                                 ApiBase::PARAM_TYPE => $this->mListModuleNames
 549                         ),
 550                         'meta' => array(
 551                                 ApiBase::PARAM_ISMULTI => true,
 552                                 ApiBase::PARAM_TYPE => $this->mMetaModuleNames
 553                         ),
 554                         'generator' => array(
 555                                 ApiBase::PARAM_TYPE => $this->mAllowedGenerators
 556                         ),
 557                         'redirects' => false,
 558                         'converttitles' => false,
 559                         'indexpageids' => false,
 560                         'export' => false,
 561                         'exportnowrap' => false,
 562                 );
 563         }
 564
 565         /**
 566          * Override the parent to generate help messages for all available query modules.
 567          * @return string
 568          */
 569         public function makeHelpMsg() {
 570                 $msg = '';
 571
 572                 // Make sure the internal object is empty
 573                 // (just in case a sub-module decides to optimize during instantiation)
 574                 $this->mPageSet = null;
 575                 $this->mAllowedGenerators = array(); // Will be repopulated
 576
 577                 $astriks = str_repeat( '--- ', 8 );
 578                 $astriks2 = str_repeat( '*** ', 10 );
 579                 $msg .= "\n$astriks Query: Prop  $astriks\n\n";
 580                 $msg .= $this->makeHelpMsgHelper( $this->mQueryPropModules, 'prop' );
 581                 $msg .= "\n$astriks Query: List  $astriks\n\n";
 582                 $msg .= $this->makeHelpMsgHelper( $this->mQueryListModules, 'list' );
 583                 $msg .= "\n$astriks Query: Meta  $astriks\n\n";
 584                 $msg .= $this->makeHelpMsgHelper( $this->mQueryMetaModules, 'meta' );
 585                 $msg .= "\n\n$astriks2 Modules: continuation  $astriks2\n\n";
 586
 587                 // Perform the base call last because the $this->mAllowedGenerators
 588                 // will be updated inside makeHelpMsgHelper()
 589                 // Use parent to make default message for the query module
 590                 $msg = parent::makeHelpMsg() . $msg;
 591
 592                 return $msg;
 593         }
 594
 595         /**
 596          * For all modules in $moduleList, generate help messages and join them together
 597          * @param $moduleList array(modulename => classname)
 598          * @param $paramName string Parameter name
 599          * @return string
 600          */
 601         private function makeHelpMsgHelper( $moduleList, $paramName ) {
 602                 $moduleDescriptions = array();
 603
 604                 foreach ( $moduleList as $moduleName => $moduleClass ) {
 605                         $module = new $moduleClass ( $this, $moduleName, null );
 606
 607                         $msg = ApiMain::makeHelpMsgHeader( $module, $paramName );
 608                         $msg2 = $module->makeHelpMsg();
 609                         if ( $msg2 !== false ) {
 610                                 $msg .= $msg2;
 611                         }
 612                         if ( $module instanceof ApiQueryGeneratorBase ) {
 613                                 $this->mAllowedGenerators[] = $moduleName;
 614                                 $msg .= "Generator:\n  This module may be used as a generator\n";
 615                         }
 616                         $moduleDescriptions[] = $msg;
 617                 }
 618
 619                 return implode( "\n", $moduleDescriptions );
 620         }
 621
 622         /**
 623          * Override to add extra parameters from PageSet
 624          * @return string
 625          */
 626         public function makeHelpMsgParameters() {
 627                 $psModule = new ApiPageSet( $this );
 628                 return $psModule->makeHelpMsgParameters() . parent::makeHelpMsgParameters();
 629         }
 630
 631         public function shouldCheckMaxlag() {
 632                 return true;
 633         }
 634
 635         public function getParamDescription() {
 636                 return array(
 637                         'prop' => 'Which properties to get for the titles/revisions/pageids. Module help is available below',
 638                         'list' => 'Which lists to get. Module help is available below',
 639                         'meta' => 'Which metadata to get about the site. Module help is available below',
 640                         'generator' => array( 'Use the output of a list as the input for other prop/list/meta items',
 641                                         'NOTE: generator parameter names must be prefixed with a \'g\', see examples' ),
 642                         'redirects' => 'Automatically resolve redirects',
 643                         'converttitles' => "Convert titles to other variants if necessary. Only works if the wiki's content language supports variant conversion.",
 644                         'indexpageids' => 'Include an additional pageids section listing all returned page IDs',
 645                         'export' => 'Export the current revisions of all given or generated pages',
 646                         'exportnowrap' => 'Return the export XML without wrapping it in an XML result (same format as Special:Export). Can only be used with export',
 647                 );
 648         }
 649
 650         public function getDescription() {
 651                 return array(
 652                         'Query API module allows applications to get needed pieces of data from the MediaWiki databases,',
 653                         'and is loosely based on the old query.php interface.',
 654                         'All data modifications will first have to use query to acquire a token to prevent abuse from malicious sites'
 655                 );
 656         }
 657
 658         public function getPossibleErrors() {
 659                 return array_merge( parent::getPossibleErrors(), array(
 660                         array( 'code' => 'badgenerator', 'info' => 'Module $generatorName cannot be used as a generator' ),
 661                 ) );
 662         }
 663
 664         protected function getExamples() {
 665                 return array(
 666                         'api.php?action=query&prop=revisions&meta=siteinfo&titles=Main%20Page&rvprop=user|comment',
 667                         'api.php?action=query&generator=allpages&gapprefix=API/&prop=revisions',
 668                 );
 669         }
 670
 671         public function getVersion() {
 672                 $psModule = new ApiPageSet( $this );
 673                 $vers = array();
 674                 $vers[] = __CLASS__ . ': $Id$';
 675                 $vers[] = $psModule->getVersion();
 676                 return $vers;
 677         }
 678 }