includes/api/ApiMain.php

   1 <?php
   2 /**
   3  *
   4  *
   5  * Created on Sep 4, 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  * @defgroup API API
  26  */
  27
  28 use MediaWiki\Logger\LoggerFactory;
  29
  30 /**
  31  * This is the main API class, used for both external and internal processing.
  32  * When executed, it will create the requested formatter object,
  33  * instantiate and execute an object associated with the needed action,
  34  * and use formatter to print results.
  35  * In case of an exception, an error message will be printed using the same formatter.
  36  *
  37  * To use API from another application, run it using FauxRequest object, in which
  38  * case any internal exceptions will not be handled but passed up to the caller.
  39  * After successful execution, use getResult() for the resulting data.
  40  *
  41  * @ingroup API
  42  */
  43 class ApiMain extends ApiBase {
  44         /**
  45          * When no format parameter is given, this format will be used
  46          */
  47         const API_DEFAULT_FORMAT = 'jsonfm';
  48
  49         /**
  50          * When no uselang parameter is given, this language will be used
  51          */
  52         const API_DEFAULT_USELANG = 'user';
  53
  54         /**
  55          * List of available modules: action name => module class
  56          */
  57         private static $Modules = [
  58                 'login' => 'ApiLogin',
  59                 'clientlogin' => 'ApiClientLogin',
  60                 'logout' => 'ApiLogout',
  61                 'createaccount' => 'ApiAMCreateAccount',
  62                 'linkaccount' => 'ApiLinkAccount',
  63                 'unlinkaccount' => 'ApiRemoveAuthenticationData',
  64                 'changeauthenticationdata' => 'ApiChangeAuthenticationData',
  65                 'removeauthenticationdata' => 'ApiRemoveAuthenticationData',
  66                 'resetpassword' => 'ApiResetPassword',
  67                 'query' => 'ApiQuery',
  68                 'expandtemplates' => 'ApiExpandTemplates',
  69                 'parse' => 'ApiParse',
  70                 'stashedit' => 'ApiStashEdit',
  71                 'opensearch' => 'ApiOpenSearch',
  72                 'feedcontributions' => 'ApiFeedContributions',
  73                 'feedrecentchanges' => 'ApiFeedRecentChanges',
  74                 'feedwatchlist' => 'ApiFeedWatchlist',
  75                 'help' => 'ApiHelp',
  76                 'paraminfo' => 'ApiParamInfo',
  77                 'rsd' => 'ApiRsd',
  78                 'compare' => 'ApiComparePages',
  79                 'tokens' => 'ApiTokens',
  80                 'checktoken' => 'ApiCheckToken',
  81                 'cspreport' => 'ApiCSPReport',
  82                 'validatepassword' => 'ApiValidatePassword',
  83
  84                 // Write modules
  85                 'purge' => 'ApiPurge',
  86                 'setnotificationtimestamp' => 'ApiSetNotificationTimestamp',
  87                 'rollback' => 'ApiRollback',
  88                 'delete' => 'ApiDelete',
  89                 'undelete' => 'ApiUndelete',
  90                 'protect' => 'ApiProtect',
  91                 'block' => 'ApiBlock',
  92                 'unblock' => 'ApiUnblock',
  93                 'move' => 'ApiMove',
  94                 'edit' => 'ApiEditPage',
  95                 'upload' => 'ApiUpload',
  96                 'filerevert' => 'ApiFileRevert',
  97                 'emailuser' => 'ApiEmailUser',
  98                 'watch' => 'ApiWatch',
  99                 'patrol' => 'ApiPatrol',
 100                 'import' => 'ApiImport',
 101                 'clearhasmsg' => 'ApiClearHasMsg',
 102                 'userrights' => 'ApiUserrights',
 103                 'options' => 'ApiOptions',
 104                 'imagerotate' => 'ApiImageRotate',
 105                 'revisiondelete' => 'ApiRevisionDelete',
 106                 'managetags' => 'ApiManageTags',
 107                 'tag' => 'ApiTag',
 108                 'mergehistory' => 'ApiMergeHistory',
 109                 'setpagelanguage' => 'ApiSetPageLanguage',
 110         ];
 111
 112         /**
 113          * List of available formats: format name => format class
 114          */
 115         private static $Formats = [
 116                 'json' => 'ApiFormatJson',
 117                 'jsonfm' => 'ApiFormatJson',
 118                 'php' => 'ApiFormatPhp',
 119                 'phpfm' => 'ApiFormatPhp',
 120                 'xml' => 'ApiFormatXml',
 121                 'xmlfm' => 'ApiFormatXml',
 122                 'rawfm' => 'ApiFormatJson',
 123                 'none' => 'ApiFormatNone',
 124         ];
 125
 126         // @codingStandardsIgnoreStart String contenation on "msg" not allowed to break long line
 127         /**
 128          * List of user roles that are specifically relevant to the API.
 129          * [ 'right' => [ 'msg'    => 'Some message with a $1',
 130          *                'params' => [ $someVarToSubst ] ],
 131          * ];
 132          */
 133         private static $mRights = [
 134                 'writeapi' => [
 135                         'msg' => 'right-writeapi',
 136                         'params' => []
 137                 ],
 138                 'apihighlimits' => [
 139                         'msg' => 'api-help-right-apihighlimits',
 140                         'params' => [ ApiBase::LIMIT_SML2, ApiBase::LIMIT_BIG2 ]
 141                 ]
 142         ];
 143         // @codingStandardsIgnoreEnd
 144
 145         /**
 146          * @var ApiFormatBase
 147          */
 148         private $mPrinter;
 149
 150         private $mModuleMgr, $mResult, $mErrorFormatter = null;
 151         /** @var ApiContinuationManager|null */
 152         private $mContinuationManager;
 153         private $mAction;
 154         private $mEnableWrite;
 155         private $mInternalMode, $mSquidMaxage;
 156         /** @var ApiBase */
 157         private $mModule;
 158
 159         private $mCacheMode = 'private';
 160         private $mCacheControl = [];
 161         private $mParamsUsed = [];
 162
 163         /** @var bool|null Cached return value from self::lacksSameOriginSecurity() */
 164         private $lacksSameOriginSecurity = null;
 165
 166         /**
 167          * Constructs an instance of ApiMain that utilizes the module and format specified by $request.
 168          *
 169          * @param IContextSource|WebRequest $context If this is an instance of
 170          *    FauxRequest, errors are thrown and no printing occurs
 171          * @param bool $enableWrite Should be set to true if the api may modify data
 172          */
 173         public function __construct( $context = null, $enableWrite = false ) {
 174                 if ( $context === null ) {
 175                         $context = RequestContext::getMain();
 176                 } elseif ( $context instanceof WebRequest ) {
 177                         // BC for pre-1.19
 178                         $request = $context;
 179                         $context = RequestContext::getMain();
 180                 }
 181                 // We set a derivative context so we can change stuff later
 182                 $this->setContext( new DerivativeContext( $context ) );
 183
 184                 if ( isset( $request ) ) {
 185                         $this->getContext()->setRequest( $request );
 186                 } else {
 187                         $request = $this->getRequest();
 188                 }
 189
 190                 $this->mInternalMode = ( $request instanceof FauxRequest );
 191
 192                 // Special handling for the main module: $parent === $this
 193                 parent::__construct( $this, $this->mInternalMode ? 'main_int' : 'main' );
 194
 195                 $config = $this->getConfig();
 196
 197                 if ( !$this->mInternalMode ) {
 198                         // Log if a request with a non-whitelisted Origin header is seen
 199                         // with session cookies.
 200                         $originHeader = $request->getHeader( 'Origin' );
 201                         if ( $originHeader === false ) {
 202                                 $origins = [];
 203                         } else {
 204                                 $originHeader = trim( $originHeader );
 205                                 $origins = preg_split( '/\s+/', $originHeader );
 206                         }
 207                         $sessionCookies = array_intersect(
 208                                 array_keys( $_COOKIE ),
 209                                 MediaWiki\Session\SessionManager::singleton()->getVaryCookies()
 210                         );
 211                         if ( $origins && $sessionCookies && (
 212                                 count( $origins ) !== 1 || !self::matchOrigin(
 213                                         $origins[0],
 214                                         $config->get( 'CrossSiteAJAXdomains' ),
 215                                         $config->get( 'CrossSiteAJAXdomainExceptions' )
 216                                 )
 217                         ) ) {
 218                                 LoggerFactory::getInstance( 'cors' )->warning(
 219                                         'Non-whitelisted CORS request with session cookies', [
 220                                                 'origin' => $originHeader,
 221                                                 'cookies' => $sessionCookies,
 222                                                 'ip' => $request->getIP(),
 223                                                 'userAgent' => $this->getUserAgent(),
 224                                                 'wiki' => wfWikiID(),
 225                                         ]
 226                                 );
 227                         }
 228
 229                         // If we're in a mode that breaks the same-origin policy, strip
 230                         // user credentials for security.
 231                         if ( $this->lacksSameOriginSecurity() ) {
 232                                 global $wgUser;
 233                                 wfDebug( "API: stripping user credentials when the same-origin policy is not applied\n" );
 234                                 $wgUser = new User();
 235                                 $this->getContext()->setUser( $wgUser );
 236                         }
 237                 }
 238
 239                 $this->mResult = new ApiResult( $this->getConfig()->get( 'APIMaxResultSize' ) );
 240
 241                 // Setup uselang. This doesn't use $this->getParameter()
 242                 // because we're not ready to handle errors yet.
 243                 $uselang = $request->getVal( 'uselang', self::API_DEFAULT_USELANG );
 244                 if ( $uselang === 'user' ) {
 245                         // Assume the parent context is going to return the user language
 246                         // for uselang=user (see T85635).
 247                 } else {
 248                         if ( $uselang === 'content' ) {
 249                                 global $wgContLang;
 250                                 $uselang = $wgContLang->getCode();
 251                         }
 252                         $code = RequestContext::sanitizeLangCode( $uselang );
 253                         $this->getContext()->setLanguage( $code );
 254                         if ( !$this->mInternalMode ) {
 255                                 global $wgLang;
 256                                 $wgLang = $this->getContext()->getLanguage();
 257                                 RequestContext::getMain()->setLanguage( $wgLang );
 258                         }
 259                 }
 260
 261                 // Set up the error formatter. This doesn't use $this->getParameter()
 262                 // because we're not ready to handle errors yet.
 263                 $errorFormat = $request->getVal( 'errorformat', 'bc' );
 264                 $errorLangCode = $request->getVal( 'errorlang', 'uselang' );
 265                 $errorsUseDB = $request->getCheck( 'errorsuselocal' );
 266                 if ( in_array( $errorFormat, [ 'plaintext', 'wikitext', 'html', 'raw', 'none' ], true ) ) {
 267                         if ( $errorLangCode === 'uselang' ) {
 268                                 $errorLang = $this->getLanguage();
 269                         } elseif ( $errorLangCode === 'content' ) {
 270                                 global $wgContLang;
 271                                 $errorLang = $wgContLang;
 272                         } else {
 273                                 $errorLangCode = RequestContext::sanitizeLangCode( $errorLangCode );
 274                                 $errorLang = Language::factory( $errorLangCode );
 275                         }
 276                         $this->mErrorFormatter = new ApiErrorFormatter(
 277                                 $this->mResult, $errorLang, $errorFormat, $errorsUseDB
 278                         );
 279                 } else {
 280                         $this->mErrorFormatter = new ApiErrorFormatter_BackCompat( $this->mResult );
 281                 }
 282                 $this->mResult->setErrorFormatter( $this->getErrorFormatter() );
 283
 284                 $this->mModuleMgr = new ApiModuleManager( $this );
 285                 $this->mModuleMgr->addModules( self::$Modules, 'action' );
 286                 $this->mModuleMgr->addModules( $config->get( 'APIModules' ), 'action' );
 287                 $this->mModuleMgr->addModules( self::$Formats, 'format' );
 288                 $this->mModuleMgr->addModules( $config->get( 'APIFormatModules' ), 'format' );
 289
 290                 Hooks::run( 'ApiMain::moduleManager', [ $this->mModuleMgr ] );
 291
 292                 $this->mContinuationManager = null;
 293                 $this->mEnableWrite = $enableWrite;
 294
 295                 $this->mSquidMaxage = -1; // flag for executeActionWithErrorHandling()
 296                 $this->mCommit = false;
 297         }
 298
 299         /**
 300          * Return true if the API was started by other PHP code using FauxRequest
 301          * @return bool
 302          */
 303         public function isInternalMode() {
 304                 return $this->mInternalMode;
 305         }
 306
 307         /**
 308          * Get the ApiResult object associated with current request
 309          *
 310          * @return ApiResult
 311          */
 312         public function getResult() {
 313                 return $this->mResult;
 314         }
 315
 316         /**
 317          * Get the security flag for the current request
 318          * @return bool
 319          */
 320         public function lacksSameOriginSecurity() {
 321                 if ( $this->lacksSameOriginSecurity !== null ) {
 322                         return $this->lacksSameOriginSecurity;
 323                 }
 324
 325                 $request = $this->getRequest();
 326
 327                 // JSONP mode
 328                 if ( $request->getVal( 'callback' ) !== null ) {
 329                         $this->lacksSameOriginSecurity = true;
 330                         return true;
 331                 }
 332
 333                 // Anonymous CORS
 334                 if ( $request->getVal( 'origin' ) === '*' ) {
 335                         $this->lacksSameOriginSecurity = true;
 336                         return true;
 337                 }
 338
 339                 // Header to be used from XMLHTTPRequest when the request might
 340                 // otherwise be used for XSS.
 341                 if ( $request->getHeader( 'Treat-as-Untrusted' ) !== false ) {
 342                         $this->lacksSameOriginSecurity = true;
 343                         return true;
 344                 }
 345
 346                 // Allow extensions to override.
 347                 $this->lacksSameOriginSecurity = !Hooks::run( 'RequestHasSameOriginSecurity', [ $request ] );
 348                 return $this->lacksSameOriginSecurity;
 349         }
 350
 351         /**
 352          * Get the ApiErrorFormatter object associated with current request
 353          * @return ApiErrorFormatter
 354          */
 355         public function getErrorFormatter() {
 356                 return $this->mErrorFormatter;
 357         }
 358
 359         /**
 360          * Get the continuation manager
 361          * @return ApiContinuationManager|null
 362          */
 363         public function getContinuationManager() {
 364                 return $this->mContinuationManager;
 365         }
 366
 367         /**
 368          * Set the continuation manager
 369          * @param ApiContinuationManager|null
 370          */
 371         public function setContinuationManager( $manager ) {
 372                 if ( $manager !== null ) {
 373                         if ( !$manager instanceof ApiContinuationManager ) {
 374                                 throw new InvalidArgumentException( __METHOD__ . ': Was passed ' .
 375                                         is_object( $manager ) ? get_class( $manager ) : gettype( $manager )
 376                                 );
 377                         }
 378                         if ( $this->mContinuationManager !== null ) {
 379                                 throw new UnexpectedValueException(
 380                                         __METHOD__ . ': tried to set manager from ' . $manager->getSource() .
 381                                         ' when a manager is already set from ' . $this->mContinuationManager->getSource()
 382                                 );
 383                         }
 384                 }
 385                 $this->mContinuationManager = $manager;
 386         }
 387
 388         /**
 389          * Get the API module object. Only works after executeAction()
 390          *
 391          * @return ApiBase
 392          */
 393         public function getModule() {
 394                 return $this->mModule;
 395         }
 396
 397         /**
 398          * Get the result formatter object. Only works after setupExecuteAction()
 399          *
 400          * @return ApiFormatBase
 401          */
 402         public function getPrinter() {
 403                 return $this->mPrinter;
 404         }
 405
 406         /**
 407          * Set how long the response should be cached.
 408          *
 409          * @param int $maxage
 410          */
 411         public function setCacheMaxAge( $maxage ) {
 412                 $this->setCacheControl( [
 413                         'max-age' => $maxage,
 414                         's-maxage' => $maxage
 415                 ] );
 416         }
 417
 418         /**
 419          * Set the type of caching headers which will be sent.
 420          *
 421          * @param string $mode One of:
 422          *    - 'public':     Cache this object in public caches, if the maxage or smaxage
 423          *         parameter is set, or if setCacheMaxAge() was called. If a maximum age is
 424          *         not provided by any of these means, the object will be private.
 425          *    - 'private':    Cache this object only in private client-side caches.
 426          *    - 'anon-public-user-private': Make this object cacheable for logged-out
 427          *         users, but private for logged-in users. IMPORTANT: If this is set, it must be
 428          *         set consistently for a given URL, it cannot be set differently depending on
 429          *         things like the contents of the database, or whether the user is logged in.
 430          *
 431          *  If the wiki does not allow anonymous users to read it, the mode set here
 432          *  will be ignored, and private caching headers will always be sent. In other words,
 433          *  the "public" mode is equivalent to saying that the data sent is as public as a page
 434          *  view.
 435          *
 436          *  For user-dependent data, the private mode should generally be used. The
 437          *  anon-public-user-private mode should only be used where there is a particularly
 438          *  good performance reason for caching the anonymous response, but where the
 439          *  response to logged-in users may differ, or may contain private data.
 440          *
 441          *  If this function is never called, then the default will be the private mode.
 442          */
 443         public function setCacheMode( $mode ) {
 444                 if ( !in_array( $mode, [ 'private', 'public', 'anon-public-user-private' ] ) ) {
 445                         wfDebug( __METHOD__ . ": unrecognised cache mode \"$mode\"\n" );
 446
 447                         // Ignore for forwards-compatibility
 448                         return;
 449                 }
 450
 451                 if ( !User::isEveryoneAllowed( 'read' ) ) {
 452                         // Private wiki, only private headers
 453                         if ( $mode !== 'private' ) {
 454                                 wfDebug( __METHOD__ . ": ignoring request for $mode cache mode, private wiki\n" );
 455
 456                                 return;
 457                         }
 458                 }
 459
 460                 if ( $mode === 'public' && $this->getParameter( 'uselang' ) === 'user' ) {
 461                         // User language is used for i18n, so we don't want to publicly
 462                         // cache. Anons are ok, because if they have non-default language
 463                         // then there's an appropriate Vary header set by whatever set
 464                         // their non-default language.
 465                         wfDebug( __METHOD__ . ": downgrading cache mode 'public' to " .
 466                                 "'anon-public-user-private' due to uselang=user\n" );
 467                         $mode = 'anon-public-user-private';
 468                 }
 469
 470                 wfDebug( __METHOD__ . ": setting cache mode $mode\n" );
 471                 $this->mCacheMode = $mode;
 472         }
 473
 474         /**
 475          * Set directives (key/value pairs) for the Cache-Control header.
 476          * Boolean values will be formatted as such, by including or omitting
 477          * without an equals sign.
 478          *
 479          * Cache control values set here will only be used if the cache mode is not
 480          * private, see setCacheMode().
 481          *
 482          * @param array $directives
 483          */
 484         public function setCacheControl( $directives ) {
 485                 $this->mCacheControl = $directives + $this->mCacheControl;
 486         }
 487
 488         /**
 489          * Create an instance of an output formatter by its name
 490          *
 491          * @param string $format
 492          *
 493          * @return ApiFormatBase
 494          */
 495         public function createPrinterByName( $format ) {
 496                 $printer = $this->mModuleMgr->getModule( $format, 'format' );
 497                 if ( $printer === null ) {
 498                         $this->dieWithError(
 499                                 [ 'apierror-unknownformat', wfEscapeWikiText( $format ) ], 'unknown_format'
 500                         );
 501                 }
 502
 503                 return $printer;
 504         }
 505
 506         /**
 507          * Execute api request. Any errors will be handled if the API was called by the remote client.
 508          */
 509         public function execute() {
 510                 if ( $this->mInternalMode ) {
 511                         $this->executeAction();
 512                 } else {
 513                         $this->executeActionWithErrorHandling();
 514                 }
 515         }
 516
 517         /**
 518          * Execute an action, and in case of an error, erase whatever partial results
 519          * have been accumulated, and replace it with an error message and a help screen.
 520          */
 521         protected function executeActionWithErrorHandling() {
 522                 // Verify the CORS header before executing the action
 523                 if ( !$this->handleCORS() ) {
 524                         // handleCORS() has sent a 403, abort
 525                         return;
 526                 }
 527
 528                 // Exit here if the request method was OPTIONS
 529                 // (assume there will be a followup GET or POST)
 530                 if ( $this->getRequest()->getMethod() === 'OPTIONS' ) {
 531                         return;
 532                 }
 533
 534                 // In case an error occurs during data output,
 535                 // clear the output buffer and print just the error information
 536                 $obLevel = ob_get_level();
 537                 ob_start();
 538
 539                 $t = microtime( true );
 540                 $isError = false;
 541                 try {
 542                         $this->executeAction();
 543                         $runTime = microtime( true ) - $t;
 544                         $this->logRequest( $runTime );
 545                         if ( $this->mModule->isWriteMode() && $this->getRequest()->wasPosted() ) {
 546                                 $this->getStats()->timing(
 547                                         'api.' . $this->mModule->getModuleName() . '.executeTiming', 1000 * $runTime
 548                                 );
 549                         }
 550                 } catch ( Exception $e ) {
 551                         $this->handleException( $e );
 552                         $this->logRequest( microtime( true ) - $t, $e );
 553                         $isError = true;
 554                 }
 555
 556                 // Commit DBs and send any related cookies and headers
 557                 MediaWiki::preOutputCommit( $this->getContext() );
 558
 559                 // Send cache headers after any code which might generate an error, to
 560                 // avoid sending public cache headers for errors.
 561                 $this->sendCacheHeaders( $isError );
 562
 563                 // Executing the action might have already messed with the output
 564                 // buffers.
 565                 while ( ob_get_level() > $obLevel ) {
 566                         ob_end_flush();
 567                 }
 568         }
 569
 570         /**
 571          * Handle an exception as an API response
 572          *
 573          * @since 1.23
 574          * @param Exception $e
 575          */
 576         protected function handleException( Exception $e ) {
 577                 // Bug 63145: Rollback any open database transactions
 578                 if ( !( $e instanceof ApiUsageException || $e instanceof UsageException ) ) {
 579                         // UsageExceptions are intentional, so don't rollback if that's the case
 580                         try {
 581                                 MWExceptionHandler::rollbackMasterChangesAndLog( $e );
 582                         } catch ( DBError $e2 ) {
 583                                 // Rollback threw an exception too. Log it, but don't interrupt
 584                                 // our regularly scheduled exception handling.
 585                                 MWExceptionHandler::logException( $e2 );
 586                         }
 587                 }
 588
 589                 // Allow extra cleanup and logging
 590                 Hooks::run( 'ApiMain::onException', [ $this, $e ] );
 591
 592                 // Log it
 593                 if ( !( $e instanceof ApiUsageException || $e instanceof UsageException ) ) {
 594                         MWExceptionHandler::logException( $e );
 595                 }
 596
 597                 // Handle any kind of exception by outputting properly formatted error message.
 598                 // If this fails, an unhandled exception should be thrown so that global error
 599                 // handler will process and log it.
 600
 601                 $errCodes = $this->substituteResultWithError( $e );
 602
 603                 // Error results should not be cached
 604                 $this->setCacheMode( 'private' );
 605
 606                 $response = $this->getRequest()->response();
 607                 $headerStr = 'MediaWiki-API-Error: ' . join( ', ', $errCodes );
 608                 $response->header( $headerStr );
 609
 610                 // Reset and print just the error message
 611                 ob_clean();
 612
 613                 // Printer may not be initialized if the extractRequestParams() fails for the main module
 614                 $this->createErrorPrinter();
 615
 616                 $failed = false;
 617                 try {
 618                         $this->printResult( $e->getCode() );
 619                 } catch ( ApiUsageException $ex ) {
 620                         // The error printer itself is failing. Try suppressing its request
 621                         // parameters and redo.
 622                         $failed = true;
 623                         $this->addWarning( 'apiwarn-errorprinterfailed' );
 624                         foreach ( $ex->getStatusValue()->getErrors() as $error ) {
 625                                 try {
 626                                         $this->mPrinter->addWarning( $error );
 627                                 } catch ( Exception $ex2 ) {
 628                                         // WTF?
 629                                         $this->addWarning( $error );
 630                                 }
 631                         }
 632                 } catch ( UsageException $ex ) {
 633                         // The error printer itself is failing. Try suppressing its request
 634                         // parameters and redo.
 635                         $failed = true;
 636                         $this->addWarning(
 637                                 [ 'apiwarn-errorprinterfailed-ex', $ex->getMessage() ], 'errorprinterfailed'
 638                         );
 639                 }
 640                 if ( $failed ) {
 641                         $this->mPrinter = null;
 642                         $this->createErrorPrinter();
 643                         $this->mPrinter->forceDefaultParams();
 644                         if ( $e->getCode() ) {
 645                                 $response->statusHeader( 200 ); // Reset in case the fallback doesn't want a non-200
 646                         }
 647                         $this->printResult( $e->getCode() );
 648                 }
 649         }
 650
 651         /**
 652          * Handle an exception from the ApiBeforeMain hook.
 653          *
 654          * This tries to print the exception as an API response, to be more
 655          * friendly to clients. If it fails, it will rethrow the exception.
 656          *
 657          * @since 1.23
 658          * @param Exception $e
 659          * @throws Exception
 660          */
 661         public static function handleApiBeforeMainException( Exception $e ) {
 662                 ob_start();
 663
 664                 try {
 665                         $main = new self( RequestContext::getMain(), false );
 666                         $main->handleException( $e );
 667                         $main->logRequest( 0, $e );
 668                 } catch ( Exception $e2 ) {
 669                         // Nope, even that didn't work. Punt.
 670                         throw $e;
 671                 }
 672
 673                 // Reset cache headers
 674                 $main->sendCacheHeaders( true );
 675
 676                 ob_end_flush();
 677         }
 678
 679         /**
 680          * Check the &origin= query parameter against the Origin: HTTP header and respond appropriately.
 681          *
 682          * If no origin parameter is present, nothing happens.
 683          * If an origin parameter is present but doesn't match the Origin header, a 403 status code
 684          * is set and false is returned.
 685          * If the parameter and the header do match, the header is checked against $wgCrossSiteAJAXdomains
 686          * and $wgCrossSiteAJAXdomainExceptions, and if the origin qualifies, the appropriate CORS
 687          * headers are set.
 688          * https://www.w3.org/TR/cors/#resource-requests
 689          * https://www.w3.org/TR/cors/#resource-preflight-requests
 690          *
 691          * @return bool False if the caller should abort (403 case), true otherwise (all other cases)
 692          */
 693         protected function handleCORS() {
 694                 $originParam = $this->getParameter( 'origin' ); // defaults to null
 695                 if ( $originParam === null ) {
 696                         // No origin parameter, nothing to do
 697                         return true;
 698                 }
 699
 700                 $request = $this->getRequest();
 701                 $response = $request->response();
 702
 703                 $matchOrigin = false;
 704                 $allowTiming = false;
 705                 $varyOrigin = true;
 706
 707                 if ( $originParam === '*' ) {
 708                         // Request for anonymous CORS
 709                         $matchOrigin = true;
 710                         $allowOrigin = '*';
 711                         $allowCredentials = 'false';
 712                         $varyOrigin = false; // No need to vary
 713                 } else {
 714                         // Non-anonymous CORS, check we allow the domain
 715
 716                         // Origin: header is a space-separated list of origins, check all of them
 717                         $originHeader = $request->getHeader( 'Origin' );
 718                         if ( $originHeader === false ) {
 719                                 $origins = [];
 720                         } else {
 721                                 $originHeader = trim( $originHeader );
 722                                 $origins = preg_split( '/\s+/', $originHeader );
 723                         }
 724
 725                         if ( !in_array( $originParam, $origins ) ) {
 726                                 // origin parameter set but incorrect
 727                                 // Send a 403 response
 728                                 $response->statusHeader( 403 );
 729                                 $response->header( 'Cache-Control: no-cache' );
 730                                 echo "'origin' parameter does not match Origin header\n";
 731
 732                                 return false;
 733                         }
 734
 735                         $config = $this->getConfig();
 736                         $matchOrigin = count( $origins ) === 1 && self::matchOrigin(
 737                                 $originParam,
 738                                 $config->get( 'CrossSiteAJAXdomains' ),
 739                                 $config->get( 'CrossSiteAJAXdomainExceptions' )
 740                         );
 741
 742                         $allowOrigin = $originHeader;
 743                         $allowCredentials = 'true';
 744                         $allowTiming = $originHeader;
 745                 }
 746
 747                 if ( $matchOrigin ) {
 748                         $requestedMethod = $request->getHeader( 'Access-Control-Request-Method' );
 749                         $preflight = $request->getMethod() === 'OPTIONS' && $requestedMethod !== false;
 750                         if ( $preflight ) {
 751                                 // This is a CORS preflight request
 752                                 if ( $requestedMethod !== 'POST' && $requestedMethod !== 'GET' ) {
 753                                         // If method is not a case-sensitive match, do not set any additional headers and terminate.
 754                                         return true;
 755                                 }
 756                                 // We allow the actual request to send the following headers
 757                                 $requestedHeaders = $request->getHeader( 'Access-Control-Request-Headers' );
 758                                 if ( $requestedHeaders !== false ) {
 759                                         if ( !self::matchRequestedHeaders( $requestedHeaders ) ) {
 760                                                 return true;
 761                                         }
 762                                         $response->header( 'Access-Control-Allow-Headers: ' . $requestedHeaders );
 763                                 }
 764
 765                                 // We only allow the actual request to be GET or POST
 766                                 $response->header( 'Access-Control-Allow-Methods: POST, GET' );
 767                         }
 768
 769                         $response->header( "Access-Control-Allow-Origin: $allowOrigin" );
 770                         $response->header( "Access-Control-Allow-Credentials: $allowCredentials" );
 771                         // https://www.w3.org/TR/resource-timing/#timing-allow-origin
 772                         if ( $allowTiming !== false ) {
 773                                 $response->header( "Timing-Allow-Origin: $allowTiming" );
 774                         }
 775
 776                         if ( !$preflight ) {
 777                                 $response->header(
 778                                         'Access-Control-Expose-Headers: MediaWiki-API-Error, Retry-After, X-Database-Lag'
 779                                 );
 780                         }
 781                 }
 782
 783                 if ( $varyOrigin ) {
 784                         $this->getOutput()->addVaryHeader( 'Origin' );
 785                 }
 786
 787                 return true;
 788         }
 789
 790         /**
 791          * Attempt to match an Origin header against a set of rules and a set of exceptions
 792          * @param string $value Origin header
 793          * @param array $rules Set of wildcard rules
 794          * @param array $exceptions Set of wildcard rules
 795          * @return bool True if $value matches a rule in $rules and doesn't match
 796          *    any rules in $exceptions, false otherwise
 797          */
 798         protected static function matchOrigin( $value, $rules, $exceptions ) {
 799                 foreach ( $rules as $rule ) {
 800                         if ( preg_match( self::wildcardToRegex( $rule ), $value ) ) {
 801                                 // Rule matches, check exceptions
 802                                 foreach ( $exceptions as $exc ) {
 803                                         if ( preg_match( self::wildcardToRegex( $exc ), $value ) ) {
 804                                                 return false;
 805                                         }
 806                                 }
 807
 808                                 return true;
 809                         }
 810                 }
 811
 812                 return false;
 813         }
 814
 815         /**
 816          * Attempt to validate the value of Access-Control-Request-Headers against a list
 817          * of headers that we allow the follow up request to send.
 818          *
 819          * @param string $requestedHeaders Comma seperated list of HTTP headers
 820          * @return bool True if all requested headers are in the list of allowed headers
 821          */
 822         protected static function matchRequestedHeaders( $requestedHeaders ) {
 823                 if ( trim( $requestedHeaders ) === '' ) {
 824                         return true;
 825                 }
 826                 $requestedHeaders = explode( ',', $requestedHeaders );
 827                 $allowedAuthorHeaders = array_flip( [
 828                         /* simple headers (see spec) */
 829                         'accept',
 830                         'accept-language',
 831                         'content-language',
 832                         'content-type',
 833                         /* non-authorable headers in XHR, which are however requested by some UAs */
 834                         'accept-encoding',
 835                         'dnt',
 836                         'origin',
 837                         /* MediaWiki whitelist */
 838                         'api-user-agent',
 839                 ] );
 840                 foreach ( $requestedHeaders as $rHeader ) {
 841                         $rHeader = strtolower( trim( $rHeader ) );
 842                         if ( !isset( $allowedAuthorHeaders[$rHeader] ) ) {
 843                                 wfDebugLog( 'api', 'CORS preflight failed on requested header: ' . $rHeader );
 844                                 return false;
 845                         }
 846                 }
 847                 return true;
 848         }
 849
 850         /**
 851          * Helper function to convert wildcard string into a regex
 852          * '*' => '.*?'
 853          * '?' => '.'
 854          *
 855          * @param string $wildcard String with wildcards
 856          * @return string Regular expression
 857          */
 858         protected static function wildcardToRegex( $wildcard ) {
 859                 $wildcard = preg_quote( $wildcard, '/' );
 860                 $wildcard = str_replace(
 861                         [ '\*', '\?' ],
 862                         [ '.*?', '.' ],
 863                         $wildcard
 864                 );
 865
 866                 return "/^https?:\/\/$wildcard$/";
 867         }
 868
 869         /**
 870          * Send caching headers
 871          * @param bool $isError Whether an error response is being output
 872          * @since 1.26 added $isError parameter
 873          */
 874         protected function sendCacheHeaders( $isError ) {
 875                 $response = $this->getRequest()->response();
 876                 $out = $this->getOutput();
 877
 878                 $out->addVaryHeader( 'Treat-as-Untrusted' );
 879
 880                 $config = $this->getConfig();
 881
 882                 if ( $config->get( 'VaryOnXFP' ) ) {
 883                         $out->addVaryHeader( 'X-Forwarded-Proto' );
 884                 }
 885
 886                 if ( !$isError && $this->mModule &&
 887                         ( $this->getRequest()->getMethod() === 'GET' || $this->getRequest()->getMethod() === 'HEAD' )
 888                 ) {
 889                         $etag = $this->mModule->getConditionalRequestData( 'etag' );
 890                         if ( $etag !== null ) {
 891                                 $response->header( "ETag: $etag" );
 892                         }
 893                         $lastMod = $this->mModule->getConditionalRequestData( 'last-modified' );
 894                         if ( $lastMod !== null ) {
 895                                 $response->header( 'Last-Modified: ' . wfTimestamp( TS_RFC2822, $lastMod ) );
 896                         }
 897                 }
 898
 899                 // The logic should be:
 900                 // $this->mCacheControl['max-age'] is set?
 901                 //    Use it, the module knows better than our guess.
 902                 // !$this->mModule || $this->mModule->isWriteMode(), and mCacheMode is private?
 903                 //    Use 0 because we can guess caching is probably the wrong thing to do.
 904                 // Use $this->getParameter( 'maxage' ), which already defaults to 0.
 905                 $maxage = 0;
 906                 if ( isset( $this->mCacheControl['max-age'] ) ) {
 907                         $maxage = $this->mCacheControl['max-age'];
 908                 } elseif ( ( $this->mModule && !$this->mModule->isWriteMode() ) ||
 909                         $this->mCacheMode !== 'private'
 910                 ) {
 911                         $maxage = $this->getParameter( 'maxage' );
 912                 }
 913                 $privateCache = 'private, must-revalidate, max-age=' . $maxage;
 914
 915                 if ( $this->mCacheMode == 'private' ) {
 916                         $response->header( "Cache-Control: $privateCache" );
 917                         return;
 918                 }
 919
 920                 $useKeyHeader = $config->get( 'UseKeyHeader' );
 921                 if ( $this->mCacheMode == 'anon-public-user-private' ) {
 922                         $out->addVaryHeader( 'Cookie' );
 923                         $response->header( $out->getVaryHeader() );
 924                         if ( $useKeyHeader ) {
 925                                 $response->header( $out->getKeyHeader() );
 926                                 if ( $out->haveCacheVaryCookies() ) {
 927                                         // Logged in, mark this request private
 928                                         $response->header( "Cache-Control: $privateCache" );
 929                                         return;
 930                                 }
 931                                 // Logged out, send normal public headers below
 932                         } elseif ( MediaWiki\Session\SessionManager::getGlobalSession()->isPersistent() ) {
 933                                 // Logged in or otherwise has session (e.g. anonymous users who have edited)
 934                                 // Mark request private
 935                                 $response->header( "Cache-Control: $privateCache" );
 936
 937                                 return;
 938                         } // else no Key and anonymous, send public headers below
 939                 }
 940
 941                 // Send public headers
 942                 $response->header( $out->getVaryHeader() );
 943                 if ( $useKeyHeader ) {
 944                         $response->header( $out->getKeyHeader() );
 945                 }
 946
 947                 // If nobody called setCacheMaxAge(), use the (s)maxage parameters
 948                 if ( !isset( $this->mCacheControl['s-maxage'] ) ) {
 949                         $this->mCacheControl['s-maxage'] = $this->getParameter( 'smaxage' );
 950                 }
 951                 if ( !isset( $this->mCacheControl['max-age'] ) ) {
 952                         $this->mCacheControl['max-age'] = $this->getParameter( 'maxage' );
 953                 }
 954
 955                 if ( !$this->mCacheControl['s-maxage'] && !$this->mCacheControl['max-age'] ) {
 956                         // Public cache not requested
 957                         // Sending a Vary header in this case is harmless, and protects us
 958                         // against conditional calls of setCacheMaxAge().
 959                         $response->header( "Cache-Control: $privateCache" );
 960
 961                         return;
 962                 }
 963
 964                 $this->mCacheControl['public'] = true;
 965
 966                 // Send an Expires header
 967                 $maxAge = min( $this->mCacheControl['s-maxage'], $this->mCacheControl['max-age'] );
 968                 $expiryUnixTime = ( $maxAge == 0 ? 1 : time() + $maxAge );
 969                 $response->header( 'Expires: ' . wfTimestamp( TS_RFC2822, $expiryUnixTime ) );
 970
 971                 // Construct the Cache-Control header
 972                 $ccHeader = '';
 973                 $separator = '';
 974                 foreach ( $this->mCacheControl as $name => $value ) {
 975                         if ( is_bool( $value ) ) {
 976                                 if ( $value ) {
 977                                         $ccHeader .= $separator . $name;
 978                                         $separator = ', ';
 979                                 }
 980                         } else {
 981                                 $ccHeader .= $separator . "$name=$value";
 982                                 $separator = ', ';
 983                         }
 984                 }
 985
 986                 $response->header( "Cache-Control: $ccHeader" );
 987         }
 988
 989         /**
 990          * Create the printer for error output
 991          */
 992         private function createErrorPrinter() {
 993                 if ( !isset( $this->mPrinter ) ) {
 994                         $value = $this->getRequest()->getVal( 'format', self::API_DEFAULT_FORMAT );
 995                         if ( !$this->mModuleMgr->isDefined( $value, 'format' ) ) {
 996                                 $value = self::API_DEFAULT_FORMAT;
 997                         }
 998                         $this->mPrinter = $this->createPrinterByName( $value );
 999                 }
1000
1001                 // Printer may not be able to handle errors. This is particularly
1002                 // likely if the module returns something for getCustomPrinter().
1003                 if ( !$this->mPrinter->canPrintErrors() ) {
1004                         $this->mPrinter = $this->createPrinterByName( self::API_DEFAULT_FORMAT );
1005                 }
1006         }
1007
1008         /**
1009          * Create an error message for the given exception.
1010          *
1011          * If an ApiUsageException, errors/warnings will be extracted from the
1012          * embedded StatusValue.
1013          *
1014          * If a base UsageException, the getMessageArray() method will be used to
1015          * extract the code and English message for a single error (no warnings).
1016          *
1017          * Any other exception will be returned with a generic code and wrapper
1018          * text around the exception's (presumably English) message as a single
1019          * error (no warnings).
1020          *
1021          * @param Exception $e
1022          * @param string $type 'error' or 'warning'
1023          * @return ApiMessage[]
1024          * @since 1.27
1025          */
1026         protected function errorMessagesFromException( $e, $type = 'error' ) {
1027                 $messages = [];
1028                 if ( $e instanceof ApiUsageException ) {
1029                         foreach ( $e->getStatusValue()->getErrorsByType( $type ) as $error ) {
1030                                 $messages[] = ApiMessage::create( $error );
1031                         }
1032                 } elseif ( $type !== 'error' ) {
1033                         // None of the rest have any messages for non-error types
1034                 } elseif ( $e instanceof UsageException ) {
1035                         // User entered incorrect parameters - generate error response
1036                         $data = $e->getMessageArray();
1037                         $code = $data['code'];
1038                         $info = $data['info'];
1039                         unset( $data['code'], $data['info'] );
1040                         $messages[] = new ApiRawMessage( [ '$1', $info ], $code, $data );
1041                 } else {
1042                         // Something is seriously wrong
1043                         $config = $this->getConfig();
1044                         $code = 'internal_api_error_' . get_class( $e );
1045                         if ( ( $e instanceof DBQueryError ) && !$config->get( 'ShowSQLErrors' ) ) {
1046                                 $params = [ 'apierror-databaseerror', WebRequest::getRequestId() ];
1047                         } else {
1048                                 $params = [
1049                                         'apierror-exceptioncaught',
1050                                         WebRequest::getRequestId(),
1051                                         $e instanceof ILocalizedException
1052                                                 ? $e->getMessageObject()
1053                                                 : wfEscapeWikiText( $e->getMessage() )
1054                                 ];
1055                         }
1056                         $messages[] = ApiMessage::create( $params, $code );
1057                 }
1058                 return $messages;
1059         }
1060
1061         /**
1062          * Replace the result data with the information about an exception.
1063          * @param Exception $e
1064          * @return string[] Error codes
1065          */
1066         protected function substituteResultWithError( $e ) {
1067                 $result = $this->getResult();
1068                 $formatter = $this->getErrorFormatter();
1069                 $config = $this->getConfig();
1070                 $errorCodes = [];
1071
1072                 // Remember existing warnings and errors across the reset
1073                 $errors = $result->getResultData( [ 'errors' ] );
1074                 $warnings = $result->getResultData( [ 'warnings' ] );
1075                 $result->reset();
1076                 if ( $warnings !== null ) {
1077                         $result->addValue( null, 'warnings', $warnings, ApiResult::NO_SIZE_CHECK );
1078                 }
1079                 if ( $errors !== null ) {
1080                         $result->addValue( null, 'errors', $errors, ApiResult::NO_SIZE_CHECK );
1081
1082                         // Collect the copied error codes for the return value
1083                         foreach ( $errors as $error ) {
1084                                 if ( isset( $error['code'] ) ) {
1085                                         $errorCodes[$error['code']] = true;
1086                                 }
1087                         }
1088                 }
1089
1090                 // Add errors from the exception
1091                 $modulePath = $e instanceof ApiUsageException ? $e->getModulePath() : null;
1092                 foreach ( $this->errorMessagesFromException( $e, 'error' ) as $msg ) {
1093                         $errorCodes[$msg->getApiCode()] = true;
1094                         $formatter->addError( $modulePath, $msg );
1095                 }
1096                 foreach ( $this->errorMessagesFromException( $e, 'warning' ) as $msg ) {
1097                         $formatter->addWarning( $modulePath, $msg );
1098                 }
1099
1100                 // Add additional data. Path depends on whether we're in BC mode or not.
1101                 // Data depends on the type of exception.
1102                 if ( $formatter instanceof ApiErrorFormatter_BackCompat ) {
1103                         $path = [ 'error' ];
1104                 } else {
1105                         $path = null;
1106                 }
1107                 if ( $e instanceof ApiUsageException || $e instanceof UsageException ) {
1108                         $link = wfExpandUrl( wfScript( 'api' ) );
1109                         $result->addContentValue(
1110                                 $path,
1111                                 'docref',
1112                                 trim(
1113                                         $this->msg( 'api-usage-docref', $link )->inLanguage( $formatter->getLanguage() )->text()
1114                                         . ' '
1115                                         . $this->msg( 'api-usage-mailinglist-ref' )->inLanguage( $formatter->getLanguage() )->text()
1116                                 )
1117                         );
1118                 } else {
1119                         if ( $config->get( 'ShowExceptionDetails' ) ) {
1120                                 $result->addContentValue(
1121                                         $path,
1122                                         'trace',
1123                                         $this->msg( 'api-exception-trace',
1124                                                 get_class( $e ),
1125                                                 $e->getFile(),
1126                                                 $e->getLine(),
1127                                                 MWExceptionHandler::getRedactedTraceAsString( $e )
1128                                         )->inLanguage( $formatter->getLanguage() )->text()
1129                                 );
1130                         }
1131                 }
1132
1133                 // Add the id and such
1134                 $this->addRequestedFields( [ 'servedby' ] );
1135
1136                 return array_keys( $errorCodes );
1137         }
1138
1139         /**
1140          * Add requested fields to the result
1141          * @param string[] $force Which fields to force even if not requested. Accepted values are:
1142          *  - servedby
1143          */
1144         protected function addRequestedFields( $force = [] ) {
1145                 $result = $this->getResult();
1146
1147                 $requestid = $this->getParameter( 'requestid' );
1148                 if ( $requestid !== null ) {
1149                         $result->addValue( null, 'requestid', $requestid, ApiResult::NO_SIZE_CHECK );
1150                 }
1151
1152                 if ( $this->getConfig()->get( 'ShowHostnames' ) && (
1153                         in_array( 'servedby', $force, true ) || $this->getParameter( 'servedby' )
1154                 ) ) {
1155                         $result->addValue( null, 'servedby', wfHostname(), ApiResult::NO_SIZE_CHECK );
1156                 }
1157
1158                 if ( $this->getParameter( 'curtimestamp' ) ) {
1159                         $result->addValue( null, 'curtimestamp', wfTimestamp( TS_ISO_8601, time() ),
1160                                 ApiResult::NO_SIZE_CHECK );
1161                 }
1162
1163                 if ( $this->getParameter( 'responselanginfo' ) ) {
1164                         $result->addValue( null, 'uselang', $this->getLanguage()->getCode(),
1165                                 ApiResult::NO_SIZE_CHECK );
1166                         $result->addValue( null, 'errorlang', $this->getErrorFormatter()->getLanguage()->getCode(),
1167                                 ApiResult::NO_SIZE_CHECK );
1168                 }
1169         }
1170
1171         /**
1172          * Set up for the execution.
1173          * @return array
1174          */
1175         protected function setupExecuteAction() {
1176                 $this->addRequestedFields();
1177
1178                 $params = $this->extractRequestParams();
1179                 $this->mAction = $params['action'];
1180
1181                 return $params;
1182         }
1183
1184         /**
1185          * Set up the module for response
1186          * @return ApiBase The module that will handle this action
1187          * @throws MWException
1188          * @throws ApiUsageException
1189          */
1190         protected function setupModule() {
1191                 // Instantiate the module requested by the user
1192                 $module = $this->mModuleMgr->getModule( $this->mAction, 'action' );
1193                 if ( $module === null ) {
1194                         $this->dieWithError(
1195                                 [ 'apierror-unknownaction', wfEscapeWikiText( $this->mAction ) ], 'unknown_action'
1196                         );
1197                 }
1198                 $moduleParams = $module->extractRequestParams();
1199
1200                 // Check token, if necessary
1201                 if ( $module->needsToken() === true ) {
1202                         throw new MWException(
1203                                 "Module '{$module->getModuleName()}' must be updated for the new token handling. " .
1204                                 'See documentation for ApiBase::needsToken for details.'
1205                         );
1206                 }
1207                 if ( $module->needsToken() ) {
1208                         if ( !$module->mustBePosted() ) {
1209                                 throw new MWException(
1210                                         "Module '{$module->getModuleName()}' must require POST to use tokens."
1211                                 );
1212                         }
1213
1214                         if ( !isset( $moduleParams['token'] ) ) {
1215                                 $module->dieWithError( [ 'apierror-missingparam', 'token' ] );
1216                         }
1217
1218                         $module->requirePostedParameters( [ 'token' ] );
1219
1220                         if ( !$module->validateToken( $moduleParams['token'], $moduleParams ) ) {
1221                                 $module->dieWithError( 'apierror-badtoken' );
1222                         }
1223                 }
1224
1225                 return $module;
1226         }
1227
1228         /**
1229          * Check the max lag if necessary
1230          * @param ApiBase $module Api module being used
1231          * @param array $params Array an array containing the request parameters.
1232          * @return bool True on success, false should exit immediately
1233          */
1234         protected function checkMaxLag( $module, $params ) {
1235                 if ( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
1236                         $maxLag = $params['maxlag'];
1237                         list( $host, $lag ) = wfGetLB()->getMaxLag();
1238                         if ( $lag > $maxLag ) {
1239                                 $response = $this->getRequest()->response();
1240
1241                                 $response->header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
1242                                 $response->header( 'X-Database-Lag: ' . intval( $lag ) );
1243
1244                                 if ( $this->getConfig()->get( 'ShowHostnames' ) ) {
1245                                         $this->dieWithError( [ 'apierror-maxlag', $lag, $host ] );
1246                                 }
1247
1248                                 $this->dieWithError( [ 'apierror-maxlag-generic', $lag ], 'maxlag' );
1249                         }
1250                 }
1251
1252                 return true;
1253         }
1254
1255         /**
1256          * Check selected RFC 7232 precondition headers
1257          *
1258          * RFC 7232 envisions a particular model where you send your request to "a
1259          * resource", and for write requests that you can read "the resource" by
1260          * changing the method to GET. When the API receives a GET request, it
1261          * works out even though "the resource" from RFC 7232's perspective might
1262          * be many resources from MediaWiki's perspective. But it totally fails for
1263          * a POST, since what HTTP sees as "the resource" is probably just
1264          * "/api.php" with all the interesting bits in the body.
1265          *
1266          * Therefore, we only support RFC 7232 precondition headers for GET (and
1267          * HEAD). That means we don't need to bother with If-Match and
1268          * If-Unmodified-Since since they only apply to modification requests.
1269          *
1270          * And since we don't support Range, If-Range is ignored too.
1271          *
1272          * @since 1.26
1273          * @param ApiBase $module Api module being used
1274          * @return bool True on success, false should exit immediately
1275          */
1276         protected function checkConditionalRequestHeaders( $module ) {
1277                 if ( $this->mInternalMode ) {
1278                         // No headers to check in internal mode
1279                         return true;
1280                 }
1281
1282                 if ( $this->getRequest()->getMethod() !== 'GET' && $this->getRequest()->getMethod() !== 'HEAD' ) {
1283                         // Don't check POSTs
1284                         return true;
1285                 }
1286
1287                 $return304 = false;
1288
1289                 $ifNoneMatch = array_diff(
1290                         $this->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST ) ?: [],
1291                         [ '' ]
1292                 );
1293                 if ( $ifNoneMatch ) {
1294                         if ( $ifNoneMatch === [ '*' ] ) {
1295                                 // API responses always "exist"
1296                                 $etag = '*';
1297                         } else {
1298                                 $etag = $module->getConditionalRequestData( 'etag' );
1299                         }
1300                 }
1301                 if ( $ifNoneMatch && $etag !== null ) {
1302                         $test = substr( $etag, 0, 2 ) === 'W/' ? substr( $etag, 2 ) : $etag;
1303                         $match = array_map( function ( $s ) {
1304                                 return substr( $s, 0, 2 ) === 'W/' ? substr( $s, 2 ) : $s;
1305                         }, $ifNoneMatch );
1306                         $return304 = in_array( $test, $match, true );
1307                 } else {
1308                         $value = trim( $this->getRequest()->getHeader( 'If-Modified-Since' ) );
1309
1310                         // Some old browsers sends sizes after the date, like this:
1311                         //  Wed, 20 Aug 2003 06:51:19 GMT; length=5202
1312                         // Ignore that.
1313                         $i = strpos( $value, ';' );
1314                         if ( $i !== false ) {
1315                                 $value = trim( substr( $value, 0, $i ) );
1316                         }
1317
1318                         if ( $value !== '' ) {
1319                                 try {
1320                                         $ts = new MWTimestamp( $value );
1321                                         if (
1322                                                 // RFC 7231 IMF-fixdate
1323                                                 $ts->getTimestamp( TS_RFC2822 ) === $value ||
1324                                                 // RFC 850
1325                                                 $ts->format( 'l, d-M-y H:i:s' ) . ' GMT' === $value ||
1326                                                 // asctime (with and without space-padded day)
1327                                                 $ts->format( 'D M j H:i:s Y' ) === $value ||
1328                                                 $ts->format( 'D M  j H:i:s Y' ) === $value
1329                                         ) {
1330                                                 $lastMod = $module->getConditionalRequestData( 'last-modified' );
1331                                                 if ( $lastMod !== null ) {
1332                                                         // Mix in some MediaWiki modification times
1333                                                         $modifiedTimes = [
1334                                                                 'page' => $lastMod,
1335                                                                 'user' => $this->getUser()->getTouched(),
1336                                                                 'epoch' => $this->getConfig()->get( 'CacheEpoch' ),
1337                                                         ];
1338                                                         if ( $this->getConfig()->get( 'UseSquid' ) ) {
1339                                                                 // T46570: the core page itself may not change, but resources might
1340                                                                 $modifiedTimes['sepoch'] = wfTimestamp(
1341                                                                         TS_MW, time() - $this->getConfig()->get( 'SquidMaxage' )
1342                                                                 );
1343                                                         }
1344                                                         Hooks::run( 'OutputPageCheckLastModified', [ &$modifiedTimes, $this->getOutput() ] );
1345                                                         $lastMod = max( $modifiedTimes );
1346                                                         $return304 = wfTimestamp( TS_MW, $lastMod ) <= $ts->getTimestamp( TS_MW );
1347                                                 }
1348                                         }
1349                                 } catch ( TimestampException $e ) {
1350                                         // Invalid timestamp, ignore it
1351                                 }
1352                         }
1353                 }
1354
1355                 if ( $return304 ) {
1356                         $this->getRequest()->response()->statusHeader( 304 );
1357
1358                         // Avoid outputting the compressed representation of a zero-length body
1359                         MediaWiki\suppressWarnings();
1360                         ini_set( 'zlib.output_compression', 0 );
1361                         MediaWiki\restoreWarnings();
1362                         wfClearOutputBuffers();
1363
1364                         return false;
1365                 }
1366
1367                 return true;
1368         }
1369
1370         /**
1371          * Check for sufficient permissions to execute
1372          * @param ApiBase $module An Api module
1373          */
1374         protected function checkExecutePermissions( $module ) {
1375                 $user = $this->getUser();
1376                 if ( $module->isReadMode() && !User::isEveryoneAllowed( 'read' ) &&
1377                         !$user->isAllowed( 'read' )
1378                 ) {
1379                         $this->dieWithError( 'apierror-readapidenied' );
1380                 }
1381
1382                 if ( $module->isWriteMode() ) {
1383                         if ( !$this->mEnableWrite ) {
1384                                 $this->dieWithError( 'apierror-noapiwrite' );
1385                         } elseif ( !$user->isAllowed( 'writeapi' ) ) {
1386                                 $this->dieWithError( 'apierror-writeapidenied' );
1387                         } elseif ( $this->getRequest()->getHeader( 'Promise-Non-Write-API-Action' ) ) {
1388                                 $this->dieWithError( 'apierror-promised-nonwrite-api' );
1389                         }
1390
1391                         $this->checkReadOnly( $module );
1392                 }
1393
1394                 // Allow extensions to stop execution for arbitrary reasons.
1395                 $message = false;
1396                 if ( !Hooks::run( 'ApiCheckCanExecute', [ $module, $user, &$message ] ) ) {
1397                         $this->dieWithError( $message );
1398                 }
1399         }
1400
1401         /**
1402          * Check if the DB is read-only for this user
1403          * @param ApiBase $module An Api module
1404          */
1405         protected function checkReadOnly( $module ) {
1406                 if ( wfReadOnly() ) {
1407                         $this->dieReadOnly();
1408                 }
1409
1410                 if ( $module->isWriteMode()
1411                         && $this->getUser()->isBot()
1412                         && wfGetLB()->getServerCount() > 1
1413                 ) {
1414                         $this->checkBotReadOnly();
1415                 }
1416         }
1417
1418         /**
1419          * Check whether we are readonly for bots
1420          */
1421         private function checkBotReadOnly() {
1422                 // Figure out how many servers have passed the lag threshold
1423                 $numLagged = 0;
1424                 $lagLimit = $this->getConfig()->get( 'APIMaxLagThreshold' );
1425                 $laggedServers = [];
1426                 $loadBalancer = wfGetLB();
1427                 foreach ( $loadBalancer->getLagTimes() as $serverIndex => $lag ) {
1428                         if ( $lag > $lagLimit ) {
1429                                 ++$numLagged;
1430                                 $laggedServers[] = $loadBalancer->getServerName( $serverIndex ) . " ({$lag}s)";
1431                         }
1432                 }
1433
1434                 // If a majority of replica DBs are too lagged then disallow writes
1435                 $replicaCount = wfGetLB()->getServerCount() - 1;
1436                 if ( $numLagged >= ceil( $replicaCount / 2 ) ) {
1437                         $laggedServers = implode( ', ', $laggedServers );
1438                         wfDebugLog(
1439                                 'api-readonly',
1440                                 "Api request failed as read only because the following DBs are lagged: $laggedServers"
1441                         );
1442
1443                         $this->dieWithError(
1444                                 'readonly_lag',
1445                                 'readonly',
1446                                 [ 'readonlyreason' => "Waiting for $numLagged lagged database(s)" ]
1447                         );
1448                 }
1449         }
1450
1451         /**
1452          * Check asserts of the user's rights
1453          * @param array $params
1454          */
1455         protected function checkAsserts( $params ) {
1456                 if ( isset( $params['assert'] ) ) {
1457                         $user = $this->getUser();
1458                         switch ( $params['assert'] ) {
1459                                 case 'user':
1460                                         if ( $user->isAnon() ) {
1461                                                 $this->dieWithError( 'apierror-assertuserfailed' );
1462                                         }
1463                                         break;
1464                                 case 'bot':
1465                                         if ( !$user->isAllowed( 'bot' ) ) {
1466                                                 $this->dieWithError( 'apierror-assertbotfailed' );
1467                                         }
1468                                         break;
1469                         }
1470                 }
1471                 if ( isset( $params['assertuser'] ) ) {
1472                         $assertUser = User::newFromName( $params['assertuser'], false );
1473                         if ( !$assertUser || !$this->getUser()->equals( $assertUser ) ) {
1474                                 $this->dieWithError(
1475                                         [ 'apierror-assertnameduserfailed', wfEscapeWikiText( $params['assertuser'] ) ]
1476                                 );
1477                         }
1478                 }
1479         }
1480
1481         /**
1482          * Check POST for external response and setup result printer
1483          * @param ApiBase $module An Api module
1484          * @param array $params An array with the request parameters
1485          */
1486         protected function setupExternalResponse( $module, $params ) {
1487                 $request = $this->getRequest();
1488                 if ( !$request->wasPosted() && $module->mustBePosted() ) {
1489                         // Module requires POST. GET request might still be allowed
1490                         // if $wgDebugApi is true, otherwise fail.
1491                         $this->dieWithErrorOrDebug( [ 'apierror-mustbeposted', $this->mAction ] );
1492                 }
1493
1494                 // See if custom printer is used
1495                 $this->mPrinter = $module->getCustomPrinter();
1496                 if ( is_null( $this->mPrinter ) ) {
1497                         // Create an appropriate printer
1498                         $this->mPrinter = $this->createPrinterByName( $params['format'] );
1499                 }
1500
1501                 if ( $request->getProtocol() === 'http' && (
1502                         $request->getSession()->shouldForceHTTPS() ||
1503                         ( $this->getUser()->isLoggedIn() &&
1504                                 $this->getUser()->requiresHTTPS() )
1505                 ) ) {
1506                         $this->addDeprecation( 'apiwarn-deprecation-httpsexpected', 'https-expected' );
1507                 }
1508         }
1509
1510         /**
1511          * Execute the actual module, without any error handling
1512          */
1513         protected function executeAction() {
1514                 $params = $this->setupExecuteAction();
1515                 $module = $this->setupModule();
1516                 $this->mModule = $module;
1517
1518                 if ( !$this->mInternalMode ) {
1519                         $this->setRequestExpectations( $module );
1520                 }
1521
1522                 $this->checkExecutePermissions( $module );
1523
1524                 if ( !$this->checkMaxLag( $module, $params ) ) {
1525                         return;
1526                 }
1527
1528                 if ( !$this->checkConditionalRequestHeaders( $module ) ) {
1529                         return;
1530                 }
1531
1532                 if ( !$this->mInternalMode ) {
1533                         $this->setupExternalResponse( $module, $params );
1534                 }
1535
1536                 $this->checkAsserts( $params );
1537
1538                 // Execute
1539                 $module->execute();
1540                 Hooks::run( 'APIAfterExecute', [ &$module ] );
1541
1542                 $this->reportUnusedParams();
1543
1544                 if ( !$this->mInternalMode ) {
1545                         // append Debug information
1546                         MWDebug::appendDebugInfoToApiResult( $this->getContext(), $this->getResult() );
1547
1548                         // Print result data
1549                         $this->printResult();
1550                 }
1551         }
1552
1553         /**
1554          * Set database connection, query, and write expectations given this module request
1555          * @param ApiBase $module
1556          */
1557         protected function setRequestExpectations( ApiBase $module ) {
1558                 $limits = $this->getConfig()->get( 'TrxProfilerLimits' );
1559                 $trxProfiler = Profiler::instance()->getTransactionProfiler();
1560                 $trxProfiler->setLogger( LoggerFactory::getInstance( 'DBPerformance' ) );
1561                 if ( $this->getRequest()->hasSafeMethod() ) {
1562                         $trxProfiler->setExpectations( $limits['GET'], __METHOD__ );
1563                 } elseif ( $this->getRequest()->wasPosted() && !$module->isWriteMode() ) {
1564                         $trxProfiler->setExpectations( $limits['POST-nonwrite'], __METHOD__ );
1565                         $this->getRequest()->markAsSafeRequest();
1566                 } else {
1567                         $trxProfiler->setExpectations( $limits['POST'], __METHOD__ );
1568                 }
1569         }
1570
1571         /**
1572          * Log the preceding request
1573          * @param float $time Time in seconds
1574          * @param Exception $e Exception caught while processing the request
1575          */
1576         protected function logRequest( $time, $e = null ) {
1577                 $request = $this->getRequest();
1578                 $logCtx = [
1579                         'ts' => time(),
1580                         'ip' => $request->getIP(),
1581                         'userAgent' => $this->getUserAgent(),
1582                         'wiki' => wfWikiID(),
1583                         'timeSpentBackend' => (int)round( $time * 1000 ),
1584                         'hadError' => $e !== null,
1585                         'errorCodes' => [],
1586                         'params' => [],
1587                 ];
1588
1589                 if ( $e ) {
1590                         foreach ( $this->errorMessagesFromException( $e ) as $msg ) {
1591                                 $logCtx['errorCodes'][] = $msg->getApiCode();
1592                         }
1593                 }
1594
1595                 // Construct space separated message for 'api' log channel
1596                 $msg = "API {$request->getMethod()} " .
1597                         wfUrlencode( str_replace( ' ', '_', $this->getUser()->getName() ) ) .
1598                         " {$logCtx['ip']} " .
1599                         "T={$logCtx['timeSpentBackend']}ms";
1600
1601                 foreach ( $this->getParamsUsed() as $name ) {
1602                         $value = $request->getVal( $name );
1603                         if ( $value === null ) {
1604                                 continue;
1605                         }
1606
1607                         if ( strlen( $value ) > 256 ) {
1608                                 $value = substr( $value, 0, 256 );
1609                                 $encValue = $this->encodeRequestLogValue( $value ) . '[...]';
1610                         } else {
1611                                 $encValue = $this->encodeRequestLogValue( $value );
1612                         }
1613
1614                         $logCtx['params'][$name] = $value;
1615                         $msg .= " {$name}={$encValue}";
1616                 }
1617
1618                 wfDebugLog( 'api', $msg, 'private' );
1619                 // ApiAction channel is for structured data consumers
1620                 wfDebugLog( 'ApiAction', '', 'private', $logCtx );
1621         }
1622
1623         /**
1624          * Encode a value in a format suitable for a space-separated log line.
1625          * @param string $s
1626          * @return string
1627          */
1628         protected function encodeRequestLogValue( $s ) {
1629                 static $table;
1630                 if ( !$table ) {
1631                         $chars = ';@$!*(),/:';
1632                         $numChars = strlen( $chars );
1633                         for ( $i = 0; $i < $numChars; $i++ ) {
1634                                 $table[rawurlencode( $chars[$i] )] = $chars[$i];
1635                         }
1636                 }
1637
1638                 return strtr( rawurlencode( $s ), $table );
1639         }
1640
1641         /**
1642          * Get the request parameters used in the course of the preceding execute() request
1643          * @return array
1644          */
1645         protected function getParamsUsed() {
1646                 return array_keys( $this->mParamsUsed );
1647         }
1648
1649         /**
1650          * Mark parameters as used
1651          * @param string|string[] $params
1652          */
1653         public function markParamsUsed( $params ) {
1654                 $this->mParamsUsed += array_fill_keys( (array)$params, true );
1655         }
1656
1657         /**
1658          * Get a request value, and register the fact that it was used, for logging.
1659          * @param string $name
1660          * @param mixed $default
1661          * @return mixed
1662          */
1663         public function getVal( $name, $default = null ) {
1664                 $this->mParamsUsed[$name] = true;
1665
1666                 $ret = $this->getRequest()->getVal( $name );
1667                 if ( $ret === null ) {
1668                         if ( $this->getRequest()->getArray( $name ) !== null ) {
1669                                 // See bug 10262 for why we don't just implode( '|', ... ) the
1670                                 // array.
1671                                 $this->addWarning( [ 'apiwarn-unsupportedarray', $name ] );
1672                         }
1673                         $ret = $default;
1674                 }
1675                 return $ret;
1676         }
1677
1678         /**
1679          * Get a boolean request value, and register the fact that the parameter
1680          * was used, for logging.
1681          * @param string $name
1682          * @return bool
1683          */
1684         public function getCheck( $name ) {
1685                 return $this->getVal( $name, null ) !== null;
1686         }
1687
1688         /**
1689          * Get a request upload, and register the fact that it was used, for logging.
1690          *
1691          * @since 1.21
1692          * @param string $name Parameter name
1693          * @return WebRequestUpload
1694          */
1695         public function getUpload( $name ) {
1696                 $this->mParamsUsed[$name] = true;
1697
1698                 return $this->getRequest()->getUpload( $name );
1699         }
1700
1701         /**
1702          * Report unused parameters, so the client gets a hint in case it gave us parameters we don't know,
1703          * for example in case of spelling mistakes or a missing 'g' prefix for generators.
1704          */
1705         protected function reportUnusedParams() {
1706                 $paramsUsed = $this->getParamsUsed();
1707                 $allParams = $this->getRequest()->getValueNames();
1708
1709                 if ( !$this->mInternalMode ) {
1710                         // Printer has not yet executed; don't warn that its parameters are unused
1711                         $printerParams = $this->mPrinter->encodeParamName(
1712                                 array_keys( $this->mPrinter->getFinalParams() ?: [] )
1713                         );
1714                         $unusedParams = array_diff( $allParams, $paramsUsed, $printerParams );
1715                 } else {
1716                         $unusedParams = array_diff( $allParams, $paramsUsed );
1717                 }
1718
1719                 if ( count( $unusedParams ) ) {
1720                         $this->addWarning( [
1721                                 'apierror-unrecognizedparams',
1722                                 Message::listParam( array_map( 'wfEscapeWikiText', $unusedParams ), 'comma' ),
1723                                 count( $unusedParams )
1724                         ] );
1725                 }
1726         }
1727
1728         /**
1729          * Print results using the current printer
1730          *
1731          * @param int $httpCode HTTP status code, or 0 to not change
1732          */
1733         protected function printResult( $httpCode = 0 ) {
1734                 if ( $this->getConfig()->get( 'DebugAPI' ) !== false ) {
1735                         $this->addWarning( 'apiwarn-wgDebugAPI' );
1736                 }
1737
1738                 $printer = $this->mPrinter;
1739                 $printer->initPrinter( false );
1740                 if ( $httpCode ) {
1741                         $printer->setHttpStatus( $httpCode );
1742                 }
1743                 $printer->execute();
1744                 $printer->closePrinter();
1745         }
1746
1747         /**
1748          * @return bool
1749          */
1750         public function isReadMode() {
1751                 return false;
1752         }
1753
1754         /**
1755          * See ApiBase for description.
1756          *
1757          * @return array
1758          */
1759         public function getAllowedParams() {
1760                 return [
1761                         'action' => [
1762                                 ApiBase::PARAM_DFLT => 'help',
1763                                 ApiBase::PARAM_TYPE => 'submodule',
1764                         ],
1765                         'format' => [
1766                                 ApiBase::PARAM_DFLT => ApiMain::API_DEFAULT_FORMAT,
1767                                 ApiBase::PARAM_TYPE => 'submodule',
1768                         ],
1769                         'maxlag' => [
1770                                 ApiBase::PARAM_TYPE => 'integer'
1771                         ],
1772                         'smaxage' => [
1773                                 ApiBase::PARAM_TYPE => 'integer',
1774                                 ApiBase::PARAM_DFLT => 0
1775                         ],
1776                         'maxage' => [
1777                                 ApiBase::PARAM_TYPE => 'integer',
1778                                 ApiBase::PARAM_DFLT => 0
1779                         ],
1780                         'assert' => [
1781                                 ApiBase::PARAM_TYPE => [ 'user', 'bot' ]
1782                         ],
1783                         'assertuser' => [
1784                                 ApiBase::PARAM_TYPE => 'user',
1785                         ],
1786                         'requestid' => null,
1787                         'servedby' => false,
1788                         'curtimestamp' => false,
1789                         'responselanginfo' => false,
1790                         'origin' => null,
1791                         'uselang' => [
1792                                 ApiBase::PARAM_DFLT => self::API_DEFAULT_USELANG,
1793                         ],
1794                         'errorformat' => [
1795                                 ApiBase::PARAM_TYPE => [ 'plaintext', 'wikitext', 'html', 'raw', 'none', 'bc' ],
1796                                 ApiBase::PARAM_DFLT => 'bc',
1797                         ],
1798                         'errorlang' => [
1799                                 ApiBase::PARAM_DFLT => 'uselang',
1800                         ],
1801                         'errorsuselocal' => [
1802                                 ApiBase::PARAM_DFLT => false,
1803                         ],
1804                 ];
1805         }
1806
1807         /** @see ApiBase::getExamplesMessages() */
1808         protected function getExamplesMessages() {
1809                 return [
1810                         'action=help'
1811                                 => 'apihelp-help-example-main',
1812                         'action=help&recursivesubmodules=1'
1813                                 => 'apihelp-help-example-recursive',
1814                 ];
1815         }
1816
1817         public function modifyHelp( array &$help, array $options, array &$tocData ) {
1818                 // Wish PHP had an "array_insert_before". Instead, we have to manually
1819                 // reindex the array to get 'permissions' in the right place.
1820                 $oldHelp = $help;
1821                 $help = [];
1822                 foreach ( $oldHelp as $k => $v ) {
1823                         if ( $k === 'submodules' ) {
1824                                 $help['permissions'] = '';
1825                         }
1826                         $help[$k] = $v;
1827                 }
1828                 $help['datatypes'] = '';
1829                 $help['credits'] = '';
1830
1831                 // Fill 'permissions'
1832                 $help['permissions'] .= Html::openElement( 'div',
1833                         [ 'class' => 'apihelp-block apihelp-permissions' ] );
1834                 $m = $this->msg( 'api-help-permissions' );
1835                 if ( !$m->isDisabled() ) {
1836                         $help['permissions'] .= Html::rawElement( 'div', [ 'class' => 'apihelp-block-head' ],
1837                                 $m->numParams( count( self::$mRights ) )->parse()
1838                         );
1839                 }
1840                 $help['permissions'] .= Html::openElement( 'dl' );
1841                 foreach ( self::$mRights as $right => $rightMsg ) {
1842                         $help['permissions'] .= Html::element( 'dt', null, $right );
1843
1844                         $rightMsg = $this->msg( $rightMsg['msg'], $rightMsg['params'] )->parse();
1845                         $help['permissions'] .= Html::rawElement( 'dd', null, $rightMsg );
1846
1847                         $groups = array_map( function ( $group ) {
1848                                 return $group == '*' ? 'all' : $group;
1849                         }, User::getGroupsWithPermission( $right ) );
1850
1851                         $help['permissions'] .= Html::rawElement( 'dd', null,
1852                                 $this->msg( 'api-help-permissions-granted-to' )
1853                                         ->numParams( count( $groups ) )
1854                                         ->params( Message::listParam( $groups ) )
1855                                         ->parse()
1856                         );
1857                 }
1858                 $help['permissions'] .= Html::closeElement( 'dl' );
1859                 $help['permissions'] .= Html::closeElement( 'div' );
1860
1861                 // Fill 'datatypes' and 'credits', if applicable
1862                 if ( empty( $options['nolead'] ) ) {
1863                         $level = $options['headerlevel'];
1864                         $tocnumber = &$options['tocnumber'];
1865
1866                         $header = $this->msg( 'api-help-datatypes-header' )->parse();
1867
1868                         // Add an additional span with sanitized ID
1869                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1870                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/datatypes' ) ] ) .
1871                                         $header;
1872                         }
1873                         $help['datatypes'] .= Html::rawElement( 'h' . min( 6, $level ),
1874                                 [ 'id' => 'main/datatypes', 'class' => 'apihelp-header' ],
1875                                 $header
1876                         );
1877                         $help['datatypes'] .= $this->msg( 'api-help-datatypes' )->parseAsBlock();
1878                         if ( !isset( $tocData['main/datatypes'] ) ) {
1879                                 $tocnumber[$level]++;
1880                                 $tocData['main/datatypes'] = [
1881                                         'toclevel' => count( $tocnumber ),
1882                                         'level' => $level,
1883                                         'anchor' => 'main/datatypes',
1884                                         'line' => $header,
1885                                         'number' => implode( '.', $tocnumber ),
1886                                         'index' => false,
1887                                 ];
1888                         }
1889
1890                         // Add an additional span with sanitized ID
1891                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1892                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/credits' ) ] ) .
1893                                         $header;
1894                         }
1895                         $header = $this->msg( 'api-credits-header' )->parse();
1896                         $help['credits'] .= Html::rawElement( 'h' . min( 6, $level ),
1897                                 [ 'id' => 'main/credits', 'class' => 'apihelp-header' ],
1898                                 $header
1899                         );
1900                         $help['credits'] .= $this->msg( 'api-credits' )->useDatabase( false )->parseAsBlock();
1901                         if ( !isset( $tocData['main/credits'] ) ) {
1902                                 $tocnumber[$level]++;
1903                                 $tocData['main/credits'] = [
1904                                         'toclevel' => count( $tocnumber ),
1905                                         'level' => $level,
1906                                         'anchor' => 'main/credits',
1907                                         'line' => $header,
1908                                         'number' => implode( '.', $tocnumber ),
1909                                         'index' => false,
1910                                 ];
1911                         }
1912                 }
1913         }
1914
1915         private $mCanApiHighLimits = null;
1916
1917         /**
1918          * Check whether the current user is allowed to use high limits
1919          * @return bool
1920          */
1921         public function canApiHighLimits() {
1922                 if ( !isset( $this->mCanApiHighLimits ) ) {
1923                         $this->mCanApiHighLimits = $this->getUser()->isAllowed( 'apihighlimits' );
1924                 }
1925
1926                 return $this->mCanApiHighLimits;
1927         }
1928
1929         /**
1930          * Overrides to return this instance's module manager.
1931          * @return ApiModuleManager
1932          */
1933         public function getModuleManager() {
1934                 return $this->mModuleMgr;
1935         }
1936
1937         /**
1938          * Fetches the user agent used for this request
1939          *
1940          * The value will be the combination of the 'Api-User-Agent' header (if
1941          * any) and the standard User-Agent header (if any).
1942          *
1943          * @return string
1944          */
1945         public function getUserAgent() {
1946                 return trim(
1947                         $this->getRequest()->getHeader( 'Api-user-agent' ) . ' ' .
1948                         $this->getRequest()->getHeader( 'User-agent' )
1949                 );
1950         }
1951 }
1952
1953 /**
1954  * For really cool vim folding this needs to be at the end:
1955  * vim: foldmarker=@{,@} foldmethod=marker
1956  */