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 use Wikimedia\Timestamp\TimestampException;
  30
  31 /**
  32  * This is the main API class, used for both external and internal processing.
  33  * When executed, it will create the requested formatter object,
  34  * instantiate and execute an object associated with the needed action,
  35  * and use formatter to print results.
  36  * In case of an exception, an error message will be printed using the same formatter.
  37  *
  38  * To use API from another application, run it using FauxRequest object, in which
  39  * case any internal exceptions will not be handled but passed up to the caller.
  40  * After successful execution, use getResult() for the resulting data.
  41  *
  42  * @ingroup API
  43  */
  44 class ApiMain extends ApiBase {
  45         /**
  46          * When no format parameter is given, this format will be used
  47          */
  48         const API_DEFAULT_FORMAT = 'jsonfm';
  49
  50         /**
  51          * When no uselang parameter is given, this language will be used
  52          */
  53         const API_DEFAULT_USELANG = 'user';
  54
  55         /**
  56          * List of available modules: action name => module class
  57          */
  58         private static $Modules = [
  59                 'login' => 'ApiLogin',
  60                 'clientlogin' => 'ApiClientLogin',
  61                 'logout' => 'ApiLogout',
  62                 'createaccount' => 'ApiAMCreateAccount',
  63                 'linkaccount' => 'ApiLinkAccount',
  64                 'unlinkaccount' => 'ApiRemoveAuthenticationData',
  65                 'changeauthenticationdata' => 'ApiChangeAuthenticationData',
  66                 'removeauthenticationdata' => 'ApiRemoveAuthenticationData',
  67                 'resetpassword' => 'ApiResetPassword',
  68                 'query' => 'ApiQuery',
  69                 'expandtemplates' => 'ApiExpandTemplates',
  70                 'parse' => 'ApiParse',
  71                 'stashedit' => 'ApiStashEdit',
  72                 'opensearch' => 'ApiOpenSearch',
  73                 'feedcontributions' => 'ApiFeedContributions',
  74                 'feedrecentchanges' => 'ApiFeedRecentChanges',
  75                 'feedwatchlist' => 'ApiFeedWatchlist',
  76                 'help' => 'ApiHelp',
  77                 'paraminfo' => 'ApiParamInfo',
  78                 'rsd' => 'ApiRsd',
  79                 'compare' => 'ApiComparePages',
  80                 'tokens' => 'ApiTokens',
  81                 'checktoken' => 'ApiCheckToken',
  82                 'cspreport' => 'ApiCSPReport',
  83                 'validatepassword' => 'ApiValidatePassword',
  84
  85                 // Write modules
  86                 'purge' => 'ApiPurge',
  87                 'setnotificationtimestamp' => 'ApiSetNotificationTimestamp',
  88                 'rollback' => 'ApiRollback',
  89                 'delete' => 'ApiDelete',
  90                 'undelete' => 'ApiUndelete',
  91                 'protect' => 'ApiProtect',
  92                 'block' => 'ApiBlock',
  93                 'unblock' => 'ApiUnblock',
  94                 'move' => 'ApiMove',
  95                 'edit' => 'ApiEditPage',
  96                 'upload' => 'ApiUpload',
  97                 'filerevert' => 'ApiFileRevert',
  98                 'emailuser' => 'ApiEmailUser',
  99                 'watch' => 'ApiWatch',
 100                 'patrol' => 'ApiPatrol',
 101                 'import' => 'ApiImport',
 102                 'clearhasmsg' => 'ApiClearHasMsg',
 103                 'userrights' => 'ApiUserrights',
 104                 'options' => 'ApiOptions',
 105                 'imagerotate' => 'ApiImageRotate',
 106                 'revisiondelete' => 'ApiRevisionDelete',
 107                 'managetags' => 'ApiManageTags',
 108                 'tag' => 'ApiTag',
 109                 'mergehistory' => 'ApiMergeHistory',
 110                 'setpagelanguage' => 'ApiSetPageLanguage',
 111         ];
 112
 113         /**
 114          * List of available formats: format name => format class
 115          */
 116         private static $Formats = [
 117                 'json' => 'ApiFormatJson',
 118                 'jsonfm' => 'ApiFormatJson',
 119                 'php' => 'ApiFormatPhp',
 120                 'phpfm' => 'ApiFormatPhp',
 121                 'xml' => 'ApiFormatXml',
 122                 'xmlfm' => 'ApiFormatXml',
 123                 'rawfm' => 'ApiFormatJson',
 124                 'none' => 'ApiFormatNone',
 125         ];
 126
 127         // @codingStandardsIgnoreStart String contenation on "msg" not allowed to break long line
 128         /**
 129          * List of user roles that are specifically relevant to the API.
 130          * [ 'right' => [ 'msg'    => 'Some message with a $1',
 131          *                'params' => [ $someVarToSubst ] ],
 132          * ];
 133          */
 134         private static $mRights = [
 135                 'writeapi' => [
 136                         'msg' => 'right-writeapi',
 137                         'params' => []
 138                 ],
 139                 'apihighlimits' => [
 140                         'msg' => 'api-help-right-apihighlimits',
 141                         'params' => [ ApiBase::LIMIT_SML2, ApiBase::LIMIT_BIG2 ]
 142                 ]
 143         ];
 144         // @codingStandardsIgnoreEnd
 145
 146         /**
 147          * @var ApiFormatBase
 148          */
 149         private $mPrinter;
 150
 151         private $mModuleMgr, $mResult, $mErrorFormatter = null;
 152         /** @var ApiContinuationManager|null */
 153         private $mContinuationManager;
 154         private $mAction;
 155         private $mEnableWrite;
 156         private $mInternalMode, $mSquidMaxage;
 157         /** @var ApiBase */
 158         private $mModule;
 159
 160         private $mCacheMode = 'private';
 161         private $mCacheControl = [];
 162         private $mParamsUsed = [];
 163
 164         /** @var bool|null Cached return value from self::lacksSameOriginSecurity() */
 165         private $lacksSameOriginSecurity = null;
 166
 167         /**
 168          * Constructs an instance of ApiMain that utilizes the module and format specified by $request.
 169          *
 170          * @param IContextSource|WebRequest $context If this is an instance of
 171          *    FauxRequest, errors are thrown and no printing occurs
 172          * @param bool $enableWrite Should be set to true if the api may modify data
 173          */
 174         public function __construct( $context = null, $enableWrite = false ) {
 175                 if ( $context === null ) {
 176                         $context = RequestContext::getMain();
 177                 } elseif ( $context instanceof WebRequest ) {
 178                         // BC for pre-1.19
 179                         $request = $context;
 180                         $context = RequestContext::getMain();
 181                 }
 182                 // We set a derivative context so we can change stuff later
 183                 $this->setContext( new DerivativeContext( $context ) );
 184
 185                 if ( isset( $request ) ) {
 186                         $this->getContext()->setRequest( $request );
 187                 } else {
 188                         $request = $this->getRequest();
 189                 }
 190
 191                 $this->mInternalMode = ( $request instanceof FauxRequest );
 192
 193                 // Special handling for the main module: $parent === $this
 194                 parent::__construct( $this, $this->mInternalMode ? 'main_int' : 'main' );
 195
 196                 $config = $this->getConfig();
 197
 198                 if ( !$this->mInternalMode ) {
 199                         // Log if a request with a non-whitelisted Origin header is seen
 200                         // with session cookies.
 201                         $originHeader = $request->getHeader( 'Origin' );
 202                         if ( $originHeader === false ) {
 203                                 $origins = [];
 204                         } else {
 205                                 $originHeader = trim( $originHeader );
 206                                 $origins = preg_split( '/\s+/', $originHeader );
 207                         }
 208                         $sessionCookies = array_intersect(
 209                                 array_keys( $_COOKIE ),
 210                                 MediaWiki\Session\SessionManager::singleton()->getVaryCookies()
 211                         );
 212                         if ( $origins && $sessionCookies && (
 213                                 count( $origins ) !== 1 || !self::matchOrigin(
 214                                         $origins[0],
 215                                         $config->get( 'CrossSiteAJAXdomains' ),
 216                                         $config->get( 'CrossSiteAJAXdomainExceptions' )
 217                                 )
 218                         ) ) {
 219                                 LoggerFactory::getInstance( 'cors' )->warning(
 220                                         'Non-whitelisted CORS request with session cookies', [
 221                                                 'origin' => $originHeader,
 222                                                 'cookies' => $sessionCookies,
 223                                                 'ip' => $request->getIP(),
 224                                                 'userAgent' => $this->getUserAgent(),
 225                                                 'wiki' => wfWikiID(),
 226                                         ]
 227                                 );
 228                         }
 229
 230                         // If we're in a mode that breaks the same-origin policy, strip
 231                         // user credentials for security.
 232                         if ( $this->lacksSameOriginSecurity() ) {
 233                                 global $wgUser;
 234                                 wfDebug( "API: stripping user credentials when the same-origin policy is not applied\n" );
 235                                 $wgUser = new User();
 236                                 $this->getContext()->setUser( $wgUser );
 237                         }
 238                 }
 239
 240                 $this->mResult = new ApiResult( $this->getConfig()->get( 'APIMaxResultSize' ) );
 241
 242                 // Setup uselang. This doesn't use $this->getParameter()
 243                 // because we're not ready to handle errors yet.
 244                 $uselang = $request->getVal( 'uselang', self::API_DEFAULT_USELANG );
 245                 if ( $uselang === 'user' ) {
 246                         // Assume the parent context is going to return the user language
 247                         // for uselang=user (see T85635).
 248                 } else {
 249                         if ( $uselang === 'content' ) {
 250                                 global $wgContLang;
 251                                 $uselang = $wgContLang->getCode();
 252                         }
 253                         $code = RequestContext::sanitizeLangCode( $uselang );
 254                         $this->getContext()->setLanguage( $code );
 255                         if ( !$this->mInternalMode ) {
 256                                 global $wgLang;
 257                                 $wgLang = $this->getContext()->getLanguage();
 258                                 RequestContext::getMain()->setLanguage( $wgLang );
 259                         }
 260                 }
 261
 262                 // Set up the error formatter. This doesn't use $this->getParameter()
 263                 // because we're not ready to handle errors yet.
 264                 $errorFormat = $request->getVal( 'errorformat', 'bc' );
 265                 $errorLangCode = $request->getVal( 'errorlang', 'uselang' );
 266                 $errorsUseDB = $request->getCheck( 'errorsuselocal' );
 267                 if ( in_array( $errorFormat, [ 'plaintext', 'wikitext', 'html', 'raw', 'none' ], true ) ) {
 268                         if ( $errorLangCode === 'uselang' ) {
 269                                 $errorLang = $this->getLanguage();
 270                         } elseif ( $errorLangCode === 'content' ) {
 271                                 global $wgContLang;
 272                                 $errorLang = $wgContLang;
 273                         } else {
 274                                 $errorLangCode = RequestContext::sanitizeLangCode( $errorLangCode );
 275                                 $errorLang = Language::factory( $errorLangCode );
 276                         }
 277                         $this->mErrorFormatter = new ApiErrorFormatter(
 278                                 $this->mResult, $errorLang, $errorFormat, $errorsUseDB
 279                         );
 280                 } else {
 281                         $this->mErrorFormatter = new ApiErrorFormatter_BackCompat( $this->mResult );
 282                 }
 283                 $this->mResult->setErrorFormatter( $this->getErrorFormatter() );
 284
 285                 $this->mModuleMgr = new ApiModuleManager( $this );
 286                 $this->mModuleMgr->addModules( self::$Modules, 'action' );
 287                 $this->mModuleMgr->addModules( $config->get( 'APIModules' ), 'action' );
 288                 $this->mModuleMgr->addModules( self::$Formats, 'format' );
 289                 $this->mModuleMgr->addModules( $config->get( 'APIFormatModules' ), 'format' );
 290
 291                 Hooks::run( 'ApiMain::moduleManager', [ $this->mModuleMgr ] );
 292
 293                 $this->mContinuationManager = null;
 294                 $this->mEnableWrite = $enableWrite;
 295
 296                 $this->mSquidMaxage = -1; // flag for executeActionWithErrorHandling()
 297                 $this->mCommit = false;
 298         }
 299
 300         /**
 301          * Return true if the API was started by other PHP code using FauxRequest
 302          * @return bool
 303          */
 304         public function isInternalMode() {
 305                 return $this->mInternalMode;
 306         }
 307
 308         /**
 309          * Get the ApiResult object associated with current request
 310          *
 311          * @return ApiResult
 312          */
 313         public function getResult() {
 314                 return $this->mResult;
 315         }
 316
 317         /**
 318          * Get the security flag for the current request
 319          * @return bool
 320          */
 321         public function lacksSameOriginSecurity() {
 322                 if ( $this->lacksSameOriginSecurity !== null ) {
 323                         return $this->lacksSameOriginSecurity;
 324                 }
 325
 326                 $request = $this->getRequest();
 327
 328                 // JSONP mode
 329                 if ( $request->getVal( 'callback' ) !== null ) {
 330                         $this->lacksSameOriginSecurity = true;
 331                         return true;
 332                 }
 333
 334                 // Anonymous CORS
 335                 if ( $request->getVal( 'origin' ) === '*' ) {
 336                         $this->lacksSameOriginSecurity = true;
 337                         return true;
 338                 }
 339
 340                 // Header to be used from XMLHTTPRequest when the request might
 341                 // otherwise be used for XSS.
 342                 if ( $request->getHeader( 'Treat-as-Untrusted' ) !== false ) {
 343                         $this->lacksSameOriginSecurity = true;
 344                         return true;
 345                 }
 346
 347                 // Allow extensions to override.
 348                 $this->lacksSameOriginSecurity = !Hooks::run( 'RequestHasSameOriginSecurity', [ $request ] );
 349                 return $this->lacksSameOriginSecurity;
 350         }
 351
 352         /**
 353          * Get the ApiErrorFormatter object associated with current request
 354          * @return ApiErrorFormatter
 355          */
 356         public function getErrorFormatter() {
 357                 return $this->mErrorFormatter;
 358         }
 359
 360         /**
 361          * Get the continuation manager
 362          * @return ApiContinuationManager|null
 363          */
 364         public function getContinuationManager() {
 365                 return $this->mContinuationManager;
 366         }
 367
 368         /**
 369          * Set the continuation manager
 370          * @param ApiContinuationManager|null
 371          */
 372         public function setContinuationManager( $manager ) {
 373                 if ( $manager !== null ) {
 374                         if ( !$manager instanceof ApiContinuationManager ) {
 375                                 throw new InvalidArgumentException( __METHOD__ . ': Was passed ' .
 376                                         is_object( $manager ) ? get_class( $manager ) : gettype( $manager )
 377                                 );
 378                         }
 379                         if ( $this->mContinuationManager !== null ) {
 380                                 throw new UnexpectedValueException(
 381                                         __METHOD__ . ': tried to set manager from ' . $manager->getSource() .
 382                                         ' when a manager is already set from ' . $this->mContinuationManager->getSource()
 383                                 );
 384                         }
 385                 }
 386                 $this->mContinuationManager = $manager;
 387         }
 388
 389         /**
 390          * Get the API module object. Only works after executeAction()
 391          *
 392          * @return ApiBase
 393          */
 394         public function getModule() {
 395                 return $this->mModule;
 396         }
 397
 398         /**
 399          * Get the result formatter object. Only works after setupExecuteAction()
 400          *
 401          * @return ApiFormatBase
 402          */
 403         public function getPrinter() {
 404                 return $this->mPrinter;
 405         }
 406
 407         /**
 408          * Set how long the response should be cached.
 409          *
 410          * @param int $maxage
 411          */
 412         public function setCacheMaxAge( $maxage ) {
 413                 $this->setCacheControl( [
 414                         'max-age' => $maxage,
 415                         's-maxage' => $maxage
 416                 ] );
 417         }
 418
 419         /**
 420          * Set the type of caching headers which will be sent.
 421          *
 422          * @param string $mode One of:
 423          *    - 'public':     Cache this object in public caches, if the maxage or smaxage
 424          *         parameter is set, or if setCacheMaxAge() was called. If a maximum age is
 425          *         not provided by any of these means, the object will be private.
 426          *    - 'private':    Cache this object only in private client-side caches.
 427          *    - 'anon-public-user-private': Make this object cacheable for logged-out
 428          *         users, but private for logged-in users. IMPORTANT: If this is set, it must be
 429          *         set consistently for a given URL, it cannot be set differently depending on
 430          *         things like the contents of the database, or whether the user is logged in.
 431          *
 432          *  If the wiki does not allow anonymous users to read it, the mode set here
 433          *  will be ignored, and private caching headers will always be sent. In other words,
 434          *  the "public" mode is equivalent to saying that the data sent is as public as a page
 435          *  view.
 436          *
 437          *  For user-dependent data, the private mode should generally be used. The
 438          *  anon-public-user-private mode should only be used where there is a particularly
 439          *  good performance reason for caching the anonymous response, but where the
 440          *  response to logged-in users may differ, or may contain private data.
 441          *
 442          *  If this function is never called, then the default will be the private mode.
 443          */
 444         public function setCacheMode( $mode ) {
 445                 if ( !in_array( $mode, [ 'private', 'public', 'anon-public-user-private' ] ) ) {
 446                         wfDebug( __METHOD__ . ": unrecognised cache mode \"$mode\"\n" );
 447
 448                         // Ignore for forwards-compatibility
 449                         return;
 450                 }
 451
 452                 if ( !User::isEveryoneAllowed( 'read' ) ) {
 453                         // Private wiki, only private headers
 454                         if ( $mode !== 'private' ) {
 455                                 wfDebug( __METHOD__ . ": ignoring request for $mode cache mode, private wiki\n" );
 456
 457                                 return;
 458                         }
 459                 }
 460
 461                 if ( $mode === 'public' && $this->getParameter( 'uselang' ) === 'user' ) {
 462                         // User language is used for i18n, so we don't want to publicly
 463                         // cache. Anons are ok, because if they have non-default language
 464                         // then there's an appropriate Vary header set by whatever set
 465                         // their non-default language.
 466                         wfDebug( __METHOD__ . ": downgrading cache mode 'public' to " .
 467                                 "'anon-public-user-private' due to uselang=user\n" );
 468                         $mode = 'anon-public-user-private';
 469                 }
 470
 471                 wfDebug( __METHOD__ . ": setting cache mode $mode\n" );
 472                 $this->mCacheMode = $mode;
 473         }
 474
 475         /**
 476          * Set directives (key/value pairs) for the Cache-Control header.
 477          * Boolean values will be formatted as such, by including or omitting
 478          * without an equals sign.
 479          *
 480          * Cache control values set here will only be used if the cache mode is not
 481          * private, see setCacheMode().
 482          *
 483          * @param array $directives
 484          */
 485         public function setCacheControl( $directives ) {
 486                 $this->mCacheControl = $directives + $this->mCacheControl;
 487         }
 488
 489         /**
 490          * Create an instance of an output formatter by its name
 491          *
 492          * @param string $format
 493          *
 494          * @return ApiFormatBase
 495          */
 496         public function createPrinterByName( $format ) {
 497                 $printer = $this->mModuleMgr->getModule( $format, 'format' );
 498                 if ( $printer === null ) {
 499                         $this->dieWithError(
 500                                 [ 'apierror-unknownformat', wfEscapeWikiText( $format ) ], 'unknown_format'
 501                         );
 502                 }
 503
 504                 return $printer;
 505         }
 506
 507         /**
 508          * Execute api request. Any errors will be handled if the API was called by the remote client.
 509          */
 510         public function execute() {
 511                 if ( $this->mInternalMode ) {
 512                         $this->executeAction();
 513                 } else {
 514                         $this->executeActionWithErrorHandling();
 515                 }
 516         }
 517
 518         /**
 519          * Execute an action, and in case of an error, erase whatever partial results
 520          * have been accumulated, and replace it with an error message and a help screen.
 521          */
 522         protected function executeActionWithErrorHandling() {
 523                 // Verify the CORS header before executing the action
 524                 if ( !$this->handleCORS() ) {
 525                         // handleCORS() has sent a 403, abort
 526                         return;
 527                 }
 528
 529                 // Exit here if the request method was OPTIONS
 530                 // (assume there will be a followup GET or POST)
 531                 if ( $this->getRequest()->getMethod() === 'OPTIONS' ) {
 532                         return;
 533                 }
 534
 535                 // In case an error occurs during data output,
 536                 // clear the output buffer and print just the error information
 537                 $obLevel = ob_get_level();
 538                 ob_start();
 539
 540                 $t = microtime( true );
 541                 $isError = false;
 542                 try {
 543                         $this->executeAction();
 544                         $runTime = microtime( true ) - $t;
 545                         $this->logRequest( $runTime );
 546                         if ( $this->mModule->isWriteMode() && $this->getRequest()->wasPosted() ) {
 547                                 $this->getStats()->timing(
 548                                         'api.' . $this->mModule->getModuleName() . '.executeTiming', 1000 * $runTime
 549                                 );
 550                         }
 551                 } catch ( Exception $e ) {
 552                         $this->handleException( $e );
 553                         $this->logRequest( microtime( true ) - $t, $e );
 554                         $isError = true;
 555                 }
 556
 557                 // Commit DBs and send any related cookies and headers
 558                 MediaWiki::preOutputCommit( $this->getContext() );
 559
 560                 // Send cache headers after any code which might generate an error, to
 561                 // avoid sending public cache headers for errors.
 562                 $this->sendCacheHeaders( $isError );
 563
 564                 // Executing the action might have already messed with the output
 565                 // buffers.
 566                 while ( ob_get_level() > $obLevel ) {
 567                         ob_end_flush();
 568                 }
 569         }
 570
 571         /**
 572          * Handle an exception as an API response
 573          *
 574          * @since 1.23
 575          * @param Exception $e
 576          */
 577         protected function handleException( Exception $e ) {
 578                 // T65145: Rollback any open database transactions
 579                 if ( !( $e instanceof ApiUsageException || $e instanceof UsageException ) ) {
 580                         // UsageExceptions are intentional, so don't rollback if that's the case
 581                         try {
 582                                 MWExceptionHandler::rollbackMasterChangesAndLog( $e );
 583                         } catch ( DBError $e2 ) {
 584                                 // Rollback threw an exception too. Log it, but don't interrupt
 585                                 // our regularly scheduled exception handling.
 586                                 MWExceptionHandler::logException( $e2 );
 587                         }
 588                 }
 589
 590                 // Allow extra cleanup and logging
 591                 Hooks::run( 'ApiMain::onException', [ $this, $e ] );
 592
 593                 // Log it
 594                 if ( !( $e instanceof ApiUsageException || $e instanceof UsageException ) ) {
 595                         MWExceptionHandler::logException( $e );
 596                 }
 597
 598                 // Handle any kind of exception by outputting properly formatted error message.
 599                 // If this fails, an unhandled exception should be thrown so that global error
 600                 // handler will process and log it.
 601
 602                 $errCodes = $this->substituteResultWithError( $e );
 603
 604                 // Error results should not be cached
 605                 $this->setCacheMode( 'private' );
 606
 607                 $response = $this->getRequest()->response();
 608                 $headerStr = 'MediaWiki-API-Error: ' . join( ', ', $errCodes );
 609                 $response->header( $headerStr );
 610
 611                 // Reset and print just the error message
 612                 ob_clean();
 613
 614                 // Printer may not be initialized if the extractRequestParams() fails for the main module
 615                 $this->createErrorPrinter();
 616
 617                 $failed = false;
 618                 try {
 619                         $this->printResult( $e->getCode() );
 620                 } catch ( ApiUsageException $ex ) {
 621                         // The error printer itself is failing. Try suppressing its request
 622                         // parameters and redo.
 623                         $failed = true;
 624                         $this->addWarning( 'apiwarn-errorprinterfailed' );
 625                         foreach ( $ex->getStatusValue()->getErrors() as $error ) {
 626                                 try {
 627                                         $this->mPrinter->addWarning( $error );
 628                                 } catch ( Exception $ex2 ) {
 629                                         // WTF?
 630                                         $this->addWarning( $error );
 631                                 }
 632                         }
 633                 } catch ( UsageException $ex ) {
 634                         // The error printer itself is failing. Try suppressing its request
 635                         // parameters and redo.
 636                         $failed = true;
 637                         $this->addWarning(
 638                                 [ 'apiwarn-errorprinterfailed-ex', $ex->getMessage() ], 'errorprinterfailed'
 639                         );
 640                 }
 641                 if ( $failed ) {
 642                         $this->mPrinter = null;
 643                         $this->createErrorPrinter();
 644                         $this->mPrinter->forceDefaultParams();
 645                         if ( $e->getCode() ) {
 646                                 $response->statusHeader( 200 ); // Reset in case the fallback doesn't want a non-200
 647                         }
 648                         $this->printResult( $e->getCode() );
 649                 }
 650         }
 651
 652         /**
 653          * Handle an exception from the ApiBeforeMain hook.
 654          *
 655          * This tries to print the exception as an API response, to be more
 656          * friendly to clients. If it fails, it will rethrow the exception.
 657          *
 658          * @since 1.23
 659          * @param Exception $e
 660          * @throws Exception
 661          */
 662         public static function handleApiBeforeMainException( Exception $e ) {
 663                 ob_start();
 664
 665                 try {
 666                         $main = new self( RequestContext::getMain(), false );
 667                         $main->handleException( $e );
 668                         $main->logRequest( 0, $e );
 669                 } catch ( Exception $e2 ) {
 670                         // Nope, even that didn't work. Punt.
 671                         throw $e;
 672                 }
 673
 674                 // Reset cache headers
 675                 $main->sendCacheHeaders( true );
 676
 677                 ob_end_flush();
 678         }
 679
 680         /**
 681          * Check the &origin= query parameter against the Origin: HTTP header and respond appropriately.
 682          *
 683          * If no origin parameter is present, nothing happens.
 684          * If an origin parameter is present but doesn't match the Origin header, a 403 status code
 685          * is set and false is returned.
 686          * If the parameter and the header do match, the header is checked against $wgCrossSiteAJAXdomains
 687          * and $wgCrossSiteAJAXdomainExceptions, and if the origin qualifies, the appropriate CORS
 688          * headers are set.
 689          * https://www.w3.org/TR/cors/#resource-requests
 690          * https://www.w3.org/TR/cors/#resource-preflight-requests
 691          *
 692          * @return bool False if the caller should abort (403 case), true otherwise (all other cases)
 693          */
 694         protected function handleCORS() {
 695                 $originParam = $this->getParameter( 'origin' ); // defaults to null
 696                 if ( $originParam === null ) {
 697                         // No origin parameter, nothing to do
 698                         return true;
 699                 }
 700
 701                 $request = $this->getRequest();
 702                 $response = $request->response();
 703
 704                 $matchOrigin = false;
 705                 $allowTiming = false;
 706                 $varyOrigin = true;
 707
 708                 if ( $originParam === '*' ) {
 709                         // Request for anonymous CORS
 710                         $matchOrigin = true;
 711                         $allowOrigin = '*';
 712                         $allowCredentials = 'false';
 713                         $varyOrigin = false; // No need to vary
 714                 } else {
 715                         // Non-anonymous CORS, check we allow the domain
 716
 717                         // Origin: header is a space-separated list of origins, check all of them
 718                         $originHeader = $request->getHeader( 'Origin' );
 719                         if ( $originHeader === false ) {
 720                                 $origins = [];
 721                         } else {
 722                                 $originHeader = trim( $originHeader );
 723                                 $origins = preg_split( '/\s+/', $originHeader );
 724                         }
 725
 726                         if ( !in_array( $originParam, $origins ) ) {
 727                                 // origin parameter set but incorrect
 728                                 // Send a 403 response
 729                                 $response->statusHeader( 403 );
 730                                 $response->header( 'Cache-Control: no-cache' );
 731                                 echo "'origin' parameter does not match Origin header\n";
 732
 733                                 return false;
 734                         }
 735
 736                         $config = $this->getConfig();
 737                         $matchOrigin = count( $origins ) === 1 && self::matchOrigin(
 738                                 $originParam,
 739                                 $config->get( 'CrossSiteAJAXdomains' ),
 740                                 $config->get( 'CrossSiteAJAXdomainExceptions' )
 741                         );
 742
 743                         $allowOrigin = $originHeader;
 744                         $allowCredentials = 'true';
 745                         $allowTiming = $originHeader;
 746                 }
 747
 748                 if ( $matchOrigin ) {
 749                         $requestedMethod = $request->getHeader( 'Access-Control-Request-Method' );
 750                         $preflight = $request->getMethod() === 'OPTIONS' && $requestedMethod !== false;
 751                         if ( $preflight ) {
 752                                 // This is a CORS preflight request
 753                                 if ( $requestedMethod !== 'POST' && $requestedMethod !== 'GET' ) {
 754                                         // If method is not a case-sensitive match, do not set any additional headers and terminate.
 755                                         return true;
 756                                 }
 757                                 // We allow the actual request to send the following headers
 758                                 $requestedHeaders = $request->getHeader( 'Access-Control-Request-Headers' );
 759                                 if ( $requestedHeaders !== false ) {
 760                                         if ( !self::matchRequestedHeaders( $requestedHeaders ) ) {
 761                                                 return true;
 762                                         }
 763                                         $response->header( 'Access-Control-Allow-Headers: ' . $requestedHeaders );
 764                                 }
 765
 766                                 // We only allow the actual request to be GET or POST
 767                                 $response->header( 'Access-Control-Allow-Methods: POST, GET' );
 768                         }
 769
 770                         $response->header( "Access-Control-Allow-Origin: $allowOrigin" );
 771                         $response->header( "Access-Control-Allow-Credentials: $allowCredentials" );
 772                         // https://www.w3.org/TR/resource-timing/#timing-allow-origin
 773                         if ( $allowTiming !== false ) {
 774                                 $response->header( "Timing-Allow-Origin: $allowTiming" );
 775                         }
 776
 777                         if ( !$preflight ) {
 778                                 $response->header(
 779                                         'Access-Control-Expose-Headers: MediaWiki-API-Error, Retry-After, X-Database-Lag'
 780                                 );
 781                         }
 782                 }
 783
 784                 if ( $varyOrigin ) {
 785                         $this->getOutput()->addVaryHeader( 'Origin' );
 786                 }
 787
 788                 return true;
 789         }
 790
 791         /**
 792          * Attempt to match an Origin header against a set of rules and a set of exceptions
 793          * @param string $value Origin header
 794          * @param array $rules Set of wildcard rules
 795          * @param array $exceptions Set of wildcard rules
 796          * @return bool True if $value matches a rule in $rules and doesn't match
 797          *    any rules in $exceptions, false otherwise
 798          */
 799         protected static function matchOrigin( $value, $rules, $exceptions ) {
 800                 foreach ( $rules as $rule ) {
 801                         if ( preg_match( self::wildcardToRegex( $rule ), $value ) ) {
 802                                 // Rule matches, check exceptions
 803                                 foreach ( $exceptions as $exc ) {
 804                                         if ( preg_match( self::wildcardToRegex( $exc ), $value ) ) {
 805                                                 return false;
 806                                         }
 807                                 }
 808
 809                                 return true;
 810                         }
 811                 }
 812
 813                 return false;
 814         }
 815
 816         /**
 817          * Attempt to validate the value of Access-Control-Request-Headers against a list
 818          * of headers that we allow the follow up request to send.
 819          *
 820          * @param string $requestedHeaders Comma seperated list of HTTP headers
 821          * @return bool True if all requested headers are in the list of allowed headers
 822          */
 823         protected static function matchRequestedHeaders( $requestedHeaders ) {
 824                 if ( trim( $requestedHeaders ) === '' ) {
 825                         return true;
 826                 }
 827                 $requestedHeaders = explode( ',', $requestedHeaders );
 828                 $allowedAuthorHeaders = array_flip( [
 829                         /* simple headers (see spec) */
 830                         'accept',
 831                         'accept-language',
 832                         'content-language',
 833                         'content-type',
 834                         /* non-authorable headers in XHR, which are however requested by some UAs */
 835                         'accept-encoding',
 836                         'dnt',
 837                         'origin',
 838                         /* MediaWiki whitelist */
 839                         'api-user-agent',
 840                 ] );
 841                 foreach ( $requestedHeaders as $rHeader ) {
 842                         $rHeader = strtolower( trim( $rHeader ) );
 843                         if ( !isset( $allowedAuthorHeaders[$rHeader] ) ) {
 844                                 wfDebugLog( 'api', 'CORS preflight failed on requested header: ' . $rHeader );
 845                                 return false;
 846                         }
 847                 }
 848                 return true;
 849         }
 850
 851         /**
 852          * Helper function to convert wildcard string into a regex
 853          * '*' => '.*?'
 854          * '?' => '.'
 855          *
 856          * @param string $wildcard String with wildcards
 857          * @return string Regular expression
 858          */
 859         protected static function wildcardToRegex( $wildcard ) {
 860                 $wildcard = preg_quote( $wildcard, '/' );
 861                 $wildcard = str_replace(
 862                         [ '\*', '\?' ],
 863                         [ '.*?', '.' ],
 864                         $wildcard
 865                 );
 866
 867                 return "/^https?:\/\/$wildcard$/";
 868         }
 869
 870         /**
 871          * Send caching headers
 872          * @param bool $isError Whether an error response is being output
 873          * @since 1.26 added $isError parameter
 874          */
 875         protected function sendCacheHeaders( $isError ) {
 876                 $response = $this->getRequest()->response();
 877                 $out = $this->getOutput();
 878
 879                 $out->addVaryHeader( 'Treat-as-Untrusted' );
 880
 881                 $config = $this->getConfig();
 882
 883                 if ( $config->get( 'VaryOnXFP' ) ) {
 884                         $out->addVaryHeader( 'X-Forwarded-Proto' );
 885                 }
 886
 887                 if ( !$isError && $this->mModule &&
 888                         ( $this->getRequest()->getMethod() === 'GET' || $this->getRequest()->getMethod() === 'HEAD' )
 889                 ) {
 890                         $etag = $this->mModule->getConditionalRequestData( 'etag' );
 891                         if ( $etag !== null ) {
 892                                 $response->header( "ETag: $etag" );
 893                         }
 894                         $lastMod = $this->mModule->getConditionalRequestData( 'last-modified' );
 895                         if ( $lastMod !== null ) {
 896                                 $response->header( 'Last-Modified: ' . wfTimestamp( TS_RFC2822, $lastMod ) );
 897                         }
 898                 }
 899
 900                 // The logic should be:
 901                 // $this->mCacheControl['max-age'] is set?
 902                 //    Use it, the module knows better than our guess.
 903                 // !$this->mModule || $this->mModule->isWriteMode(), and mCacheMode is private?
 904                 //    Use 0 because we can guess caching is probably the wrong thing to do.
 905                 // Use $this->getParameter( 'maxage' ), which already defaults to 0.
 906                 $maxage = 0;
 907                 if ( isset( $this->mCacheControl['max-age'] ) ) {
 908                         $maxage = $this->mCacheControl['max-age'];
 909                 } elseif ( ( $this->mModule && !$this->mModule->isWriteMode() ) ||
 910                         $this->mCacheMode !== 'private'
 911                 ) {
 912                         $maxage = $this->getParameter( 'maxage' );
 913                 }
 914                 $privateCache = 'private, must-revalidate, max-age=' . $maxage;
 915
 916                 if ( $this->mCacheMode == 'private' ) {
 917                         $response->header( "Cache-Control: $privateCache" );
 918                         return;
 919                 }
 920
 921                 $useKeyHeader = $config->get( 'UseKeyHeader' );
 922                 if ( $this->mCacheMode == 'anon-public-user-private' ) {
 923                         $out->addVaryHeader( 'Cookie' );
 924                         $response->header( $out->getVaryHeader() );
 925                         if ( $useKeyHeader ) {
 926                                 $response->header( $out->getKeyHeader() );
 927                                 if ( $out->haveCacheVaryCookies() ) {
 928                                         // Logged in, mark this request private
 929                                         $response->header( "Cache-Control: $privateCache" );
 930                                         return;
 931                                 }
 932                                 // Logged out, send normal public headers below
 933                         } elseif ( MediaWiki\Session\SessionManager::getGlobalSession()->isPersistent() ) {
 934                                 // Logged in or otherwise has session (e.g. anonymous users who have edited)
 935                                 // Mark request private
 936                                 $response->header( "Cache-Control: $privateCache" );
 937
 938                                 return;
 939                         } // else no Key and anonymous, send public headers below
 940                 }
 941
 942                 // Send public headers
 943                 $response->header( $out->getVaryHeader() );
 944                 if ( $useKeyHeader ) {
 945                         $response->header( $out->getKeyHeader() );
 946                 }
 947
 948                 // If nobody called setCacheMaxAge(), use the (s)maxage parameters
 949                 if ( !isset( $this->mCacheControl['s-maxage'] ) ) {
 950                         $this->mCacheControl['s-maxage'] = $this->getParameter( 'smaxage' );
 951                 }
 952                 if ( !isset( $this->mCacheControl['max-age'] ) ) {
 953                         $this->mCacheControl['max-age'] = $this->getParameter( 'maxage' );
 954                 }
 955
 956                 if ( !$this->mCacheControl['s-maxage'] && !$this->mCacheControl['max-age'] ) {
 957                         // Public cache not requested
 958                         // Sending a Vary header in this case is harmless, and protects us
 959                         // against conditional calls of setCacheMaxAge().
 960                         $response->header( "Cache-Control: $privateCache" );
 961
 962                         return;
 963                 }
 964
 965                 $this->mCacheControl['public'] = true;
 966
 967                 // Send an Expires header
 968                 $maxAge = min( $this->mCacheControl['s-maxage'], $this->mCacheControl['max-age'] );
 969                 $expiryUnixTime = ( $maxAge == 0 ? 1 : time() + $maxAge );
 970                 $response->header( 'Expires: ' . wfTimestamp( TS_RFC2822, $expiryUnixTime ) );
 971
 972                 // Construct the Cache-Control header
 973                 $ccHeader = '';
 974                 $separator = '';
 975                 foreach ( $this->mCacheControl as $name => $value ) {
 976                         if ( is_bool( $value ) ) {
 977                                 if ( $value ) {
 978                                         $ccHeader .= $separator . $name;
 979                                         $separator = ', ';
 980                                 }
 981                         } else {
 982                                 $ccHeader .= $separator . "$name=$value";
 983                                 $separator = ', ';
 984                         }
 985                 }
 986
 987                 $response->header( "Cache-Control: $ccHeader" );
 988         }
 989
 990         /**
 991          * Create the printer for error output
 992          */
 993         private function createErrorPrinter() {
 994                 if ( !isset( $this->mPrinter ) ) {
 995                         $value = $this->getRequest()->getVal( 'format', self::API_DEFAULT_FORMAT );
 996                         if ( !$this->mModuleMgr->isDefined( $value, 'format' ) ) {
 997                                 $value = self::API_DEFAULT_FORMAT;
 998                         }
 999                         $this->mPrinter = $this->createPrinterByName( $value );
1000                 }
1001
1002                 // Printer may not be able to handle errors. This is particularly
1003                 // likely if the module returns something for getCustomPrinter().
1004                 if ( !$this->mPrinter->canPrintErrors() ) {
1005                         $this->mPrinter = $this->createPrinterByName( self::API_DEFAULT_FORMAT );
1006                 }
1007         }
1008
1009         /**
1010          * Create an error message for the given exception.
1011          *
1012          * If an ApiUsageException, errors/warnings will be extracted from the
1013          * embedded StatusValue.
1014          *
1015          * If a base UsageException, the getMessageArray() method will be used to
1016          * extract the code and English message for a single error (no warnings).
1017          *
1018          * Any other exception will be returned with a generic code and wrapper
1019          * text around the exception's (presumably English) message as a single
1020          * error (no warnings).
1021          *
1022          * @param Exception $e
1023          * @param string $type 'error' or 'warning'
1024          * @return ApiMessage[]
1025          * @since 1.27
1026          */
1027         protected function errorMessagesFromException( $e, $type = 'error' ) {
1028                 $messages = [];
1029                 if ( $e instanceof ApiUsageException ) {
1030                         foreach ( $e->getStatusValue()->getErrorsByType( $type ) as $error ) {
1031                                 $messages[] = ApiMessage::create( $error );
1032                         }
1033                 } elseif ( $type !== 'error' ) {
1034                         // None of the rest have any messages for non-error types
1035                 } elseif ( $e instanceof UsageException ) {
1036                         // User entered incorrect parameters - generate error response
1037                         $data = $e->getMessageArray();
1038                         $code = $data['code'];
1039                         $info = $data['info'];
1040                         unset( $data['code'], $data['info'] );
1041                         $messages[] = new ApiRawMessage( [ '$1', $info ], $code, $data );
1042                 } else {
1043                         // Something is seriously wrong
1044                         $config = $this->getConfig();
1045                         $code = 'internal_api_error_' . get_class( $e );
1046                         if ( ( $e instanceof DBQueryError ) && !$config->get( 'ShowSQLErrors' ) ) {
1047                                 $params = [ 'apierror-databaseerror', WebRequest::getRequestId() ];
1048                         } else {
1049                                 $params = [
1050                                         'apierror-exceptioncaught',
1051                                         WebRequest::getRequestId(),
1052                                         $e instanceof ILocalizedException
1053                                                 ? $e->getMessageObject()
1054                                                 : wfEscapeWikiText( $e->getMessage() )
1055                                 ];
1056                         }
1057                         $messages[] = ApiMessage::create( $params, $code );
1058                 }
1059                 return $messages;
1060         }
1061
1062         /**
1063          * Replace the result data with the information about an exception.
1064          * @param Exception $e
1065          * @return string[] Error codes
1066          */
1067         protected function substituteResultWithError( $e ) {
1068                 $result = $this->getResult();
1069                 $formatter = $this->getErrorFormatter();
1070                 $config = $this->getConfig();
1071                 $errorCodes = [];
1072
1073                 // Remember existing warnings and errors across the reset
1074                 $errors = $result->getResultData( [ 'errors' ] );
1075                 $warnings = $result->getResultData( [ 'warnings' ] );
1076                 $result->reset();
1077                 if ( $warnings !== null ) {
1078                         $result->addValue( null, 'warnings', $warnings, ApiResult::NO_SIZE_CHECK );
1079                 }
1080                 if ( $errors !== null ) {
1081                         $result->addValue( null, 'errors', $errors, ApiResult::NO_SIZE_CHECK );
1082
1083                         // Collect the copied error codes for the return value
1084                         foreach ( $errors as $error ) {
1085                                 if ( isset( $error['code'] ) ) {
1086                                         $errorCodes[$error['code']] = true;
1087                                 }
1088                         }
1089                 }
1090
1091                 // Add errors from the exception
1092                 $modulePath = $e instanceof ApiUsageException ? $e->getModulePath() : null;
1093                 foreach ( $this->errorMessagesFromException( $e, 'error' ) as $msg ) {
1094                         $errorCodes[$msg->getApiCode()] = true;
1095                         $formatter->addError( $modulePath, $msg );
1096                 }
1097                 foreach ( $this->errorMessagesFromException( $e, 'warning' ) as $msg ) {
1098                         $formatter->addWarning( $modulePath, $msg );
1099                 }
1100
1101                 // Add additional data. Path depends on whether we're in BC mode or not.
1102                 // Data depends on the type of exception.
1103                 if ( $formatter instanceof ApiErrorFormatter_BackCompat ) {
1104                         $path = [ 'error' ];
1105                 } else {
1106                         $path = null;
1107                 }
1108                 if ( $e instanceof ApiUsageException || $e instanceof UsageException ) {
1109                         $link = wfExpandUrl( wfScript( 'api' ) );
1110                         $result->addContentValue(
1111                                 $path,
1112                                 'docref',
1113                                 trim(
1114                                         $this->msg( 'api-usage-docref', $link )->inLanguage( $formatter->getLanguage() )->text()
1115                                         . ' '
1116                                         . $this->msg( 'api-usage-mailinglist-ref' )->inLanguage( $formatter->getLanguage() )->text()
1117                                 )
1118                         );
1119                 } else {
1120                         if ( $config->get( 'ShowExceptionDetails' ) &&
1121                                 ( !$e instanceof DBError || $config->get( 'ShowDBErrorBacktrace' ) )
1122                         ) {
1123                                 $result->addContentValue(
1124                                         $path,
1125                                         'trace',
1126                                         $this->msg( 'api-exception-trace',
1127                                                 get_class( $e ),
1128                                                 $e->getFile(),
1129                                                 $e->getLine(),
1130                                                 MWExceptionHandler::getRedactedTraceAsString( $e )
1131                                         )->inLanguage( $formatter->getLanguage() )->text()
1132                                 );
1133                         }
1134                 }
1135
1136                 // Add the id and such
1137                 $this->addRequestedFields( [ 'servedby' ] );
1138
1139                 return array_keys( $errorCodes );
1140         }
1141
1142         /**
1143          * Add requested fields to the result
1144          * @param string[] $force Which fields to force even if not requested. Accepted values are:
1145          *  - servedby
1146          */
1147         protected function addRequestedFields( $force = [] ) {
1148                 $result = $this->getResult();
1149
1150                 $requestid = $this->getParameter( 'requestid' );
1151                 if ( $requestid !== null ) {
1152                         $result->addValue( null, 'requestid', $requestid, ApiResult::NO_SIZE_CHECK );
1153                 }
1154
1155                 if ( $this->getConfig()->get( 'ShowHostnames' ) && (
1156                         in_array( 'servedby', $force, true ) || $this->getParameter( 'servedby' )
1157                 ) ) {
1158                         $result->addValue( null, 'servedby', wfHostname(), ApiResult::NO_SIZE_CHECK );
1159                 }
1160
1161                 if ( $this->getParameter( 'curtimestamp' ) ) {
1162                         $result->addValue( null, 'curtimestamp', wfTimestamp( TS_ISO_8601, time() ),
1163                                 ApiResult::NO_SIZE_CHECK );
1164                 }
1165
1166                 if ( $this->getParameter( 'responselanginfo' ) ) {
1167                         $result->addValue( null, 'uselang', $this->getLanguage()->getCode(),
1168                                 ApiResult::NO_SIZE_CHECK );
1169                         $result->addValue( null, 'errorlang', $this->getErrorFormatter()->getLanguage()->getCode(),
1170                                 ApiResult::NO_SIZE_CHECK );
1171                 }
1172         }
1173
1174         /**
1175          * Set up for the execution.
1176          * @return array
1177          */
1178         protected function setupExecuteAction() {
1179                 $this->addRequestedFields();
1180
1181                 $params = $this->extractRequestParams();
1182                 $this->mAction = $params['action'];
1183
1184                 return $params;
1185         }
1186
1187         /**
1188          * Set up the module for response
1189          * @return ApiBase The module that will handle this action
1190          * @throws MWException
1191          * @throws ApiUsageException
1192          */
1193         protected function setupModule() {
1194                 // Instantiate the module requested by the user
1195                 $module = $this->mModuleMgr->getModule( $this->mAction, 'action' );
1196                 if ( $module === null ) {
1197                         $this->dieWithError(
1198                                 [ 'apierror-unknownaction', wfEscapeWikiText( $this->mAction ) ], 'unknown_action'
1199                         );
1200                 }
1201                 $moduleParams = $module->extractRequestParams();
1202
1203                 // Check token, if necessary
1204                 if ( $module->needsToken() === true ) {
1205                         throw new MWException(
1206                                 "Module '{$module->getModuleName()}' must be updated for the new token handling. " .
1207                                 'See documentation for ApiBase::needsToken for details.'
1208                         );
1209                 }
1210                 if ( $module->needsToken() ) {
1211                         if ( !$module->mustBePosted() ) {
1212                                 throw new MWException(
1213                                         "Module '{$module->getModuleName()}' must require POST to use tokens."
1214                                 );
1215                         }
1216
1217                         if ( !isset( $moduleParams['token'] ) ) {
1218                                 $module->dieWithError( [ 'apierror-missingparam', 'token' ] );
1219                         }
1220
1221                         $module->requirePostedParameters( [ 'token' ] );
1222
1223                         if ( !$module->validateToken( $moduleParams['token'], $moduleParams ) ) {
1224                                 $module->dieWithError( 'apierror-badtoken' );
1225                         }
1226                 }
1227
1228                 return $module;
1229         }
1230
1231         /**
1232          * Check the max lag if necessary
1233          * @param ApiBase $module Api module being used
1234          * @param array $params Array an array containing the request parameters.
1235          * @return bool True on success, false should exit immediately
1236          */
1237         protected function checkMaxLag( $module, $params ) {
1238                 if ( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
1239                         $maxLag = $params['maxlag'];
1240                         list( $host, $lag ) = wfGetLB()->getMaxLag();
1241                         if ( $lag > $maxLag ) {
1242                                 $response = $this->getRequest()->response();
1243
1244                                 $response->header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
1245                                 $response->header( 'X-Database-Lag: ' . intval( $lag ) );
1246
1247                                 if ( $this->getConfig()->get( 'ShowHostnames' ) ) {
1248                                         $this->dieWithError( [ 'apierror-maxlag', $lag, $host ] );
1249                                 }
1250
1251                                 $this->dieWithError( [ 'apierror-maxlag-generic', $lag ], 'maxlag' );
1252                         }
1253                 }
1254
1255                 return true;
1256         }
1257
1258         /**
1259          * Check selected RFC 7232 precondition headers
1260          *
1261          * RFC 7232 envisions a particular model where you send your request to "a
1262          * resource", and for write requests that you can read "the resource" by
1263          * changing the method to GET. When the API receives a GET request, it
1264          * works out even though "the resource" from RFC 7232's perspective might
1265          * be many resources from MediaWiki's perspective. But it totally fails for
1266          * a POST, since what HTTP sees as "the resource" is probably just
1267          * "/api.php" with all the interesting bits in the body.
1268          *
1269          * Therefore, we only support RFC 7232 precondition headers for GET (and
1270          * HEAD). That means we don't need to bother with If-Match and
1271          * If-Unmodified-Since since they only apply to modification requests.
1272          *
1273          * And since we don't support Range, If-Range is ignored too.
1274          *
1275          * @since 1.26
1276          * @param ApiBase $module Api module being used
1277          * @return bool True on success, false should exit immediately
1278          */
1279         protected function checkConditionalRequestHeaders( $module ) {
1280                 if ( $this->mInternalMode ) {
1281                         // No headers to check in internal mode
1282                         return true;
1283                 }
1284
1285                 if ( $this->getRequest()->getMethod() !== 'GET' && $this->getRequest()->getMethod() !== 'HEAD' ) {
1286                         // Don't check POSTs
1287                         return true;
1288                 }
1289
1290                 $return304 = false;
1291
1292                 $ifNoneMatch = array_diff(
1293                         $this->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST ) ?: [],
1294                         [ '' ]
1295                 );
1296                 if ( $ifNoneMatch ) {
1297                         if ( $ifNoneMatch === [ '*' ] ) {
1298                                 // API responses always "exist"
1299                                 $etag = '*';
1300                         } else {
1301                                 $etag = $module->getConditionalRequestData( 'etag' );
1302                         }
1303                 }
1304                 if ( $ifNoneMatch && $etag !== null ) {
1305                         $test = substr( $etag, 0, 2 ) === 'W/' ? substr( $etag, 2 ) : $etag;
1306                         $match = array_map( function ( $s ) {
1307                                 return substr( $s, 0, 2 ) === 'W/' ? substr( $s, 2 ) : $s;
1308                         }, $ifNoneMatch );
1309                         $return304 = in_array( $test, $match, true );
1310                 } else {
1311                         $value = trim( $this->getRequest()->getHeader( 'If-Modified-Since' ) );
1312
1313                         // Some old browsers sends sizes after the date, like this:
1314                         //  Wed, 20 Aug 2003 06:51:19 GMT; length=5202
1315                         // Ignore that.
1316                         $i = strpos( $value, ';' );
1317                         if ( $i !== false ) {
1318                                 $value = trim( substr( $value, 0, $i ) );
1319                         }
1320
1321                         if ( $value !== '' ) {
1322                                 try {
1323                                         $ts = new MWTimestamp( $value );
1324                                         if (
1325                                                 // RFC 7231 IMF-fixdate
1326                                                 $ts->getTimestamp( TS_RFC2822 ) === $value ||
1327                                                 // RFC 850
1328                                                 $ts->format( 'l, d-M-y H:i:s' ) . ' GMT' === $value ||
1329                                                 // asctime (with and without space-padded day)
1330                                                 $ts->format( 'D M j H:i:s Y' ) === $value ||
1331                                                 $ts->format( 'D M  j H:i:s Y' ) === $value
1332                                         ) {
1333                                                 $lastMod = $module->getConditionalRequestData( 'last-modified' );
1334                                                 if ( $lastMod !== null ) {
1335                                                         // Mix in some MediaWiki modification times
1336                                                         $modifiedTimes = [
1337                                                                 'page' => $lastMod,
1338                                                                 'user' => $this->getUser()->getTouched(),
1339                                                                 'epoch' => $this->getConfig()->get( 'CacheEpoch' ),
1340                                                         ];
1341                                                         if ( $this->getConfig()->get( 'UseSquid' ) ) {
1342                                                                 // T46570: the core page itself may not change, but resources might
1343                                                                 $modifiedTimes['sepoch'] = wfTimestamp(
1344                                                                         TS_MW, time() - $this->getConfig()->get( 'SquidMaxage' )
1345                                                                 );
1346                                                         }
1347                                                         Hooks::run( 'OutputPageCheckLastModified', [ &$modifiedTimes, $this->getOutput() ] );
1348                                                         $lastMod = max( $modifiedTimes );
1349                                                         $return304 = wfTimestamp( TS_MW, $lastMod ) <= $ts->getTimestamp( TS_MW );
1350                                                 }
1351                                         }
1352                                 } catch ( TimestampException $e ) {
1353                                         // Invalid timestamp, ignore it
1354                                 }
1355                         }
1356                 }
1357
1358                 if ( $return304 ) {
1359                         $this->getRequest()->response()->statusHeader( 304 );
1360
1361                         // Avoid outputting the compressed representation of a zero-length body
1362                         MediaWiki\suppressWarnings();
1363                         ini_set( 'zlib.output_compression', 0 );
1364                         MediaWiki\restoreWarnings();
1365                         wfClearOutputBuffers();
1366
1367                         return false;
1368                 }
1369
1370                 return true;
1371         }
1372
1373         /**
1374          * Check for sufficient permissions to execute
1375          * @param ApiBase $module An Api module
1376          */
1377         protected function checkExecutePermissions( $module ) {
1378                 $user = $this->getUser();
1379                 if ( $module->isReadMode() && !User::isEveryoneAllowed( 'read' ) &&
1380                         !$user->isAllowed( 'read' )
1381                 ) {
1382                         $this->dieWithError( 'apierror-readapidenied' );
1383                 }
1384
1385                 if ( $module->isWriteMode() ) {
1386                         if ( !$this->mEnableWrite ) {
1387                                 $this->dieWithError( 'apierror-noapiwrite' );
1388                         } elseif ( !$user->isAllowed( 'writeapi' ) ) {
1389                                 $this->dieWithError( 'apierror-writeapidenied' );
1390                         } elseif ( $this->getRequest()->getHeader( 'Promise-Non-Write-API-Action' ) ) {
1391                                 $this->dieWithError( 'apierror-promised-nonwrite-api' );
1392                         }
1393
1394                         $this->checkReadOnly( $module );
1395                 }
1396
1397                 // Allow extensions to stop execution for arbitrary reasons.
1398                 $message = false;
1399                 if ( !Hooks::run( 'ApiCheckCanExecute', [ $module, $user, &$message ] ) ) {
1400                         $this->dieWithError( $message );
1401                 }
1402         }
1403
1404         /**
1405          * Check if the DB is read-only for this user
1406          * @param ApiBase $module An Api module
1407          */
1408         protected function checkReadOnly( $module ) {
1409                 if ( wfReadOnly() ) {
1410                         $this->dieReadOnly();
1411                 }
1412
1413                 if ( $module->isWriteMode()
1414                         && $this->getUser()->isBot()
1415                         && wfGetLB()->getServerCount() > 1
1416                 ) {
1417                         $this->checkBotReadOnly();
1418                 }
1419         }
1420
1421         /**
1422          * Check whether we are readonly for bots
1423          */
1424         private function checkBotReadOnly() {
1425                 // Figure out how many servers have passed the lag threshold
1426                 $numLagged = 0;
1427                 $lagLimit = $this->getConfig()->get( 'APIMaxLagThreshold' );
1428                 $laggedServers = [];
1429                 $loadBalancer = wfGetLB();
1430                 foreach ( $loadBalancer->getLagTimes() as $serverIndex => $lag ) {
1431                         if ( $lag > $lagLimit ) {
1432                                 ++$numLagged;
1433                                 $laggedServers[] = $loadBalancer->getServerName( $serverIndex ) . " ({$lag}s)";
1434                         }
1435                 }
1436
1437                 // If a majority of replica DBs are too lagged then disallow writes
1438                 $replicaCount = wfGetLB()->getServerCount() - 1;
1439                 if ( $numLagged >= ceil( $replicaCount / 2 ) ) {
1440                         $laggedServers = implode( ', ', $laggedServers );
1441                         wfDebugLog(
1442                                 'api-readonly',
1443                                 "Api request failed as read only because the following DBs are lagged: $laggedServers"
1444                         );
1445
1446                         $this->dieWithError(
1447                                 'readonly_lag',
1448                                 'readonly',
1449                                 [ 'readonlyreason' => "Waiting for $numLagged lagged database(s)" ]
1450                         );
1451                 }
1452         }
1453
1454         /**
1455          * Check asserts of the user's rights
1456          * @param array $params
1457          */
1458         protected function checkAsserts( $params ) {
1459                 if ( isset( $params['assert'] ) ) {
1460                         $user = $this->getUser();
1461                         switch ( $params['assert'] ) {
1462                                 case 'user':
1463                                         if ( $user->isAnon() ) {
1464                                                 $this->dieWithError( 'apierror-assertuserfailed' );
1465                                         }
1466                                         break;
1467                                 case 'bot':
1468                                         if ( !$user->isAllowed( 'bot' ) ) {
1469                                                 $this->dieWithError( 'apierror-assertbotfailed' );
1470                                         }
1471                                         break;
1472                         }
1473                 }
1474                 if ( isset( $params['assertuser'] ) ) {
1475                         $assertUser = User::newFromName( $params['assertuser'], false );
1476                         if ( !$assertUser || !$this->getUser()->equals( $assertUser ) ) {
1477                                 $this->dieWithError(
1478                                         [ 'apierror-assertnameduserfailed', wfEscapeWikiText( $params['assertuser'] ) ]
1479                                 );
1480                         }
1481                 }
1482         }
1483
1484         /**
1485          * Check POST for external response and setup result printer
1486          * @param ApiBase $module An Api module
1487          * @param array $params An array with the request parameters
1488          */
1489         protected function setupExternalResponse( $module, $params ) {
1490                 $request = $this->getRequest();
1491                 if ( !$request->wasPosted() && $module->mustBePosted() ) {
1492                         // Module requires POST. GET request might still be allowed
1493                         // if $wgDebugApi is true, otherwise fail.
1494                         $this->dieWithErrorOrDebug( [ 'apierror-mustbeposted', $this->mAction ] );
1495                 }
1496
1497                 // See if custom printer is used
1498                 $this->mPrinter = $module->getCustomPrinter();
1499                 if ( is_null( $this->mPrinter ) ) {
1500                         // Create an appropriate printer
1501                         $this->mPrinter = $this->createPrinterByName( $params['format'] );
1502                 }
1503
1504                 if ( $request->getProtocol() === 'http' && (
1505                         $request->getSession()->shouldForceHTTPS() ||
1506                         ( $this->getUser()->isLoggedIn() &&
1507                                 $this->getUser()->requiresHTTPS() )
1508                 ) ) {
1509                         $this->addDeprecation( 'apiwarn-deprecation-httpsexpected', 'https-expected' );
1510                 }
1511         }
1512
1513         /**
1514          * Execute the actual module, without any error handling
1515          */
1516         protected function executeAction() {
1517                 $params = $this->setupExecuteAction();
1518                 $module = $this->setupModule();
1519                 $this->mModule = $module;
1520
1521                 if ( !$this->mInternalMode ) {
1522                         $this->setRequestExpectations( $module );
1523                 }
1524
1525                 $this->checkExecutePermissions( $module );
1526
1527                 if ( !$this->checkMaxLag( $module, $params ) ) {
1528                         return;
1529                 }
1530
1531                 if ( !$this->checkConditionalRequestHeaders( $module ) ) {
1532                         return;
1533                 }
1534
1535                 if ( !$this->mInternalMode ) {
1536                         $this->setupExternalResponse( $module, $params );
1537                 }
1538
1539                 $this->checkAsserts( $params );
1540
1541                 // Execute
1542                 $module->execute();
1543                 Hooks::run( 'APIAfterExecute', [ &$module ] );
1544
1545                 $this->reportUnusedParams();
1546
1547                 if ( !$this->mInternalMode ) {
1548                         // append Debug information
1549                         MWDebug::appendDebugInfoToApiResult( $this->getContext(), $this->getResult() );
1550
1551                         // Print result data
1552                         $this->printResult();
1553                 }
1554         }
1555
1556         /**
1557          * Set database connection, query, and write expectations given this module request
1558          * @param ApiBase $module
1559          */
1560         protected function setRequestExpectations( ApiBase $module ) {
1561                 $limits = $this->getConfig()->get( 'TrxProfilerLimits' );
1562                 $trxProfiler = Profiler::instance()->getTransactionProfiler();
1563                 $trxProfiler->setLogger( LoggerFactory::getInstance( 'DBPerformance' ) );
1564                 if ( $this->getRequest()->hasSafeMethod() ) {
1565                         $trxProfiler->setExpectations( $limits['GET'], __METHOD__ );
1566                 } elseif ( $this->getRequest()->wasPosted() && !$module->isWriteMode() ) {
1567                         $trxProfiler->setExpectations( $limits['POST-nonwrite'], __METHOD__ );
1568                         $this->getRequest()->markAsSafeRequest();
1569                 } else {
1570                         $trxProfiler->setExpectations( $limits['POST'], __METHOD__ );
1571                 }
1572         }
1573
1574         /**
1575          * Log the preceding request
1576          * @param float $time Time in seconds
1577          * @param Exception $e Exception caught while processing the request
1578          */
1579         protected function logRequest( $time, $e = null ) {
1580                 $request = $this->getRequest();
1581                 $logCtx = [
1582                         'ts' => time(),
1583                         'ip' => $request->getIP(),
1584                         'userAgent' => $this->getUserAgent(),
1585                         'wiki' => wfWikiID(),
1586                         'timeSpentBackend' => (int)round( $time * 1000 ),
1587                         'hadError' => $e !== null,
1588                         'errorCodes' => [],
1589                         'params' => [],
1590                 ];
1591
1592                 if ( $e ) {
1593                         foreach ( $this->errorMessagesFromException( $e ) as $msg ) {
1594                                 $logCtx['errorCodes'][] = $msg->getApiCode();
1595                         }
1596                 }
1597
1598                 // Construct space separated message for 'api' log channel
1599                 $msg = "API {$request->getMethod()} " .
1600                         wfUrlencode( str_replace( ' ', '_', $this->getUser()->getName() ) ) .
1601                         " {$logCtx['ip']} " .
1602                         "T={$logCtx['timeSpentBackend']}ms";
1603
1604                 foreach ( $this->getParamsUsed() as $name ) {
1605                         $value = $request->getVal( $name );
1606                         if ( $value === null ) {
1607                                 continue;
1608                         }
1609
1610                         if ( strlen( $value ) > 256 ) {
1611                                 $value = substr( $value, 0, 256 );
1612                                 $encValue = $this->encodeRequestLogValue( $value ) . '[...]';
1613                         } else {
1614                                 $encValue = $this->encodeRequestLogValue( $value );
1615                         }
1616
1617                         $logCtx['params'][$name] = $value;
1618                         $msg .= " {$name}={$encValue}";
1619                 }
1620
1621                 wfDebugLog( 'api', $msg, 'private' );
1622                 // ApiAction channel is for structured data consumers
1623                 wfDebugLog( 'ApiAction', '', 'private', $logCtx );
1624         }
1625
1626         /**
1627          * Encode a value in a format suitable for a space-separated log line.
1628          * @param string $s
1629          * @return string
1630          */
1631         protected function encodeRequestLogValue( $s ) {
1632                 static $table;
1633                 if ( !$table ) {
1634                         $chars = ';@$!*(),/:';
1635                         $numChars = strlen( $chars );
1636                         for ( $i = 0; $i < $numChars; $i++ ) {
1637                                 $table[rawurlencode( $chars[$i] )] = $chars[$i];
1638                         }
1639                 }
1640
1641                 return strtr( rawurlencode( $s ), $table );
1642         }
1643
1644         /**
1645          * Get the request parameters used in the course of the preceding execute() request
1646          * @return array
1647          */
1648         protected function getParamsUsed() {
1649                 return array_keys( $this->mParamsUsed );
1650         }
1651
1652         /**
1653          * Mark parameters as used
1654          * @param string|string[] $params
1655          */
1656         public function markParamsUsed( $params ) {
1657                 $this->mParamsUsed += array_fill_keys( (array)$params, true );
1658         }
1659
1660         /**
1661          * Get a request value, and register the fact that it was used, for logging.
1662          * @param string $name
1663          * @param mixed $default
1664          * @return mixed
1665          */
1666         public function getVal( $name, $default = null ) {
1667                 $this->mParamsUsed[$name] = true;
1668
1669                 $ret = $this->getRequest()->getVal( $name );
1670                 if ( $ret === null ) {
1671                         if ( $this->getRequest()->getArray( $name ) !== null ) {
1672                                 // See T12262 for why we don't just implode( '|', ... ) the
1673                                 // array.
1674                                 $this->addWarning( [ 'apiwarn-unsupportedarray', $name ] );
1675                         }
1676                         $ret = $default;
1677                 }
1678                 return $ret;
1679         }
1680
1681         /**
1682          * Get a boolean request value, and register the fact that the parameter
1683          * was used, for logging.
1684          * @param string $name
1685          * @return bool
1686          */
1687         public function getCheck( $name ) {
1688                 return $this->getVal( $name, null ) !== null;
1689         }
1690
1691         /**
1692          * Get a request upload, and register the fact that it was used, for logging.
1693          *
1694          * @since 1.21
1695          * @param string $name Parameter name
1696          * @return WebRequestUpload
1697          */
1698         public function getUpload( $name ) {
1699                 $this->mParamsUsed[$name] = true;
1700
1701                 return $this->getRequest()->getUpload( $name );
1702         }
1703
1704         /**
1705          * Report unused parameters, so the client gets a hint in case it gave us parameters we don't know,
1706          * for example in case of spelling mistakes or a missing 'g' prefix for generators.
1707          */
1708         protected function reportUnusedParams() {
1709                 $paramsUsed = $this->getParamsUsed();
1710                 $allParams = $this->getRequest()->getValueNames();
1711
1712                 if ( !$this->mInternalMode ) {
1713                         // Printer has not yet executed; don't warn that its parameters are unused
1714                         $printerParams = $this->mPrinter->encodeParamName(
1715                                 array_keys( $this->mPrinter->getFinalParams() ?: [] )
1716                         );
1717                         $unusedParams = array_diff( $allParams, $paramsUsed, $printerParams );
1718                 } else {
1719                         $unusedParams = array_diff( $allParams, $paramsUsed );
1720                 }
1721
1722                 if ( count( $unusedParams ) ) {
1723                         $this->addWarning( [
1724                                 'apierror-unrecognizedparams',
1725                                 Message::listParam( array_map( 'wfEscapeWikiText', $unusedParams ), 'comma' ),
1726                                 count( $unusedParams )
1727                         ] );
1728                 }
1729         }
1730
1731         /**
1732          * Print results using the current printer
1733          *
1734          * @param int $httpCode HTTP status code, or 0 to not change
1735          */
1736         protected function printResult( $httpCode = 0 ) {
1737                 if ( $this->getConfig()->get( 'DebugAPI' ) !== false ) {
1738                         $this->addWarning( 'apiwarn-wgDebugAPI' );
1739                 }
1740
1741                 $printer = $this->mPrinter;
1742                 $printer->initPrinter( false );
1743                 if ( $httpCode ) {
1744                         $printer->setHttpStatus( $httpCode );
1745                 }
1746                 $printer->execute();
1747                 $printer->closePrinter();
1748         }
1749
1750         /**
1751          * @return bool
1752          */
1753         public function isReadMode() {
1754                 return false;
1755         }
1756
1757         /**
1758          * See ApiBase for description.
1759          *
1760          * @return array
1761          */
1762         public function getAllowedParams() {
1763                 return [
1764                         'action' => [
1765                                 ApiBase::PARAM_DFLT => 'help',
1766                                 ApiBase::PARAM_TYPE => 'submodule',
1767                         ],
1768                         'format' => [
1769                                 ApiBase::PARAM_DFLT => ApiMain::API_DEFAULT_FORMAT,
1770                                 ApiBase::PARAM_TYPE => 'submodule',
1771                         ],
1772                         'maxlag' => [
1773                                 ApiBase::PARAM_TYPE => 'integer'
1774                         ],
1775                         'smaxage' => [
1776                                 ApiBase::PARAM_TYPE => 'integer',
1777                                 ApiBase::PARAM_DFLT => 0
1778                         ],
1779                         'maxage' => [
1780                                 ApiBase::PARAM_TYPE => 'integer',
1781                                 ApiBase::PARAM_DFLT => 0
1782                         ],
1783                         'assert' => [
1784                                 ApiBase::PARAM_TYPE => [ 'user', 'bot' ]
1785                         ],
1786                         'assertuser' => [
1787                                 ApiBase::PARAM_TYPE => 'user',
1788                         ],
1789                         'requestid' => null,
1790                         'servedby' => false,
1791                         'curtimestamp' => false,
1792                         'responselanginfo' => false,
1793                         'origin' => null,
1794                         'uselang' => [
1795                                 ApiBase::PARAM_DFLT => self::API_DEFAULT_USELANG,
1796                         ],
1797                         'errorformat' => [
1798                                 ApiBase::PARAM_TYPE => [ 'plaintext', 'wikitext', 'html', 'raw', 'none', 'bc' ],
1799                                 ApiBase::PARAM_DFLT => 'bc',
1800                         ],
1801                         'errorlang' => [
1802                                 ApiBase::PARAM_DFLT => 'uselang',
1803                         ],
1804                         'errorsuselocal' => [
1805                                 ApiBase::PARAM_DFLT => false,
1806                         ],
1807                 ];
1808         }
1809
1810         /** @see ApiBase::getExamplesMessages() */
1811         protected function getExamplesMessages() {
1812                 return [
1813                         'action=help'
1814                                 => 'apihelp-help-example-main',
1815                         'action=help&recursivesubmodules=1'
1816                                 => 'apihelp-help-example-recursive',
1817                 ];
1818         }
1819
1820         public function modifyHelp( array &$help, array $options, array &$tocData ) {
1821                 // Wish PHP had an "array_insert_before". Instead, we have to manually
1822                 // reindex the array to get 'permissions' in the right place.
1823                 $oldHelp = $help;
1824                 $help = [];
1825                 foreach ( $oldHelp as $k => $v ) {
1826                         if ( $k === 'submodules' ) {
1827                                 $help['permissions'] = '';
1828                         }
1829                         $help[$k] = $v;
1830                 }
1831                 $help['datatypes'] = '';
1832                 $help['credits'] = '';
1833
1834                 // Fill 'permissions'
1835                 $help['permissions'] .= Html::openElement( 'div',
1836                         [ 'class' => 'apihelp-block apihelp-permissions' ] );
1837                 $m = $this->msg( 'api-help-permissions' );
1838                 if ( !$m->isDisabled() ) {
1839                         $help['permissions'] .= Html::rawElement( 'div', [ 'class' => 'apihelp-block-head' ],
1840                                 $m->numParams( count( self::$mRights ) )->parse()
1841                         );
1842                 }
1843                 $help['permissions'] .= Html::openElement( 'dl' );
1844                 foreach ( self::$mRights as $right => $rightMsg ) {
1845                         $help['permissions'] .= Html::element( 'dt', null, $right );
1846
1847                         $rightMsg = $this->msg( $rightMsg['msg'], $rightMsg['params'] )->parse();
1848                         $help['permissions'] .= Html::rawElement( 'dd', null, $rightMsg );
1849
1850                         $groups = array_map( function ( $group ) {
1851                                 return $group == '*' ? 'all' : $group;
1852                         }, User::getGroupsWithPermission( $right ) );
1853
1854                         $help['permissions'] .= Html::rawElement( 'dd', null,
1855                                 $this->msg( 'api-help-permissions-granted-to' )
1856                                         ->numParams( count( $groups ) )
1857                                         ->params( Message::listParam( $groups ) )
1858                                         ->parse()
1859                         );
1860                 }
1861                 $help['permissions'] .= Html::closeElement( 'dl' );
1862                 $help['permissions'] .= Html::closeElement( 'div' );
1863
1864                 // Fill 'datatypes' and 'credits', if applicable
1865                 if ( empty( $options['nolead'] ) ) {
1866                         $level = $options['headerlevel'];
1867                         $tocnumber = &$options['tocnumber'];
1868
1869                         $header = $this->msg( 'api-help-datatypes-header' )->parse();
1870
1871                         // Add an additional span with sanitized ID
1872                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1873                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/datatypes' ) ] ) .
1874                                         $header;
1875                         }
1876                         $help['datatypes'] .= Html::rawElement( 'h' . min( 6, $level ),
1877                                 [ 'id' => 'main/datatypes', 'class' => 'apihelp-header' ],
1878                                 $header
1879                         );
1880                         $help['datatypes'] .= $this->msg( 'api-help-datatypes' )->parseAsBlock();
1881                         if ( !isset( $tocData['main/datatypes'] ) ) {
1882                                 $tocnumber[$level]++;
1883                                 $tocData['main/datatypes'] = [
1884                                         'toclevel' => count( $tocnumber ),
1885                                         'level' => $level,
1886                                         'anchor' => 'main/datatypes',
1887                                         'line' => $header,
1888                                         'number' => implode( '.', $tocnumber ),
1889                                         'index' => false,
1890                                 ];
1891                         }
1892
1893                         // Add an additional span with sanitized ID
1894                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1895                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/credits' ) ] ) .
1896                                         $header;
1897                         }
1898                         $header = $this->msg( 'api-credits-header' )->parse();
1899                         $help['credits'] .= Html::rawElement( 'h' . min( 6, $level ),
1900                                 [ 'id' => 'main/credits', 'class' => 'apihelp-header' ],
1901                                 $header
1902                         );
1903                         $help['credits'] .= $this->msg( 'api-credits' )->useDatabase( false )->parseAsBlock();
1904                         if ( !isset( $tocData['main/credits'] ) ) {
1905                                 $tocnumber[$level]++;
1906                                 $tocData['main/credits'] = [
1907                                         'toclevel' => count( $tocnumber ),
1908                                         'level' => $level,
1909                                         'anchor' => 'main/credits',
1910                                         'line' => $header,
1911                                         'number' => implode( '.', $tocnumber ),
1912                                         'index' => false,
1913                                 ];
1914                         }
1915                 }
1916         }
1917
1918         private $mCanApiHighLimits = null;
1919
1920         /**
1921          * Check whether the current user is allowed to use high limits
1922          * @return bool
1923          */
1924         public function canApiHighLimits() {
1925                 if ( !isset( $this->mCanApiHighLimits ) ) {
1926                         $this->mCanApiHighLimits = $this->getUser()->isAllowed( 'apihighlimits' );
1927                 }
1928
1929                 return $this->mCanApiHighLimits;
1930         }
1931
1932         /**
1933          * Overrides to return this instance's module manager.
1934          * @return ApiModuleManager
1935          */
1936         public function getModuleManager() {
1937                 return $this->mModuleMgr;
1938         }
1939
1940         /**
1941          * Fetches the user agent used for this request
1942          *
1943          * The value will be the combination of the 'Api-User-Agent' header (if
1944          * any) and the standard User-Agent header (if any).
1945          *
1946          * @return string
1947          */
1948         public function getUserAgent() {
1949                 return trim(
1950                         $this->getRequest()->getHeader( 'Api-user-agent' ) . ' ' .
1951                         $this->getRequest()->getHeader( 'User-agent' )
1952                 );
1953         }
1954 }
1955
1956 /**
1957  * For really cool vim folding this needs to be at the end:
1958  * vim: foldmarker=@{,@} foldmethod=marker
1959  */