(bug 30836) API siteinfo specialpagealiases should not return nonexistent special...
[lhc/web/wiklou.git] / includes / api / ApiQuery.php
index d882a53..866b71c 100644 (file)
-<?php\r
-\r
-\r
-/*\r
- * Created on Sep 7, 2006\r
- *\r
- * API for MediaWiki 1.8+\r
- *\r
- * Copyright (C) 2006 Yuri Astrakhan <FirstnameLastname@gmail.com>\r
- *\r
- * This program is free software; you can redistribute it and/or modify\r
- * it under the terms of the GNU General Public License as published by\r
- * the Free Software Foundation; either version 2 of the License, or\r
- * (at your option) any later version.\r
- *\r
- * This program is distributed in the hope that it will be useful,\r
- * but WITHOUT ANY WARRANTY; without even the implied warranty of\r
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\r
- * GNU General Public License for more details.\r
- *\r
- * You should have received a copy of the GNU General Public License along\r
- * with this program; if not, write to the Free Software Foundation, Inc.,\r
- * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.\r
- * http://www.gnu.org/copyleft/gpl.html\r
- */\r
-\r
-if (!defined('MEDIAWIKI')) {\r
-       // Eclipse helper - will be ignored in production\r
-       require_once ("ApiBase.php");\r
-}\r
-\r
-class ApiQuery extends ApiBase {\r
-\r
-       private $mMetaModuleNames, $mPropModuleNames, $mListModuleNames;\r
-       private $mData;\r
-\r
-       private $mQueryMetaModules = array (\r
-               'siteinfo' => 'ApiQuerySiteinfo'\r
-       );\r
-       //      'userinfo' => 'ApiQueryUserinfo',\r
-\r
-       private $mQueryPropModules = array (\r
-               'info' => 'ApiQueryInfo',\r
-               'revisions' => 'ApiQueryRevisions'\r
-       );\r
-       //      'categories' => 'ApiQueryCategories',\r
-       //      'imageinfo' => 'ApiQueryImageinfo',\r
-       //      'langlinks' => 'ApiQueryLanglinks',\r
-       //      'links' => 'ApiQueryLinks',\r
-       //      'templates' => 'ApiQueryTemplates',\r
-\r
-       private $mQueryListModules = array (\r
-               'allpages' => 'ApiQueryAllpages'\r
-       );\r
-       //      'backlinks' => 'ApiQueryBacklinks',\r
-       //      'categorymembers' => 'ApiQueryCategorymembers',\r
-       //      'embeddedin' => 'ApiQueryEmbeddedin',\r
-       //      'imagelinks' => 'ApiQueryImagelinks',\r
-       //      'logevents' => 'ApiQueryLogevents',\r
-       //      'recentchanges' => 'ApiQueryRecentchanges',\r
-       //      'usercontribs' => 'ApiQueryUsercontribs',\r
-       //      'users' => 'ApiQueryUsers',\r
-       //      'watchlist' => 'ApiQueryWatchlist',\r
-\r
-       private $mSlaveDB = null;\r
-\r
-       public function __construct($main, $action) {\r
-               parent :: __construct($main);\r
-               $this->mMetaModuleNames = array_keys($this->mQueryMetaModules);\r
-               $this->mPropModuleNames = array_keys($this->mQueryPropModules);\r
-               $this->mListModuleNames = array_keys($this->mQueryListModules);\r
-\r
-               // Allow the entire list of modules at first,\r
-               // but during module instantiation check if it can be used as a generator.\r
-               $this->mAllowedGenerators = array_merge($this->mListModuleNames, $this->mPropModuleNames);\r
-       }\r
-\r
-       public function getDB() {\r
-               if (!isset ($this->mSlaveDB))\r
-                       $this->mSlaveDB = & wfGetDB(DB_SLAVE);\r
-               return $this->mSlaveDB;\r
-       }\r
-\r
-       public function getData() {\r
-               return $this->mData;\r
-       }\r
-\r
-       /**\r
-        * Query execution happens in the following steps:\r
-        * #1 Create a PageSet object with any pages requested by the user\r
-        * #2 If using generator, execute it to get a new PageSet object\r
-        * #3 Instantiate all requested modules. \r
-        *    This way the PageSet object will know what shared data is required,\r
-        *    and minimize DB calls. \r
-        * #4 Output all normalization and redirect resolution information\r
-        * #5 Execute all requested modules\r
-        */\r
-       public function execute() {\r
-               $meta = $prop = $list = $generator = null;\r
-               extract($this->extractRequestParams());\r
-\r
-               //\r
-               // Create and initialize PageSet\r
-               //\r
-               $this->mData = new ApiPageSet($this);\r
-               $this->mData->profileIn();\r
-               $this->mData->execute();\r
-               $this->mData->profileOut();\r
-\r
-               //\r
-               // If generator is provided, get a new dataset to work on\r
-               //\r
-               if (isset ($generator))\r
-                       $this->executeGenerator($generator);\r
-\r
-               // Instantiate required modules\r
-               // During instantiation, modules may optimize data requests through the $this->mData object \r
-               // $this->mData will be lazy loaded when modules begin to request data during execution\r
-               $modules = array ();\r
-               if (isset ($meta))\r
-                       foreach ($meta as $moduleName)\r
-                               $modules[] = new $this->mQueryMetaModules[$moduleName] ($this, $moduleName);\r
-               if (isset ($prop))\r
-                       foreach ($prop as $moduleName)\r
-                               $modules[] = new $this->mQueryPropModules[$moduleName] ($this, $moduleName);\r
-               if (isset ($list))\r
-                       foreach ($list as $moduleName)\r
-                               $modules[] = new $this->mQueryListModules[$moduleName] ($this, $moduleName);\r
-\r
-               // Title normalizations\r
-               foreach ($this->mData->getNormalizedTitles() as $rawTitleStr => $titleStr) {\r
-                       $this->getResult()->addMessage('query', 'normalized', array (\r
-                               'from' => $rawTitleStr,\r
-                               'to' => $titleStr,\r
-                               '*' => ''\r
-                       ), 'n');\r
-               }\r
-\r
-               // Show redirect information\r
-               foreach ($this->mData->getRedirectTitles() as $titleStrFrom => $titleStrTo) {\r
-                       $this->getResult()->addMessage('query', 'redirects', array (\r
-                               'from' => $titleStrFrom,\r
-                               'to' => $titleStrTo,\r
-                               '*' => ''\r
-                       ), 'r');\r
-               }\r
-\r
-               // Execute all requested modules.\r
-               foreach ($modules as $module) {\r
-                       $module->profileIn();\r
-                       $module->execute();\r
-                       $module->profileOut();\r
-               }\r
-       }\r
-\r
-       protected function executeGenerator($generator) {\r
-\r
-               // Find class that implements requested generator\r
-               if (isset ($this->mQueryListModules[$generator]))\r
-                       $className = $this->mQueryListModules[$generator];\r
-               else\r
-                       if (isset ($this->mQueryPropModules[$generator]))\r
-                               $className = $this->mQueryPropModules[$generator];\r
-                       else\r
-                               $this->dieDebug("Unknown generator=$generator");\r
-\r
-               $module = new $className ($this, $generator, true);\r
-\r
-               // change $this->mData\r
-\r
-               // TODO: implement\r
-               $this->dieUsage("Generator execution has not been implemented", 'notimplemented');\r
-       }\r
-\r
-       protected function getAllowedParams() {\r
-               return array (\r
-                       'meta' => array (\r
-                               GN_ENUM_ISMULTI => true,\r
-                               GN_ENUM_TYPE => $this->mMetaModuleNames\r
-                       ),\r
-                       'prop' => array (\r
-                               GN_ENUM_ISMULTI => true,\r
-                               GN_ENUM_TYPE => $this->mPropModuleNames\r
-                       ),\r
-                       'list' => array (\r
-                               GN_ENUM_ISMULTI => true,\r
-                               GN_ENUM_TYPE => $this->mListModuleNames\r
-                       )\r
-                       //                      'generator' => array (\r
-                       //                              GN_ENUM_TYPE => $this->mAllowedGenerators\r
-                       //                      ),\r
-               );\r
-       }\r
-\r
-       /**\r
-        * Override the parent to generate help messages for all available query modules.\r
-        */\r
-       public function makeHelpMsg() {\r
-\r
-               // Use parent to make default message for the query module\r
-               $msg = parent :: makeHelpMsg();\r
-\r
-               // Make sure the internal object is empty\r
-               // (just in case a sub-module decides to optimize during instantiation)\r
-               $this->mData = null;\r
-\r
-               $astriks = str_repeat('--- ', 8);\r
-               $msg .= "\n$astriks Query: Meta  $astriks\n\n";\r
-               $msg .= $this->makeHelpMsgHelper($this->mQueryMetaModules, 'meta');\r
-               $msg .= "\n$astriks Query: Prop  $astriks\n\n";\r
-               $msg .= $this->makeHelpMsgHelper($this->mQueryPropModules, 'prop');\r
-               $msg .= "\n$astriks Query: List  $astriks\n\n";\r
-               $msg .= $this->makeHelpMsgHelper($this->mQueryListModules, 'list');\r
-\r
-               return $msg;\r
-       }\r
-\r
-       private function makeHelpMsgHelper($moduleList, $paramName) {\r
-               $msg = '';\r
-\r
-               foreach ($moduleList as $moduleName => $moduleClass) {\r
-                       $msg .= "* $paramName=$moduleName *";\r
-                       $module = new $moduleClass ($this, $moduleName, null);\r
-                       $msg2 = $module->makeHelpMsg();\r
-                       if ($msg2 !== false)\r
-                               $msg .= $msg2;\r
-                       $msg .= "\n";\r
-                       if ($module->getCanGenerate())\r
-                               $msg .= "  * Can be used as a generator\n";\r
-               }\r
-\r
-               return $msg;\r
-       }\r
-\r
-       /**\r
-        * Override to add extra parameters from PageSet\r
-        */     \r
-       public function makeHelpMsgParameters() {\r
-               $module = new ApiPageSet($this);\r
-               return $module->makeHelpMsgParameters() . parent :: makeHelpMsgParameters();\r
-       }\r
-       \r
-\r
-       protected function getParamDescription() {\r
-               return array (\r
-                       'meta' => 'Which meta data to get about the site',\r
-                       'prop' => 'Which properties to get for the titles/revisions/pageids',\r
-                       'list' => 'Which lists to get',\r
-                       'generator' => 'Use the output of a list as the input for other prop/list/meta items',\r
-               );\r
-       }\r
-\r
-       protected function getDescription() {\r
-               return array (\r
-                       'Query API module allows applications to get needed pieces of data from the MediaWiki databases,',\r
-                       'and is loosely based on the Query API interface currently available on all MediaWiki servers.',\r
-                       'All data modifications will first have to use query to acquire a token to prevent abuse from malicious sites.'\r
-               );\r
-       }\r
-\r
-       protected function getExamples() {\r
-               return array (\r
-                       'api.php?action=query&what=content&titles=ArticleA|ArticleB'\r
-               );\r
-       }\r
-}\r
-?>
\ No newline at end of file
+<?php
+/**
+ *
+ *
+ * Created on Sep 7, 2006
+ *
+ * Copyright © 2006 Yuri Astrakhan <Firstname><Lastname>@gmail.com
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * This is the main query class. It behaves similar to ApiMain: based on the
+ * parameters given, it will create a list of titles to work on (an ApiPageSet
+ * object), instantiate and execute various property/list/meta modules, and
+ * assemble all resulting data into a single ApiResult object.
+ *
+ * In generator mode, a generator will be executed first to populate a second
+ * ApiPageSet object, and that object will be used for all subsequent modules.
+ *
+ * @ingroup API
+ */
+class ApiQuery extends ApiBase {
+
+       private $mPropModuleNames, $mListModuleNames, $mMetaModuleNames;
+
+       /**
+        * @var ApiPageSet
+        */
+       private $mPageSet;
+
+       private $params, $redirects, $convertTitles, $iwUrl;
+
+       private $mQueryPropModules = array(
+               'info' => 'ApiQueryInfo',
+               'revisions' => 'ApiQueryRevisions',
+               'links' => 'ApiQueryLinks',
+               'iwlinks' => 'ApiQueryIWLinks',
+               'langlinks' => 'ApiQueryLangLinks',
+               'images' => 'ApiQueryImages',
+               'imageinfo' => 'ApiQueryImageInfo',
+               'stashimageinfo' => 'ApiQueryStashImageInfo',
+               'templates' => 'ApiQueryLinks',
+               'categories' => 'ApiQueryCategories',
+               'extlinks' => 'ApiQueryExternalLinks',
+               'categoryinfo' => 'ApiQueryCategoryInfo',
+               'duplicatefiles' => 'ApiQueryDuplicateFiles',
+               'pageprops' => 'ApiQueryPageProps',
+       );
+
+       private $mQueryListModules = array(
+               'allimages' => 'ApiQueryAllImages',
+               'allpages' => 'ApiQueryAllPages',
+               'alllinks' => 'ApiQueryAllLinks',
+               'allcategories' => 'ApiQueryAllCategories',
+               'allusers' => 'ApiQueryAllUsers',
+               'backlinks' => 'ApiQueryBacklinks',
+               'blocks' => 'ApiQueryBlocks',
+               'categorymembers' => 'ApiQueryCategoryMembers',
+               'deletedrevs' => 'ApiQueryDeletedrevs',
+               'embeddedin' => 'ApiQueryBacklinks',
+               'filearchive' => 'ApiQueryFilearchive',
+               'imageusage' => 'ApiQueryBacklinks',
+               'iwbacklinks' => 'ApiQueryIWBacklinks',
+               'langbacklinks' => 'ApiQueryLangBacklinks',
+               'logevents' => 'ApiQueryLogEvents',
+               'recentchanges' => 'ApiQueryRecentChanges',
+               'search' => 'ApiQuerySearch',
+               'tags' => 'ApiQueryTags',
+               'usercontribs' => 'ApiQueryContributions',
+               'watchlist' => 'ApiQueryWatchlist',
+               'watchlistraw' => 'ApiQueryWatchlistRaw',
+               'exturlusage' => 'ApiQueryExtLinksUsage',
+               'users' => 'ApiQueryUsers',
+               'random' => 'ApiQueryRandom',
+               'protectedtitles' => 'ApiQueryProtectedTitles',
+               'querypage' => 'ApiQueryQueryPage',
+       );
+
+       private $mQueryMetaModules = array(
+               'siteinfo' => 'ApiQuerySiteinfo',
+               'userinfo' => 'ApiQueryUserInfo',
+               'allmessages' => 'ApiQueryAllMessages',
+       );
+
+       private $mSlaveDB = null;
+       private $mNamedDB = array();
+
+       protected $mAllowedGenerators = array();
+
+       public function __construct( $main, $action ) {
+               parent::__construct( $main, $action );
+
+               // Allow custom modules to be added in LocalSettings.php
+               global $wgAPIPropModules, $wgAPIListModules, $wgAPIMetaModules;
+               self::appendUserModules( $this->mQueryPropModules, $wgAPIPropModules );
+               self::appendUserModules( $this->mQueryListModules, $wgAPIListModules );
+               self::appendUserModules( $this->mQueryMetaModules, $wgAPIMetaModules );
+
+               $this->mPropModuleNames = array_keys( $this->mQueryPropModules );
+               $this->mListModuleNames = array_keys( $this->mQueryListModules );
+               $this->mMetaModuleNames = array_keys( $this->mQueryMetaModules );
+
+               $this->makeHelpMsgHelper( $this->mQueryPropModules, 'prop' );
+               $this->makeHelpMsgHelper( $this->mQueryListModules, 'list' );
+       }
+
+       /**
+        * Helper function to append any add-in modules to the list
+        * @param $modules array Module array
+        * @param $newModules array Module array to add to $modules
+        */
+       private static function appendUserModules( &$modules, $newModules ) {
+               if ( is_array( $newModules ) ) {
+                       foreach ( $newModules as $moduleName => $moduleClass ) {
+                               $modules[$moduleName] = $moduleClass;
+                       }
+               }
+       }
+
+       /**
+        * Gets a default slave database connection object
+        * @return DatabaseBase
+        */
+       public function getDB() {
+               if ( !isset( $this->mSlaveDB ) ) {
+                       $this->profileDBIn();
+                       $this->mSlaveDB = wfGetDB( DB_SLAVE, 'api' );
+                       $this->profileDBOut();
+               }
+               return $this->mSlaveDB;
+       }
+
+       /**
+        * Get the query database connection with the given name.
+        * If no such connection has been requested before, it will be created.
+        * Subsequent calls with the same $name will return the same connection
+        * as the first, regardless of the values of $db and $groups
+        * @param $name string Name to assign to the database connection
+        * @param $db int One of the DB_* constants
+        * @param $groups array Query groups
+        * @return DatabaseBase
+        */
+       public function getNamedDB( $name, $db, $groups ) {
+               if ( !array_key_exists( $name, $this->mNamedDB ) ) {
+                       $this->profileDBIn();
+                       $this->mNamedDB[$name] = wfGetDB( $db, $groups );
+                       $this->profileDBOut();
+               }
+               return $this->mNamedDB[$name];
+       }
+
+       /**
+        * Gets the set of pages the user has requested (or generated)
+        * @return ApiPageSet
+        */
+       public function getPageSet() {
+               return $this->mPageSet;
+       }
+
+       /**
+        * Get the array mapping module names to class names
+        * @return array array(modulename => classname)
+        */
+       function getModules() {
+               return array_merge( $this->mQueryPropModules, $this->mQueryListModules, $this->mQueryMetaModules );
+       }
+
+       /**
+        * Get whether the specified module is a prop, list or a meta query module
+        * @param $moduleName string Name of the module to find type for
+        * @return mixed string or null
+        */
+       function getModuleType( $moduleName ) {
+               if ( isset( $this->mQueryPropModules[$moduleName] ) ) {
+                       return 'prop';
+               }
+
+               if ( isset( $this->mQueryListModules[$moduleName] ) ) {
+                       return 'list';
+               }
+
+               if ( isset( $this->mQueryMetaModules[$moduleName] ) ) {
+                       return 'meta';
+               }
+
+               return null;
+       }
+
+       public function getCustomPrinter() {
+               // If &exportnowrap is set, use the raw formatter
+               if ( $this->getParameter( 'export' ) &&
+                               $this->getParameter( 'exportnowrap' ) )
+               {
+                       return new ApiFormatRaw( $this->getMain(),
+                               $this->getMain()->createPrinterByName( 'xml' ) );
+               } else {
+                       return null;
+               }
+       }
+
+       /**
+        * Query execution happens in the following steps:
+        * #1 Create a PageSet object with any pages requested by the user
+        * #2 If using a generator, execute it to get a new ApiPageSet object
+        * #3 Instantiate all requested modules.
+        *    This way the PageSet object will know what shared data is required,
+        *    and minimize DB calls.
+        * #4 Output all normalization and redirect resolution information
+        * #5 Execute all requested modules
+        */
+       public function execute() {
+               $this->params = $this->extractRequestParams();
+               $this->redirects = $this->params['redirects'];
+               $this->convertTitles = $this->params['converttitles'];
+               $this->iwUrl = $this->params['iwurl'];
+
+               // Create PageSet
+               $this->mPageSet = new ApiPageSet( $this, $this->redirects, $this->convertTitles );
+
+               // Instantiate requested modules
+               $modules = array();
+               $this->instantiateModules( $modules, 'prop', $this->mQueryPropModules );
+               $this->instantiateModules( $modules, 'list', $this->mQueryListModules );
+               $this->instantiateModules( $modules, 'meta', $this->mQueryMetaModules );
+
+               $cacheMode = 'public';
+
+               // If given, execute generator to substitute user supplied data with generated data.
+               if ( isset( $this->params['generator'] ) ) {
+                       $generator = $this->newGenerator( $this->params['generator'] );
+                       $params = $generator->extractRequestParams();
+                       $cacheMode = $this->mergeCacheMode( $cacheMode,
+                               $generator->getCacheMode( $params ) );
+                       $this->executeGeneratorModule( $generator, $modules );
+               } else {
+                       // Append custom fields and populate page/revision information
+                       $this->addCustomFldsToPageSet( $modules, $this->mPageSet );
+                       $this->mPageSet->execute();
+               }
+
+               // Record page information (title, namespace, if exists, etc)
+               $this->outputGeneralPageInfo();
+
+               // Execute all requested modules.
+               foreach ( $modules as $module ) {
+                       $params = $module->extractRequestParams();
+                       $cacheMode = $this->mergeCacheMode(
+                               $cacheMode, $module->getCacheMode( $params ) );
+                       $module->profileIn();
+                       $module->execute();
+                       wfRunHooks( 'APIQueryAfterExecute', array( &$module ) );
+                       $module->profileOut();
+               }
+
+               // Set the cache mode
+               $this->getMain()->setCacheMode( $cacheMode );
+       }
+
+       /**
+        * Update a cache mode string, applying the cache mode of a new module to it.
+        * The cache mode may increase in the level of privacy, but public modules
+        * added to private data do not decrease the level of privacy.
+        *
+        * @param $cacheMode string
+        * @param $modCacheMode string
+        * @return string
+        */
+       protected function mergeCacheMode( $cacheMode, $modCacheMode ) {
+               if ( $modCacheMode === 'anon-public-user-private' ) {
+                       if ( $cacheMode !== 'private' ) {
+                               $cacheMode = 'anon-public-user-private';
+                       }
+               } elseif ( $modCacheMode === 'public' ) {
+                       // do nothing, if it's public already it will stay public
+               } else { // private
+                       $cacheMode = 'private';
+               }
+               return $cacheMode;
+       }
+
+       /**
+        * Query modules may optimize data requests through the $this->getPageSet() object
+        * by adding extra fields from the page table.
+        * This function will gather all the extra request fields from the modules.
+        * @param $modules array of module objects
+        * @param $pageSet ApiPageSet
+        */
+       private function addCustomFldsToPageSet( $modules, $pageSet ) {
+               // Query all requested modules.
+               foreach ( $modules as $module ) {
+                       $module->requestExtraData( $pageSet );
+               }
+       }
+
+       /**
+        * Create instances of all modules requested by the client
+        * @param $modules Array to append instantiated modules to
+        * @param $param string Parameter name to read modules from
+        * @param $moduleList Array array(modulename => classname)
+        */
+       private function instantiateModules( &$modules, $param, $moduleList ) {
+               if ( isset( $this->params[$param] ) ) {
+                       foreach ( $this->params[$param] as $moduleName ) {
+                               $modules[] = new $moduleList[$moduleName] ( $this, $moduleName );
+                       }
+               }
+       }
+
+       /**
+        * Appends an element for each page in the current pageSet with the
+        * most general information (id, title), plus any title normalizations
+        * and missing or invalid title/pageids/revids.
+        */
+       private function outputGeneralPageInfo() {
+               $pageSet = $this->getPageSet();
+               $result = $this->getResult();
+
+               // We don't check for a full result set here because we can't be adding
+               // more than 380K. The maximum revision size is in the megabyte range,
+               // and the maximum result size must be even higher than that.
+
+               // Title normalizations
+               $normValues = array();
+               foreach ( $pageSet->getNormalizedTitles() as $rawTitleStr => $titleStr ) {
+                       $normValues[] = array(
+                               'from' => $rawTitleStr,
+                               'to' => $titleStr
+                       );
+               }
+
+               if ( count( $normValues ) ) {
+                       $result->setIndexedTagName( $normValues, 'n' );
+                       $result->addValue( 'query', 'normalized', $normValues );
+               }
+
+               // Title conversions
+               $convValues = array();
+               foreach ( $pageSet->getConvertedTitles() as $rawTitleStr => $titleStr ) {
+                       $convValues[] = array(
+                               'from' => $rawTitleStr,
+                               'to' => $titleStr
+                       );
+               }
+
+               if ( count( $convValues ) ) {
+                       $result->setIndexedTagName( $convValues, 'c' );
+                       $result->addValue( 'query', 'converted', $convValues );
+               }
+
+               // Interwiki titles
+               $intrwValues = array();
+               foreach ( $pageSet->getInterwikiTitles() as $rawTitleStr => $interwikiStr ) {
+                       $item = array(
+                               'title' => $rawTitleStr,
+                               'iw' => $interwikiStr,
+                       );
+                       if ( $this->iwUrl ) {
+                               $title = Title::newFromText( $rawTitleStr );
+                               $item['url'] = wfExpandUrl( $title->getFullURL(), PROTO_CURRENT );
+                       }
+                       $intrwValues[] = $item;
+               }
+
+               if ( count( $intrwValues ) ) {
+                       $result->setIndexedTagName( $intrwValues, 'i' );
+                       $result->addValue( 'query', 'interwiki', $intrwValues );
+               }
+
+               // Show redirect information
+               $redirValues = array();
+               foreach ( $pageSet->getRedirectTitles() as $titleStrFrom => $titleTo ) {
+                       $r = array(
+                               'from' => strval( $titleStrFrom ),
+                               'to' => $titleTo->getPrefixedText(),
+                       );
+                       if ( $titleTo->getFragment() !== '' ) {
+                               $r['tofragment'] = $titleTo->getFragment();
+                       }
+                       $redirValues[] = $r;
+               }
+
+               if ( count( $redirValues ) ) {
+                       $result->setIndexedTagName( $redirValues, 'r' );
+                       $result->addValue( 'query', 'redirects', $redirValues );
+               }
+
+               // Missing revision elements
+               $missingRevIDs = $pageSet->getMissingRevisionIDs();
+               if ( count( $missingRevIDs ) ) {
+                       $revids = array();
+                       foreach ( $missingRevIDs as $revid ) {
+                               $revids[$revid] = array(
+                                       'revid' => $revid
+                               );
+                       }
+                       $result->setIndexedTagName( $revids, 'rev' );
+                       $result->addValue( 'query', 'badrevids', $revids );
+               }
+
+               // Page elements
+               $pages = array();
+
+               // Report any missing titles
+               foreach ( $pageSet->getMissingTitles() as $fakeId => $title ) {
+                       $vals = array();
+                       ApiQueryBase::addTitleInfo( $vals, $title );
+                       $vals['missing'] = '';
+                       $pages[$fakeId] = $vals;
+               }
+               // Report any invalid titles
+               foreach ( $pageSet->getInvalidTitles() as $fakeId => $title ) {
+                       $pages[$fakeId] = array( 'title' => $title, 'invalid' => '' );
+               }
+               // Report any missing page ids
+               foreach ( $pageSet->getMissingPageIDs() as $pageid ) {
+                       $pages[$pageid] = array(
+                               'pageid' => $pageid,
+                               'missing' => ''
+                       );
+               }
+               // Report special pages
+               foreach ( $pageSet->getSpecialTitles() as $fakeId => $title ) {
+                       $vals = array();
+                       ApiQueryBase::addTitleInfo( $vals, $title );
+                       $vals['special'] = '';
+                       if ( $title->isSpecialPage() &&
+                                       !SpecialPageFactory::exists( $title->getDbKey() ) ) {
+                               $vals['missing'] = '';
+                       } elseif ( $title->getNamespace() == NS_MEDIA &&
+                                       !wfFindFile( $title ) ) {
+                               $vals['missing'] = '';
+                       }
+                       $pages[$fakeId] = $vals;
+               }
+
+               // Output general page information for found titles
+               foreach ( $pageSet->getGoodTitles() as $pageid => $title ) {
+                       $vals = array();
+                       $vals['pageid'] = $pageid;
+                       ApiQueryBase::addTitleInfo( $vals, $title );
+                       $pages[$pageid] = $vals;
+               }
+
+               if ( count( $pages ) ) {
+                       if ( $this->params['indexpageids'] ) {
+                               $pageIDs = array_keys( $pages );
+                               // json treats all map keys as strings - converting to match
+                               $pageIDs = array_map( 'strval', $pageIDs );
+                               $result->setIndexedTagName( $pageIDs, 'id' );
+                               $result->addValue( 'query', 'pageids', $pageIDs );
+                       }
+
+                       $result->setIndexedTagName( $pages, 'page' );
+                       $result->addValue( 'query', 'pages', $pages );
+               }
+               if ( $this->params['export'] ) {
+                       $this->doExport( $pageSet, $result );
+               }
+       }
+
+       /**
+        * @param  $pageSet ApiPageSet Pages to be exported
+        * @param  $result ApiResult Result to output to
+        */
+       private function doExport( $pageSet, $result )  {
+               $exportTitles = array();
+               $titles = $pageSet->getGoodTitles();
+               if ( count( $titles ) ) {
+                       foreach ( $titles as $title ) {
+                               if ( $title->userCan( 'read' ) ) {
+                                       $exportTitles[] = $title;
+                               }
+                       }
+               }
+
+               $exporter = new WikiExporter( $this->getDB() );
+               // WikiExporter writes to stdout, so catch its
+               // output with an ob
+               ob_start();
+               $exporter->openStream();
+               foreach ( $exportTitles as $title ) {
+                       $exporter->pageByTitle( $title );
+               }
+               $exporter->closeStream();
+               $exportxml = ob_get_contents();
+               ob_end_clean();
+
+               // Don't check the size of exported stuff
+               // It's not continuable, so it would cause more
+               // problems than it'd solve
+               $result->disableSizeCheck();
+               if ( $this->params['exportnowrap'] ) {
+                       $result->reset();
+                       // Raw formatter will handle this
+                       $result->addValue( null, 'text', $exportxml );
+                       $result->addValue( null, 'mime', 'text/xml' );
+               } else {
+                       $r = array();
+                       ApiResult::setContent( $r, $exportxml );
+                       $result->addValue( 'query', 'export', $r );
+               }
+               $result->enableSizeCheck();
+       }
+
+       /**
+        * Create a generator object of the given type and return it
+        * @param $generatorName string Module name
+        * @return ApiQueryGeneratorBase
+        */
+       public function newGenerator( $generatorName ) {
+               // Find class that implements requested generator
+               if ( isset( $this->mQueryListModules[$generatorName] ) ) {
+                       $className = $this->mQueryListModules[$generatorName];
+               } elseif ( isset( $this->mQueryPropModules[$generatorName] ) ) {
+                       $className = $this->mQueryPropModules[$generatorName];
+               } else {
+                       ApiBase::dieDebug( __METHOD__, "Unknown generator=$generatorName" );
+               }
+               $generator = new $className ( $this, $generatorName );
+               if ( !$generator instanceof ApiQueryGeneratorBase ) {
+                       $this->dieUsage( "Module $generatorName cannot be used as a generator", 'badgenerator' );
+               }
+               $generator->setGeneratorMode();
+               return $generator;
+       }
+
+       /**
+        * For generator mode, execute generator, and use its output as new
+        * ApiPageSet
+        * @param $generator ApiQueryGeneratorBase Generator Module
+        * @param $modules array of module objects
+        */
+       protected function executeGeneratorModule( $generator, $modules ) {
+               // Generator results
+               $resultPageSet = new ApiPageSet( $this, $this->redirects, $this->convertTitles );
+
+               // Add any additional fields modules may need
+               $generator->requestExtraData( $this->mPageSet );
+               $this->addCustomFldsToPageSet( $modules, $resultPageSet );
+
+               // Populate page information with the original user input
+               $this->mPageSet->execute();
+
+               // populate resultPageSet with the generator output
+               $generator->profileIn();
+               $generator->executeGenerator( $resultPageSet );
+               wfRunHooks( 'APIQueryGeneratorAfterExecute', array( &$generator, &$resultPageSet ) );
+               $resultPageSet->finishPageSetGeneration();
+               $generator->profileOut();
+
+               // Swap the resulting pageset back in
+               $this->mPageSet = $resultPageSet;
+       }
+
+       public function getAllowedParams() {
+               return array(
+                       'prop' => array(
+                               ApiBase::PARAM_ISMULTI => true,
+                               ApiBase::PARAM_TYPE => $this->mPropModuleNames
+                       ),
+                       'list' => array(
+                               ApiBase::PARAM_ISMULTI => true,
+                               ApiBase::PARAM_TYPE => $this->mListModuleNames
+                       ),
+                       'meta' => array(
+                               ApiBase::PARAM_ISMULTI => true,
+                               ApiBase::PARAM_TYPE => $this->mMetaModuleNames
+                       ),
+                       'generator' => array(
+                               ApiBase::PARAM_TYPE => $this->mAllowedGenerators
+                       ),
+                       'redirects' => false,
+                       'converttitles' => false,
+                       'indexpageids' => false,
+                       'export' => false,
+                       'exportnowrap' => false,
+                       'iwurl' => false,
+               );
+       }
+
+       /**
+        * Override the parent to generate help messages for all available query modules.
+        * @return string
+        */
+       public function makeHelpMsg() {
+               // Make sure the internal object is empty
+               // (just in case a sub-module decides to optimize during instantiation)
+               $this->mPageSet = null;
+               $this->mAllowedGenerators = array(); // Will be repopulated
+
+               $querySeparator = str_repeat( '--- ', 12 );
+               $moduleSeparator = str_repeat( '*** ', 14 );
+               $msg = "\n$querySeparator Query: Prop  $querySeparator\n\n";
+               $msg .= $this->makeHelpMsgHelper( $this->mQueryPropModules, 'prop' );
+               $msg .= "\n$querySeparator Query: List  $querySeparator\n\n";
+               $msg .= $this->makeHelpMsgHelper( $this->mQueryListModules, 'list' );
+               $msg .= "\n$querySeparator Query: Meta  $querySeparator\n\n";
+               $msg .= $this->makeHelpMsgHelper( $this->mQueryMetaModules, 'meta' );
+               $msg .= "\n\n$moduleSeparator Modules: continuation  $moduleSeparator\n\n";
+
+               // Perform the base call last because the $this->mAllowedGenerators
+               // will be updated inside makeHelpMsgHelper()
+               // Use parent to make default message for the query module
+               $msg = parent::makeHelpMsg() . $msg;
+
+               return $msg;
+       }
+
+       /**
+        * For all modules in $moduleList, generate help messages and join them together
+        * @param $moduleList Array array(modulename => classname)
+        * @param $paramName string Parameter name
+        * @return string
+        */
+       private function makeHelpMsgHelper( $moduleList, $paramName ) {
+               $moduleDescriptions = array();
+
+               foreach ( $moduleList as $moduleName => $moduleClass ) {
+                       /**
+                        * @var $module ApiQueryBase
+                        */
+                       $module = new $moduleClass( $this, $moduleName, null );
+
+                       $msg = ApiMain::makeHelpMsgHeader( $module, $paramName );
+                       $msg2 = $module->makeHelpMsg();
+                       if ( $msg2 !== false ) {
+                               $msg .= $msg2;
+                       }
+                       if ( $module instanceof ApiQueryGeneratorBase ) {
+                               $this->mAllowedGenerators[] = $moduleName;
+                               $msg .= "Generator:\n  This module may be used as a generator\n";
+                       }
+                       $moduleDescriptions[] = $msg;
+               }
+
+               return implode( "\n", $moduleDescriptions );
+       }
+
+       /**
+        * Override to add extra parameters from PageSet
+        * @return string
+        */
+       public function makeHelpMsgParameters() {
+               $psModule = new ApiPageSet( $this );
+               return $psModule->makeHelpMsgParameters() . parent::makeHelpMsgParameters();
+       }
+
+       public function shouldCheckMaxlag() {
+               return true;
+       }
+
+       public function getParamDescription() {
+               return array(
+                       'prop' => 'Which properties to get for the titles/revisions/pageids. Module help is available below',
+                       'list' => 'Which lists to get. Module help is available below',
+                       'meta' => 'Which metadata to get about the site. Module help is available below',
+                       'generator' => array( 'Use the output of a list as the input for other prop/list/meta items',
+                                       'NOTE: generator parameter names must be prefixed with a \'g\', see examples' ),
+                       'redirects' => 'Automatically resolve redirects',
+                       'converttitles' => array( "Convert titles to other variants if necessary. Only works if the wiki's content language supports variant conversion.",
+                                       'Languages that support variant conversion include gan, iu, kk, ku, shi, sr, tg, zh' ),
+                       'indexpageids' => 'Include an additional pageids section listing all returned page IDs',
+                       'export' => 'Export the current revisions of all given or generated pages',
+                       'exportnowrap' => 'Return the export XML without wrapping it in an XML result (same format as Special:Export). Can only be used with export',
+                       'iwurl' => 'Whether to get the full URL if the title is an interwiki link',
+               );
+       }
+
+       public function getDescription() {
+               return array(
+                       'Query API module allows applications to get needed pieces of data from the MediaWiki databases,',
+                       'and is loosely based on the old query.php interface.',
+                       'All data modifications will first have to use query to acquire a token to prevent abuse from malicious sites'
+               );
+       }
+
+       public function getPossibleErrors() {
+               return array_merge( parent::getPossibleErrors(), array(
+                       array( 'code' => 'badgenerator', 'info' => 'Module $generatorName cannot be used as a generator' ),
+               ) );
+       }
+
+       public function getExamples() {
+               return array(
+                       'api.php?action=query&prop=revisions&meta=siteinfo&titles=Main%20Page&rvprop=user|comment',
+                       'api.php?action=query&generator=allpages&gapprefix=API/&prop=revisions',
+               );
+       }
+
+       public function getHelpUrls() {
+               return array(
+                       'https://www.mediawiki.org/wiki/API:Meta',
+                       'https://www.mediawiki.org/wiki/API:Properties',
+                       'https://www.mediawiki.org/wiki/API:Lists',
+               );
+       }
+
+       public function getVersion() {
+               $psModule = new ApiPageSet( $this );
+               $vers = array();
+               $vers[] = __CLASS__ . ': $Id$';
+               $vers[] = $psModule->getVersion();
+               return $vers;
+       }
+}