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                 if ( $e->getCode() === 0 ) {
 576                         $response->header( $headerStr );
 577                 } else {
 578                         $response->header( $headerStr, true, $e->getCode() );
 579                 }
 580
 581                 // Reset and print just the error message
 582                 ob_clean();
 583
 584                 // Printer may not be initialized if the extractRequestParams() fails for the main module
 585                 $this->createErrorPrinter();
 586
 587                 try {
 588                         $this->printResult( true );
 589                 } catch ( UsageException $ex ) {
 590                         // The error printer itself is failing. Try suppressing its request
 591                         // parameters and redo.
 592                         $this->setWarning(
 593                                 'Error printer failed (will retry without params): ' . $ex->getMessage()
 594                         );
 595                         $this->mPrinter = null;
 596                         $this->createErrorPrinter();
 597                         $this->mPrinter->forceDefaultParams();
 598                         $this->printResult( true );
 599                 }
 600         }
 601
 602         /**
 603          * Handle an exception from the ApiBeforeMain hook.
 604          *
 605          * This tries to print the exception as an API response, to be more
 606          * friendly to clients. If it fails, it will rethrow the exception.
 607          *
 608          * @since 1.23
 609          * @param Exception $e
 610          * @throws Exception
 611          */
 612         public static function handleApiBeforeMainException( Exception $e ) {
 613                 ob_start();
 614
 615                 try {
 616                         $main = new self( RequestContext::getMain(), false );
 617                         $main->handleException( $e );
 618                         $main->logRequest( 0, $e );
 619                 } catch ( Exception $e2 ) {
 620                         // Nope, even that didn't work. Punt.
 621                         throw $e;
 622                 }
 623
 624                 // Reset cache headers
 625                 $main->sendCacheHeaders( true );
 626
 627                 ob_end_flush();
 628         }
 629
 630         /**
 631          * Check the &origin= query parameter against the Origin: HTTP header and respond appropriately.
 632          *
 633          * If no origin parameter is present, nothing happens.
 634          * If an origin parameter is present but doesn't match the Origin header, a 403 status code
 635          * is set and false is returned.
 636          * If the parameter and the header do match, the header is checked against $wgCrossSiteAJAXdomains
 637          * and $wgCrossSiteAJAXdomainExceptions, and if the origin qualifies, the appropriate CORS
 638          * headers are set.
 639          * https://www.w3.org/TR/cors/#resource-requests
 640          * https://www.w3.org/TR/cors/#resource-preflight-requests
 641          *
 642          * @return bool False if the caller should abort (403 case), true otherwise (all other cases)
 643          */
 644         protected function handleCORS() {
 645                 $originParam = $this->getParameter( 'origin' ); // defaults to null
 646                 if ( $originParam === null ) {
 647                         // No origin parameter, nothing to do
 648                         return true;
 649                 }
 650
 651                 $request = $this->getRequest();
 652                 $response = $request->response();
 653
 654                 $matchOrigin = false;
 655                 $allowTiming = false;
 656                 $varyOrigin = true;
 657
 658                 if ( $originParam === '*' ) {
 659                         // Request for anonymous CORS
 660                         $matchOrigin = true;
 661                         $allowOrigin = '*';
 662                         $allowCredentials = 'false';
 663                         $varyOrigin = false; // No need to vary
 664                 } else {
 665                         // Non-anonymous CORS, check we allow the domain
 666
 667                         // Origin: header is a space-separated list of origins, check all of them
 668                         $originHeader = $request->getHeader( 'Origin' );
 669                         if ( $originHeader === false ) {
 670                                 $origins = [];
 671                         } else {
 672                                 $originHeader = trim( $originHeader );
 673                                 $origins = preg_split( '/\s+/', $originHeader );
 674                         }
 675
 676                         if ( !in_array( $originParam, $origins ) ) {
 677                                 // origin parameter set but incorrect
 678                                 // Send a 403 response
 679                                 $response->statusHeader( 403 );
 680                                 $response->header( 'Cache-Control: no-cache' );
 681                                 echo "'origin' parameter does not match Origin header\n";
 682
 683                                 return false;
 684                         }
 685
 686                         $config = $this->getConfig();
 687                         $matchOrigin = count( $origins ) === 1 && self::matchOrigin(
 688                                 $originParam,
 689                                 $config->get( 'CrossSiteAJAXdomains' ),
 690                                 $config->get( 'CrossSiteAJAXdomainExceptions' )
 691                         );
 692
 693                         $allowOrigin = $originHeader;
 694                         $allowCredentials = 'true';
 695                         $allowTiming = $originHeader;
 696                 }
 697
 698                 if ( $matchOrigin ) {
 699                         $requestedMethod = $request->getHeader( 'Access-Control-Request-Method' );
 700                         $preflight = $request->getMethod() === 'OPTIONS' && $requestedMethod !== false;
 701                         if ( $preflight ) {
 702                                 // This is a CORS preflight request
 703                                 if ( $requestedMethod !== 'POST' && $requestedMethod !== 'GET' ) {
 704                                         // If method is not a case-sensitive match, do not set any additional headers and terminate.
 705                                         return true;
 706                                 }
 707                                 // We allow the actual request to send the following headers
 708                                 $requestedHeaders = $request->getHeader( 'Access-Control-Request-Headers' );
 709                                 if ( $requestedHeaders !== false ) {
 710                                         if ( !self::matchRequestedHeaders( $requestedHeaders ) ) {
 711                                                 return true;
 712                                         }
 713                                         $response->header( 'Access-Control-Allow-Headers: ' . $requestedHeaders );
 714                                 }
 715
 716                                 // We only allow the actual request to be GET or POST
 717                                 $response->header( 'Access-Control-Allow-Methods: POST, GET' );
 718                         }
 719
 720                         $response->header( "Access-Control-Allow-Origin: $allowOrigin" );
 721                         $response->header( "Access-Control-Allow-Credentials: $allowCredentials" );
 722                         // https://www.w3.org/TR/resource-timing/#timing-allow-origin
 723                         if ( $allowTiming !== false ) {
 724                                 $response->header( "Timing-Allow-Origin: $allowTiming" );
 725                         }
 726
 727                         if ( !$preflight ) {
 728                                 $response->header(
 729                                         'Access-Control-Expose-Headers: MediaWiki-API-Error, Retry-After, X-Database-Lag'
 730                                 );
 731                         }
 732                 }
 733
 734                 if ( $varyOrigin ) {
 735                         $this->getOutput()->addVaryHeader( 'Origin' );
 736                 }
 737
 738                 return true;
 739         }
 740
 741         /**
 742          * Attempt to match an Origin header against a set of rules and a set of exceptions
 743          * @param string $value Origin header
 744          * @param array $rules Set of wildcard rules
 745          * @param array $exceptions Set of wildcard rules
 746          * @return bool True if $value matches a rule in $rules and doesn't match
 747          *    any rules in $exceptions, false otherwise
 748          */
 749         protected static function matchOrigin( $value, $rules, $exceptions ) {
 750                 foreach ( $rules as $rule ) {
 751                         if ( preg_match( self::wildcardToRegex( $rule ), $value ) ) {
 752                                 // Rule matches, check exceptions
 753                                 foreach ( $exceptions as $exc ) {
 754                                         if ( preg_match( self::wildcardToRegex( $exc ), $value ) ) {
 755                                                 return false;
 756                                         }
 757                                 }
 758
 759                                 return true;
 760                         }
 761                 }
 762
 763                 return false;
 764         }
 765
 766         /**
 767          * Attempt to validate the value of Access-Control-Request-Headers against a list
 768          * of headers that we allow the follow up request to send.
 769          *
 770          * @param string $requestedHeaders Comma seperated list of HTTP headers
 771          * @return bool True if all requested headers are in the list of allowed headers
 772          */
 773         protected static function matchRequestedHeaders( $requestedHeaders ) {
 774                 if ( trim( $requestedHeaders ) === '' ) {
 775                         return true;
 776                 }
 777                 $requestedHeaders = explode( ',', $requestedHeaders );
 778                 $allowedAuthorHeaders = array_flip( [
 779                         /* simple headers (see spec) */
 780                         'accept',
 781                         'accept-language',
 782                         'content-language',
 783                         'content-type',
 784                         /* non-authorable headers in XHR, which are however requested by some UAs */
 785                         'accept-encoding',
 786                         'dnt',
 787                         'origin',
 788                         /* MediaWiki whitelist */
 789                         'api-user-agent',
 790                 ] );
 791                 foreach ( $requestedHeaders as $rHeader ) {
 792                         $rHeader = strtolower( trim( $rHeader ) );
 793                         if ( !isset( $allowedAuthorHeaders[$rHeader] ) ) {
 794                                 wfDebugLog( 'api', 'CORS preflight failed on requested header: ' . $rHeader );
 795                                 return false;
 796                         }
 797                 }
 798                 return true;
 799         }
 800
 801         /**
 802          * Helper function to convert wildcard string into a regex
 803          * '*' => '.*?'
 804          * '?' => '.'
 805          *
 806          * @param string $wildcard String with wildcards
 807          * @return string Regular expression
 808          */
 809         protected static function wildcardToRegex( $wildcard ) {
 810                 $wildcard = preg_quote( $wildcard, '/' );
 811                 $wildcard = str_replace(
 812                         [ '\*', '\?' ],
 813                         [ '.*?', '.' ],
 814                         $wildcard
 815                 );
 816
 817                 return "/^https?:\/\/$wildcard$/";
 818         }
 819
 820         /**
 821          * Send caching headers
 822          * @param bool $isError Whether an error response is being output
 823          * @since 1.26 added $isError parameter
 824          */
 825         protected function sendCacheHeaders( $isError ) {
 826                 $response = $this->getRequest()->response();
 827                 $out = $this->getOutput();
 828
 829                 $out->addVaryHeader( 'Treat-as-Untrusted' );
 830
 831                 $config = $this->getConfig();
 832
 833                 if ( $config->get( 'VaryOnXFP' ) ) {
 834                         $out->addVaryHeader( 'X-Forwarded-Proto' );
 835                 }
 836
 837                 if ( !$isError && $this->mModule &&
 838                         ( $this->getRequest()->getMethod() === 'GET' || $this->getRequest()->getMethod() === 'HEAD' )
 839                 ) {
 840                         $etag = $this->mModule->getConditionalRequestData( 'etag' );
 841                         if ( $etag !== null ) {
 842                                 $response->header( "ETag: $etag" );
 843                         }
 844                         $lastMod = $this->mModule->getConditionalRequestData( 'last-modified' );
 845                         if ( $lastMod !== null ) {
 846                                 $response->header( 'Last-Modified: ' . wfTimestamp( TS_RFC2822, $lastMod ) );
 847                         }
 848                 }
 849
 850                 // The logic should be:
 851                 // $this->mCacheControl['max-age'] is set?
 852                 //    Use it, the module knows better than our guess.
 853                 // !$this->mModule || $this->mModule->isWriteMode(), and mCacheMode is private?
 854                 //    Use 0 because we can guess caching is probably the wrong thing to do.
 855                 // Use $this->getParameter( 'maxage' ), which already defaults to 0.
 856                 $maxage = 0;
 857                 if ( isset( $this->mCacheControl['max-age'] ) ) {
 858                         $maxage = $this->mCacheControl['max-age'];
 859                 } elseif ( ( $this->mModule && !$this->mModule->isWriteMode() ) ||
 860                         $this->mCacheMode !== 'private'
 861                 ) {
 862                         $maxage = $this->getParameter( 'maxage' );
 863                 }
 864                 $privateCache = 'private, must-revalidate, max-age=' . $maxage;
 865
 866                 if ( $this->mCacheMode == 'private' ) {
 867                         $response->header( "Cache-Control: $privateCache" );
 868                         return;
 869                 }
 870
 871                 $useKeyHeader = $config->get( 'UseKeyHeader' );
 872                 if ( $this->mCacheMode == 'anon-public-user-private' ) {
 873                         $out->addVaryHeader( 'Cookie' );
 874                         $response->header( $out->getVaryHeader() );
 875                         if ( $useKeyHeader ) {
 876                                 $response->header( $out->getKeyHeader() );
 877                                 if ( $out->haveCacheVaryCookies() ) {
 878                                         // Logged in, mark this request private
 879                                         $response->header( "Cache-Control: $privateCache" );
 880                                         return;
 881                                 }
 882                                 // Logged out, send normal public headers below
 883                         } elseif ( MediaWiki\Session\SessionManager::getGlobalSession()->isPersistent() ) {
 884                                 // Logged in or otherwise has session (e.g. anonymous users who have edited)
 885                                 // Mark request private
 886                                 $response->header( "Cache-Control: $privateCache" );
 887
 888                                 return;
 889                         } // else no Key and anonymous, send public headers below
 890                 }
 891
 892                 // Send public headers
 893                 $response->header( $out->getVaryHeader() );
 894                 if ( $useKeyHeader ) {
 895                         $response->header( $out->getKeyHeader() );
 896                 }
 897
 898                 // If nobody called setCacheMaxAge(), use the (s)maxage parameters
 899                 if ( !isset( $this->mCacheControl['s-maxage'] ) ) {
 900                         $this->mCacheControl['s-maxage'] = $this->getParameter( 'smaxage' );
 901                 }
 902                 if ( !isset( $this->mCacheControl['max-age'] ) ) {
 903                         $this->mCacheControl['max-age'] = $this->getParameter( 'maxage' );
 904                 }
 905
 906                 if ( !$this->mCacheControl['s-maxage'] && !$this->mCacheControl['max-age'] ) {
 907                         // Public cache not requested
 908                         // Sending a Vary header in this case is harmless, and protects us
 909                         // against conditional calls of setCacheMaxAge().
 910                         $response->header( "Cache-Control: $privateCache" );
 911
 912                         return;
 913                 }
 914
 915                 $this->mCacheControl['public'] = true;
 916
 917                 // Send an Expires header
 918                 $maxAge = min( $this->mCacheControl['s-maxage'], $this->mCacheControl['max-age'] );
 919                 $expiryUnixTime = ( $maxAge == 0 ? 1 : time() + $maxAge );
 920                 $response->header( 'Expires: ' . wfTimestamp( TS_RFC2822, $expiryUnixTime ) );
 921
 922                 // Construct the Cache-Control header
 923                 $ccHeader = '';
 924                 $separator = '';
 925                 foreach ( $this->mCacheControl as $name => $value ) {
 926                         if ( is_bool( $value ) ) {
 927                                 if ( $value ) {
 928                                         $ccHeader .= $separator . $name;
 929                                         $separator = ', ';
 930                                 }
 931                         } else {
 932                                 $ccHeader .= $separator . "$name=$value";
 933                                 $separator = ', ';
 934                         }
 935                 }
 936
 937                 $response->header( "Cache-Control: $ccHeader" );
 938         }
 939
 940         /**
 941          * Create the printer for error output
 942          */
 943         private function createErrorPrinter() {
 944                 if ( !isset( $this->mPrinter ) ) {
 945                         $value = $this->getRequest()->getVal( 'format', self::API_DEFAULT_FORMAT );
 946                         if ( !$this->mModuleMgr->isDefined( $value, 'format' ) ) {
 947                                 $value = self::API_DEFAULT_FORMAT;
 948                         }
 949                         $this->mPrinter = $this->createPrinterByName( $value );
 950                 }
 951
 952                 // Printer may not be able to handle errors. This is particularly
 953                 // likely if the module returns something for getCustomPrinter().
 954                 if ( !$this->mPrinter->canPrintErrors() ) {
 955                         $this->mPrinter = $this->createPrinterByName( self::API_DEFAULT_FORMAT );
 956                 }
 957         }
 958
 959         /**
 960          * Create an error message for the given exception.
 961          *
 962          * If the exception is a UsageException then
 963          * UsageException::getMessageArray() will be called to create the message.
 964          *
 965          * @param Exception $e
 966          * @return array ['code' => 'some string', 'info' => 'some other string']
 967          * @since 1.27
 968          */
 969         protected function errorMessageFromException( $e ) {
 970                 if ( $e instanceof UsageException ) {
 971                         // User entered incorrect parameters - generate error response
 972                         $errMessage = $e->getMessageArray();
 973                 } else {
 974                         $config = $this->getConfig();
 975                         // Something is seriously wrong
 976                         if ( ( $e instanceof DBQueryError ) && !$config->get( 'ShowSQLErrors' ) ) {
 977                                 $info = 'Database query error';
 978                         } else {
 979                                 $info = "Exception Caught: {$e->getMessage()}";
 980                         }
 981
 982                         $errMessage = [
 983                                 'code' => 'internal_api_error_' . get_class( $e ),
 984                                 'info' => '[' . WebRequest::getRequestId() . '] ' . $info,
 985                         ];
 986                 }
 987                 return $errMessage;
 988         }
 989
 990         /**
 991          * Replace the result data with the information about an exception.
 992          * Returns the error code
 993          * @param Exception $e
 994          * @return string
 995          */
 996         protected function substituteResultWithError( $e ) {
 997                 $result = $this->getResult();
 998                 $config = $this->getConfig();
 999
1000                 $errMessage = $this->errorMessageFromException( $e );
1001                 if ( $e instanceof UsageException ) {
1002                         // User entered incorrect parameters - generate error response
1003                         $link = wfExpandUrl( wfScript( 'api' ) );
1004                         ApiResult::setContentValue( $errMessage, 'docref', "See $link for API usage" );
1005                 } else {
1006                         // Something is seriously wrong
1007                         if ( $config->get( 'ShowExceptionDetails' ) ) {
1008                                 ApiResult::setContentValue(
1009                                         $errMessage,
1010                                         'trace',
1011                                         MWExceptionHandler::getRedactedTraceAsString( $e )
1012                                 );
1013                         }
1014                 }
1015
1016                 // Remember all the warnings to re-add them later
1017                 $warnings = $result->getResultData( [ 'warnings' ] );
1018
1019                 $result->reset();
1020                 // Re-add the id
1021                 $requestid = $this->getParameter( 'requestid' );
1022                 if ( !is_null( $requestid ) ) {
1023                         $result->addValue( null, 'requestid', $requestid, ApiResult::NO_SIZE_CHECK );
1024                 }
1025                 if ( $config->get( 'ShowHostnames' ) ) {
1026                         // servedby is especially useful when debugging errors
1027                         $result->addValue( null, 'servedby', wfHostname(), ApiResult::NO_SIZE_CHECK );
1028                 }
1029                 if ( $warnings !== null ) {
1030                         $result->addValue( null, 'warnings', $warnings, ApiResult::NO_SIZE_CHECK );
1031                 }
1032
1033                 $result->addValue( null, 'error', $errMessage, ApiResult::NO_SIZE_CHECK );
1034
1035                 return $errMessage['code'];
1036         }
1037
1038         /**
1039          * Set up for the execution.
1040          * @return array
1041          */
1042         protected function setupExecuteAction() {
1043                 // First add the id to the top element
1044                 $result = $this->getResult();
1045                 $requestid = $this->getParameter( 'requestid' );
1046                 if ( !is_null( $requestid ) ) {
1047                         $result->addValue( null, 'requestid', $requestid );
1048                 }
1049
1050                 if ( $this->getConfig()->get( 'ShowHostnames' ) ) {
1051                         $servedby = $this->getParameter( 'servedby' );
1052                         if ( $servedby ) {
1053                                 $result->addValue( null, 'servedby', wfHostname() );
1054                         }
1055                 }
1056
1057                 if ( $this->getParameter( 'curtimestamp' ) ) {
1058                         $result->addValue( null, 'curtimestamp', wfTimestamp( TS_ISO_8601, time() ),
1059                                 ApiResult::NO_SIZE_CHECK );
1060                 }
1061
1062                 $params = $this->extractRequestParams();
1063
1064                 $this->mAction = $params['action'];
1065
1066                 if ( !is_string( $this->mAction ) ) {
1067                         $this->dieUsage( 'The API requires a valid action parameter', 'unknown_action' );
1068                 }
1069
1070                 return $params;
1071         }
1072
1073         /**
1074          * Set up the module for response
1075          * @return ApiBase The module that will handle this action
1076          * @throws MWException
1077          * @throws UsageException
1078          */
1079         protected function setupModule() {
1080                 // Instantiate the module requested by the user
1081                 $module = $this->mModuleMgr->getModule( $this->mAction, 'action' );
1082                 if ( $module === null ) {
1083                         $this->dieUsage( 'The API requires a valid action parameter', 'unknown_action' );
1084                 }
1085                 $moduleParams = $module->extractRequestParams();
1086
1087                 // Check token, if necessary
1088                 if ( $module->needsToken() === true ) {
1089                         throw new MWException(
1090                                 "Module '{$module->getModuleName()}' must be updated for the new token handling. " .
1091                                 'See documentation for ApiBase::needsToken for details.'
1092                         );
1093                 }
1094                 if ( $module->needsToken() ) {
1095                         if ( !$module->mustBePosted() ) {
1096                                 throw new MWException(
1097                                         "Module '{$module->getModuleName()}' must require POST to use tokens."
1098                                 );
1099                         }
1100
1101                         if ( !isset( $moduleParams['token'] ) ) {
1102                                 $this->dieUsageMsg( [ 'missingparam', 'token' ] );
1103                         }
1104
1105                         $module->requirePostedParameters( [ 'token' ] );
1106
1107                         if ( !$module->validateToken( $moduleParams['token'], $moduleParams ) ) {
1108                                 $this->dieUsageMsg( 'sessionfailure' );
1109                         }
1110                 }
1111
1112                 return $module;
1113         }
1114
1115         /**
1116          * Check the max lag if necessary
1117          * @param ApiBase $module Api module being used
1118          * @param array $params Array an array containing the request parameters.
1119          * @return bool True on success, false should exit immediately
1120          */
1121         protected function checkMaxLag( $module, $params ) {
1122                 if ( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
1123                         $maxLag = $params['maxlag'];
1124                         list( $host, $lag ) = wfGetLB()->getMaxLag();
1125                         if ( $lag > $maxLag ) {
1126                                 $response = $this->getRequest()->response();
1127
1128                                 $response->header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
1129                                 $response->header( 'X-Database-Lag: ' . intval( $lag ) );
1130
1131                                 if ( $this->getConfig()->get( 'ShowHostnames' ) ) {
1132                                         $this->dieUsage( "Waiting for $host: $lag seconds lagged", 'maxlag' );
1133                                 }
1134
1135                                 $this->dieUsage( "Waiting for a database server: $lag seconds lagged", 'maxlag' );
1136                         }
1137                 }
1138
1139                 return true;
1140         }
1141
1142         /**
1143          * Check selected RFC 7232 precondition headers
1144          *
1145          * RFC 7232 envisions a particular model where you send your request to "a
1146          * resource", and for write requests that you can read "the resource" by
1147          * changing the method to GET. When the API receives a GET request, it
1148          * works out even though "the resource" from RFC 7232's perspective might
1149          * be many resources from MediaWiki's perspective. But it totally fails for
1150          * a POST, since what HTTP sees as "the resource" is probably just
1151          * "/api.php" with all the interesting bits in the body.
1152          *
1153          * Therefore, we only support RFC 7232 precondition headers for GET (and
1154          * HEAD). That means we don't need to bother with If-Match and
1155          * If-Unmodified-Since since they only apply to modification requests.
1156          *
1157          * And since we don't support Range, If-Range is ignored too.
1158          *
1159          * @since 1.26
1160          * @param ApiBase $module Api module being used
1161          * @return bool True on success, false should exit immediately
1162          */
1163         protected function checkConditionalRequestHeaders( $module ) {
1164                 if ( $this->mInternalMode ) {
1165                         // No headers to check in internal mode
1166                         return true;
1167                 }
1168
1169                 if ( $this->getRequest()->getMethod() !== 'GET' && $this->getRequest()->getMethod() !== 'HEAD' ) {
1170                         // Don't check POSTs
1171                         return true;
1172                 }
1173
1174                 $return304 = false;
1175
1176                 $ifNoneMatch = array_diff(
1177                         $this->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST ) ?: [],
1178                         [ '' ]
1179                 );
1180                 if ( $ifNoneMatch ) {
1181                         if ( $ifNoneMatch === [ '*' ] ) {
1182                                 // API responses always "exist"
1183                                 $etag = '*';
1184                         } else {
1185                                 $etag = $module->getConditionalRequestData( 'etag' );
1186                         }
1187                 }
1188                 if ( $ifNoneMatch && $etag !== null ) {
1189                         $test = substr( $etag, 0, 2 ) === 'W/' ? substr( $etag, 2 ) : $etag;
1190                         $match = array_map( function ( $s ) {
1191                                 return substr( $s, 0, 2 ) === 'W/' ? substr( $s, 2 ) : $s;
1192                         }, $ifNoneMatch );
1193                         $return304 = in_array( $test, $match, true );
1194                 } else {
1195                         $value = trim( $this->getRequest()->getHeader( 'If-Modified-Since' ) );
1196
1197                         // Some old browsers sends sizes after the date, like this:
1198                         //  Wed, 20 Aug 2003 06:51:19 GMT; length=5202
1199                         // Ignore that.
1200                         $i = strpos( $value, ';' );
1201                         if ( $i !== false ) {
1202                                 $value = trim( substr( $value, 0, $i ) );
1203                         }
1204
1205                         if ( $value !== '' ) {
1206                                 try {
1207                                         $ts = new MWTimestamp( $value );
1208                                         if (
1209                                                 // RFC 7231 IMF-fixdate
1210                                                 $ts->getTimestamp( TS_RFC2822 ) === $value ||
1211                                                 // RFC 850
1212                                                 $ts->format( 'l, d-M-y H:i:s' ) . ' GMT' === $value ||
1213                                                 // asctime (with and without space-padded day)
1214                                                 $ts->format( 'D M j H:i:s Y' ) === $value ||
1215                                                 $ts->format( 'D M  j H:i:s Y' ) === $value
1216                                         ) {
1217                                                 $lastMod = $module->getConditionalRequestData( 'last-modified' );
1218                                                 if ( $lastMod !== null ) {
1219                                                         // Mix in some MediaWiki modification times
1220                                                         $modifiedTimes = [
1221                                                                 'page' => $lastMod,
1222                                                                 'user' => $this->getUser()->getTouched(),
1223                                                                 'epoch' => $this->getConfig()->get( 'CacheEpoch' ),
1224                                                         ];
1225                                                         if ( $this->getConfig()->get( 'UseSquid' ) ) {
1226                                                                 // T46570: the core page itself may not change, but resources might
1227                                                                 $modifiedTimes['sepoch'] = wfTimestamp(
1228                                                                         TS_MW, time() - $this->getConfig()->get( 'SquidMaxage' )
1229                                                                 );
1230                                                         }
1231                                                         Hooks::run( 'OutputPageCheckLastModified', [ &$modifiedTimes, $this->getOutput() ] );
1232                                                         $lastMod = max( $modifiedTimes );
1233                                                         $return304 = wfTimestamp( TS_MW, $lastMod ) <= $ts->getTimestamp( TS_MW );
1234                                                 }
1235                                         }
1236                                 } catch ( TimestampException $e ) {
1237                                         // Invalid timestamp, ignore it
1238                                 }
1239                         }
1240                 }
1241
1242                 if ( $return304 ) {
1243                         $this->getRequest()->response()->statusHeader( 304 );
1244
1245                         // Avoid outputting the compressed representation of a zero-length body
1246                         MediaWiki\suppressWarnings();
1247                         ini_set( 'zlib.output_compression', 0 );
1248                         MediaWiki\restoreWarnings();
1249                         wfClearOutputBuffers();
1250
1251                         return false;
1252                 }
1253
1254                 return true;
1255         }
1256
1257         /**
1258          * Check for sufficient permissions to execute
1259          * @param ApiBase $module An Api module
1260          */
1261         protected function checkExecutePermissions( $module ) {
1262                 $user = $this->getUser();
1263                 if ( $module->isReadMode() && !User::isEveryoneAllowed( 'read' ) &&
1264                         !$user->isAllowed( 'read' )
1265                 ) {
1266                         $this->dieUsageMsg( 'readrequired' );
1267                 }
1268
1269                 if ( $module->isWriteMode() ) {
1270                         if ( !$this->mEnableWrite ) {
1271                                 $this->dieUsageMsg( 'writedisabled' );
1272                         } elseif ( !$user->isAllowed( 'writeapi' ) ) {
1273                                 $this->dieUsageMsg( 'writerequired' );
1274                         } elseif ( $this->getRequest()->getHeader( 'Promise-Non-Write-API-Action' ) ) {
1275                                 $this->dieUsage(
1276                                         'Promise-Non-Write-API-Action HTTP header cannot be sent to write API modules',
1277                                         'promised-nonwrite-api'
1278                                 );
1279                         }
1280
1281                         $this->checkReadOnly( $module );
1282                 }
1283
1284                 // Allow extensions to stop execution for arbitrary reasons.
1285                 $message = false;
1286                 if ( !Hooks::run( 'ApiCheckCanExecute', [ $module, $user, &$message ] ) ) {
1287                         $this->dieUsageMsg( $message );
1288                 }
1289         }
1290
1291         /**
1292          * Check if the DB is read-only for this user
1293          * @param ApiBase $module An Api module
1294          */
1295         protected function checkReadOnly( $module ) {
1296                 if ( wfReadOnly() ) {
1297                         $this->dieReadOnly();
1298                 }
1299
1300                 if ( $module->isWriteMode()
1301                         && $this->getUser()->isBot()
1302                         && wfGetLB()->getServerCount() > 1
1303                 ) {
1304                         $this->checkBotReadOnly();
1305                 }
1306         }
1307
1308         /**
1309          * Check whether we are readonly for bots
1310          */
1311         private function checkBotReadOnly() {
1312                 // Figure out how many servers have passed the lag threshold
1313                 $numLagged = 0;
1314                 $lagLimit = $this->getConfig()->get( 'APIMaxLagThreshold' );
1315                 $laggedServers = [];
1316                 $loadBalancer = wfGetLB();
1317                 foreach ( $loadBalancer->getLagTimes() as $serverIndex => $lag ) {
1318                         if ( $lag > $lagLimit ) {
1319                                 ++$numLagged;
1320                                 $laggedServers[] = $loadBalancer->getServerName( $serverIndex ) . " ({$lag}s)";
1321                         }
1322                 }
1323
1324                 // If a majority of replica DBs are too lagged then disallow writes
1325                 $replicaCount = wfGetLB()->getServerCount() - 1;
1326                 if ( $numLagged >= ceil( $replicaCount / 2 ) ) {
1327                         $laggedServers = implode( ', ', $laggedServers );
1328                         wfDebugLog(
1329                                 'api-readonly',
1330                                 "Api request failed as read only because the following DBs are lagged: $laggedServers"
1331                         );
1332
1333                         $parsed = $this->parseMsg( [ 'readonlytext' ] );
1334                         $this->dieUsage(
1335                                 $parsed['info'],
1336                                 $parsed['code'],
1337                                 /* http error */
1338                                 0,
1339                                 [ 'readonlyreason' => "Waiting for $numLagged lagged database(s)" ]
1340                         );
1341                 }
1342         }
1343
1344         /**
1345          * Check asserts of the user's rights
1346          * @param array $params
1347          */
1348         protected function checkAsserts( $params ) {
1349                 if ( isset( $params['assert'] ) ) {
1350                         $user = $this->getUser();
1351                         switch ( $params['assert'] ) {
1352                                 case 'user':
1353                                         if ( $user->isAnon() ) {
1354                                                 $this->dieUsage( 'Assertion that the user is logged in failed', 'assertuserfailed' );
1355                                         }
1356                                         break;
1357                                 case 'bot':
1358                                         if ( !$user->isAllowed( 'bot' ) ) {
1359                                                 $this->dieUsage( 'Assertion that the user has the bot right failed', 'assertbotfailed' );
1360                                         }
1361                                         break;
1362                         }
1363                 }
1364                 if ( isset( $params['assertuser'] ) ) {
1365                         $assertUser = User::newFromName( $params['assertuser'], false );
1366                         if ( !$assertUser || !$this->getUser()->equals( $assertUser ) ) {
1367                                 $this->dieUsage(
1368                                         'Assertion that the user is "' . $params['assertuser'] . '" failed',
1369                                         'assertnameduserfailed'
1370                                 );
1371                         }
1372                 }
1373         }
1374
1375         /**
1376          * Check POST for external response and setup result printer
1377          * @param ApiBase $module An Api module
1378          * @param array $params An array with the request parameters
1379          */
1380         protected function setupExternalResponse( $module, $params ) {
1381                 $request = $this->getRequest();
1382                 if ( !$request->wasPosted() && $module->mustBePosted() ) {
1383                         // Module requires POST. GET request might still be allowed
1384                         // if $wgDebugApi is true, otherwise fail.
1385                         $this->dieUsageMsgOrDebug( [ 'mustbeposted', $this->mAction ] );
1386                 }
1387
1388                 // See if custom printer is used
1389                 $this->mPrinter = $module->getCustomPrinter();
1390                 if ( is_null( $this->mPrinter ) ) {
1391                         // Create an appropriate printer
1392                         $this->mPrinter = $this->createPrinterByName( $params['format'] );
1393                 }
1394
1395                 if ( $request->getProtocol() === 'http' && (
1396                         $request->getSession()->shouldForceHTTPS() ||
1397                         ( $this->getUser()->isLoggedIn() &&
1398                                 $this->getUser()->requiresHTTPS() )
1399                 ) ) {
1400                         $this->logFeatureUsage( 'https-expected' );
1401                         $this->setWarning( 'HTTP used when HTTPS was expected' );
1402                 }
1403         }
1404
1405         /**
1406          * Execute the actual module, without any error handling
1407          */
1408         protected function executeAction() {
1409                 $params = $this->setupExecuteAction();
1410                 $module = $this->setupModule();
1411                 $this->mModule = $module;
1412
1413                 if ( !$this->mInternalMode ) {
1414                         $this->setRequestExpectations( $module );
1415                 }
1416
1417                 $this->checkExecutePermissions( $module );
1418
1419                 if ( !$this->checkMaxLag( $module, $params ) ) {
1420                         return;
1421                 }
1422
1423                 if ( !$this->checkConditionalRequestHeaders( $module ) ) {
1424                         return;
1425                 }
1426
1427                 if ( !$this->mInternalMode ) {
1428                         $this->setupExternalResponse( $module, $params );
1429                 }
1430
1431                 $this->checkAsserts( $params );
1432
1433                 // Execute
1434                 $module->execute();
1435                 Hooks::run( 'APIAfterExecute', [ &$module ] );
1436
1437                 $this->reportUnusedParams();
1438
1439                 if ( !$this->mInternalMode ) {
1440                         // append Debug information
1441                         MWDebug::appendDebugInfoToApiResult( $this->getContext(), $this->getResult() );
1442
1443                         // Print result data
1444                         $this->printResult( false );
1445                 }
1446         }
1447
1448         /**
1449          * Set database connection, query, and write expectations given this module request
1450          * @param ApiBase $module
1451          */
1452         protected function setRequestExpectations( ApiBase $module ) {
1453                 $limits = $this->getConfig()->get( 'TrxProfilerLimits' );
1454                 $trxProfiler = Profiler::instance()->getTransactionProfiler();
1455                 $trxProfiler->setLogger( LoggerFactory::getInstance( 'DBPerformance' ) );
1456                 if ( $this->getRequest()->hasSafeMethod() ) {
1457                         $trxProfiler->setExpectations( $limits['GET'], __METHOD__ );
1458                 } elseif ( $this->getRequest()->wasPosted() && !$module->isWriteMode() ) {
1459                         $trxProfiler->setExpectations( $limits['POST-nonwrite'], __METHOD__ );
1460                         $this->getRequest()->markAsSafeRequest();
1461                 } else {
1462                         $trxProfiler->setExpectations( $limits['POST'], __METHOD__ );
1463                 }
1464         }
1465
1466         /**
1467          * Log the preceding request
1468          * @param float $time Time in seconds
1469          * @param Exception $e Exception caught while processing the request
1470          */
1471         protected function logRequest( $time, $e = null ) {
1472                 $request = $this->getRequest();
1473                 $logCtx = [
1474                         'ts' => time(),
1475                         'ip' => $request->getIP(),
1476                         'userAgent' => $this->getUserAgent(),
1477                         'wiki' => wfWikiID(),
1478                         'timeSpentBackend' => (int)round( $time * 1000 ),
1479                         'hadError' => $e !== null,
1480                         'errorCodes' => [],
1481                         'params' => [],
1482                 ];
1483
1484                 if ( $e ) {
1485                         $logCtx['errorCodes'][] = $this->errorMessageFromException( $e )['code'];
1486                 }
1487
1488                 // Construct space separated message for 'api' log channel
1489                 $msg = "API {$request->getMethod()} " .
1490                         wfUrlencode( str_replace( ' ', '_', $this->getUser()->getName() ) ) .
1491                         " {$logCtx['ip']} " .
1492                         "T={$logCtx['timeSpentBackend']}ms";
1493
1494                 foreach ( $this->getParamsUsed() as $name ) {
1495                         $value = $request->getVal( $name );
1496                         if ( $value === null ) {
1497                                 continue;
1498                         }
1499
1500                         if ( strlen( $value ) > 256 ) {
1501                                 $value = substr( $value, 0, 256 );
1502                                 $encValue = $this->encodeRequestLogValue( $value ) . '[...]';
1503                         } else {
1504                                 $encValue = $this->encodeRequestLogValue( $value );
1505                         }
1506
1507                         $logCtx['params'][$name] = $value;
1508                         $msg .= " {$name}={$encValue}";
1509                 }
1510
1511                 wfDebugLog( 'api', $msg, 'private' );
1512                 // ApiAction channel is for structured data consumers
1513                 wfDebugLog( 'ApiAction', '', 'private', $logCtx );
1514         }
1515
1516         /**
1517          * Encode a value in a format suitable for a space-separated log line.
1518          * @param string $s
1519          * @return string
1520          */
1521         protected function encodeRequestLogValue( $s ) {
1522                 static $table;
1523                 if ( !$table ) {
1524                         $chars = ';@$!*(),/:';
1525                         $numChars = strlen( $chars );
1526                         for ( $i = 0; $i < $numChars; $i++ ) {
1527                                 $table[rawurlencode( $chars[$i] )] = $chars[$i];
1528                         }
1529                 }
1530
1531                 return strtr( rawurlencode( $s ), $table );
1532         }
1533
1534         /**
1535          * Get the request parameters used in the course of the preceding execute() request
1536          * @return array
1537          */
1538         protected function getParamsUsed() {
1539                 return array_keys( $this->mParamsUsed );
1540         }
1541
1542         /**
1543          * Mark parameters as used
1544          * @param string|string[] $params
1545          */
1546         public function markParamsUsed( $params ) {
1547                 $this->mParamsUsed += array_fill_keys( (array)$params, true );
1548         }
1549
1550         /**
1551          * Get a request value, and register the fact that it was used, for logging.
1552          * @param string $name
1553          * @param mixed $default
1554          * @return mixed
1555          */
1556         public function getVal( $name, $default = null ) {
1557                 $this->mParamsUsed[$name] = true;
1558
1559                 $ret = $this->getRequest()->getVal( $name );
1560                 if ( $ret === null ) {
1561                         if ( $this->getRequest()->getArray( $name ) !== null ) {
1562                                 // See bug 10262 for why we don't just implode( '|', ... ) the
1563                                 // array.
1564                                 $this->setWarning(
1565                                         "Parameter '$name' uses unsupported PHP array syntax"
1566                                 );
1567                         }
1568                         $ret = $default;
1569                 }
1570                 return $ret;
1571         }
1572
1573         /**
1574          * Get a boolean request value, and register the fact that the parameter
1575          * was used, for logging.
1576          * @param string $name
1577          * @return bool
1578          */
1579         public function getCheck( $name ) {
1580                 return $this->getVal( $name, null ) !== null;
1581         }
1582
1583         /**
1584          * Get a request upload, and register the fact that it was used, for logging.
1585          *
1586          * @since 1.21
1587          * @param string $name Parameter name
1588          * @return WebRequestUpload
1589          */
1590         public function getUpload( $name ) {
1591                 $this->mParamsUsed[$name] = true;
1592
1593                 return $this->getRequest()->getUpload( $name );
1594         }
1595
1596         /**
1597          * Report unused parameters, so the client gets a hint in case it gave us parameters we don't know,
1598          * for example in case of spelling mistakes or a missing 'g' prefix for generators.
1599          */
1600         protected function reportUnusedParams() {
1601                 $paramsUsed = $this->getParamsUsed();
1602                 $allParams = $this->getRequest()->getValueNames();
1603
1604                 if ( !$this->mInternalMode ) {
1605                         // Printer has not yet executed; don't warn that its parameters are unused
1606                         $printerParams = array_map(
1607                                 [ $this->mPrinter, 'encodeParamName' ],
1608                                 array_keys( $this->mPrinter->getFinalParams() ?: [] )
1609                         );
1610                         $unusedParams = array_diff( $allParams, $paramsUsed, $printerParams );
1611                 } else {
1612                         $unusedParams = array_diff( $allParams, $paramsUsed );
1613                 }
1614
1615                 if ( count( $unusedParams ) ) {
1616                         $s = count( $unusedParams ) > 1 ? 's' : '';
1617                         $this->setWarning( "Unrecognized parameter$s: '" . implode( $unusedParams, "', '" ) . "'" );
1618                 }
1619         }
1620
1621         /**
1622          * Print results using the current printer
1623          *
1624          * @param bool $isError
1625          */
1626         protected function printResult( $isError ) {
1627                 if ( $this->getConfig()->get( 'DebugAPI' ) !== false ) {
1628                         $this->setWarning( 'SECURITY WARNING: $wgDebugAPI is enabled' );
1629                 }
1630
1631                 $printer = $this->mPrinter;
1632                 $printer->initPrinter( false );
1633                 $printer->execute();
1634                 $printer->closePrinter();
1635         }
1636
1637         /**
1638          * @return bool
1639          */
1640         public function isReadMode() {
1641                 return false;
1642         }
1643
1644         /**
1645          * See ApiBase for description.
1646          *
1647          * @return array
1648          */
1649         public function getAllowedParams() {
1650                 return [
1651                         'action' => [
1652                                 ApiBase::PARAM_DFLT => 'help',
1653                                 ApiBase::PARAM_TYPE => 'submodule',
1654                         ],
1655                         'format' => [
1656                                 ApiBase::PARAM_DFLT => ApiMain::API_DEFAULT_FORMAT,
1657                                 ApiBase::PARAM_TYPE => 'submodule',
1658                         ],
1659                         'maxlag' => [
1660                                 ApiBase::PARAM_TYPE => 'integer'
1661                         ],
1662                         'smaxage' => [
1663                                 ApiBase::PARAM_TYPE => 'integer',
1664                                 ApiBase::PARAM_DFLT => 0
1665                         ],
1666                         'maxage' => [
1667                                 ApiBase::PARAM_TYPE => 'integer',
1668                                 ApiBase::PARAM_DFLT => 0
1669                         ],
1670                         'assert' => [
1671                                 ApiBase::PARAM_TYPE => [ 'user', 'bot' ]
1672                         ],
1673                         'assertuser' => [
1674                                 ApiBase::PARAM_TYPE => 'user',
1675                         ],
1676                         'requestid' => null,
1677                         'servedby' => false,
1678                         'curtimestamp' => false,
1679                         'origin' => null,
1680                         'uselang' => [
1681                                 ApiBase::PARAM_DFLT => 'user',
1682                         ],
1683                 ];
1684         }
1685
1686         /** @see ApiBase::getExamplesMessages() */
1687         protected function getExamplesMessages() {
1688                 return [
1689                         'action=help'
1690                                 => 'apihelp-help-example-main',
1691                         'action=help&recursivesubmodules=1'
1692                                 => 'apihelp-help-example-recursive',
1693                 ];
1694         }
1695
1696         public function modifyHelp( array &$help, array $options, array &$tocData ) {
1697                 // Wish PHP had an "array_insert_before". Instead, we have to manually
1698                 // reindex the array to get 'permissions' in the right place.
1699                 $oldHelp = $help;
1700                 $help = [];
1701                 foreach ( $oldHelp as $k => $v ) {
1702                         if ( $k === 'submodules' ) {
1703                                 $help['permissions'] = '';
1704                         }
1705                         $help[$k] = $v;
1706                 }
1707                 $help['datatypes'] = '';
1708                 $help['credits'] = '';
1709
1710                 // Fill 'permissions'
1711                 $help['permissions'] .= Html::openElement( 'div',
1712                         [ 'class' => 'apihelp-block apihelp-permissions' ] );
1713                 $m = $this->msg( 'api-help-permissions' );
1714                 if ( !$m->isDisabled() ) {
1715                         $help['permissions'] .= Html::rawElement( 'div', [ 'class' => 'apihelp-block-head' ],
1716                                 $m->numParams( count( self::$mRights ) )->parse()
1717                         );
1718                 }
1719                 $help['permissions'] .= Html::openElement( 'dl' );
1720                 foreach ( self::$mRights as $right => $rightMsg ) {
1721                         $help['permissions'] .= Html::element( 'dt', null, $right );
1722
1723                         $rightMsg = $this->msg( $rightMsg['msg'], $rightMsg['params'] )->parse();
1724                         $help['permissions'] .= Html::rawElement( 'dd', null, $rightMsg );
1725
1726                         $groups = array_map( function ( $group ) {
1727                                 return $group == '*' ? 'all' : $group;
1728                         }, User::getGroupsWithPermission( $right ) );
1729
1730                         $help['permissions'] .= Html::rawElement( 'dd', null,
1731                                 $this->msg( 'api-help-permissions-granted-to' )
1732                                         ->numParams( count( $groups ) )
1733                                         ->params( $this->getLanguage()->commaList( $groups ) )
1734                                         ->parse()
1735                         );
1736                 }
1737                 $help['permissions'] .= Html::closeElement( 'dl' );
1738                 $help['permissions'] .= Html::closeElement( 'div' );
1739
1740                 // Fill 'datatypes' and 'credits', if applicable
1741                 if ( empty( $options['nolead'] ) ) {
1742                         $level = $options['headerlevel'];
1743                         $tocnumber = &$options['tocnumber'];
1744
1745                         $header = $this->msg( 'api-help-datatypes-header' )->parse();
1746
1747                         // Add an additional span with sanitized ID
1748                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1749                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/datatypes' ) ] ) .
1750                                         $header;
1751                         }
1752                         $help['datatypes'] .= Html::rawElement( 'h' . min( 6, $level ),
1753                                 [ 'id' => 'main/datatypes', 'class' => 'apihelp-header' ],
1754                                 $header
1755                         );
1756                         $help['datatypes'] .= $this->msg( 'api-help-datatypes' )->parseAsBlock();
1757                         if ( !isset( $tocData['main/datatypes'] ) ) {
1758                                 $tocnumber[$level]++;
1759                                 $tocData['main/datatypes'] = [
1760                                         'toclevel' => count( $tocnumber ),
1761                                         'level' => $level,
1762                                         'anchor' => 'main/datatypes',
1763                                         'line' => $header,
1764                                         'number' => implode( '.', $tocnumber ),
1765                                         'index' => false,
1766                                 ];
1767                         }
1768
1769                         // Add an additional span with sanitized ID
1770                         if ( !$this->getConfig()->get( 'ExperimentalHtmlIds' ) ) {
1771                                 $header = Html::element( 'span', [ 'id' => Sanitizer::escapeId( 'main/credits' ) ] ) .
1772                                         $header;
1773                         }
1774                         $header = $this->msg( 'api-credits-header' )->parse();
1775                         $help['credits'] .= Html::rawElement( 'h' . min( 6, $level ),
1776                                 [ 'id' => 'main/credits', 'class' => 'apihelp-header' ],
1777                                 $header
1778                         );
1779                         $help['credits'] .= $this->msg( 'api-credits' )->useDatabase( false )->parseAsBlock();
1780                         if ( !isset( $tocData['main/credits'] ) ) {
1781                                 $tocnumber[$level]++;
1782                                 $tocData['main/credits'] = [
1783                                         'toclevel' => count( $tocnumber ),
1784                                         'level' => $level,
1785                                         'anchor' => 'main/credits',
1786                                         'line' => $header,
1787                                         'number' => implode( '.', $tocnumber ),
1788                                         'index' => false,
1789                                 ];
1790                         }
1791                 }
1792         }
1793
1794         private $mCanApiHighLimits = null;
1795
1796         /**
1797          * Check whether the current user is allowed to use high limits
1798          * @return bool
1799          */
1800         public function canApiHighLimits() {
1801                 if ( !isset( $this->mCanApiHighLimits ) ) {
1802                         $this->mCanApiHighLimits = $this->getUser()->isAllowed( 'apihighlimits' );
1803                 }
1804
1805                 return $this->mCanApiHighLimits;
1806         }
1807
1808         /**
1809          * Overrides to return this instance's module manager.
1810          * @return ApiModuleManager
1811          */
1812         public function getModuleManager() {
1813                 return $this->mModuleMgr;
1814         }
1815
1816         /**
1817          * Fetches the user agent used for this request
1818          *
1819          * The value will be the combination of the 'Api-User-Agent' header (if
1820          * any) and the standard User-Agent header (if any).
1821          *
1822          * @return string
1823          */
1824         public function getUserAgent() {
1825                 return trim(
1826                         $this->getRequest()->getHeader( 'Api-user-agent' ) . ' ' .
1827                         $this->getRequest()->getHeader( 'User-agent' )
1828                 );
1829         }
1830 }
1831
1832 /**
1833  * This exception will be thrown when dieUsage is called to stop module execution.
1834  *
1835  * @ingroup API
1836  */
1837 class UsageException extends MWException {
1838
1839         private $mCodestr;
1840
1841         /**
1842          * @var null|array
1843          */
1844         private $mExtraData;
1845
1846         /**
1847          * @param string $message
1848          * @param string $codestr
1849          * @param int $code
1850          * @param array|null $extradata
1851          */
1852         public function __construct( $message, $codestr, $code = 0, $extradata = null ) {
1853                 parent::__construct( $message, $code );
1854                 $this->mCodestr = $codestr;
1855                 $this->mExtraData = $extradata;
1856
1857                 // This should never happen, so throw an exception about it that will
1858                 // hopefully get logged with a backtrace (T138585)
1859                 if ( !is_string( $codestr ) || $codestr === '' ) {
1860                         throw new InvalidArgumentException( 'Invalid $codestr, was ' .
1861                                 ( $codestr === '' ? 'empty string' : gettype( $codestr ) )
1862                         );
1863                 }
1864         }
1865
1866         /**
1867          * @return string
1868          */
1869         public function getCodeString() {
1870                 return $this->mCodestr;
1871         }
1872
1873         /**
1874          * @return array
1875          */
1876         public function getMessageArray() {
1877                 $result = [
1878                         'code' => $this->mCodestr,
1879                         'info' => $this->getMessage()
1880                 ];
1881                 if ( is_array( $this->mExtraData ) ) {
1882                         $result = array_merge( $result, $this->mExtraData );
1883                 }
1884
1885                 return $result;
1886         }
1887
1888         /**
1889          * @return string
1890          */
1891         public function __toString() {
1892                 return "{$this->getCodeString()}: {$this->getMessage()}";
1893         }
1894 }
1895
1896 /**
1897  * For really cool vim folding this needs to be at the end:
1898  * vim: foldmarker=@{,@} foldmethod=marker
1899  */