includes/api/ApiQuery.php

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