includes/api/ApiMain.php

   1 <?php
   2 /**
   3  * Created on Sep 4, 2006
   4  *
   5  * Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  * @defgroup API API
  24  */
  25
  26 use MediaWiki\Logger\LoggerFactory;
  27 use MediaWiki\MediaWikiServices;
  28 use Wikimedia\Timestamp\TimestampException;
  29 use Wikimedia\Rdbms\DBQueryError;
  30 use Wikimedia\Rdbms\DBError;
  31
  32 /**
  33  * This is the main API class, used for both external and internal processing.
  34  * When executed, it will create the requested formatter object,
  35  * instantiate and execute an object associated with the needed action,
  36  * and use formatter to print results.
  37  * In case of an exception, an error message will be printed using the same formatter.
  38  *
  39  * To use API from another application, run it using FauxRequest object, in which
  40  * case any internal exceptions will not be handled but passed up to the caller.
  41  * After successful execution, use getResult() for the resulting data.
  42  *
  43  * @ingroup API
  44  */
  45 class ApiMain extends ApiBase {
  46         /**
  47          * When no format parameter is given, this format will be used
  48          */
  49         const API_DEFAULT_FORMAT = 'jsonfm';
  50
  51         /**
  52          * When no uselang parameter is given, this language will be used
  53          */
  54         const API_DEFAULT_USELANG = 'user';
  55
  56         /**
  57          * List of available modules: action name => module class
  58          */
  59         private static $Modules = [
  60                 'login' => 'ApiLogin',
  61                 'clientlogin' => 'ApiClientLogin',
  62                 'logout' => 'ApiLogout',
  63                 'createaccount' => 'ApiAMCreateAccount',
  64                 'linkaccount' => 'ApiLinkAccount',
  65                 'unlinkaccount' => 'ApiRemoveAuthenticationData',
  66                 'changeauthenticationdata' => 'ApiChangeAuthenticationData',
  67                 'removeauthenticationdata' => 'ApiRemoveAuthenticationData',
  68                 'resetpassword' => 'ApiResetPassword',
  69                 'query' => 'ApiQuery',
  70                 'expandtemplates' => 'ApiExpandTemplates',
  71                 'parse' => 'ApiParse',
  72                 'stashedit' => 'ApiStashEdit',
  73                 'opensearch' => 'ApiOpenSearch',
  74                 'feedcontributions' => 'ApiFeedContributions',
  75                 'feedrecentchanges' => 'ApiFeedRecentChanges',
  76                 'feedwatchlist' => 'ApiFeedWatchlist',
  77                 'help' => 'ApiHelp',
  78                 'paraminfo' => 'ApiParamInfo',
  79                 'rsd' => 'ApiRsd',
  80                 'compare' => 'ApiComparePages',
  81                 'tokens' => 'ApiTokens',
  82                 'checktoken' => 'ApiCheckToken',
  83                 'cspreport' => 'ApiCSPReport',
  84                 'validatepassword' => 'ApiValidatePassword',
  85
  86                 // Write modules
  87                 'purge' => 'ApiPurge',
  88                 'setnotificationtimestamp' => 'ApiSetNotificationTimestamp',
  89                 'rollback' => 'ApiRollback',
  90                 'delete' => 'ApiDelete',
  91                 'undelete' => 'ApiUndelete',
  92                 'protect' => 'ApiProtect',
  93                 'block' => 'ApiBlock',
  94                 'unblock' => 'ApiUnblock',
  95                 'move' => 'ApiMove',
  96                 'edit' => 'ApiEditPage',
  97                 'upload' => 'ApiUpload',
  98                 'filerevert' => 'ApiFileRevert',
  99                 'emailuser' => 'ApiEmailUser',
 100                 'watch' => 'ApiWatch',
 101                 'patrol' => 'ApiPatrol',
 102                 'import' => 'ApiImport',
 103                 'clearhasmsg' => 'ApiClearHasMsg',
 104                 'userrights' => 'ApiUserrights',
 105                 'options' => 'ApiOptions',
 106                 'imagerotate' => 'ApiImageRotate',
 107                 'revisiondelete' => 'ApiRevisionDelete',
 108                 'managetags' => 'ApiManageTags',
 109                 'tag' => 'ApiTag',
 110                 'mergehistory' => 'ApiMergeHistory',
 111                 'setpagelanguage' => 'ApiSetPageLanguage',
 112         ];
 113
 114         /**
 115          * List of available formats: format name => format class
 116          */
 117         private static $Formats = [
 118                 'json' => 'ApiFormatJson',
 119                 'jsonfm' => 'ApiFormatJson',
 120                 'php' => 'ApiFormatPhp',
 121                 'phpfm' => 'ApiFormatPhp',
 122                 'xml' => 'ApiFormatXml',
 123                 'xmlfm' => 'ApiFormatXml',
 124                 'rawfm' => 'ApiFormatJson',
 125                 'none' => 'ApiFormatNone',
 126         ];
 127
 128         // @codingStandardsIgnoreStart String contenation on "msg" not allowed to break long line
 129         /**
 130          * List of user roles that are specifically relevant to the API.
 131          * [ 'right' => [ 'msg'    => 'Some message with a $1',
 132          *                'params' => [ $someVarToSubst ] ],
 133          * ];
 134          */
 135         private static $mRights = [
 136                 'writeapi' => [
 137                         'msg' => 'right-writeapi',
 138                         'params' => []
 139                 ],
 140                 'apihighlimits' => [
 141                         'msg' => 'api-help-right-apihighlimits',
 142                         'params' => [ ApiBase::LIMIT_SML2, ApiBase::LIMIT_BIG2 ]
 143                 ]
 144         ];
 145         // @codingStandardsIgnoreEnd
 146
 147         /**
 148          * @var ApiFormatBase
 149          */
 150         private $mPrinter;
 151
 152         private $mModuleMgr, $mResult, $mErrorFormatter = null;
 153         /** @var ApiContinuationManager|null */
 154         private $mContinuationManager;
 155         private $mAction;
 156         private $mEnableWrite;
 157         private $mInternalMode, $mSquidMaxage;
 158         /** @var ApiBase */
 159         private $mModule;
 160
 161         private $mCacheMode = 'private';
 162         private $mCacheControl = [];
 163         private $mParamsUsed = [];
 164         private $mParamsSensitive = [];
 165
 166         /** @var bool|null Cached return value from self::lacksSameOriginSecurity() */
 167         private $lacksSameOriginSecurity = null;
 168
 169         /**
 170          * Constructs an instance of ApiMain that utilizes the module and format specified by $request.
 171          *
 172          * @param IContextSource|WebRequest $context If this is an instance of
 173          *    FauxRequest, errors are thrown and no printing occurs
 174          * @param bool $enableWrite Should be set to true if the api may modify data
 175          */
 176         public function __construct( $context = null, $enableWrite = false ) {
 177                 if ( $context === null ) {
 178                         $context = RequestContext::getMain();
 179                 } elseif ( $context instanceof WebRequest ) {
 180                         // BC for pre-1.19
 181                         $request = $context;
 182                         $context = RequestContext::getMain();
 183                 }
 184                 // We set a derivative context so we can change stuff later
 185                 $this->setContext( new DerivativeContext( $context ) );
 186
 187                 if ( isset( $request ) ) {
 188                         $this->getContext()->setRequest( $request );
 189                 } else {
 190                         $request = $this->getRequest();
 191                 }
 192
 193                 $this->mInternalMode = ( $request instanceof FauxRequest );
 194
 195                 // Special handling for the main module: $parent === $this
 196                 parent::__construct( $this, $this->mInternalMode ? 'main_int' : 'main' );
 197
 198                 $config = $this->getConfig();
 199
 200                 if ( !$this->mInternalMode ) {
 201                         // Log if a request with a non-whitelisted Origin header is seen
 202                         // with session cookies.
 203                         $originHeader = $request->getHeader( 'Origin' );
 204                         if ( $originHeader === false ) {
 205                                 $origins = [];
 206                         } else {
 207                                 $originHeader = trim( $originHeader );
 208                                 $origins = preg_split( '/\s+/', $originHeader );
 209                         }
 210                         $sessionCookies = array_intersect(
 211                                 array_keys( $_COOKIE ),
 212                                 MediaWiki\Session\SessionManager::singleton()->getVaryCookies()
 213                         );
 214                         if ( $origins && $sessionCookies && (
 215                                 count( $origins ) !== 1 || !self::matchOrigin(
 216                                         $origins[0],
 217                                         $config->get( 'CrossSiteAJAXdomains' ),
 218                                         $config->get( 'CrossSiteAJAXdomainExceptions' )
 219                                 )
 220                         ) ) {
 221                                 LoggerFactory::getInstance( 'cors' )->warning(
 222                                         'Non-whitelisted CORS request with session cookies', [
 223                                                 'origin' => $originHeader,
 224                                                 'cookies' => $sessionCookies,
 225                                                 'ip' => $request->getIP(),
 226                                                 'userAgent' => $this->getUserAgent(),
 227                                                 'wiki' => wfWikiID(),
 228                                         ]
 229                                 );
 230                         }
 231
 232                         // If we're in a mode that breaks the same-origin policy, strip
 233                         // user credentials for security.
 234                         if ( $this->lacksSameOriginSecurity() ) {
 235                                 global $wgUser;
 236                                 wfDebug( "API: stripping user credentials when the same-origin policy is not applied\n" );
 237                                 $wgUser = new User();
 238                                 $this->getContext()->setUser( $wgUser );
 239                         }
 240                 }
 241
 242                 $this->mResult = new ApiResult( $this->getConfig()->get( 'APIMaxResultSize' ) );
 243
 244                 // Setup uselang. This doesn't use $this->getParameter()
 245                 // because we're not ready to handle errors yet.
 246                 $uselang = $request->getVal( 'uselang', self::API_DEFAULT_USELANG );
 247                 if ( $uselang === 'user' ) {
 248                         // Assume the parent context is going to return the user language
 249                         // for uselang=user (see T85635).
 250                 } else {
 251                         if ( $uselang === 'content' ) {
 252                                 global $wgContLang;
 253                                 $uselang = $wgContLang->getCode();
 254                         }
 255                         $code = RequestContext::sanitizeLangCode( $uselang );
 256                         $this->getContext()->setLanguage( $code );
 257                         if ( !$this->mInternalMode ) {
 258                                 global $wgLang;
 259                                 $wgLang = $this->getContext()->getLanguage();
 260                                 RequestContext::getMain()->setLanguage( $wgLang );
 261                         }
 262                 }
 263
 264                 // Set up the error formatter. This doesn't use $this->getParameter()
 265                 // because we're not ready to handle errors yet.
 266                 $errorFormat = $request->getVal( 'errorformat', 'bc' );
 267                 $errorLangCode = $request->getVal( 'errorlang', 'uselang' );
 268                 $errorsUseDB = $request->getCheck( 'errorsuselocal' );
 269                 if ( in_array( $errorFormat, [ 'plaintext', 'wikitext', 'html', 'raw', 'none' ], true ) ) {
 270                         if ( $errorLangCode === 'uselang' ) {
 271                                 $errorLang = $this->getLanguage();
 272                         } elseif ( $errorLangCode === 'content' ) {
 273                                 global $wgContLang;
 274                                 $errorLang = $wgContLang;
 275                         } else {
 276                                 $errorLangCode = RequestContext::sanitizeLangCode( $errorLangCode );
 277                                 $errorLang = Language::factory( $errorLangCode );
 278                         }
 279                         $this->mErrorFormatter = new ApiErrorFormatter(
 280                                 $this->mResult, $errorLang, $errorFormat, $errorsUseDB
 281                         );
 282                 } else {
 283                         $this->mErrorFormatter = new ApiErrorFormatter_BackCompat( $this->mResult );
 284                 }
 285                 $this->mResult->setErrorFormatter( $this->getErrorFormatter() );
 286
 287                 $this->mModuleMgr = new ApiModuleManager( $this );
 288                 $this->mModuleMgr->addModules( self::$Modules, 'action' );
 289                 $this->mModuleMgr->addModules( $config->get( 'APIModules' ), 'action' );
 290                 $this->mModuleMgr->addModules( self::$Formats, 'format' );
 291                 $this->mModuleMgr->addModules( $config->get( 'APIFormatModules' ), 'format' );
 292
 293                 Hooks::run( 'ApiMain::moduleManager', [ $this->mModuleMgr ] );
 294
 295                 $this->mContinuationManager = null;
 296                 $this->mEnableWrite = $enableWrite;
 297
 298                 $this->mSquidMaxage = -1; // flag for executeActionWithErrorHandling()
 299                 $this->mCommit = false;
 300         }
 301
 302         /**
 303          * Return true if the API was started by other PHP code using FauxRequest
 304          * @return bool
 305          */
 306         public function isInternalMode() {
 307                 return $this->mInternalMode;
 308         }
 309
 310         /**
 311          * Get the ApiResult object associated with current request
 312          *
 313          * @return ApiResult
 314          */
 315         public function getResult() {
 316                 return $this->mResult;
 317         }
 318
 319         /**
 320          * Get the security flag for the current request
 321          * @return bool
 322          */
 323         public function lacksSameOriginSecurity() {
 324                 if ( $this->lacksSameOriginSecurity !== null ) {
 325                         return $this->lacksSameOriginSecurity;
 326                 }
 327
 328                 $request = $this->getRequest();
 329
 330                 // JSONP mode
 331                 if ( $request->getVal( 'callback' ) !== null ) {
 332                         $this->lacksSameOriginSecurity = true;
 333                         return true;
 334                 }
 335
 336                 // Anonymous CORS
 337                 if ( $request->getVal( 'origin' ) === '*' ) {
 338                         $this->lacksSameOriginSecurity = true;
 339                         return true;
 340                 }
 341
 342                 // Header to be used from XMLHTTPRequest when the request might
 343                 // otherwise be used for XSS.
 344                 if ( $request->getHeader( 'Treat-as-Untrusted' ) !== false ) {
 345                         $this->lacksSameOriginSecurity = true;
 346                         return true;
 347                 }
 348
 349                 // Allow extensions to override.
 350                 $this->lacksSameOriginSecurity = !Hooks::run( 'RequestHasSameOriginSecurity', [ $request ] );
 351                 return $this->lacksSameOriginSecurity;
 352         }
 353
 354         /**
 355          * Get the ApiErrorFormatter object associated with current request
 356          * @return ApiErrorFormatter
 357          */
 358         public function getErrorFormatter() {
 359                 return $this->mErrorFormatter;
 360         }
 361
 362         /**
 363          * Get the continuation manager
 364          * @return ApiContinuationManager|null
 365          */
 366         public function getContinuationManager() {
 367                 return $this->mContinuationManager;
 368         }
 369
 370         /**
 371          * Set the continuation manager
 372          * @param ApiContinuationManager|null
 373          */
 374         public function setContinuationManager( $manager ) {
 375                 if ( $manager !== null ) {
 376                         if ( !$manager instanceof ApiContinuationManager ) {
 377                                 throw new InvalidArgumentException( __METHOD__ . ': Was passed ' .
 378                                         is_object( $manager ) ? get_class( $manager ) : gettype( $manager )
 379                                 );
 380                         }
 381                         if ( $this->mContinuationManager !== null ) {
 382                                 throw new UnexpectedValueException(
 383                                         __METHOD__ . ': tried to set manager from ' . $manager->getSource() .
 384                                         ' when a manager is already set from ' . $this->mContinuationManager->getSource()
 385                                 );
 386                         }
 387                 }
 388                 $this->mContinuationManager = $manager;
 389         }
 390
 391         /**
 392          * Get the API module object. Only works after executeAction()
 393          *
 394          * @return ApiBase
 395          */
 396         public function getModule() {
 397                 return $this->mModule;
 398         }
 399
 400         /**
 401          * Get the result formatter object. Only works after setupExecuteAction()
 402          *
 403          * @return ApiFormatBase
 404          */
 405         public function getPrinter() {
 406                 return $this->mPrinter;
 407         }
 408
 409         /**
 410          * Set how long the response should be cached.
 411          *
 412          * @param int $maxage
 413          */
 414         public function setCacheMaxAge( $maxage ) {
 415                 $this->setCacheControl( [
 416                         'max-age' => $maxage,
 417                         's-maxage' => $maxage
 418                 ] );
 419         }
 420
 421         /**
 422          * Set the type of caching headers which will be sent.
 423          *
 424          * @param string $mode One of:
 425          *    - 'public':     Cache this object in public caches, if the maxage or smaxage
 426          *         parameter is set, or if setCacheMaxAge() was called. If a maximum age is
 427          *         not provided by any of these means, the object will be private.
 428          *    - 'private':    Cache this object only in private client-side caches.
 429          *    - 'anon-public-user-private': Make this object cacheable for logged-out
 430          *         users, but private for logged-in users. IMPORTANT: If this is set, it must be
 431          *         set consistently for a given URL, it cannot be set differently depending on
 432          *         things like the contents of the database, or whether the user is logged in.
 433          *
 434          *  If the wiki does not allow anonymous users to read it, the mode set here
 435          *  will be ignored, and private caching headers will always be sent. In other words,
 436          *  the "public" mode is equivalent to saying that the data sent is as public as a page
 437          *  view.
 438          *
 439          *  For user-dependent data, the private mode should generally be used. The
 440          *  anon-public-user-private mode should only be used where there is a particularly
 441          *  good performance reason for caching the anonymous response, but where the
 442          *  response to logged-in users may differ, or may contain private data.
 443          *
 444          *  If this function is never called, then the default will be the private mode.
 445          */
 446         public function setCacheMode( $mode ) {
 447                 if ( !in_array( $mode, [ 'private', 'public', 'anon-public-user-private' ] ) ) {
 448                         wfDebug( __METHOD__ . ": unrecognised cache mode \"$mode\"\n" );
 449
 450                         // Ignore for forwards-compatibility
 451                         return;
 452                 }
 453
 454                 if ( !User::isEveryoneAllowed( 'read' ) ) {
 455                         // Private wiki, only private headers
 456                         if ( $mode !== 'private' ) {
 457                                 wfDebug( __METHOD__ . ": ignoring request for $mode cache mode, private wiki\n" );
 458
 459                                 return;
 460                         }
 461                 }
 462
 463                 if ( $mode === 'public' && $this->getParameter( 'uselang' ) === 'user' ) {
 464                         // User language is used for i18n, so we don't want to publicly
 465                         // cache. Anons are ok, because if they have non-default language
 466                         // then there's an appropriate Vary header set by whatever set
 467                         // their non-default language.
 468                         wfDebug( __METHOD__ . ": downgrading cache mode 'public' to " .
 469                                 "'anon-public-user-private' due to uselang=user\n" );
 470                         $mode = 'anon-public-user-private';
 471                 }
 472
 473                 wfDebug( __METHOD__ . ": setting cache mode $mode\n" );
 474                 $this->mCacheMode = $mode;
 475         }
 476
 477         /**
 478          * Set directives (key/value pairs) for the Cache-Control header.
 479          * Boolean values will be formatted as such, by including or omitting
 480          * without an equals sign.
 481          *
 482          * Cache control values set here will only be used if the cache mode is not
 483          * private, see setCacheMode().
 484          *
 485          * @param array $directives
 486          */
 487         public function setCacheControl( $directives ) {
 488                 $this->mCacheControl = $directives + $this->mCacheControl;
 489         }
 490
 491         /**
 492          * Create an instance of an output formatter by its name
 493          *
 494          * @param string $format
 495          *
 496          * @return ApiFormatBase
 497          */
 498         public function createPrinterByName( $format ) {
 499                 $printer = $this->mModuleMgr->getModule( $format, 'format' );
 500                 if ( $printer === null ) {
 501                         $this->dieWithError(
 502                                 [ 'apierror-unknownformat', wfEscapeWikiText( $format ) ], 'unknown_format'
 503                         );
 504                 }
 505
 506                 return $printer;
 507         }
 508
 509         /**
 510          * Execute api request. Any errors will be handled if the API was called by the remote client.
 511          */
 512         public function execute() {
 513                 if ( $this->mInternalMode ) {
 514                         $this->executeAction();
 515                 } else {
 516                         $this->executeActionWithErrorHandling();
 517                 }
 518         }
 519
 520         /**
 521          * Execute an action, and in case of an error, erase whatever partial results
 522          * have been accumulated, and replace it with an error message and a help screen.
 523          */
 524         protected function executeActionWithErrorHandling() {
 525                 // Verify the CORS header before executing the action
 526                 if ( !$this->handleCORS() ) {
 527                         // handleCORS() has sent a 403, abort
 528                         return;
 529                 }
 530
 531                 // Exit here if the request method was OPTIONS
 532                 // (assume there will be a followup GET or POST)
 533                 if ( $this->getRequest()->getMethod() === 'OPTIONS' ) {
 534                         return;
 535                 }
 536
 537                 // In case an error occurs during data output,
 538                 // clear the output buffer and print just the error information
 539                 $obLevel = ob_get_level();
 540                 ob_start();
 541
 542                 $t = microtime( true );
 543                 $isError = false;
 544                 try {
 545                         $this->executeAction();
 546                         $runTime = microtime( true ) - $t;
 547                         $this->logRequest( $runTime );
 548                         if ( $this->mModule->isWriteMode() && $this->getRequest()->wasPosted() ) {
 549                                 MediaWikiServices::getInstance()->getStatsdDataFactory()->timing(
 550                                         'api.' . $this->mModule->getModuleName() . '.executeTiming', 1000 * $runTime
 551                                 );
 552                         }
 553                 } catch ( Exception $e ) {
 554                         $this->handleException( $e );
 555                         $this->logRequest( microtime( true ) - $t, $e );
 556                         $isError = true;
 557                 }
 558
 559                 // Commit DBs and send any related cookies and headers
 560                 MediaWiki::preOutputCommit( $this->getContext() );
 561
 562                 // Send cache headers after any code which might generate an error, to
 563                 // avoid sending public cache headers for errors.
 564                 $this->sendCacheHeaders( $isError );
 565
 566                 // Executing the action might have already messed with the output
 567                 // buffers.
 568                 while ( ob_get_level() > $obLevel ) {
 569                         ob_end_flush();
 570                 }
 571         }
 572
 573         /**
 574          * Handle an exception as an API response
 575          *
 576          * @since 1.23
 577          * @param Exception $e
 578          */
 579         protected function handleException( Exception $e ) {
 580                 // T65145: Rollback any open database transactions
 581                 if ( !( $e instanceof ApiUsageException || $e instanceof UsageException ) ) {
 582                         // UsageExceptions are intentional, so don't rollback if that's the case
 583                         try {
 584                                 MWExceptionHandler::rollbackMasterChangesAndLog( $e );
 585                         } catch ( DBError $e2 ) {
 586                                 // Rollback threw an exception too. Log it, but don't interrupt
 587                                 // our regularly scheduled exception handling.
 588                                 MWExceptionHandler::logException( $e2 );
 589                         }
 590                 }
 591
 592                 // Allow extra cleanup and logging
 593                 Hooks::run( 'ApiMain::onException', [ $this, $e ] );
 594
 595                 // Log it
 596                 if ( !( $e instanceof ApiUsageException || $e instanceof UsageException ) ) {
 597                         MWExceptionHandler::logException( $e );
 598                 }
 599
 600                 // Handle any kind of exception by outputting properly formatted error message.
 601                 // If this fails, an unhandled exception should be thrown so that global error
 602                 // handler will process and log it.
 603
 604                 $errCodes = $this->substituteResultWithError( $e );
 605
 606                 // Error results should not be cached
 607                 $this->setCacheMode( 'private' );
 608
 609                 $response = $this->getRequest()->response();
 610                 $headerStr = 'MediaWiki-API-Error: ' . join( ', ', $errCodes );
 611                 $response->header( $headerStr );
 612
 613                 // Reset and print just the error message
 614                 ob_clean();
 615
 616                 // Printer may not be initialized if the extractRequestParams() fails for the main module
 617                 $this->createErrorPrinter();
 618
 619                 $failed = false;
 620                 try {
 621                         $this->printResult( $e->getCode() );
 622                 } catch ( ApiUsageException $ex ) {
 623                         // The error printer itself is failing. Try suppressing its request
 624                         // parameters and redo.
 625                         $failed = true;
 626                         $this->addWarning( 'apiwarn-errorprinterfailed' );
 627                         foreach ( $ex->getStatusValue()->getErrors() as $error ) {
 628                                 try {
 629                                         $this->mPrinter->addWarning( $error );
 630                                 } catch ( Exception $ex2 ) {
 631                                         // WTF?
 632                                         $this->addWarning( $error );
 633                                 }
 634                         }
 635                 } catch ( UsageException $ex ) {
 636                         // The error printer itself is failing. Try suppressing its request
 637                         // parameters and redo.
 638                         $failed = true;
 639                         $this->addWarning(
 640                                 [ 'apiwarn-errorprinterfailed-ex', $ex->getMessage() ], 'errorprinterfailed'
 641                         );
 642                 }
 643                 if ( $failed ) {
 644                         $this->mPrinter = null;
 645                         $this->createErrorPrinter();
 646                         $this->mPrinter->forceDefaultParams();
 647                         if ( $e->getCode() ) {
 648                                 $response->statusHeader( 200 ); // Reset in case the fallback doesn't want a non-200
 649                         }
 650                         $this->printResult( $e->getCode() );
 651                 }
 652         }
 653
 654         /**
 655          * Handle an exception from the ApiBeforeMain hook.
 656          *
 657          * This tries to print the exception as an API response, to be more
 658          * friendly to clients. If it fails, it will rethrow the exception.
 659          *
 660          * @since 1.23
 661          * @param Exception $e
 662          * @throws Exception
 663          */
 664         public static function handleApiBeforeMainException( Exception $e ) {
 665                 ob_start();
 666
 667                 try {
 668                         $main = new self( RequestContext::getMain(), false );
 669                         $main->handleException( $e );
 670                         $main->logRequest( 0, $e );
 671                 } catch ( Exception $e2 ) {
 672                         // Nope, even that didn't work. Punt.
 673                         throw $e;
 674                 }
 675
 676                 // Reset cache headers
 677                 $main->sendCacheHeaders( true );
 678
 679                 ob_end_flush();
 680         }
 681
 682         /**
 683          * Check the &origin= query parameter against the Origin: HTTP header and respond appropriately.
 684          *
 685          * If no origin parameter is present, nothing happens.
 686          * If an origin parameter is present but doesn't match the Origin header, a 403 status code
 687          * is set and false is returned.
 688          * If the parameter and the header do match, the header is checked against $wgCrossSiteAJAXdomains
 689          * and $wgCrossSiteAJAXdomainExceptions, and if the origin qualifies, the appropriate CORS
 690          * headers are set.
 691          * https://www.w3.org/TR/cors/#resource-requests
 692          * https://www.w3.org/TR/cors/#resource-preflight-requests
 693          *
 694          * @return bool False if the caller should abort (403 case), true otherwise (all other cases)
 695          */
 696         protected function handleCORS() {
 697                 $originParam = $this->getParameter( 'origin' ); // defaults to null
 698                 if ( $originParam === null ) {
 699                         // No origin parameter, nothing to do
 700                         return true;
 701                 }
 702
 703                 $request = $this->getRequest();
 704                 $response = $request->response();
 705
 706                 $matchOrigin = false;
 707                 $allowTiming = false;
 708                 $varyOrigin = true;
 709
 710                 if ( $originParam === '*' ) {
 711                         // Request for anonymous CORS
 712                         $matchOrigin = true;
 713                         $allowOrigin = '*';
 714                         $allowCredentials = 'false';
 715                         $varyOrigin = false; // No need to vary
 716                 } else {
 717                         // Non-anonymous CORS, check we allow the domain
 718
 719                         // Origin: header is a space-separated list of origins, check all of them
 720                         $originHeader = $request->getHeader( 'Origin' );
 721                         if ( $originHeader === false ) {
 722                                 $origins = [];
 723                         } else {
 724                                 $originHeader = trim( $originHeader );
 725                                 $origins = preg_split( '/\s+/', $originHeader );
 726                         }
 727
 728                         if ( !in_array( $originParam, $origins ) ) {
 729                                 // origin parameter set but incorrect
 730                                 // Send a 403 response
 731                                 $response->statusHeader( 403 );
 732                                 $response->header( 'Cache-Control: no-cache' );
 733                                 echo "'origin' parameter does not match Origin header\n";
 734
 735                                 return false;
 736                         }
 737
 738                         $config = $this->getConfig();
 739                         $matchOrigin = count( $origins ) === 1 && self::matchOrigin(
 740                                 $originParam,
 741                                 $config->get( 'CrossSiteAJAXdomains' ),
 742                                 $config->get( 'CrossSiteAJAXdomainExceptions' )
 743                         );
 744
 745                         $allowOrigin = $originHeader;
 746                         $allowCredentials = 'true';
 747                         $allowTiming = $originHeader;
 748                 }
 749
 750                 if ( $matchOrigin ) {
 751                         $requestedMethod = $request->getHeader( 'Access-Control-Request-Method' );
 752                         $preflight = $request->getMethod() === 'OPTIONS' && $requestedMethod !== false;
 753                         if ( $preflight ) {
 754                                 // This is a CORS preflight request
 755                                 if ( $requestedMethod !== 'POST' && $requestedMethod !== 'GET' ) {
 756                                         // If method is not a case-sensitive match, do not set any additional headers and terminate.
 757                                         return true;
 758                                 }
 759                                 // We allow the actual request to send the following headers
 760                                 $requestedHeaders = $request->getHeader( 'Access-Control-Request-Headers' );
 761                                 if ( $requestedHeaders !== false ) {
 762                                         if ( !self::matchRequestedHeaders( $requestedHeaders ) ) {
 763                                                 return true;
 764                                         }
 765                                         $response->header( 'Access-Control-Allow-Headers: ' . $requestedHeaders );
 766                                 }
 767
 768                                 // We only allow the actual request to be GET or POST
 769                                 $response->header( 'Access-Control-Allow-Methods: POST, GET' );
 770                         }
 771
 772                         $response->header( "Access-Control-Allow-Origin: $allowOrigin" );
 773                         $response->header( "Access-Control-Allow-Credentials: $allowCredentials" );
 774                         // https://www.w3.org/TR/resource-timing/#timing-allow-origin
 775                         if ( $allowTiming !== false ) {
 776                                 $response->header( "Timing-Allow-Origin: $allowTiming" );
 777                         }
 778
 779                         if ( !$preflight ) {
 780                                 $response->header(
 781                                         'Access-Control-Expose-Headers: MediaWiki-API-Error, Retry-After, X-Database-Lag'
 782                                 );
 783                         }
 784                 }
 785
 786                 if ( $varyOrigin ) {
 787                         $this->getOutput()->addVaryHeader( 'Origin' );
 788                 }
 789
 790                 return true;
 791         }
 792
 793         /**
 794          * Attempt to match an Origin header against a set of rules and a set of exceptions
 795          * @param string $value Origin header
 796          * @param array $rules Set of wildcard rules
 797          * @param array $exceptions Set of wildcard rules
 798          * @return bool True if $value matches a rule in $rules and doesn't match
 799          *    any rules in $exceptions, false otherwise
 800          */
 801         protected static function matchOrigin( $value, $rules, $exceptions ) {
 802                 foreach ( $rules as $rule ) {
 803                         if ( preg_match( self::wildcardToRegex( $rule ), $value ) ) {
 804                                 // Rule matches, check exceptions
 805                                 foreach ( $exceptions as $exc ) {
 806                                         if ( preg_match( self::wildcardToRegex( $exc ), $value ) ) {
 807                                                 return false;
 808                                         }
 809                                 }
 810
 811                                 return true;
 812                         }
 813                 }
 814
 815                 return false;
 816         }
 817
 818         /**
 819          * Attempt to validate the value of Access-Control-Request-Headers against a list
 820          * of headers that we allow the follow up request to send.
 821          *
 822          * @param string $requestedHeaders Comma seperated list of HTTP headers
 823          * @return bool True if all requested headers are in the list of allowed headers
 824          */
 825         protected static function matchRequestedHeaders( $requestedHeaders ) {
 826                 if ( trim( $requestedHeaders ) === '' ) {
 827                         return true;
 828                 }
 829                 $requestedHeaders = explode( ',', $requestedHeaders );
 830                 $allowedAuthorHeaders = array_flip( [
 831                         /* simple headers (see spec) */
 832                         'accept',
 833                         'accept-language',
 834                         'content-language',
 835                         'content-type',
 836                         /* non-authorable headers in XHR, which are however requested by some UAs */
 837                         'accept-encoding',
 838                         'dnt',
 839                         'origin',
 840                         /* MediaWiki whitelist */
 841                         'api-user-agent',
 842                 ] );
 843                 foreach ( $requestedHeaders as $rHeader ) {
 844                         $rHeader = strtolower( trim( $rHeader ) );
 845                         if ( !isset( $allowedAuthorHeaders[$rHeader] ) ) {
 846                                 wfDebugLog( 'api', 'CORS preflight failed on requested header: ' . $rHeader );
 847                                 return false;
 848                         }
 849                 }
 850                 return true;
 851         }
 852
 853         /**
 854          * Helper function to convert wildcard string into a regex
 855          * '*' => '.*?'
 856          * '?' => '.'
 857          *
 858          * @param string $wildcard String with wildcards
 859          * @return string Regular expression
 860          */
 861         protected static function wildcardToRegex( $wildcard ) {
 862                 $wildcard = preg_quote( $wildcard, '/' );
 863                 $wildcard = str_replace(
 864                         [ '\*', '\?' ],
 865                         [ '.*?', '.' ],
 866                         $wildcard
 867                 );
 868
 869                 return "/^https?:\/\/$wildcard$/";
 870         }
 871
 872         /**
 873          * Send caching headers
 874          * @param bool $isError Whether an error response is being output
 875          * @since 1.26 added $isError parameter
 876          */
 877         protected function sendCacheHeaders( $isError ) {
 878                 $response = $this->getRequest()->response();
 879                 $out = $this->getOutput();
 880
 881                 $out->addVaryHeader( 'Treat-as-Untrusted' );
 882
 883                 $config = $this->getConfig();
 884
 885                 if ( $config->get( 'VaryOnXFP' ) ) {
 886                         $out->addVaryHeader( 'X-Forwarded-Proto' );
 887                 }
 888
 889                 if ( !$isError && $this->mModule &&
 890                         ( $this->getRequest()->getMethod() === 'GET' || $this->getRequest()->getMethod() === 'HEAD' )
 891                 ) {
 892                         $etag = $this->mModule->getConditionalRequestData( 'etag' );
 893                         if ( $etag !== null ) {
 894                                 $response->header( "ETag: $etag" );
 895                         }
 896                         $lastMod = $this->mModule->getConditionalRequestData( 'last-modified' );
 897                         if ( $lastMod !== null ) {
 898                                 $response->header( 'Last-Modified: ' . wfTimestamp( TS_RFC2822, $lastMod ) );
 899                         }
 900                 }
 901
 902                 // The logic should be:
 903                 // $this->mCacheControl['max-age'] is set?
 904                 //    Use it, the module knows better than our guess.
 905                 // !$this->mModule || $this->mModule->isWriteMode(), and mCacheMode is private?
 906                 //    Use 0 because we can guess caching is probably the wrong thing to do.
 907                 // Use $this->getParameter( 'maxage' ), which already defaults to 0.
 908                 $maxage = 0;
 909                 if ( isset( $this->mCacheControl['max-age'] ) ) {
 910                         $maxage = $this->mCacheControl['max-age'];
 911                 } elseif ( ( $this->mModule && !$this->mModule->isWriteMode() ) ||
 912                         $this->mCacheMode !== 'private'
 913                 ) {
 914                         $maxage = $this->getParameter( 'maxage' );
 915                 }
 916                 $privateCache = 'private, must-revalidate, max-age=' . $maxage;
 917
 918                 if ( $this->mCacheMode == 'private' ) {
 919                         $response->header( "Cache-Control: $privateCache" );
 920                         return;
 921                 }
 922
 923                 $useKeyHeader = $config->get( 'UseKeyHeader' );
 924                 if ( $this->mCacheMode == 'anon-public-user-private' ) {
 925                         $out->addVaryHeader( 'Cookie' );
 926                         $response->header( $out->getVaryHeader() );
 927                         if ( $useKeyHeader ) {
 928                                 $response->header( $out->getKeyHeader() );
 929                                 if ( $out->haveCacheVaryCookies() ) {
 930                                         // Logged in, mark this request private
 931                                         $response->header( "Cache-Control: $privateCache" );
 932                                         return;
 933                                 }
 934                                 // Logged out, send normal public headers below
 935                         } elseif ( MediaWiki\Session\SessionManager::getGlobalSession()->isPersistent() ) {
 936                                 // Logged in or otherwise has session (e.g. anonymous users who have edited)
 937                                 // Mark request private
 938                                 $response->header( "Cache-Control: $privateCache" );
 939
 940                                 return;
 941                         } // else no Key and anonymous, send public headers below
 942                 }
 943
 944                 // Send public headers
 945                 $response->header( $out->getVaryHeader() );
 946                 if ( $useKeyHeader ) {
 947                         $response->header( $out->getKeyHeader() );
 948                 }
 949
 950                 // If nobody called setCacheMaxAge(), use the (s)maxage parameters
 951                 if ( !isset( $this->mCacheControl['s-maxage'] ) ) {
 952                         $this->mCacheControl['s-maxage'] = $this->getParameter( 'smaxage' );
 953                 }
 954                 if ( !isset( $this->mCacheControl['max-age'] ) ) {
 955                         $this->mCacheControl['max-age'] = $this->getParameter( 'maxage' );
 956                 }
 957
 958                 if ( !$this->mCacheControl['s-maxage'] && !$this->mCacheControl['max-age'] ) {
 959                         // Public cache not requested
 960                         // Sending a Vary header in this case is harmless, and protects us
 961                         // against conditional calls of setCacheMaxAge().
 962                         $response->header( "Cache-Control: $privateCache" );
 963
 964                         return;
 965                 }
 966
 967                 $this->mCacheControl['public'] = true;
 968
 969                 // Send an Expires header
 970                 $maxAge = min( $this->mCacheControl['s-maxage'], $this->mCacheControl['max-age'] );
 971                 $expiryUnixTime = ( $maxAge == 0 ? 1 : time() + $maxAge );
 972                 $response->header( 'Expires: ' . wfTimestamp( TS_RFC2822, $expiryUnixTime ) );
 973
 974                 // Construct the Cache-Control header
 975                 $ccHeader = '';
 976                 $separator = '';
 977                 foreach ( $this->mCacheControl as $name => $value ) {
 978                         if ( is_bool( $value ) ) {
 979                                 if ( $value ) {
 980                                         $ccHeader .= $separator . $name;
 981                                         $separator = ', ';
 982                                 }
 983                         } else {
 984                                 $ccHeader .= $separator . "$name=$value";
 985                                 $separator = ', ';
 986                         }
 987                 }
 988
 989                 $response->header( "Cache-Control: $ccHeader" );
 990         }
 991
 992         /**
 993          * Create the printer for error output
 994          */
 995         private function createErrorPrinter() {
 996                 if ( !isset( $this->mPrinter ) ) {
 997                         $value = $this->getRequest()->getVal( 'format', self::API_DEFAULT_FORMAT );
 998                         if ( !$this->mModuleMgr->isDefined( $value, 'format' ) ) {
 999                                 $value = self::API_DEFAULT_FORMAT;
1000                         }
1001                         $this->mPrinter = $this->createPrinterByName( $value );
1002                 }
1003
1004                 // Printer may not be able to handle errors. This is particularly
1005                 // likely if the module returns something for getCustomPrinter().
1006                 if ( !$this->mPrinter->canPrintErrors() ) {
1007                         $this->mPrinter = $this->createPrinterByName( self::API_DEFAULT_FORMAT );
1008                 }
1009         }
1010
1011         /**
1012          * Create an error message for the given exception.
1013          *
1014          * If an ApiUsageException, errors/warnings will be extracted from the
1015          * embedded StatusValue.
1016          *
1017          * If a base UsageException, the getMessageArray() method will be used to
1018          * extract the code and English message for a single error (no warnings).
1019          *
1020          * Any other exception will be returned with a generic code and wrapper
1021          * text around the exception's (presumably English) message as a single
1022          * error (no warnings).
1023          *
1024          * @param Exception $e
1025          * @param string $type 'error' or 'warning'
1026          * @return ApiMessage[]
1027          * @since 1.27
1028          */
1029         protected function errorMessagesFromException( $e, $type = 'error' ) {
1030                 $messages = [];
1031                 if ( $e instanceof ApiUsageException ) {
1032                         foreach ( $e->getStatusValue()->getErrorsByType( $type ) as $error ) {
1033                                 $messages[] = ApiMessage::create( $error );
1034                         }
1035                 } elseif ( $type !== 'error' ) {
1036                         // None of the rest have any messages for non-error types
1037                 } elseif ( $e instanceof UsageException ) {
1038                         // User entered incorrect parameters - generate error response
1039                         $data = $e->getMessageArray();
1040                         $code = $data['code'];
1041                         $info = $data['info'];
1042                         unset( $data['code'], $data['info'] );
1043                         $messages[] = new ApiRawMessage( [ '$1', $info ], $code, $data );
1044                 } else {
1045                         // Something is seriously wrong
1046                         $config = $this->getConfig();
1047                         $class = preg_replace( '#^Wikimedia\\\Rdbms\\\#', '', get_class( $e ) );
1048                         $code = 'internal_api_error_' . $class;
1049                         if ( ( $e instanceof DBQueryError ) && !$config->get( 'ShowSQLErrors' ) ) {
1050                                 $params = [ 'apierror-databaseerror', WebRequest::getRequestId() ];
1051                         } else {
1052                                 $params = [
1053                                         'apierror-exceptioncaught',
1054                                         WebRequest::getRequestId(),
1055                                         $e instanceof ILocalizedException
1056                                                 ? $e->getMessageObject()
1057                                                 : wfEscapeWikiText( $e->getMessage() )
1058                                 ];
1059                         }
1060                         $messages[] = ApiMessage::create( $params, $code );
1061                 }
1062                 return $messages;
1063         }
1064
1065         /**
1066          * Replace the result data with the information about an exception.
1067          * @param Exception $e
1068          * @return string[] Error codes
1069          */
1070         protected function substituteResultWithError( $e ) {
1071                 $result = $this->getResult();
1072                 $formatter = $this->getErrorFormatter();
1073                 $config = $this->getConfig();
1074                 $errorCodes = [];
1075
1076                 // Remember existing warnings and errors across the reset
1077                 $errors = $result->getResultData( [ 'errors' ] );
1078                 $warnings = $result->getResultData( [ 'warnings' ] );
1079                 $result->reset();
1080                 if ( $warnings !== null ) {
1081                         $result->addValue( null, 'warnings', $warnings, ApiResult::NO_SIZE_CHECK );
1082                 }
1083                 if ( $errors !== null ) {
1084                         $result->addValue( null, 'errors', $errors, ApiResult::NO_SIZE_CHECK );
1085
1086                         // Collect the copied error codes for the return value
1087                         foreach ( $errors as $error ) {
1088                                 if ( isset( $error['code'] ) ) {
1089                                         $errorCodes[$error['code']] = true;
1090                                 }
1091                         }
1092                 }
1093
1094                 // Add errors from the exception
1095                 $modulePath = $e instanceof ApiUsageException ? $e->getModulePath() : null;
1096                 foreach ( $this->errorMessagesFromException( $e, 'error' ) as $msg ) {
1097                         $errorCodes[$msg->getApiCode()] = true;
1098                         $formatter->addError( $modulePath, $msg );
1099                 }
1100                 foreach ( $this->errorMessagesFromException( $e, 'warning' ) as $msg ) {
1101                         $formatter->addWarning( $modulePath, $msg );
1102                 }
1103
1104                 // Add additional data. Path depends on whether we're in BC mode or not.
1105                 // Data depends on the type of exception.
1106                 if ( $formatter instanceof ApiErrorFormatter_BackCompat ) {
1107                         $path = [ 'error' ];
1108                 } else {
1109                         $path = null;
1110                 }
1111                 if ( $e instanceof ApiUsageException || $e instanceof UsageException ) {
1112                         $link = wfExpandUrl( wfScript( 'api' ) );
1113                         $result->addContentValue(
1114                                 $path,
1115                                 'docref',
1116                                 trim(
1117                                         $this->msg( 'api-usage-docref', $link )->inLanguage( $formatter->getLanguage() )->text()
1118                                         . ' '
1119                                         . $this->msg( 'api-usage-mailinglist-ref' )->inLanguage( $formatter->getLanguage() )->text()
1120                                 )
1121                         );
1122                 } else {
1123                         if ( $config->get( 'ShowExceptionDetails' ) &&
1124                                 ( !$e instanceof DBError || $config->get( 'ShowDBErrorBacktrace' ) )
1125                         ) {
1126                                 $result->addContentValue(
1127                                         $path,
1128                                         'trace',
1129                                         $this->msg( 'api-exception-trace',
1130                                                 get_class( $e ),
1131                                                 $e->getFile(),
1132                                                 $e->getLine(),
1133                                                 MWExceptionHandler::getRedactedTraceAsString( $e )
1134                                         )->inLanguage( $formatter->getLanguage() )->text()
1135                                 );
1136                         }
1137                 }
1138
1139                 // Add the id and such
1140                 $this->addRequestedFields( [ 'servedby' ] );
1141
1142                 return array_keys( $errorCodes );
1143         }
1144
1145         /**
1146          * Add requested fields to the result
1147          * @param string[] $force Which fields to force even if not requested. Accepted values are:
1148          *  - servedby
1149          */
1150         protected function addRequestedFields( $force = [] ) {
1151                 $result = $this->getResult();
1152
1153                 $requestid = $this->getParameter( 'requestid' );
1154                 if ( $requestid !== null ) {
1155                         $result->addValue( null, 'requestid', $requestid, ApiResult::NO_SIZE_CHECK );
1156                 }
1157
1158                 if ( $this->getConfig()->get( 'ShowHostnames' ) && (
1159                         in_array( 'servedby', $force, true ) || $this->getParameter( 'servedby' )
1160                 ) ) {
1161                         $result->addValue( null, 'servedby', wfHostname(), ApiResult::NO_SIZE_CHECK );
1162                 }
1163
1164                 if ( $this->getParameter( 'curtimestamp' ) ) {
1165                         $result->addValue( null, 'curtimestamp', wfTimestamp( TS_ISO_8601, time() ),
1166                                 ApiResult::NO_SIZE_CHECK );
1167                 }
1168
1169                 if ( $this->getParameter( 'responselanginfo' ) ) {
1170                         $result->addValue( null, 'uselang', $this->getLanguage()->getCode(),
1171                                 ApiResult::NO_SIZE_CHECK );
1172                         $result->addValue( null, 'errorlang', $this->getErrorFormatter()->getLanguage()->getCode(),
1173                                 ApiResult::NO_SIZE_CHECK );
1174                 }
1175         }
1176
1177         /**
1178          * Set up for the execution.
1179          * @return array
1180          */
1181         protected function setupExecuteAction() {
1182                 $this->addRequestedFields();
1183
1184                 $params = $this->extractRequestParams();
1185                 $this->mAction = $params['action'];
1186
1187                 return $params;
1188         }
1189
1190         /**
1191          * Set up the module for response
1192          * @return ApiBase The module that will handle this action
1193          * @throws MWException
1194          * @throws ApiUsageException
1195          */
1196         protected function setupModule() {
1197                 // Instantiate the module requested by the user
1198                 $module = $this->mModuleMgr->getModule( $this->mAction, 'action' );
1199                 if ( $module === null ) {
1200                         $this->dieWithError(
1201                                 [ 'apierror-unknownaction', wfEscapeWikiText( $this->mAction ) ], 'unknown_action'
1202                         );
1203                 }
1204                 $moduleParams = $module->extractRequestParams();
1205
1206                 // Check token, if necessary
1207                 if ( $module->needsToken() === true ) {
1208                         throw new MWException(
1209                                 "Module '{$module->getModuleName()}' must be updated for the new token handling. " .
1210                                 'See documentation for ApiBase::needsToken for details.'
1211                         );
1212                 }
1213                 if ( $module->needsToken() ) {
1214                         if ( !$module->mustBePosted() ) {
1215                                 throw new MWException(
1216                                         "Module '{$module->getModuleName()}' must require POST to use tokens."
1217                                 );
1218                         }
1219
1220                         if ( !isset( $moduleParams['token'] ) ) {
1221                                 $module->dieWithError( [ 'apierror-missingparam', 'token' ] );
1222                         }
1223
1224                         $module->requirePostedParameters( [ 'token' ] );
1225
1226                         if ( !$module->validateToken( $moduleParams['token'], $moduleParams ) ) {
1227                                 $module->dieWithError( 'apierror-badtoken' );
1228                         }
1229                 }
1230
1231                 return $module;
1232         }
1233
1234         /**
1235          * @return array
1236          */
1237         private function getMaxLag() {
1238                 $dbLag = MediaWikiServices::getInstance()->getDBLoadBalancer()->getMaxLag();
1239                 $lagInfo = [
1240                         'host' => $dbLag[0],
1241                         'lag' => $dbLag[1],
1242                         'type' => 'db'
1243                 ];
1244
1245                 $jobQueueLagFactor = $this->getConfig()->get( 'JobQueueIncludeInMaxLagFactor' );
1246                 if ( $jobQueueLagFactor ) {
1247                         // Turn total number of jobs into seconds by using the configured value
1248                         $totalJobs = array_sum( JobQueueGroup::singleton()->getQueueSizes() );
1249                         $jobQueueLag = $totalJobs / (float)$jobQueueLagFactor;
1250                         if ( $jobQueueLag > $lagInfo['lag'] ) {
1251                                 $lagInfo = [
1252                                         'host' => wfHostname(), // XXX: Is there a better value that could be used?
1253                                         'lag' => $jobQueueLag,
1254                                         'type' => 'jobqueue',
1255                                         'jobs' => $totalJobs,
1256                                 ];
1257                         }
1258                 }
1259
1260                 return $lagInfo;
1261         }
1262
1263         /**
1264          * Check the max lag if necessary
1265          * @param ApiBase $module Api module being used
1266          * @param array $params Array an array containing the request parameters.
1267          * @return bool True on success, false should exit immediately
1268          */
1269         protected function checkMaxLag( $module, $params ) {
1270                 if ( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
1271                         $maxLag = $params['maxlag'];
1272                         $lagInfo = $this->getMaxLag();
1273                         if ( $lagInfo['lag'] > $maxLag ) {
1274                                 $response = $this->getRequest()->response();
1275
1276                                 $response->header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
1277                                 $response->header( 'X-Database-Lag: ' . intval( $lagInfo['lag'] ) );
1278
1279                                 if ( $this->getConfig()->get( 'ShowHostnames' ) ) {
1280                                         $this->dieWithError(
1281                                                 [ 'apierror-maxlag', $lagInfo['lag'], $lagInfo['host'] ],
1282                                                 'maxlag',
1283                                                 $lagInfo
1284                                         );
1285                                 }
1286
1287                                 $this->dieWithError( [ 'apierror-maxlag-generic', $lagInfo['lag'] ], 'maxlag', $lagInfo );
1288                         }
1289                 }
1290
1291                 return true;
1292         }
1293
1294         /**
1295          * Check selected RFC 7232 precondition headers
1296          *
1297          * RFC 7232 envisions a particular model where you send your request to "a
1298          * resource", and for write requests that you can read "the resource" by
1299          * changing the method to GET. When the API receives a GET request, it
1300          * works out even though "the resource" from RFC 7232's perspective might
1301          * be many resources from MediaWiki's perspective. But it totally fails for
1302          * a POST, since what HTTP sees as "the resource" is probably just
1303          * "/api.php" with all the interesting bits in the body.
1304          *
1305          * Therefore, we only support RFC 7232 precondition headers for GET (and
1306          * HEAD). That means we don't need to bother with If-Match and
1307          * If-Unmodified-Since since they only apply to modification requests.
1308          *
1309          * And since we don't support Range, If-Range is ignored too.
1310          *
1311          * @since 1.26
1312          * @param ApiBase $module Api module being used
1313          * @return bool True on success, false should exit immediately
1314          */
1315         protected function checkConditionalRequestHeaders( $module ) {
1316                 if ( $this->mInternalMode ) {
1317                         // No headers to check in internal mode
1318                         return true;
1319                 }
1320
1321                 if ( $this->getRequest()->getMethod() !== 'GET' && $this->getRequest()->getMethod() !== 'HEAD' ) {
1322                         // Don't check POSTs
1323                         return true;
1324                 }
1325
1326                 $return304 = false;
1327
1328                 $ifNoneMatch = array_diff(
1329                         $this->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST ) ?: [],
1330                         [ '' ]
1331                 );
1332                 if ( $ifNoneMatch ) {
1333                         if ( $ifNoneMatch === [ '*' ] ) {
1334                                 // API responses always "exist"
1335                                 $etag = '*';
1336                         } else {
1337                                 $etag = $module->getConditionalRequestData( 'etag' );
1338                         }
1339                 }
1340                 if ( $ifNoneMatch && $etag !== null ) {
1341                         $test = substr( $etag, 0, 2 ) === 'W/' ? substr( $etag, 2 ) : $etag;
1342                         $match = array_map( function ( $s ) {
1343                                 return substr( $s, 0, 2 ) === 'W/' ? substr( $s, 2 ) : $s;
1344                         }, $ifNoneMatch );
1345                         $return304 = in_array( $test, $match, true );
1346                 } else {
1347                         $value = trim( $this->getRequest()->getHeader( 'If-Modified-Since' ) );
1348
1349                         // Some old browsers sends sizes after the date, like this:
1350                         //  Wed, 20 Aug 2003 06:51:19 GMT; length=5202
1351                         // Ignore that.
1352                         $i = strpos( $value, ';' );
1353                         if ( $i !== false ) {
1354                                 $value = trim( substr( $value, 0, $i ) );
1355                         }
1356
1357                         if ( $value !== '' ) {
1358                                 try {
1359                                         $ts = new MWTimestamp( $value );
1360                                         if (
1361                                                 // RFC 7231 IMF-fixdate
1362                                                 $ts->getTimestamp( TS_RFC2822 ) === $value ||
1363                                                 // RFC 850
1364                                                 $ts->format( 'l, d-M-y H:i:s' ) . ' GMT' === $value ||
1365                                                 // asctime (with and without space-padded day)
1366                                                 $ts->format( 'D M j H:i:s Y' ) === $value ||
1367                                                 $ts->format( 'D M  j H:i:s Y' ) === $value
1368                                         ) {
1369                                                 $lastMod = $module->getConditionalRequestData( 'last-modified' );
1370                                                 if ( $lastMod !== null ) {
1371                                                         // Mix in some MediaWiki modification times
1372                                                         $modifiedTimes = [
1373                                                                 'page' => $lastMod,
1374                                                                 'user' => $this->getUser()->getTouched(),
1375                                                                 'epoch' => $this->getConfig()->get( 'CacheEpoch' ),
1376                                                         ];
1377                                                         if ( $this->getConfig()->get( 'UseSquid' ) ) {
1378                                                                 // T46570: the core page itself may not change, but resources might
1379                                                                 $modifiedTimes['sepoch'] = wfTimestamp(
1380                                                                         TS_MW, time() - $this->getConfig()->get( 'SquidMaxage' )
1381                                                                 );
1382                                                         }
1383                                                         Hooks::run( 'OutputPageCheckLastModified', [ &$modifiedTimes, $this->getOutput() ] );
1384                                                         $lastMod = max( $modifiedTimes );
1385                                                         $return304 = wfTimestamp( TS_MW, $lastMod ) <= $ts->getTimestamp( TS_MW );
1386                                                 }
1387                                         }
1388                                 } catch ( TimestampException $e ) {
1389                                         // Invalid timestamp, ignore it
1390                                 }
1391                         }
1392                 }
1393
1394                 if ( $return304 ) {
1395                         $this->getRequest()->response()->statusHeader( 304 );
1396
1397                         // Avoid outputting the compressed representation of a zero-length body
1398                         MediaWiki\suppressWarnings();
1399                         ini_set( 'zlib.output_compression', 0 );
1400                         MediaWiki\restoreWarnings();
1401                         wfClearOutputBuffers();
1402
1403                         return false;
1404                 }
1405
1406                 return true;
1407         }
1408
1409         /**
1410          * Check for sufficient permissions to execute
1411          * @param ApiBase $module An Api module
1412          */
1413         protected function checkExecutePermissions( $module ) {
1414                 $user = $this->getUser();
1415                 if ( $module->isReadMode() && !User::isEveryoneAllowed( 'read' ) &&
1416                         !$user->isAllowed( 'read' )
1417                 ) {
1418                         $this->dieWithError( 'apierror-readapidenied' );
1419                 }
1420
1421                 if ( $module->isWriteMode() ) {
1422                         if ( !$this->mEnableWrite ) {
1423                                 $this->dieWithError( 'apierror-noapiwrite' );
1424                         } elseif ( !$user->isAllowed( 'writeapi' ) ) {
1425                                 $this->dieWithError( 'apierror-writeapidenied' );
1426                         } elseif ( $this->getRequest()->getHeader( 'Promise-Non-Write-API-Action' ) ) {
1427                                 $this->dieWithError( 'apierror-promised-nonwrite-api' );
1428                         }
1429
1430                         $this->checkReadOnly( $module );
1431                 }
1432
1433                 // Allow extensions to stop execution for arbitrary reasons.
1434                 $message = false;
1435                 if ( !Hooks::run( 'ApiCheckCanExecute', [ $module, $user, &$message ] ) ) {
1436                         $this->dieWithError( $message );
1437                 }
1438         }
1439
1440         /**
1441          * Check if the DB is read-only for this user
1442          * @param ApiBase $module An Api module
1443          */
1444         protected function checkReadOnly( $module ) {
1445                 if ( wfReadOnly() ) {
1446                         $this->dieReadOnly();
1447                 }
1448
1449                 if ( $module->isWriteMode()
1450                         && $this->getUser()->isBot()
1451                         && wfGetLB()->getServerCount() > 1
1452                 ) {
1453                         $this->checkBotReadOnly();
1454                 }
1455         }
1456
1457         /**
1458          * Check whether we are readonly for bots
1459          */
1460         private function checkBotReadOnly() {
1461                 // Figure out how many servers have passed the lag threshold
1462                 $numLagged = 0;
1463                 $lagLimit = $this->getConfig()->get( 'APIMaxLagThreshold' );
1464                 $laggedServers = [];
1465                 $loadBalancer = wfGetLB();
1466                 foreach ( $loadBalancer->getLagTimes() as $serverIndex => $lag ) {
1467                         if ( $lag > $lagLimit ) {
1468                                 ++$numLagged;
1469                                 $laggedServers[] = $loadBalancer->getServerName( $serverIndex ) . " ({$lag}s)";
1470                         }
1471                 }
1472
1473                 // If a majority of replica DBs are too lagged then disallow writes
1474                 $replicaCount = wfGetLB()->getServerCount() - 1;
1475                 if ( $numLagged >= ceil( $replicaCount / 2 ) ) {
1476                         $laggedServers = implode( ', ', $laggedServers );
1477                         wfDebugLog(
1478                                 'api-readonly',
1479                                 "Api request failed as read only because the following DBs are lagged: $laggedServers"
1480                         );
1481
1482                         $this->dieWithError(
1483                                 'readonly_lag',
1484                                 'readonly',
1485                                 [ 'readonlyreason' => "Waiting for $numLagged lagged database(s)" ]
1486                         );
1487                 }
1488         }
1489
1490         /**
1491          * Check asserts of the user's rights
1492          * @param array $params
1493          */
1494         protected function checkAsserts( $params ) {
1495                 if ( isset( $params['assert'] ) ) {
1496                         $user = $this->getUser();
1497                         switch ( $params['assert'] ) {
1498                                 case 'user':
1499                                         if ( $user->isAnon() ) {
1500                                                 $this->dieWithError( 'apierror-assertuserfailed' );
1501                                         }
1502                                         break;
1503                                 case 'bot':
1504                                         if ( !$user->isAllowed( 'bot' ) ) {
1505                                                 $this->dieWithError( 'apierror-assertbotfailed' );
1506                                         }
1507                                         break;
1508                         }
1509                 }
1510                 if ( isset( $params['assertuser'] ) ) {
1511                         $assertUser = User::newFromName( $params['assertuser'], false );
1512                         if ( !$assertUser || !$this->getUser()->equals( $assertUser ) ) {
1513                                 $this->dieWithError(
1514                                         [ 'apierror-assertnameduserfailed', wfEscapeWikiText( $params['assertuser'] ) ]
1515                                 );
1516                         }
1517                 }
1518         }
1519
1520         /**
1521          * Check POST for external response and setup result printer
1522          * @param ApiBase $module An Api module
1523          * @param array $params An array with the request parameters
1524          */
1525         protected function setupExternalResponse( $module, $params ) {
1526                 $request = $this->getRequest();
1527                 if ( !$request->wasPosted() && $module->mustBePosted() ) {
1528                         // Module requires POST. GET request might still be allowed
1529                         // if $wgDebugApi is true, otherwise fail.
1530                         $this->dieWithErrorOrDebug( [ 'apierror-mustbeposted', $this->mAction ] );
1531                 }
1532
1533                 // See if custom printer is used
1534                 $this->mPrinter = $module->getCustomPrinter();
1535                 if ( is_null( $this->mPrinter ) ) {
1536                         // Create an appropriate printer
1537                         $this->mPrinter = $this->createPrinterByName( $params['format'] );
1538                 }
1539
1540                 if ( $request->getProtocol() === 'http' && (
1541                         $request->getSession()->shouldForceHTTPS() ||
1542                         ( $this->getUser()->isLoggedIn() &&
1543                                 $this->getUser()->requiresHTTPS() )
1544                 ) ) {
1545                         $this->addDeprecation( 'apiwarn-deprecation-httpsexpected', 'https-expected' );
1546                 }
1547         }
1548
1549         /**
1550          * Execute the actual module, without any error handling
1551          */
1552         protected function executeAction() {
1553                 $params = $this->setupExecuteAction();
1554                 $module = $this->setupModule();
1555                 $this->mModule = $module;
1556
1557                 if ( !$this->mInternalMode ) {
1558                         $this->setRequestExpectations( $module );
1559                 }
1560
1561                 $this->checkExecutePermissions( $module );
1562
1563                 if ( !$this->checkMaxLag( $module, $params ) ) {
1564                         return;
1565                 }
1566
1567                 if ( !$this->checkConditionalRequestHeaders( $module ) ) {
1568                         return;
1569                 }
1570
1571                 if ( !$this->mInternalMode ) {
1572                         $this->setupExternalResponse( $module, $params );
1573                 }
1574
1575                 $this->checkAsserts( $params );
1576
1577                 // Execute
1578                 $module->execute();
1579                 Hooks::run( 'APIAfterExecute', [ &$module ] );
1580
1581                 $this->reportUnusedParams();
1582
1583                 if ( !$this->mInternalMode ) {
1584                         // append Debug information
1585                         MWDebug::appendDebugInfoToApiResult( $this->getContext(), $this->getResult() );
1586
1587                         // Print result data
1588                         $this->printResult();
1589                 }
1590         }
1591
1592         /**
1593          * Set database connection, query, and write expectations given this module request
1594          * @param ApiBase $module
1595          */
1596         protected function setRequestExpectations( ApiBase $module ) {
1597                 $limits = $this->getConfig()->get( 'TrxProfilerLimits' );
1598                 $trxProfiler = Profiler::instance()->getTransactionProfiler();
1599                 $trxProfiler->setLogger( LoggerFactory::getInstance( 'DBPerformance' ) );
1600                 if ( $this->getRequest()->hasSafeMethod() ) {
1601                         $trxProfiler->setExpectations( $limits['GET'], __METHOD__ );
1602                 } elseif ( $this->getRequest()->wasPosted() && !$module->isWriteMode() ) {
1603                         $trxProfiler->setExpectations( $limits['POST-nonwrite'], __METHOD__ );
1604                         $this->getRequest()->markAsSafeRequest();
1605                 } else {
1606                         $trxProfiler->setExpectations( $limits['POST'], __METHOD__ );
1607                 }
1608         }
1609
1610         /**
1611          * Log the preceding request
1612          * @param float $time Time in seconds
1613          * @param Exception $e Exception caught while processing the request
1614          */
1615         protected function logRequest( $time, $e = null ) {
1616                 $request = $this->getRequest();
1617                 $logCtx = [
1618                         'ts' => time(),
1619                         'ip' => $request->getIP(),
1620                         'userAgent' => $this->getUserAgent(),
1621                         'wiki' => wfWikiID(),
1622                         'timeSpentBackend' => (int)round( $time * 1000 ),
1623                         'hadError' => $e !== null,
1624                         'errorCodes' => [],
1625                         'params' => [],
1626                 ];
1627
1628                 if ( $e ) {
1629                         foreach ( $this->errorMessagesFromException( $e ) as $msg ) {
1630                                 $logCtx['errorCodes'][] = $msg->getApiCode();
1631                         }
1632                 }
1633
1634                 // Construct space separated message for 'api' log channel
1635                 $msg = "API {$request->getMethod()} " .
1636                         wfUrlencode( str_replace( ' ', '_', $this->getUser()->getName() ) ) .
1637                         " {$logCtx['ip']} " .
1638                         "T={$logCtx['timeSpentBackend']}ms";
1639
1640                 $sensitive = array_flip( $this->getSensitiveParams() );
1641                 foreach ( $this->getParamsUsed() as $name ) {
1642                         $value = $request->getVal( $name );
1643                         if ( $value === null ) {
1644                                 continue;
1645                         }
1646
1647                         if ( isset( $sensitive[$name] ) ) {
1648                                 $value = '[redacted]';
1649                                 $encValue = '[redacted]';
1650                         } elseif ( strlen( $value ) > 256 ) {
1651                                 $value = substr( $value, 0, 256 );
1652                                 $encValue = $this->encodeRequestLogValue( $value ) . '[...]';
1653                         } else {
1654                                 $encValue = $this->encodeRequestLogValue( $value );
1655                         }
1656
1657                         $logCtx['params'][$name] = $value;
1658                         $msg .= " {$name}={$encValue}";
1659                 }
1660
1661                 wfDebugLog( 'api', $msg, 'private' );
1662                 // ApiAction channel is for structured data consumers
1663                 wfDebugLog( 'ApiAction', '', 'private', $logCtx );
1664         }
1665
1666         /**
1667          * Encode a value in a format suitable for a space-separated log line.
1668          * @param string $s
1669          * @return string
1670          */
1671         protected function encodeRequestLogValue( $s ) {
1672                 static $table;
1673                 if ( !$table ) {
1674                         $chars = ';@$!*(),/:';
1675                         $numChars = strlen( $chars );
1676                         for ( $i = 0; $i < $numChars; $i++ ) {
1677                                 $table[rawurlencode( $chars[$i] )] = $chars[$i];
1678                         }
1679                 }
1680
1681                 return strtr( rawurlencode( $s ), $table );
1682         }
1683
1684         /**
1685          * Get the request parameters used in the course of the preceding execute() request
1686          * @return array
1687          */
1688         protected function getParamsUsed() {
1689                 return array_keys( $this->mParamsUsed );
1690         }
1691
1692         /**
1693          * Mark parameters as used
1694          * @param string|string[] $params
1695          */
1696         public function markParamsUsed( $params ) {
1697                 $this->mParamsUsed += array_fill_keys( (array)$params, true );
1698         }
1699
1700         /**
1701          * Get the request parameters that should be considered sensitive
1702          * @since 1.29
1703          * @return array
1704          */
1705         protected function getSensitiveParams() {
1706                 return array_keys( $this->mParamsSensitive );
1707         }
1708
1709         /**
1710          * Mark parameters as sensitive
1711          * @since 1.29
1712          * @param string|string[] $params
1713          */
1714         public function markParamsSensitive( $params ) {
1715                 $this->mParamsSensitive += array_fill_keys( (array)$params, true );
1716         }
1717
1718         /**
1719          * Get a request value, and register the fact that it was used, for logging.
1720          * @param string $name
1721          * @param mixed $default
1722          * @return mixed
1723          */
1724         public function getVal( $name, $default = null ) {
1725                 $this->mParamsUsed[$name] = true;
1726
1727                 $ret = $this->getRequest()->getVal( $name );
1728                 if ( $ret === null ) {
1729                         if ( $this->getRequest()->getArray( $name ) !== null ) {
1730                                 // See T12262 for why we don't just implode( '|', ... ) the
1731                                 // array.
1732                                 $this->addWarning( [ 'apiwarn-unsupportedarray', $name ] );
1733                         }
1734                         $ret = $default;
1735                 }
1736                 return $ret;
1737         }
1738
1739         /**
1740          * Get a boolean request value, and register the fact that the parameter
1741          * was used, for logging.
1742          * @param string $name
1743          * @return bool
1744          */
1745         public function getCheck( $name ) {
1746                 return $this->getVal( $name, null ) !== null;
1747         }
1748
1749         /**
1750          * Get a request upload, and register the fact that it was used, for logging.
1751          *
1752          * @since 1.21
1753          * @param string $name Parameter name
1754          * @return WebRequestUpload
1755          */
1756         public function getUpload( $name ) {
1757                 $this->mParamsUsed[$name] = true;
1758
1759                 return $this->getRequest()->getUpload( $name );
1760         }
1761
1762         /**
1763          * Report unused parameters, so the client gets a hint in case it gave us parameters we don't know,
1764          * for example in case of spelling mistakes or a missing 'g' prefix for generators.
1765          */
1766         protected function reportUnusedParams() {
1767                 $paramsUsed = $this->getParamsUsed();
1768                 $allParams = $this->getRequest()->getValueNames();
1769
1770                 if ( !$this->mInternalMode ) {
1771                         // Printer has not yet executed; don't warn that its parameters are unused
1772                         $printerParams = $this->mPrinter->encodeParamName(
1773                                 array_keys( $this->mPrinter->getFinalParams() ?: [] )
1774                         );
1775                         $unusedParams = array_diff( $allParams, $paramsUsed, $printerParams );
1776                 } else {
1777                         $unusedParams = array_diff( $allParams, $paramsUsed );
1778                 }
1779
1780                 if ( count( $unusedParams ) ) {
1781                         $this->addWarning( [
1782                                 'apierror-unrecognizedparams',
1783                                 Message::listParam( array_map( 'wfEscapeWikiText', $unusedParams ), 'comma' ),
1784                                 count( $unusedParams )
1785                         ] );
1786                 }
1787         }
1788
1789         /**
1790          * Print results using the current printer
1791          *
1792          * @param int $httpCode HTTP status code, or 0 to not change
1793          */
1794         protected function printResult( $httpCode = 0 ) {
1795                 if ( $this->getConfig()->get( 'DebugAPI' ) !== false ) {
1796                         $this->addWarning( 'apiwarn-wgDebugAPI' );
1797                 }
1798
1799                 $printer = $this->mPrinter;
1800                 $printer->initPrinter( false );
1801                 if ( $httpCode ) {
1802                         $printer->setHttpStatus( $httpCode );
1803                 }
1804                 $printer->execute();
1805                 $printer->closePrinter();
1806         }
1807
1808         /**
1809          * @return bool
1810          */
1811         public function isReadMode() {
1812                 return false;
1813         }
1814
1815         /**
1816          * See ApiBase for description.
1817          *
1818          * @return array
1819          */
1820         public function getAllowedParams() {
1821                 return [
1822                         'action' => [
1823                                 ApiBase::PARAM_DFLT => 'help',
1824                                 ApiBase::PARAM_TYPE => 'submodule',
1825                         ],
1826                         'format' => [
1827                                 ApiBase::PARAM_DFLT => ApiMain::API_DEFAULT_FORMAT,
1828                                 ApiBase::PARAM_TYPE => 'submodule',
1829                         ],
1830                         'maxlag' => [
1831                                 ApiBase::PARAM_TYPE => 'integer'
1832                         ],
1833                         'smaxage' => [
1834                                 ApiBase::PARAM_TYPE => 'integer',
1835                                 ApiBase::PARAM_DFLT => 0
1836                         ],
1837                         'maxage' => [
1838                                 ApiBase::PARAM_TYPE => 'integer',
1839                                 ApiBase::PARAM_DFLT => 0
1840                         ],
1841                         'assert' => [
1842                                 ApiBase::PARAM_TYPE => [ 'user', 'bot' ]
1843                         ],
1844                         'assertuser' => [
1845                                 ApiBase::PARAM_TYPE => 'user',
1846                         ],
1847                         'requestid' => null,
1848                         'servedby' => false,
1849                         'curtimestamp' => false,
1850                         'responselanginfo' => false,
1851                         'origin' => null,
1852                         'uselang' => [
1853                                 ApiBase::PARAM_DFLT => self::API_DEFAULT_USELANG,
1854                         ],
1855                         'errorformat' => [
1856                                 ApiBase::PARAM_TYPE => [ 'plaintext', 'wikitext', 'html', 'raw', 'none', 'bc' ],
1857                                 ApiBase::PARAM_DFLT => 'bc',
1858                         ],
1859                         'errorlang' => [
1860                                 ApiBase::PARAM_DFLT => 'uselang',
1861                         ],
1862                         'errorsuselocal' => [
1863                                 ApiBase::PARAM_DFLT => false,
1864                         ],
1865                 ];
1866         }
1867
1868         /** @see ApiBase::getExamplesMessages() */
1869         protected function getExamplesMessages() {
1870                 return [
1871                         'action=help'
1872                                 => 'apihelp-help-example-main',
1873                         'action=help&recursivesubmodules=1'
1874                                 => 'apihelp-help-example-recursive',
1875                 ];
1876         }
1877
1878         public function modifyHelp( array &$help, array $options, array &$tocData ) {
1879                 // Wish PHP had an "array_insert_before". Instead, we have to manually
1880                 // reindex the array to get 'permissions' in the right place.
1881                 $oldHelp = $help;
1882                 $help = [];
1883                 foreach ( $oldHelp as $k => $v ) {
1884                         if ( $k === 'submodules' ) {
1885                                 $help['permissions'] = '';
1886                         }
1887                         $help[$k] = $v;
1888                 }
1889                 $help['datatypes'] = '';
1890                 $help['credits'] = '';
1891
1892                 // Fill 'permissions'
1893                 $help['permissions'] .= Html::openElement( 'div',
1894                         [ 'class' => 'apihelp-block apihelp-permissions' ] );
1895                 $m = $this->msg( 'api-help-permissions' );
1896                 if ( !$m->isDisabled() ) {
1897                         $help['permissions'] .= Html::rawElement( 'div', [ 'class' => 'apihelp-block-head' ],
1898                                 $m->numParams( count( self::$mRights ) )->parse()
1899                         );
1900                 }
1901                 $help['permissions'] .= Html::openElement( 'dl' );
1902                 foreach ( self::$mRights as $right => $rightMsg ) {
1903                         $help['permissions'] .= Html::element( 'dt', null, $right );
1904
1905                         $rightMsg = $this->msg( $rightMsg['msg'], $rightMsg['params'] )->parse();
1906                         $help['permissions'] .= Html::rawElement( 'dd', null, $rightMsg );
1907
1908                         $groups = array_map( function ( $group ) {
1909                                 return $group == '*' ? 'all' : $group;
1910                         }, User::getGroupsWithPermission( $right ) );
1911
1912                         $help['permissions'] .= Html::rawElement( 'dd', null,
1913                                 $this->msg( 'api-help-permissions-granted-to' )
1914                                         ->numParams( count( $groups ) )
1915                                         ->params( Message::listParam( $groups ) )
1916                                         ->parse()
1917                         );
1918                 }
1919                 $help['permissions'] .= Html::closeElement( 'dl' );
1920                 $help['permissions'] .= Html::closeElement( 'div' );
1921
1922                 // Fill 'datatypes' and 'credits', if applicable
1923                 if ( empty( $options['nolead'] ) ) {
1924                         $level = $options['headerlevel'];
1925                         $tocnumber = &$options['tocnumber'];
1926
1927                         $header = $this->msg( 'api-help-datatypes-header' )->parse();
1928
1929                         // Add an additional span with sanitized ID
1930                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1931                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/datatypes' ) ] ) .
1932                                         $header;
1933                         }
1934                         $help['datatypes'] .= Html::rawElement( 'h' . min( 6, $level ),
1935                                 [ 'id' => 'main/datatypes', 'class' => 'apihelp-header' ],
1936                                 $header
1937                         );
1938                         $help['datatypes'] .= $this->msg( 'api-help-datatypes' )->parseAsBlock();
1939                         if ( !isset( $tocData['main/datatypes'] ) ) {
1940                                 $tocnumber[$level]++;
1941                                 $tocData['main/datatypes'] = [
1942                                         'toclevel' => count( $tocnumber ),
1943                                         'level' => $level,
1944                                         'anchor' => 'main/datatypes',
1945                                         'line' => $header,
1946                                         'number' => implode( '.', $tocnumber ),
1947                                         'index' => false,
1948                                 ];
1949                         }
1950
1951                         // Add an additional span with sanitized ID
1952                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1953                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/credits' ) ] ) .
1954                                         $header;
1955                         }
1956                         $header = $this->msg( 'api-credits-header' )->parse();
1957                         $help['credits'] .= Html::rawElement( 'h' . min( 6, $level ),
1958                                 [ 'id' => 'main/credits', 'class' => 'apihelp-header' ],
1959                                 $header
1960                         );
1961                         $help['credits'] .= $this->msg( 'api-credits' )->useDatabase( false )->parseAsBlock();
1962                         if ( !isset( $tocData['main/credits'] ) ) {
1963                                 $tocnumber[$level]++;
1964                                 $tocData['main/credits'] = [
1965                                         'toclevel' => count( $tocnumber ),
1966                                         'level' => $level,
1967                                         'anchor' => 'main/credits',
1968                                         'line' => $header,
1969                                         'number' => implode( '.', $tocnumber ),
1970                                         'index' => false,
1971                                 ];
1972                         }
1973                 }
1974         }
1975
1976         private $mCanApiHighLimits = null;
1977
1978         /**
1979          * Check whether the current user is allowed to use high limits
1980          * @return bool
1981          */
1982         public function canApiHighLimits() {
1983                 if ( !isset( $this->mCanApiHighLimits ) ) {
1984                         $this->mCanApiHighLimits = $this->getUser()->isAllowed( 'apihighlimits' );
1985                 }
1986
1987                 return $this->mCanApiHighLimits;
1988         }
1989
1990         /**
1991          * Overrides to return this instance's module manager.
1992          * @return ApiModuleManager
1993          */
1994         public function getModuleManager() {
1995                 return $this->mModuleMgr;
1996         }
1997
1998         /**
1999          * Fetches the user agent used for this request
2000          *
2001          * The value will be the combination of the 'Api-User-Agent' header (if
2002          * any) and the standard User-Agent header (if any).
2003          *
2004          * @return string
2005          */
2006         public function getUserAgent() {
2007                 return trim(
2008                         $this->getRequest()->getHeader( 'Api-user-agent' ) . ' ' .
2009                         $this->getRequest()->getHeader( 'User-agent' )
2010                 );
2011         }
2012 }
2013
2014 /**
2015  * For really cool vim folding this needs to be at the end:
2016  * vim: foldmarker=@{,@} foldmethod=marker
2017  */