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