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