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