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