includes/api/ApiMain.php

   1 <?php
   2 /**
   3  *
   4  *
   5  * Created on Sep 4, 2006
   6  *
   7  * Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  22  * http://www.gnu.org/copyleft/gpl.html
  23  *
  24  * @file
  25  * @defgroup API API
  26  */
  27
  28 use MediaWiki\Logger\LoggerFactory;
  29
  30 /**
  31  * This is the main API class, used for both external and internal processing.
  32  * When executed, it will create the requested formatter object,
  33  * instantiate and execute an object associated with the needed action,
  34  * and use formatter to print results.
  35  * In case of an exception, an error message will be printed using the same formatter.
  36  *
  37  * To use API from another application, run it using FauxRequest object, in which
  38  * case any internal exceptions will not be handled but passed up to the caller.
  39  * After successful execution, use getResult() for the resulting data.
  40  *
  41  * @ingroup API
  42  */
  43 class ApiMain extends ApiBase {
  44         /**
  45          * When no format parameter is given, this format will be used
  46          */
  47         const API_DEFAULT_FORMAT = 'jsonfm';
  48
  49         /**
  50          * List of available modules: action name => module class
  51          */
  52         private static $Modules = [
  53                 'login' => 'ApiLogin',
  54                 'clientlogin' => 'ApiClientLogin',
  55                 'logout' => 'ApiLogout',
  56                 'createaccount' => 'ApiAMCreateAccount',
  57                 'linkaccount' => 'ApiLinkAccount',
  58                 'unlinkaccount' => 'ApiRemoveAuthenticationData',
  59                 'changeauthenticationdata' => 'ApiChangeAuthenticationData',
  60                 'removeauthenticationdata' => 'ApiRemoveAuthenticationData',
  61                 'resetpassword' => 'ApiResetPassword',
  62                 'query' => 'ApiQuery',
  63                 'expandtemplates' => 'ApiExpandTemplates',
  64                 'parse' => 'ApiParse',
  65                 'stashedit' => 'ApiStashEdit',
  66                 'opensearch' => 'ApiOpenSearch',
  67                 'feedcontributions' => 'ApiFeedContributions',
  68                 'feedrecentchanges' => 'ApiFeedRecentChanges',
  69                 'feedwatchlist' => 'ApiFeedWatchlist',
  70                 'help' => 'ApiHelp',
  71                 'paraminfo' => 'ApiParamInfo',
  72                 'rsd' => 'ApiRsd',
  73                 'compare' => 'ApiComparePages',
  74                 'tokens' => 'ApiTokens',
  75                 'checktoken' => 'ApiCheckToken',
  76                 'cspreport' => 'ApiCSPReport',
  77
  78                 // Write modules
  79                 'purge' => 'ApiPurge',
  80                 'setnotificationtimestamp' => 'ApiSetNotificationTimestamp',
  81                 'rollback' => 'ApiRollback',
  82                 'delete' => 'ApiDelete',
  83                 'undelete' => 'ApiUndelete',
  84                 'protect' => 'ApiProtect',
  85                 'block' => 'ApiBlock',
  86                 'unblock' => 'ApiUnblock',
  87                 'move' => 'ApiMove',
  88                 'edit' => 'ApiEditPage',
  89                 'upload' => 'ApiUpload',
  90                 'filerevert' => 'ApiFileRevert',
  91                 'emailuser' => 'ApiEmailUser',
  92                 'watch' => 'ApiWatch',
  93                 'patrol' => 'ApiPatrol',
  94                 'import' => 'ApiImport',
  95                 'clearhasmsg' => 'ApiClearHasMsg',
  96                 'userrights' => 'ApiUserrights',
  97                 'options' => 'ApiOptions',
  98                 'imagerotate' => 'ApiImageRotate',
  99                 'revisiondelete' => 'ApiRevisionDelete',
 100                 'managetags' => 'ApiManageTags',
 101                 'tag' => 'ApiTag',
 102                 'mergehistory' => 'ApiMergeHistory',
 103         ];
 104
 105         /**
 106          * List of available formats: format name => format class
 107          */
 108         private static $Formats = [
 109                 'json' => 'ApiFormatJson',
 110                 'jsonfm' => 'ApiFormatJson',
 111                 'php' => 'ApiFormatPhp',
 112                 'phpfm' => 'ApiFormatPhp',
 113                 'xml' => 'ApiFormatXml',
 114                 'xmlfm' => 'ApiFormatXml',
 115                 'rawfm' => 'ApiFormatJson',
 116                 'none' => 'ApiFormatNone',
 117         ];
 118
 119         // @codingStandardsIgnoreStart String contenation on "msg" not allowed to break long line
 120         /**
 121          * List of user roles that are specifically relevant to the API.
 122          * [ 'right' => [ 'msg'    => 'Some message with a $1',
 123          *                'params' => [ $someVarToSubst ] ],
 124          * ];
 125          */
 126         private static $mRights = [
 127                 'writeapi' => [
 128                         'msg' => 'right-writeapi',
 129                         'params' => []
 130                 ],
 131                 'apihighlimits' => [
 132                         'msg' => 'api-help-right-apihighlimits',
 133                         'params' => [ ApiBase::LIMIT_SML2, ApiBase::LIMIT_BIG2 ]
 134                 ]
 135         ];
 136         // @codingStandardsIgnoreEnd
 137
 138         /**
 139          * @var ApiFormatBase
 140          */
 141         private $mPrinter;
 142
 143         private $mModuleMgr, $mResult, $mErrorFormatter;
 144         /** @var ApiContinuationManager|null */
 145         private $mContinuationManager;
 146         private $mAction;
 147         private $mEnableWrite;
 148         private $mInternalMode, $mSquidMaxage;
 149         /** @var ApiBase */
 150         private $mModule;
 151
 152         private $mCacheMode = 'private';
 153         private $mCacheControl = [];
 154         private $mParamsUsed = [];
 155
 156         /** @var bool|null Cached return value from self::lacksSameOriginSecurity() */
 157         private $lacksSameOriginSecurity = null;
 158
 159         /**
 160          * Constructs an instance of ApiMain that utilizes the module and format specified by $request.
 161          *
 162          * @param IContextSource|WebRequest $context If this is an instance of
 163          *    FauxRequest, errors are thrown and no printing occurs
 164          * @param bool $enableWrite Should be set to true if the api may modify data
 165          */
 166         public function __construct( $context = null, $enableWrite = false ) {
 167                 if ( $context === null ) {
 168                         $context = RequestContext::getMain();
 169                 } elseif ( $context instanceof WebRequest ) {
 170                         // BC for pre-1.19
 171                         $request = $context;
 172                         $context = RequestContext::getMain();
 173                 }
 174                 // We set a derivative context so we can change stuff later
 175                 $this->setContext( new DerivativeContext( $context ) );
 176
 177                 if ( isset( $request ) ) {
 178                         $this->getContext()->setRequest( $request );
 179                 } else {
 180                         $request = $this->getRequest();
 181                 }
 182
 183                 $this->mInternalMode = ( $request instanceof FauxRequest );
 184
 185                 // Special handling for the main module: $parent === $this
 186                 parent::__construct( $this, $this->mInternalMode ? 'main_int' : 'main' );
 187
 188                 $config = $this->getConfig();
 189
 190                 if ( !$this->mInternalMode ) {
 191                         // Log if a request with a non-whitelisted Origin header is seen
 192                         // with session cookies.
 193                         $originHeader = $request->getHeader( 'Origin' );
 194                         if ( $originHeader === false ) {
 195                                 $origins = [];
 196                         } else {
 197                                 $originHeader = trim( $originHeader );
 198                                 $origins = preg_split( '/\s+/', $originHeader );
 199                         }
 200                         $sessionCookies = array_intersect(
 201                                 array_keys( $_COOKIE ),
 202                                 MediaWiki\Session\SessionManager::singleton()->getVaryCookies()
 203                         );
 204                         if ( $origins && $sessionCookies && (
 205                                 count( $origins ) !== 1 || !self::matchOrigin(
 206                                         $origins[0],
 207                                         $config->get( 'CrossSiteAJAXdomains' ),
 208                                         $config->get( 'CrossSiteAJAXdomainExceptions' )
 209                                 )
 210                         ) ) {
 211                                 LoggerFactory::getInstance( 'cors' )->warning(
 212                                         'Non-whitelisted CORS request with session cookies', [
 213                                                 'origin' => $originHeader,
 214                                                 'cookies' => $sessionCookies,
 215                                                 'ip' => $request->getIP(),
 216                                                 'userAgent' => $this->getUserAgent(),
 217                                                 'wiki' => wfWikiID(),
 218                                         ]
 219                                 );
 220                         }
 221
 222                         // If we're in a mode that breaks the same-origin policy, strip
 223                         // user credentials for security.
 224                         if ( $this->lacksSameOriginSecurity() ) {
 225                                 global $wgUser;
 226                                 wfDebug( "API: stripping user credentials when the same-origin policy is not applied\n" );
 227                                 $wgUser = new User();
 228                                 $this->getContext()->setUser( $wgUser );
 229                         }
 230                 }
 231
 232                 $uselang = $this->getParameter( 'uselang' );
 233                 if ( $uselang === 'user' ) {
 234                         // Assume the parent context is going to return the user language
 235                         // for uselang=user (see T85635).
 236                 } else {
 237                         if ( $uselang === 'content' ) {
 238                                 global $wgContLang;
 239                                 $uselang = $wgContLang->getCode();
 240                         }
 241                         $code = RequestContext::sanitizeLangCode( $uselang );
 242                         $this->getContext()->setLanguage( $code );
 243                         if ( !$this->mInternalMode ) {
 244                                 global $wgLang;
 245                                 $wgLang = $this->getContext()->getLanguage();
 246                                 RequestContext::getMain()->setLanguage( $wgLang );
 247                         }
 248                 }
 249
 250                 $this->mModuleMgr = new ApiModuleManager( $this );
 251                 $this->mModuleMgr->addModules( self::$Modules, 'action' );
 252                 $this->mModuleMgr->addModules( $config->get( 'APIModules' ), 'action' );
 253                 $this->mModuleMgr->addModules( self::$Formats, 'format' );
 254                 $this->mModuleMgr->addModules( $config->get( 'APIFormatModules' ), 'format' );
 255
 256                 Hooks::run( 'ApiMain::moduleManager', [ $this->mModuleMgr ] );
 257
 258                 $this->mResult = new ApiResult( $this->getConfig()->get( 'APIMaxResultSize' ) );
 259                 $this->mErrorFormatter = new ApiErrorFormatter_BackCompat( $this->mResult );
 260                 $this->mResult->setErrorFormatter( $this->mErrorFormatter );
 261                 $this->mContinuationManager = null;
 262                 $this->mEnableWrite = $enableWrite;
 263
 264                 $this->mSquidMaxage = -1; // flag for executeActionWithErrorHandling()
 265                 $this->mCommit = false;
 266         }
 267
 268         /**
 269          * Return true if the API was started by other PHP code using FauxRequest
 270          * @return bool
 271          */
 272         public function isInternalMode() {
 273                 return $this->mInternalMode;
 274         }
 275
 276         /**
 277          * Get the ApiResult object associated with current request
 278          *
 279          * @return ApiResult
 280          */
 281         public function getResult() {
 282                 return $this->mResult;
 283         }
 284
 285         /**
 286          * Get the security flag for the current request
 287          * @return bool
 288          */
 289         public function lacksSameOriginSecurity() {
 290                 if ( $this->lacksSameOriginSecurity !== null ) {
 291                         return $this->lacksSameOriginSecurity;
 292                 }
 293
 294                 $request = $this->getRequest();
 295
 296                 // JSONP mode
 297                 if ( $request->getVal( 'callback' ) !== null ) {
 298                         $this->lacksSameOriginSecurity = true;
 299                         return true;
 300                 }
 301
 302                 // Anonymous CORS
 303                 if ( $request->getVal( 'origin' ) === '*' ) {
 304                         $this->lacksSameOriginSecurity = true;
 305                         return true;
 306                 }
 307
 308                 // Header to be used from XMLHTTPRequest when the request might
 309                 // otherwise be used for XSS.
 310                 if ( $request->getHeader( 'Treat-as-Untrusted' ) !== false ) {
 311                         $this->lacksSameOriginSecurity = true;
 312                         return true;
 313                 }
 314
 315                 // Allow extensions to override.
 316                 $this->lacksSameOriginSecurity = !Hooks::run( 'RequestHasSameOriginSecurity', [ $request ] );
 317                 return $this->lacksSameOriginSecurity;
 318         }
 319
 320         /**
 321          * Get the ApiErrorFormatter object associated with current request
 322          * @return ApiErrorFormatter
 323          */
 324         public function getErrorFormatter() {
 325                 return $this->mErrorFormatter;
 326         }
 327
 328         /**
 329          * Get the continuation manager
 330          * @return ApiContinuationManager|null
 331          */
 332         public function getContinuationManager() {
 333                 return $this->mContinuationManager;
 334         }
 335
 336         /**
 337          * Set the continuation manager
 338          * @param ApiContinuationManager|null
 339          */
 340         public function setContinuationManager( $manager ) {
 341                 if ( $manager !== null ) {
 342                         if ( !$manager instanceof ApiContinuationManager ) {
 343                                 throw new InvalidArgumentException( __METHOD__ . ': Was passed ' .
 344                                         is_object( $manager ) ? get_class( $manager ) : gettype( $manager )
 345                                 );
 346                         }
 347                         if ( $this->mContinuationManager !== null ) {
 348                                 throw new UnexpectedValueException(
 349                                         __METHOD__ . ': tried to set manager from ' . $manager->getSource() .
 350                                         ' when a manager is already set from ' . $this->mContinuationManager->getSource()
 351                                 );
 352                         }
 353                 }
 354                 $this->mContinuationManager = $manager;
 355         }
 356
 357         /**
 358          * Get the API module object. Only works after executeAction()
 359          *
 360          * @return ApiBase
 361          */
 362         public function getModule() {
 363                 return $this->mModule;
 364         }
 365
 366         /**
 367          * Get the result formatter object. Only works after setupExecuteAction()
 368          *
 369          * @return ApiFormatBase
 370          */
 371         public function getPrinter() {
 372                 return $this->mPrinter;
 373         }
 374
 375         /**
 376          * Set how long the response should be cached.
 377          *
 378          * @param int $maxage
 379          */
 380         public function setCacheMaxAge( $maxage ) {
 381                 $this->setCacheControl( [
 382                         'max-age' => $maxage,
 383                         's-maxage' => $maxage
 384                 ] );
 385         }
 386
 387         /**
 388          * Set the type of caching headers which will be sent.
 389          *
 390          * @param string $mode One of:
 391          *    - 'public':     Cache this object in public caches, if the maxage or smaxage
 392          *         parameter is set, or if setCacheMaxAge() was called. If a maximum age is
 393          *         not provided by any of these means, the object will be private.
 394          *    - 'private':    Cache this object only in private client-side caches.
 395          *    - 'anon-public-user-private': Make this object cacheable for logged-out
 396          *         users, but private for logged-in users. IMPORTANT: If this is set, it must be
 397          *         set consistently for a given URL, it cannot be set differently depending on
 398          *         things like the contents of the database, or whether the user is logged in.
 399          *
 400          *  If the wiki does not allow anonymous users to read it, the mode set here
 401          *  will be ignored, and private caching headers will always be sent. In other words,
 402          *  the "public" mode is equivalent to saying that the data sent is as public as a page
 403          *  view.
 404          *
 405          *  For user-dependent data, the private mode should generally be used. The
 406          *  anon-public-user-private mode should only be used where there is a particularly
 407          *  good performance reason for caching the anonymous response, but where the
 408          *  response to logged-in users may differ, or may contain private data.
 409          *
 410          *  If this function is never called, then the default will be the private mode.
 411          */
 412         public function setCacheMode( $mode ) {
 413                 if ( !in_array( $mode, [ 'private', 'public', 'anon-public-user-private' ] ) ) {
 414                         wfDebug( __METHOD__ . ": unrecognised cache mode \"$mode\"\n" );
 415
 416                         // Ignore for forwards-compatibility
 417                         return;
 418                 }
 419
 420                 if ( !User::isEveryoneAllowed( 'read' ) ) {
 421                         // Private wiki, only private headers
 422                         if ( $mode !== 'private' ) {
 423                                 wfDebug( __METHOD__ . ": ignoring request for $mode cache mode, private wiki\n" );
 424
 425                                 return;
 426                         }
 427                 }
 428
 429                 if ( $mode === 'public' && $this->getParameter( 'uselang' ) === 'user' ) {
 430                         // User language is used for i18n, so we don't want to publicly
 431                         // cache. Anons are ok, because if they have non-default language
 432                         // then there's an appropriate Vary header set by whatever set
 433                         // their non-default language.
 434                         wfDebug( __METHOD__ . ": downgrading cache mode 'public' to " .
 435                                 "'anon-public-user-private' due to uselang=user\n" );
 436                         $mode = 'anon-public-user-private';
 437                 }
 438
 439                 wfDebug( __METHOD__ . ": setting cache mode $mode\n" );
 440                 $this->mCacheMode = $mode;
 441         }
 442
 443         /**
 444          * Set directives (key/value pairs) for the Cache-Control header.
 445          * Boolean values will be formatted as such, by including or omitting
 446          * without an equals sign.
 447          *
 448          * Cache control values set here will only be used if the cache mode is not
 449          * private, see setCacheMode().
 450          *
 451          * @param array $directives
 452          */
 453         public function setCacheControl( $directives ) {
 454                 $this->mCacheControl = $directives + $this->mCacheControl;
 455         }
 456
 457         /**
 458          * Create an instance of an output formatter by its name
 459          *
 460          * @param string $format
 461          *
 462          * @return ApiFormatBase
 463          */
 464         public function createPrinterByName( $format ) {
 465                 $printer = $this->mModuleMgr->getModule( $format, 'format' );
 466                 if ( $printer === null ) {
 467                         $this->dieUsage( "Unrecognized format: {$format}", 'unknown_format' );
 468                 }
 469
 470                 return $printer;
 471         }
 472
 473         /**
 474          * Execute api request. Any errors will be handled if the API was called by the remote client.
 475          */
 476         public function execute() {
 477                 if ( $this->mInternalMode ) {
 478                         $this->executeAction();
 479                 } else {
 480                         $this->executeActionWithErrorHandling();
 481                 }
 482         }
 483
 484         /**
 485          * Execute an action, and in case of an error, erase whatever partial results
 486          * have been accumulated, and replace it with an error message and a help screen.
 487          */
 488         protected function executeActionWithErrorHandling() {
 489                 // Verify the CORS header before executing the action
 490                 if ( !$this->handleCORS() ) {
 491                         // handleCORS() has sent a 403, abort
 492                         return;
 493                 }
 494
 495                 // Exit here if the request method was OPTIONS
 496                 // (assume there will be a followup GET or POST)
 497                 if ( $this->getRequest()->getMethod() === 'OPTIONS' ) {
 498                         return;
 499                 }
 500
 501                 // In case an error occurs during data output,
 502                 // clear the output buffer and print just the error information
 503                 $obLevel = ob_get_level();
 504                 ob_start();
 505
 506                 $t = microtime( true );
 507                 $isError = false;
 508                 try {
 509                         $this->executeAction();
 510                         $runTime = microtime( true ) - $t;
 511                         $this->logRequest( $runTime );
 512                         if ( $this->mModule->isWriteMode() && $this->getRequest()->wasPosted() ) {
 513                                 $this->getStats()->timing(
 514                                         'api.' . $this->mModule->getModuleName() . '.executeTiming', 1000 * $runTime
 515                                 );
 516                         }
 517                 } catch ( Exception $e ) {
 518                         $this->handleException( $e );
 519                         $this->logRequest( microtime( true ) - $t, $e );
 520                         $isError = true;
 521                 }
 522
 523                 // Commit DBs and send any related cookies and headers
 524                 MediaWiki::preOutputCommit( $this->getContext() );
 525
 526                 // Send cache headers after any code which might generate an error, to
 527                 // avoid sending public cache headers for errors.
 528                 $this->sendCacheHeaders( $isError );
 529
 530                 // Executing the action might have already messed with the output
 531                 // buffers.
 532                 while ( ob_get_level() > $obLevel ) {
 533                         ob_end_flush();
 534                 }
 535         }
 536
 537         /**
 538          * Handle an exception as an API response
 539          *
 540          * @since 1.23
 541          * @param Exception $e
 542          */
 543         protected function handleException( Exception $e ) {
 544                 // Bug 63145: Rollback any open database transactions
 545                 if ( !( $e instanceof UsageException ) ) {
 546                         // UsageExceptions are intentional, so don't rollback if that's the case
 547                         try {
 548                                 MWExceptionHandler::rollbackMasterChangesAndLog( $e );
 549                         } catch ( DBError $e2 ) {
 550                                 // Rollback threw an exception too. Log it, but don't interrupt
 551                                 // our regularly scheduled exception handling.
 552                                 MWExceptionHandler::logException( $e2 );
 553                         }
 554                 }
 555
 556                 // Allow extra cleanup and logging
 557                 Hooks::run( 'ApiMain::onException', [ $this, $e ] );
 558
 559                 // Log it
 560                 if ( !( $e instanceof UsageException ) ) {
 561                         MWExceptionHandler::logException( $e );
 562                 }
 563
 564                 // Handle any kind of exception by outputting properly formatted error message.
 565                 // If this fails, an unhandled exception should be thrown so that global error
 566                 // handler will process and log it.
 567
 568                 $errCode = $this->substituteResultWithError( $e );
 569
 570                 // Error results should not be cached
 571                 $this->setCacheMode( 'private' );
 572
 573                 $response = $this->getRequest()->response();
 574                 $headerStr = 'MediaWiki-API-Error: ' . $errCode;
 575                 $response->header( $headerStr );
 576
 577                 // Reset and print just the error message
 578                 ob_clean();
 579
 580                 // Printer may not be initialized if the extractRequestParams() fails for the main module
 581                 $this->createErrorPrinter();
 582
 583                 try {
 584                         $this->printResult( $e->getCode() );
 585                 } catch ( UsageException $ex ) {
 586                         // The error printer itself is failing. Try suppressing its request
 587                         // parameters and redo.
 588                         $this->setWarning(
 589                                 'Error printer failed (will retry without params): ' . $ex->getMessage()
 590                         );
 591                         $this->mPrinter = null;
 592                         $this->createErrorPrinter();
 593                         $this->mPrinter->forceDefaultParams();
 594                         if ( $e->getCode() ) {
 595                                 $response->statusHeader( 200 ); // Reset in case the fallback doesn't want a non-200
 596                         }
 597                         $this->printResult( $e->getCode() );
 598                 }
 599         }
 600
 601         /**
 602          * Handle an exception from the ApiBeforeMain hook.
 603          *
 604          * This tries to print the exception as an API response, to be more
 605          * friendly to clients. If it fails, it will rethrow the exception.
 606          *
 607          * @since 1.23
 608          * @param Exception $e
 609          * @throws Exception
 610          */
 611         public static function handleApiBeforeMainException( Exception $e ) {
 612                 ob_start();
 613
 614                 try {
 615                         $main = new self( RequestContext::getMain(), false );
 616                         $main->handleException( $e );
 617                         $main->logRequest( 0, $e );
 618                 } catch ( Exception $e2 ) {
 619                         // Nope, even that didn't work. Punt.
 620                         throw $e;
 621                 }
 622
 623                 // Reset cache headers
 624                 $main->sendCacheHeaders( true );
 625
 626                 ob_end_flush();
 627         }
 628
 629         /**
 630          * Check the &origin= query parameter against the Origin: HTTP header and respond appropriately.
 631          *
 632          * If no origin parameter is present, nothing happens.
 633          * If an origin parameter is present but doesn't match the Origin header, a 403 status code
 634          * is set and false is returned.
 635          * If the parameter and the header do match, the header is checked against $wgCrossSiteAJAXdomains
 636          * and $wgCrossSiteAJAXdomainExceptions, and if the origin qualifies, the appropriate CORS
 637          * headers are set.
 638          * https://www.w3.org/TR/cors/#resource-requests
 639          * https://www.w3.org/TR/cors/#resource-preflight-requests
 640          *
 641          * @return bool False if the caller should abort (403 case), true otherwise (all other cases)
 642          */
 643         protected function handleCORS() {
 644                 $originParam = $this->getParameter( 'origin' ); // defaults to null
 645                 if ( $originParam === null ) {
 646                         // No origin parameter, nothing to do
 647                         return true;
 648                 }
 649
 650                 $request = $this->getRequest();
 651                 $response = $request->response();
 652
 653                 $matchOrigin = false;
 654                 $allowTiming = false;
 655                 $varyOrigin = true;
 656
 657                 if ( $originParam === '*' ) {
 658                         // Request for anonymous CORS
 659                         $matchOrigin = true;
 660                         $allowOrigin = '*';
 661                         $allowCredentials = 'false';
 662                         $varyOrigin = false; // No need to vary
 663                 } else {
 664                         // Non-anonymous CORS, check we allow the domain
 665
 666                         // Origin: header is a space-separated list of origins, check all of them
 667                         $originHeader = $request->getHeader( 'Origin' );
 668                         if ( $originHeader === false ) {
 669                                 $origins = [];
 670                         } else {
 671                                 $originHeader = trim( $originHeader );
 672                                 $origins = preg_split( '/\s+/', $originHeader );
 673                         }
 674
 675                         if ( !in_array( $originParam, $origins ) ) {
 676                                 // origin parameter set but incorrect
 677                                 // Send a 403 response
 678                                 $response->statusHeader( 403 );
 679                                 $response->header( 'Cache-Control: no-cache' );
 680                                 echo "'origin' parameter does not match Origin header\n";
 681
 682                                 return false;
 683                         }
 684
 685                         $config = $this->getConfig();
 686                         $matchOrigin = count( $origins ) === 1 && self::matchOrigin(
 687                                 $originParam,
 688                                 $config->get( 'CrossSiteAJAXdomains' ),
 689                                 $config->get( 'CrossSiteAJAXdomainExceptions' )
 690                         );
 691
 692                         $allowOrigin = $originHeader;
 693                         $allowCredentials = 'true';
 694                         $allowTiming = $originHeader;
 695                 }
 696
 697                 if ( $matchOrigin ) {
 698                         $requestedMethod = $request->getHeader( 'Access-Control-Request-Method' );
 699                         $preflight = $request->getMethod() === 'OPTIONS' && $requestedMethod !== false;
 700                         if ( $preflight ) {
 701                                 // This is a CORS preflight request
 702                                 if ( $requestedMethod !== 'POST' && $requestedMethod !== 'GET' ) {
 703                                         // If method is not a case-sensitive match, do not set any additional headers and terminate.
 704                                         return true;
 705                                 }
 706                                 // We allow the actual request to send the following headers
 707                                 $requestedHeaders = $request->getHeader( 'Access-Control-Request-Headers' );
 708                                 if ( $requestedHeaders !== false ) {
 709                                         if ( !self::matchRequestedHeaders( $requestedHeaders ) ) {
 710                                                 return true;
 711                                         }
 712                                         $response->header( 'Access-Control-Allow-Headers: ' . $requestedHeaders );
 713                                 }
 714
 715                                 // We only allow the actual request to be GET or POST
 716                                 $response->header( 'Access-Control-Allow-Methods: POST, GET' );
 717                         }
 718
 719                         $response->header( "Access-Control-Allow-Origin: $allowOrigin" );
 720                         $response->header( "Access-Control-Allow-Credentials: $allowCredentials" );
 721                         // https://www.w3.org/TR/resource-timing/#timing-allow-origin
 722                         if ( $allowTiming !== false ) {
 723                                 $response->header( "Timing-Allow-Origin: $allowTiming" );
 724                         }
 725
 726                         if ( !$preflight ) {
 727                                 $response->header(
 728                                         'Access-Control-Expose-Headers: MediaWiki-API-Error, Retry-After, X-Database-Lag'
 729                                 );
 730                         }
 731                 }
 732
 733                 if ( $varyOrigin ) {
 734                         $this->getOutput()->addVaryHeader( 'Origin' );
 735                 }
 736
 737                 return true;
 738         }
 739
 740         /**
 741          * Attempt to match an Origin header against a set of rules and a set of exceptions
 742          * @param string $value Origin header
 743          * @param array $rules Set of wildcard rules
 744          * @param array $exceptions Set of wildcard rules
 745          * @return bool True if $value matches a rule in $rules and doesn't match
 746          *    any rules in $exceptions, false otherwise
 747          */
 748         protected static function matchOrigin( $value, $rules, $exceptions ) {
 749                 foreach ( $rules as $rule ) {
 750                         if ( preg_match( self::wildcardToRegex( $rule ), $value ) ) {
 751                                 // Rule matches, check exceptions
 752                                 foreach ( $exceptions as $exc ) {
 753                                         if ( preg_match( self::wildcardToRegex( $exc ), $value ) ) {
 754                                                 return false;
 755                                         }
 756                                 }
 757
 758                                 return true;
 759                         }
 760                 }
 761
 762                 return false;
 763         }
 764
 765         /**
 766          * Attempt to validate the value of Access-Control-Request-Headers against a list
 767          * of headers that we allow the follow up request to send.
 768          *
 769          * @param string $requestedHeaders Comma seperated list of HTTP headers
 770          * @return bool True if all requested headers are in the list of allowed headers
 771          */
 772         protected static function matchRequestedHeaders( $requestedHeaders ) {
 773                 if ( trim( $requestedHeaders ) === '' ) {
 774                         return true;
 775                 }
 776                 $requestedHeaders = explode( ',', $requestedHeaders );
 777                 $allowedAuthorHeaders = array_flip( [
 778                         /* simple headers (see spec) */
 779                         'accept',
 780                         'accept-language',
 781                         'content-language',
 782                         'content-type',
 783                         /* non-authorable headers in XHR, which are however requested by some UAs */
 784                         'accept-encoding',
 785                         'dnt',
 786                         'origin',
 787                         /* MediaWiki whitelist */
 788                         'api-user-agent',
 789                 ] );
 790                 foreach ( $requestedHeaders as $rHeader ) {
 791                         $rHeader = strtolower( trim( $rHeader ) );
 792                         if ( !isset( $allowedAuthorHeaders[$rHeader] ) ) {
 793                                 wfDebugLog( 'api', 'CORS preflight failed on requested header: ' . $rHeader );
 794                                 return false;
 795                         }
 796                 }
 797                 return true;
 798         }
 799
 800         /**
 801          * Helper function to convert wildcard string into a regex
 802          * '*' => '.*?'
 803          * '?' => '.'
 804          *
 805          * @param string $wildcard String with wildcards
 806          * @return string Regular expression
 807          */
 808         protected static function wildcardToRegex( $wildcard ) {
 809                 $wildcard = preg_quote( $wildcard, '/' );
 810                 $wildcard = str_replace(
 811                         [ '\*', '\?' ],
 812                         [ '.*?', '.' ],
 813                         $wildcard
 814                 );
 815
 816                 return "/^https?:\/\/$wildcard$/";
 817         }
 818
 819         /**
 820          * Send caching headers
 821          * @param bool $isError Whether an error response is being output
 822          * @since 1.26 added $isError parameter
 823          */
 824         protected function sendCacheHeaders( $isError ) {
 825                 $response = $this->getRequest()->response();
 826                 $out = $this->getOutput();
 827
 828                 $out->addVaryHeader( 'Treat-as-Untrusted' );
 829
 830                 $config = $this->getConfig();
 831
 832                 if ( $config->get( 'VaryOnXFP' ) ) {
 833                         $out->addVaryHeader( 'X-Forwarded-Proto' );
 834                 }
 835
 836                 if ( !$isError && $this->mModule &&
 837                         ( $this->getRequest()->getMethod() === 'GET' || $this->getRequest()->getMethod() === 'HEAD' )
 838                 ) {
 839                         $etag = $this->mModule->getConditionalRequestData( 'etag' );
 840                         if ( $etag !== null ) {
 841                                 $response->header( "ETag: $etag" );
 842                         }
 843                         $lastMod = $this->mModule->getConditionalRequestData( 'last-modified' );
 844                         if ( $lastMod !== null ) {
 845                                 $response->header( 'Last-Modified: ' . wfTimestamp( TS_RFC2822, $lastMod ) );
 846                         }
 847                 }
 848
 849                 // The logic should be:
 850                 // $this->mCacheControl['max-age'] is set?
 851                 //    Use it, the module knows better than our guess.
 852                 // !$this->mModule || $this->mModule->isWriteMode(), and mCacheMode is private?
 853                 //    Use 0 because we can guess caching is probably the wrong thing to do.
 854                 // Use $this->getParameter( 'maxage' ), which already defaults to 0.
 855                 $maxage = 0;
 856                 if ( isset( $this->mCacheControl['max-age'] ) ) {
 857                         $maxage = $this->mCacheControl['max-age'];
 858                 } elseif ( ( $this->mModule && !$this->mModule->isWriteMode() ) ||
 859                         $this->mCacheMode !== 'private'
 860                 ) {
 861                         $maxage = $this->getParameter( 'maxage' );
 862                 }
 863                 $privateCache = 'private, must-revalidate, max-age=' . $maxage;
 864
 865                 if ( $this->mCacheMode == 'private' ) {
 866                         $response->header( "Cache-Control: $privateCache" );
 867                         return;
 868                 }
 869
 870                 $useKeyHeader = $config->get( 'UseKeyHeader' );
 871                 if ( $this->mCacheMode == 'anon-public-user-private' ) {
 872                         $out->addVaryHeader( 'Cookie' );
 873                         $response->header( $out->getVaryHeader() );
 874                         if ( $useKeyHeader ) {
 875                                 $response->header( $out->getKeyHeader() );
 876                                 if ( $out->haveCacheVaryCookies() ) {
 877                                         // Logged in, mark this request private
 878                                         $response->header( "Cache-Control: $privateCache" );
 879                                         return;
 880                                 }
 881                                 // Logged out, send normal public headers below
 882                         } elseif ( MediaWiki\Session\SessionManager::getGlobalSession()->isPersistent() ) {
 883                                 // Logged in or otherwise has session (e.g. anonymous users who have edited)
 884                                 // Mark request private
 885                                 $response->header( "Cache-Control: $privateCache" );
 886
 887                                 return;
 888                         } // else no Key and anonymous, send public headers below
 889                 }
 890
 891                 // Send public headers
 892                 $response->header( $out->getVaryHeader() );
 893                 if ( $useKeyHeader ) {
 894                         $response->header( $out->getKeyHeader() );
 895                 }
 896
 897                 // If nobody called setCacheMaxAge(), use the (s)maxage parameters
 898                 if ( !isset( $this->mCacheControl['s-maxage'] ) ) {
 899                         $this->mCacheControl['s-maxage'] = $this->getParameter( 'smaxage' );
 900                 }
 901                 if ( !isset( $this->mCacheControl['max-age'] ) ) {
 902                         $this->mCacheControl['max-age'] = $this->getParameter( 'maxage' );
 903                 }
 904
 905                 if ( !$this->mCacheControl['s-maxage'] && !$this->mCacheControl['max-age'] ) {
 906                         // Public cache not requested
 907                         // Sending a Vary header in this case is harmless, and protects us
 908                         // against conditional calls of setCacheMaxAge().
 909                         $response->header( "Cache-Control: $privateCache" );
 910
 911                         return;
 912                 }
 913
 914                 $this->mCacheControl['public'] = true;
 915
 916                 // Send an Expires header
 917                 $maxAge = min( $this->mCacheControl['s-maxage'], $this->mCacheControl['max-age'] );
 918                 $expiryUnixTime = ( $maxAge == 0 ? 1 : time() + $maxAge );
 919                 $response->header( 'Expires: ' . wfTimestamp( TS_RFC2822, $expiryUnixTime ) );
 920
 921                 // Construct the Cache-Control header
 922                 $ccHeader = '';
 923                 $separator = '';
 924                 foreach ( $this->mCacheControl as $name => $value ) {
 925                         if ( is_bool( $value ) ) {
 926                                 if ( $value ) {
 927                                         $ccHeader .= $separator . $name;
 928                                         $separator = ', ';
 929                                 }
 930                         } else {
 931                                 $ccHeader .= $separator . "$name=$value";
 932                                 $separator = ', ';
 933                         }
 934                 }
 935
 936                 $response->header( "Cache-Control: $ccHeader" );
 937         }
 938
 939         /**
 940          * Create the printer for error output
 941          */
 942         private function createErrorPrinter() {
 943                 if ( !isset( $this->mPrinter ) ) {
 944                         $value = $this->getRequest()->getVal( 'format', self::API_DEFAULT_FORMAT );
 945                         if ( !$this->mModuleMgr->isDefined( $value, 'format' ) ) {
 946                                 $value = self::API_DEFAULT_FORMAT;
 947                         }
 948                         $this->mPrinter = $this->createPrinterByName( $value );
 949                 }
 950
 951                 // Printer may not be able to handle errors. This is particularly
 952                 // likely if the module returns something for getCustomPrinter().
 953                 if ( !$this->mPrinter->canPrintErrors() ) {
 954                         $this->mPrinter = $this->createPrinterByName( self::API_DEFAULT_FORMAT );
 955                 }
 956         }
 957
 958         /**
 959          * Create an error message for the given exception.
 960          *
 961          * If the exception is a UsageException then
 962          * UsageException::getMessageArray() will be called to create the message.
 963          *
 964          * @param Exception $e
 965          * @return array ['code' => 'some string', 'info' => 'some other string']
 966          * @since 1.27
 967          */
 968         protected function errorMessageFromException( $e ) {
 969                 if ( $e instanceof UsageException ) {
 970                         // User entered incorrect parameters - generate error response
 971                         $errMessage = $e->getMessageArray();
 972                 } else {
 973                         $config = $this->getConfig();
 974                         // Something is seriously wrong
 975                         if ( ( $e instanceof DBQueryError ) && !$config->get( 'ShowSQLErrors' ) ) {
 976                                 $info = 'Database query error';
 977                         } else {
 978                                 $info = "Exception Caught: {$e->getMessage()}";
 979                         }
 980
 981                         $errMessage = [
 982                                 'code' => 'internal_api_error_' . get_class( $e ),
 983                                 'info' => '[' . WebRequest::getRequestId() . '] ' . $info,
 984                         ];
 985                 }
 986                 return $errMessage;
 987         }
 988
 989         /**
 990          * Replace the result data with the information about an exception.
 991          * Returns the error code
 992          * @param Exception $e
 993          * @return string
 994          */
 995         protected function substituteResultWithError( $e ) {
 996                 $result = $this->getResult();
 997                 $config = $this->getConfig();
 998
 999                 $errMessage = $this->errorMessageFromException( $e );
1000                 if ( $e instanceof UsageException ) {
1001                         // User entered incorrect parameters - generate error response
1002                         $link = wfExpandUrl( wfScript( 'api' ) );
1003                         ApiResult::setContentValue( $errMessage, 'docref', "See $link for API usage" );
1004                 } else {
1005                         // Something is seriously wrong
1006                         if ( $config->get( 'ShowExceptionDetails' ) ) {
1007                                 ApiResult::setContentValue(
1008                                         $errMessage,
1009                                         'trace',
1010                                         MWExceptionHandler::getRedactedTraceAsString( $e )
1011                                 );
1012                         }
1013                 }
1014
1015                 // Remember all the warnings to re-add them later
1016                 $warnings = $result->getResultData( [ 'warnings' ] );
1017
1018                 $result->reset();
1019                 // Re-add the id
1020                 $requestid = $this->getParameter( 'requestid' );
1021                 if ( !is_null( $requestid ) ) {
1022                         $result->addValue( null, 'requestid', $requestid, ApiResult::NO_SIZE_CHECK );
1023                 }
1024                 if ( $config->get( 'ShowHostnames' ) ) {
1025                         // servedby is especially useful when debugging errors
1026                         $result->addValue( null, 'servedby', wfHostname(), ApiResult::NO_SIZE_CHECK );
1027                 }
1028                 if ( $warnings !== null ) {
1029                         $result->addValue( null, 'warnings', $warnings, ApiResult::NO_SIZE_CHECK );
1030                 }
1031
1032                 $result->addValue( null, 'error', $errMessage, ApiResult::NO_SIZE_CHECK );
1033
1034                 return $errMessage['code'];
1035         }
1036
1037         /**
1038          * Set up for the execution.
1039          * @return array
1040          */
1041         protected function setupExecuteAction() {
1042                 // First add the id to the top element
1043                 $result = $this->getResult();
1044                 $requestid = $this->getParameter( 'requestid' );
1045                 if ( !is_null( $requestid ) ) {
1046                         $result->addValue( null, 'requestid', $requestid );
1047                 }
1048
1049                 if ( $this->getConfig()->get( 'ShowHostnames' ) ) {
1050                         $servedby = $this->getParameter( 'servedby' );
1051                         if ( $servedby ) {
1052                                 $result->addValue( null, 'servedby', wfHostname() );
1053                         }
1054                 }
1055
1056                 if ( $this->getParameter( 'curtimestamp' ) ) {
1057                         $result->addValue( null, 'curtimestamp', wfTimestamp( TS_ISO_8601, time() ),
1058                                 ApiResult::NO_SIZE_CHECK );
1059                 }
1060
1061                 $params = $this->extractRequestParams();
1062
1063                 $this->mAction = $params['action'];
1064
1065                 if ( !is_string( $this->mAction ) ) {
1066                         $this->dieUsage( 'The API requires a valid action parameter', 'unknown_action' );
1067                 }
1068
1069                 return $params;
1070         }
1071
1072         /**
1073          * Set up the module for response
1074          * @return ApiBase The module that will handle this action
1075          * @throws MWException
1076          * @throws UsageException
1077          */
1078         protected function setupModule() {
1079                 // Instantiate the module requested by the user
1080                 $module = $this->mModuleMgr->getModule( $this->mAction, 'action' );
1081                 if ( $module === null ) {
1082                         $this->dieUsage( 'The API requires a valid action parameter', 'unknown_action' );
1083                 }
1084                 $moduleParams = $module->extractRequestParams();
1085
1086                 // Check token, if necessary
1087                 if ( $module->needsToken() === true ) {
1088                         throw new MWException(
1089                                 "Module '{$module->getModuleName()}' must be updated for the new token handling. " .
1090                                 'See documentation for ApiBase::needsToken for details.'
1091                         );
1092                 }
1093                 if ( $module->needsToken() ) {
1094                         if ( !$module->mustBePosted() ) {
1095                                 throw new MWException(
1096                                         "Module '{$module->getModuleName()}' must require POST to use tokens."
1097                                 );
1098                         }
1099
1100                         if ( !isset( $moduleParams['token'] ) ) {
1101                                 $this->dieUsageMsg( [ 'missingparam', 'token' ] );
1102                         }
1103
1104                         $module->requirePostedParameters( [ 'token' ] );
1105
1106                         if ( !$module->validateToken( $moduleParams['token'], $moduleParams ) ) {
1107                                 $this->dieUsageMsg( 'sessionfailure' );
1108                         }
1109                 }
1110
1111                 return $module;
1112         }
1113
1114         /**
1115          * Check the max lag if necessary
1116          * @param ApiBase $module Api module being used
1117          * @param array $params Array an array containing the request parameters.
1118          * @return bool True on success, false should exit immediately
1119          */
1120         protected function checkMaxLag( $module, $params ) {
1121                 if ( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
1122                         $maxLag = $params['maxlag'];
1123                         list( $host, $lag ) = wfGetLB()->getMaxLag();
1124                         if ( $lag > $maxLag ) {
1125                                 $response = $this->getRequest()->response();
1126
1127                                 $response->header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
1128                                 $response->header( 'X-Database-Lag: ' . intval( $lag ) );
1129
1130                                 if ( $this->getConfig()->get( 'ShowHostnames' ) ) {
1131                                         $this->dieUsage( "Waiting for $host: $lag seconds lagged", 'maxlag' );
1132                                 }
1133
1134                                 $this->dieUsage( "Waiting for a database server: $lag seconds lagged", 'maxlag' );
1135                         }
1136                 }
1137
1138                 return true;
1139         }
1140
1141         /**
1142          * Check selected RFC 7232 precondition headers
1143          *
1144          * RFC 7232 envisions a particular model where you send your request to "a
1145          * resource", and for write requests that you can read "the resource" by
1146          * changing the method to GET. When the API receives a GET request, it
1147          * works out even though "the resource" from RFC 7232's perspective might
1148          * be many resources from MediaWiki's perspective. But it totally fails for
1149          * a POST, since what HTTP sees as "the resource" is probably just
1150          * "/api.php" with all the interesting bits in the body.
1151          *
1152          * Therefore, we only support RFC 7232 precondition headers for GET (and
1153          * HEAD). That means we don't need to bother with If-Match and
1154          * If-Unmodified-Since since they only apply to modification requests.
1155          *
1156          * And since we don't support Range, If-Range is ignored too.
1157          *
1158          * @since 1.26
1159          * @param ApiBase $module Api module being used
1160          * @return bool True on success, false should exit immediately
1161          */
1162         protected function checkConditionalRequestHeaders( $module ) {
1163                 if ( $this->mInternalMode ) {
1164                         // No headers to check in internal mode
1165                         return true;
1166                 }
1167
1168                 if ( $this->getRequest()->getMethod() !== 'GET' && $this->getRequest()->getMethod() !== 'HEAD' ) {
1169                         // Don't check POSTs
1170                         return true;
1171                 }
1172
1173                 $return304 = false;
1174
1175                 $ifNoneMatch = array_diff(
1176                         $this->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST ) ?: [],
1177                         [ '' ]
1178                 );
1179                 if ( $ifNoneMatch ) {
1180                         if ( $ifNoneMatch === [ '*' ] ) {
1181                                 // API responses always "exist"
1182                                 $etag = '*';
1183                         } else {
1184                                 $etag = $module->getConditionalRequestData( 'etag' );
1185                         }
1186                 }
1187                 if ( $ifNoneMatch && $etag !== null ) {
1188                         $test = substr( $etag, 0, 2 ) === 'W/' ? substr( $etag, 2 ) : $etag;
1189                         $match = array_map( function ( $s ) {
1190                                 return substr( $s, 0, 2 ) === 'W/' ? substr( $s, 2 ) : $s;
1191                         }, $ifNoneMatch );
1192                         $return304 = in_array( $test, $match, true );
1193                 } else {
1194                         $value = trim( $this->getRequest()->getHeader( 'If-Modified-Since' ) );
1195
1196                         // Some old browsers sends sizes after the date, like this:
1197                         //  Wed, 20 Aug 2003 06:51:19 GMT; length=5202
1198                         // Ignore that.
1199                         $i = strpos( $value, ';' );
1200                         if ( $i !== false ) {
1201                                 $value = trim( substr( $value, 0, $i ) );
1202                         }
1203
1204                         if ( $value !== '' ) {
1205                                 try {
1206                                         $ts = new MWTimestamp( $value );
1207                                         if (
1208                                                 // RFC 7231 IMF-fixdate
1209                                                 $ts->getTimestamp( TS_RFC2822 ) === $value ||
1210                                                 // RFC 850
1211                                                 $ts->format( 'l, d-M-y H:i:s' ) . ' GMT' === $value ||
1212                                                 // asctime (with and without space-padded day)
1213                                                 $ts->format( 'D M j H:i:s Y' ) === $value ||
1214                                                 $ts->format( 'D M  j H:i:s Y' ) === $value
1215                                         ) {
1216                                                 $lastMod = $module->getConditionalRequestData( 'last-modified' );
1217                                                 if ( $lastMod !== null ) {
1218                                                         // Mix in some MediaWiki modification times
1219                                                         $modifiedTimes = [
1220                                                                 'page' => $lastMod,
1221                                                                 'user' => $this->getUser()->getTouched(),
1222                                                                 'epoch' => $this->getConfig()->get( 'CacheEpoch' ),
1223                                                         ];
1224                                                         if ( $this->getConfig()->get( 'UseSquid' ) ) {
1225                                                                 // T46570: the core page itself may not change, but resources might
1226                                                                 $modifiedTimes['sepoch'] = wfTimestamp(
1227                                                                         TS_MW, time() - $this->getConfig()->get( 'SquidMaxage' )
1228                                                                 );
1229                                                         }
1230                                                         Hooks::run( 'OutputPageCheckLastModified', [ &$modifiedTimes, $this->getOutput() ] );
1231                                                         $lastMod = max( $modifiedTimes );
1232                                                         $return304 = wfTimestamp( TS_MW, $lastMod ) <= $ts->getTimestamp( TS_MW );
1233                                                 }
1234                                         }
1235                                 } catch ( TimestampException $e ) {
1236                                         // Invalid timestamp, ignore it
1237                                 }
1238                         }
1239                 }
1240
1241                 if ( $return304 ) {
1242                         $this->getRequest()->response()->statusHeader( 304 );
1243
1244                         // Avoid outputting the compressed representation of a zero-length body
1245                         MediaWiki\suppressWarnings();
1246                         ini_set( 'zlib.output_compression', 0 );
1247                         MediaWiki\restoreWarnings();
1248                         wfClearOutputBuffers();
1249
1250                         return false;
1251                 }
1252
1253                 return true;
1254         }
1255
1256         /**
1257          * Check for sufficient permissions to execute
1258          * @param ApiBase $module An Api module
1259          */
1260         protected function checkExecutePermissions( $module ) {
1261                 $user = $this->getUser();
1262                 if ( $module->isReadMode() && !User::isEveryoneAllowed( 'read' ) &&
1263                         !$user->isAllowed( 'read' )
1264                 ) {
1265                         $this->dieUsageMsg( 'readrequired' );
1266                 }
1267
1268                 if ( $module->isWriteMode() ) {
1269                         if ( !$this->mEnableWrite ) {
1270                                 $this->dieUsageMsg( 'writedisabled' );
1271                         } elseif ( !$user->isAllowed( 'writeapi' ) ) {
1272                                 $this->dieUsageMsg( 'writerequired' );
1273                         } elseif ( $this->getRequest()->getHeader( 'Promise-Non-Write-API-Action' ) ) {
1274                                 $this->dieUsage(
1275                                         'Promise-Non-Write-API-Action HTTP header cannot be sent to write API modules',
1276                                         'promised-nonwrite-api'
1277                                 );
1278                         }
1279
1280                         $this->checkReadOnly( $module );
1281                 }
1282
1283                 // Allow extensions to stop execution for arbitrary reasons.
1284                 $message = false;
1285                 if ( !Hooks::run( 'ApiCheckCanExecute', [ $module, $user, &$message ] ) ) {
1286                         $this->dieUsageMsg( $message );
1287                 }
1288         }
1289
1290         /**
1291          * Check if the DB is read-only for this user
1292          * @param ApiBase $module An Api module
1293          */
1294         protected function checkReadOnly( $module ) {
1295                 if ( wfReadOnly() ) {
1296                         $this->dieReadOnly();
1297                 }
1298
1299                 if ( $module->isWriteMode()
1300                         && $this->getUser()->isBot()
1301                         && wfGetLB()->getServerCount() > 1
1302                 ) {
1303                         $this->checkBotReadOnly();
1304                 }
1305         }
1306
1307         /**
1308          * Check whether we are readonly for bots
1309          */
1310         private function checkBotReadOnly() {
1311                 // Figure out how many servers have passed the lag threshold
1312                 $numLagged = 0;
1313                 $lagLimit = $this->getConfig()->get( 'APIMaxLagThreshold' );
1314                 $laggedServers = [];
1315                 $loadBalancer = wfGetLB();
1316                 foreach ( $loadBalancer->getLagTimes() as $serverIndex => $lag ) {
1317                         if ( $lag > $lagLimit ) {
1318                                 ++$numLagged;
1319                                 $laggedServers[] = $loadBalancer->getServerName( $serverIndex ) . " ({$lag}s)";
1320                         }
1321                 }
1322
1323                 // If a majority of replica DBs are too lagged then disallow writes
1324                 $replicaCount = wfGetLB()->getServerCount() - 1;
1325                 if ( $numLagged >= ceil( $replicaCount / 2 ) ) {
1326                         $laggedServers = implode( ', ', $laggedServers );
1327                         wfDebugLog(
1328                                 'api-readonly',
1329                                 "Api request failed as read only because the following DBs are lagged: $laggedServers"
1330                         );
1331
1332                         $parsed = $this->parseMsg( [ 'readonlytext' ] );
1333                         $this->dieUsage(
1334                                 $parsed['info'],
1335                                 $parsed['code'],
1336                                 /* http error */
1337                                 0,
1338                                 [ 'readonlyreason' => "Waiting for $numLagged lagged database(s)" ]
1339                         );
1340                 }
1341         }
1342
1343         /**
1344          * Check asserts of the user's rights
1345          * @param array $params
1346          */
1347         protected function checkAsserts( $params ) {
1348                 if ( isset( $params['assert'] ) ) {
1349                         $user = $this->getUser();
1350                         switch ( $params['assert'] ) {
1351                                 case 'user':
1352                                         if ( $user->isAnon() ) {
1353                                                 $this->dieUsage( 'Assertion that the user is logged in failed', 'assertuserfailed' );
1354                                         }
1355                                         break;
1356                                 case 'bot':
1357                                         if ( !$user->isAllowed( 'bot' ) ) {
1358                                                 $this->dieUsage( 'Assertion that the user has the bot right failed', 'assertbotfailed' );
1359                                         }
1360                                         break;
1361                         }
1362                 }
1363                 if ( isset( $params['assertuser'] ) ) {
1364                         $assertUser = User::newFromName( $params['assertuser'], false );
1365                         if ( !$assertUser || !$this->getUser()->equals( $assertUser ) ) {
1366                                 $this->dieUsage(
1367                                         'Assertion that the user is "' . $params['assertuser'] . '" failed',
1368                                         'assertnameduserfailed'
1369                                 );
1370                         }
1371                 }
1372         }
1373
1374         /**
1375          * Check POST for external response and setup result printer
1376          * @param ApiBase $module An Api module
1377          * @param array $params An array with the request parameters
1378          */
1379         protected function setupExternalResponse( $module, $params ) {
1380                 $request = $this->getRequest();
1381                 if ( !$request->wasPosted() && $module->mustBePosted() ) {
1382                         // Module requires POST. GET request might still be allowed
1383                         // if $wgDebugApi is true, otherwise fail.
1384                         $this->dieUsageMsgOrDebug( [ 'mustbeposted', $this->mAction ] );
1385                 }
1386
1387                 // See if custom printer is used
1388                 $this->mPrinter = $module->getCustomPrinter();
1389                 if ( is_null( $this->mPrinter ) ) {
1390                         // Create an appropriate printer
1391                         $this->mPrinter = $this->createPrinterByName( $params['format'] );
1392                 }
1393
1394                 if ( $request->getProtocol() === 'http' && (
1395                         $request->getSession()->shouldForceHTTPS() ||
1396                         ( $this->getUser()->isLoggedIn() &&
1397                                 $this->getUser()->requiresHTTPS() )
1398                 ) ) {
1399                         $this->logFeatureUsage( 'https-expected' );
1400                         $this->setWarning( 'HTTP used when HTTPS was expected' );
1401                 }
1402         }
1403
1404         /**
1405          * Execute the actual module, without any error handling
1406          */
1407         protected function executeAction() {
1408                 $params = $this->setupExecuteAction();
1409                 $module = $this->setupModule();
1410                 $this->mModule = $module;
1411
1412                 if ( !$this->mInternalMode ) {
1413                         $this->setRequestExpectations( $module );
1414                 }
1415
1416                 $this->checkExecutePermissions( $module );
1417
1418                 if ( !$this->checkMaxLag( $module, $params ) ) {
1419                         return;
1420                 }
1421
1422                 if ( !$this->checkConditionalRequestHeaders( $module ) ) {
1423                         return;
1424                 }
1425
1426                 if ( !$this->mInternalMode ) {
1427                         $this->setupExternalResponse( $module, $params );
1428                 }
1429
1430                 $this->checkAsserts( $params );
1431
1432                 // Execute
1433                 $module->execute();
1434                 Hooks::run( 'APIAfterExecute', [ &$module ] );
1435
1436                 $this->reportUnusedParams();
1437
1438                 if ( !$this->mInternalMode ) {
1439                         // append Debug information
1440                         MWDebug::appendDebugInfoToApiResult( $this->getContext(), $this->getResult() );
1441
1442                         // Print result data
1443                         $this->printResult();
1444                 }
1445         }
1446
1447         /**
1448          * Set database connection, query, and write expectations given this module request
1449          * @param ApiBase $module
1450          */
1451         protected function setRequestExpectations( ApiBase $module ) {
1452                 $limits = $this->getConfig()->get( 'TrxProfilerLimits' );
1453                 $trxProfiler = Profiler::instance()->getTransactionProfiler();
1454                 $trxProfiler->setLogger( LoggerFactory::getInstance( 'DBPerformance' ) );
1455                 if ( $this->getRequest()->hasSafeMethod() ) {
1456                         $trxProfiler->setExpectations( $limits['GET'], __METHOD__ );
1457                 } elseif ( $this->getRequest()->wasPosted() && !$module->isWriteMode() ) {
1458                         $trxProfiler->setExpectations( $limits['POST-nonwrite'], __METHOD__ );
1459                         $this->getRequest()->markAsSafeRequest();
1460                 } else {
1461                         $trxProfiler->setExpectations( $limits['POST'], __METHOD__ );
1462                 }
1463         }
1464
1465         /**
1466          * Log the preceding request
1467          * @param float $time Time in seconds
1468          * @param Exception $e Exception caught while processing the request
1469          */
1470         protected function logRequest( $time, $e = null ) {
1471                 $request = $this->getRequest();
1472                 $logCtx = [
1473                         'ts' => time(),
1474                         'ip' => $request->getIP(),
1475                         'userAgent' => $this->getUserAgent(),
1476                         'wiki' => wfWikiID(),
1477                         'timeSpentBackend' => (int)round( $time * 1000 ),
1478                         'hadError' => $e !== null,
1479                         'errorCodes' => [],
1480                         'params' => [],
1481                 ];
1482
1483                 if ( $e ) {
1484                         $logCtx['errorCodes'][] = $this->errorMessageFromException( $e )['code'];
1485                 }
1486
1487                 // Construct space separated message for 'api' log channel
1488                 $msg = "API {$request->getMethod()} " .
1489                         wfUrlencode( str_replace( ' ', '_', $this->getUser()->getName() ) ) .
1490                         " {$logCtx['ip']} " .
1491                         "T={$logCtx['timeSpentBackend']}ms";
1492
1493                 foreach ( $this->getParamsUsed() as $name ) {
1494                         $value = $request->getVal( $name );
1495                         if ( $value === null ) {
1496                                 continue;
1497                         }
1498
1499                         if ( strlen( $value ) > 256 ) {
1500                                 $value = substr( $value, 0, 256 );
1501                                 $encValue = $this->encodeRequestLogValue( $value ) . '[...]';
1502                         } else {
1503                                 $encValue = $this->encodeRequestLogValue( $value );
1504                         }
1505
1506                         $logCtx['params'][$name] = $value;
1507                         $msg .= " {$name}={$encValue}";
1508                 }
1509
1510                 wfDebugLog( 'api', $msg, 'private' );
1511                 // ApiAction channel is for structured data consumers
1512                 wfDebugLog( 'ApiAction', '', 'private', $logCtx );
1513         }
1514
1515         /**
1516          * Encode a value in a format suitable for a space-separated log line.
1517          * @param string $s
1518          * @return string
1519          */
1520         protected function encodeRequestLogValue( $s ) {
1521                 static $table;
1522                 if ( !$table ) {
1523                         $chars = ';@$!*(),/:';
1524                         $numChars = strlen( $chars );
1525                         for ( $i = 0; $i < $numChars; $i++ ) {
1526                                 $table[rawurlencode( $chars[$i] )] = $chars[$i];
1527                         }
1528                 }
1529
1530                 return strtr( rawurlencode( $s ), $table );
1531         }
1532
1533         /**
1534          * Get the request parameters used in the course of the preceding execute() request
1535          * @return array
1536          */
1537         protected function getParamsUsed() {
1538                 return array_keys( $this->mParamsUsed );
1539         }
1540
1541         /**
1542          * Mark parameters as used
1543          * @param string|string[] $params
1544          */
1545         public function markParamsUsed( $params ) {
1546                 $this->mParamsUsed += array_fill_keys( (array)$params, true );
1547         }
1548
1549         /**
1550          * Get a request value, and register the fact that it was used, for logging.
1551          * @param string $name
1552          * @param mixed $default
1553          * @return mixed
1554          */
1555         public function getVal( $name, $default = null ) {
1556                 $this->mParamsUsed[$name] = true;
1557
1558                 $ret = $this->getRequest()->getVal( $name );
1559                 if ( $ret === null ) {
1560                         if ( $this->getRequest()->getArray( $name ) !== null ) {
1561                                 // See bug 10262 for why we don't just implode( '|', ... ) the
1562                                 // array.
1563                                 $this->setWarning(
1564                                         "Parameter '$name' uses unsupported PHP array syntax"
1565                                 );
1566                         }
1567                         $ret = $default;
1568                 }
1569                 return $ret;
1570         }
1571
1572         /**
1573          * Get a boolean request value, and register the fact that the parameter
1574          * was used, for logging.
1575          * @param string $name
1576          * @return bool
1577          */
1578         public function getCheck( $name ) {
1579                 return $this->getVal( $name, null ) !== null;
1580         }
1581
1582         /**
1583          * Get a request upload, and register the fact that it was used, for logging.
1584          *
1585          * @since 1.21
1586          * @param string $name Parameter name
1587          * @return WebRequestUpload
1588          */
1589         public function getUpload( $name ) {
1590                 $this->mParamsUsed[$name] = true;
1591
1592                 return $this->getRequest()->getUpload( $name );
1593         }
1594
1595         /**
1596          * Report unused parameters, so the client gets a hint in case it gave us parameters we don't know,
1597          * for example in case of spelling mistakes or a missing 'g' prefix for generators.
1598          */
1599         protected function reportUnusedParams() {
1600                 $paramsUsed = $this->getParamsUsed();
1601                 $allParams = $this->getRequest()->getValueNames();
1602
1603                 if ( !$this->mInternalMode ) {
1604                         // Printer has not yet executed; don't warn that its parameters are unused
1605                         $printerParams = array_map(
1606                                 [ $this->mPrinter, 'encodeParamName' ],
1607                                 array_keys( $this->mPrinter->getFinalParams() ?: [] )
1608                         );
1609                         $unusedParams = array_diff( $allParams, $paramsUsed, $printerParams );
1610                 } else {
1611                         $unusedParams = array_diff( $allParams, $paramsUsed );
1612                 }
1613
1614                 if ( count( $unusedParams ) ) {
1615                         $s = count( $unusedParams ) > 1 ? 's' : '';
1616                         $this->setWarning( "Unrecognized parameter$s: '" . implode( $unusedParams, "', '" ) . "'" );
1617                 }
1618         }
1619
1620         /**
1621          * Print results using the current printer
1622          *
1623          * @param int $httpCode HTTP status code, or 0 to not change
1624          */
1625         protected function printResult( $httpCode = 0 ) {
1626                 if ( $this->getConfig()->get( 'DebugAPI' ) !== false ) {
1627                         $this->setWarning( 'SECURITY WARNING: $wgDebugAPI is enabled' );
1628                 }
1629
1630                 $printer = $this->mPrinter;
1631                 $printer->initPrinter( false );
1632                 if ( $httpCode ) {
1633                         $printer->setHttpStatus( $httpCode );
1634                 }
1635                 $printer->execute();
1636                 $printer->closePrinter();
1637         }
1638
1639         /**
1640          * @return bool
1641          */
1642         public function isReadMode() {
1643                 return false;
1644         }
1645
1646         /**
1647          * See ApiBase for description.
1648          *
1649          * @return array
1650          */
1651         public function getAllowedParams() {
1652                 return [
1653                         'action' => [
1654                                 ApiBase::PARAM_DFLT => 'help',
1655                                 ApiBase::PARAM_TYPE => 'submodule',
1656                         ],
1657                         'format' => [
1658                                 ApiBase::PARAM_DFLT => ApiMain::API_DEFAULT_FORMAT,
1659                                 ApiBase::PARAM_TYPE => 'submodule',
1660                         ],
1661                         'maxlag' => [
1662                                 ApiBase::PARAM_TYPE => 'integer'
1663                         ],
1664                         'smaxage' => [
1665                                 ApiBase::PARAM_TYPE => 'integer',
1666                                 ApiBase::PARAM_DFLT => 0
1667                         ],
1668                         'maxage' => [
1669                                 ApiBase::PARAM_TYPE => 'integer',
1670                                 ApiBase::PARAM_DFLT => 0
1671                         ],
1672                         'assert' => [
1673                                 ApiBase::PARAM_TYPE => [ 'user', 'bot' ]
1674                         ],
1675                         'assertuser' => [
1676                                 ApiBase::PARAM_TYPE => 'user',
1677                         ],
1678                         'requestid' => null,
1679                         'servedby' => false,
1680                         'curtimestamp' => false,
1681                         'origin' => null,
1682                         'uselang' => [
1683                                 ApiBase::PARAM_DFLT => 'user',
1684                         ],
1685                 ];
1686         }
1687
1688         /** @see ApiBase::getExamplesMessages() */
1689         protected function getExamplesMessages() {
1690                 return [
1691                         'action=help'
1692                                 => 'apihelp-help-example-main',
1693                         'action=help&recursivesubmodules=1'
1694                                 => 'apihelp-help-example-recursive',
1695                 ];
1696         }
1697
1698         public function modifyHelp( array &$help, array $options, array &$tocData ) {
1699                 // Wish PHP had an "array_insert_before". Instead, we have to manually
1700                 // reindex the array to get 'permissions' in the right place.
1701                 $oldHelp = $help;
1702                 $help = [];
1703                 foreach ( $oldHelp as $k => $v ) {
1704                         if ( $k === 'submodules' ) {
1705                                 $help['permissions'] = '';
1706                         }
1707                         $help[$k] = $v;
1708                 }
1709                 $help['datatypes'] = '';
1710                 $help['credits'] = '';
1711
1712                 // Fill 'permissions'
1713                 $help['permissions'] .= Html::openElement( 'div',
1714                         [ 'class' => 'apihelp-block apihelp-permissions' ] );
1715                 $m = $this->msg( 'api-help-permissions' );
1716                 if ( !$m->isDisabled() ) {
1717                         $help['permissions'] .= Html::rawElement( 'div', [ 'class' => 'apihelp-block-head' ],
1718                                 $m->numParams( count( self::$mRights ) )->parse()
1719                         );
1720                 }
1721                 $help['permissions'] .= Html::openElement( 'dl' );
1722                 foreach ( self::$mRights as $right => $rightMsg ) {
1723                         $help['permissions'] .= Html::element( 'dt', null, $right );
1724
1725                         $rightMsg = $this->msg( $rightMsg['msg'], $rightMsg['params'] )->parse();
1726                         $help['permissions'] .= Html::rawElement( 'dd', null, $rightMsg );
1727
1728                         $groups = array_map( function ( $group ) {
1729                                 return $group == '*' ? 'all' : $group;
1730                         }, User::getGroupsWithPermission( $right ) );
1731
1732                         $help['permissions'] .= Html::rawElement( 'dd', null,
1733                                 $this->msg( 'api-help-permissions-granted-to' )
1734                                         ->numParams( count( $groups ) )
1735                                         ->params( $this->getLanguage()->commaList( $groups ) )
1736                                         ->parse()
1737                         );
1738                 }
1739                 $help['permissions'] .= Html::closeElement( 'dl' );
1740                 $help['permissions'] .= Html::closeElement( 'div' );
1741
1742                 // Fill 'datatypes' and 'credits', if applicable
1743                 if ( empty( $options['nolead'] ) ) {
1744                         $level = $options['headerlevel'];
1745                         $tocnumber = &$options['tocnumber'];
1746
1747                         $header = $this->msg( 'api-help-datatypes-header' )->parse();
1748
1749                         // Add an additional span with sanitized ID
1750                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1751                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/datatypes' ) ] ) .
1752                                         $header;
1753                         }
1754                         $help['datatypes'] .= Html::rawElement( 'h' . min( 6, $level ),
1755                                 [ 'id' => 'main/datatypes', 'class' => 'apihelp-header' ],
1756                                 $header
1757                         );
1758                         $help['datatypes'] .= $this->msg( 'api-help-datatypes' )->parseAsBlock();
1759                         if ( !isset( $tocData['main/datatypes'] ) ) {
1760                                 $tocnumber[$level]++;
1761                                 $tocData['main/datatypes'] = [
1762                                         'toclevel' => count( $tocnumber ),
1763                                         'level' => $level,
1764                                         'anchor' => 'main/datatypes',
1765                                         'line' => $header,
1766                                         'number' => implode( '.', $tocnumber ),
1767                                         'index' => false,
1768                                 ];
1769                         }
1770
1771                         // Add an additional span with sanitized ID
1772                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1773                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/credits' ) ] ) .
1774                                         $header;
1775                         }
1776                         $header = $this->msg( 'api-credits-header' )->parse();
1777                         $help['credits'] .= Html::rawElement( 'h' . min( 6, $level ),
1778                                 [ 'id' => 'main/credits', 'class' => 'apihelp-header' ],
1779                                 $header
1780                         );
1781                         $help['credits'] .= $this->msg( 'api-credits' )->useDatabase( false )->parseAsBlock();
1782                         if ( !isset( $tocData['main/credits'] ) ) {
1783                                 $tocnumber[$level]++;
1784                                 $tocData['main/credits'] = [
1785                                         'toclevel' => count( $tocnumber ),
1786                                         'level' => $level,
1787                                         'anchor' => 'main/credits',
1788                                         'line' => $header,
1789                                         'number' => implode( '.', $tocnumber ),
1790                                         'index' => false,
1791                                 ];
1792                         }
1793                 }
1794         }
1795
1796         private $mCanApiHighLimits = null;
1797
1798         /**
1799          * Check whether the current user is allowed to use high limits
1800          * @return bool
1801          */
1802         public function canApiHighLimits() {
1803                 if ( !isset( $this->mCanApiHighLimits ) ) {
1804                         $this->mCanApiHighLimits = $this->getUser()->isAllowed( 'apihighlimits' );
1805                 }
1806
1807                 return $this->mCanApiHighLimits;
1808         }
1809
1810         /**
1811          * Overrides to return this instance's module manager.
1812          * @return ApiModuleManager
1813          */
1814         public function getModuleManager() {
1815                 return $this->mModuleMgr;
1816         }
1817
1818         /**
1819          * Fetches the user agent used for this request
1820          *
1821          * The value will be the combination of the 'Api-User-Agent' header (if
1822          * any) and the standard User-Agent header (if any).
1823          *
1824          * @return string
1825          */
1826         public function getUserAgent() {
1827                 return trim(
1828                         $this->getRequest()->getHeader( 'Api-user-agent' ) . ' ' .
1829                         $this->getRequest()->getHeader( 'User-agent' )
1830                 );
1831         }
1832 }
1833
1834 /**
1835  * This exception will be thrown when dieUsage is called to stop module execution.
1836  *
1837  * @ingroup API
1838  */
1839 class UsageException extends MWException {
1840
1841         private $mCodestr;
1842
1843         /**
1844          * @var null|array
1845          */
1846         private $mExtraData;
1847
1848         /**
1849          * @param string $message
1850          * @param string $codestr
1851          * @param int $code
1852          * @param array|null $extradata
1853          */
1854         public function __construct( $message, $codestr, $code = 0, $extradata = null ) {
1855                 parent::__construct( $message, $code );
1856                 $this->mCodestr = $codestr;
1857                 $this->mExtraData = $extradata;
1858
1859                 // This should never happen, so throw an exception about it that will
1860                 // hopefully get logged with a backtrace (T138585)
1861                 if ( !is_string( $codestr ) || $codestr === '' ) {
1862                         throw new InvalidArgumentException( 'Invalid $codestr, was ' .
1863                                 ( $codestr === '' ? 'empty string' : gettype( $codestr ) )
1864                         );
1865                 }
1866         }
1867
1868         /**
1869          * @return string
1870          */
1871         public function getCodeString() {
1872                 return $this->mCodestr;
1873         }
1874
1875         /**
1876          * @return array
1877          */
1878         public function getMessageArray() {
1879                 $result = [
1880                         'code' => $this->mCodestr,
1881                         'info' => $this->getMessage()
1882                 ];
1883                 if ( is_array( $this->mExtraData ) ) {
1884                         $result = array_merge( $result, $this->mExtraData );
1885                 }
1886
1887                 return $result;
1888         }
1889
1890         /**
1891          * @return string
1892          */
1893         public function __toString() {
1894                 return "{$this->getCodeString()}: {$this->getMessage()}";
1895         }
1896 }
1897
1898 /**
1899  * For really cool vim folding this needs to be at the end:
1900  * vim: foldmarker=@{,@} foldmethod=marker
1901  */