includes/MediaWikiServices.php

   1 <?php
   2 namespace MediaWiki;
   3
   4 use Config;
   5 use ConfigFactory;
   6 use CryptHKDF;
   7 use CryptRand;
   8 use EventRelayerGroup;
   9 use GenderCache;
  10 use GlobalVarConfig;
  11 use Hooks;
  12 use Wikimedia\Rdbms\LBFactory;
  13 use LinkCache;
  14 use Liuggio\StatsdClient\Factory\StatsdDataFactory;
  15 use Wikimedia\Rdbms\LoadBalancer;
  16 use MediaHandlerFactory;
  17 use MediaWiki\Linker\LinkRenderer;
  18 use MediaWiki\Linker\LinkRendererFactory;
  19 use MediaWiki\Services\SalvageableService;
  20 use MediaWiki\Services\ServiceContainer;
  21 use MediaWiki\Services\NoSuchServiceException;
  22 use MWException;
  23 use MimeAnalyzer;
  24 use ObjectCache;
  25 use Parser;
  26 use ProxyLookup;
  27 use SearchEngine;
  28 use SearchEngineConfig;
  29 use SearchEngineFactory;
  30 use SiteLookup;
  31 use SiteStore;
  32 use WatchedItemStore;
  33 use WatchedItemQueryService;
  34 use SkinFactory;
  35 use TitleFormatter;
  36 use TitleParser;
  37 use VirtualRESTServiceClient;
  38 use MediaWiki\Interwiki\InterwikiLookup;
  39
  40 /**
  41  * Service locator for MediaWiki core services.
  42  *
  43  * This program is free software; you can redistribute it and/or modify
  44  * it under the terms of the GNU General Public License as published by
  45  * the Free Software Foundation; either version 2 of the License, or
  46  * (at your option) any later version.
  47  *
  48  * This program is distributed in the hope that it will be useful,
  49  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  50  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  51  * GNU General Public License for more details.
  52  *
  53  * You should have received a copy of the GNU General Public License along
  54  * with this program; if not, write to the Free Software Foundation, Inc.,
  55  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  56  * http://www.gnu.org/copyleft/gpl.html
  57  *
  58  * @file
  59  *
  60  * @since 1.27
  61  */
  62
  63 /**
  64  * MediaWikiServices is the service locator for the application scope of MediaWiki.
  65  * Its implemented as a simple configurable DI container.
  66  * MediaWikiServices acts as a top level factory/registry for top level services, and builds
  67  * the network of service objects that defines MediaWiki's application logic.
  68  * It acts as an entry point to MediaWiki's dependency injection mechanism.
  69  *
  70  * Services are defined in the "wiring" array passed to the constructor,
  71  * or by calling defineService().
  72  *
  73  * @see docs/injection.txt for an overview of using dependency injection in the
  74  *      MediaWiki code base.
  75  */
  76 class MediaWikiServices extends ServiceContainer {
  77
  78         /**
  79          * @var MediaWikiServices|null
  80          */
  81         private static $instance = null;
  82
  83         /**
  84          * Returns the global default instance of the top level service locator.
  85          *
  86          * @since 1.27
  87          *
  88          * The default instance is initialized using the service instantiator functions
  89          * defined in ServiceWiring.php.
  90          *
  91          * @note This should only be called by static functions! The instance returned here
  92          * should not be passed around! Objects that need access to a service should have
  93          * that service injected into the constructor, never a service locator!
  94          *
  95          * @return MediaWikiServices
  96          */
  97         public static function getInstance() {
  98                 if ( self::$instance === null ) {
  99                         // NOTE: constructing GlobalVarConfig here is not particularly pretty,
 100                         // but some information from the global scope has to be injected here,
 101                         // even if it's just a file name or database credentials to load
 102                         // configuration from.
 103                         $bootstrapConfig = new GlobalVarConfig();
 104                         self::$instance = self::newInstance( $bootstrapConfig, 'load' );
 105                 }
 106
 107                 return self::$instance;
 108         }
 109
 110         /**
 111          * Replaces the global MediaWikiServices instance.
 112          *
 113          * @since 1.28
 114          *
 115          * @note This is for use in PHPUnit tests only!
 116          *
 117          * @throws MWException if called outside of PHPUnit tests.
 118          *
 119          * @param MediaWikiServices $services The new MediaWikiServices object.
 120          *
 121          * @return MediaWikiServices The old MediaWikiServices object, so it can be restored later.
 122          */
 123         public static function forceGlobalInstance( MediaWikiServices $services ) {
 124                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 125                         throw new MWException( __METHOD__ . ' must not be used outside unit tests.' );
 126                 }
 127
 128                 $old = self::getInstance();
 129                 self::$instance = $services;
 130
 131                 return $old;
 132         }
 133
 134         /**
 135          * Creates a new instance of MediaWikiServices and sets it as the global default
 136          * instance. getInstance() will return a different MediaWikiServices object
 137          * after every call to resetGlobalInstance().
 138          *
 139          * @since 1.28
 140          *
 141          * @warning This should not be used during normal operation. It is intended for use
 142          * when the configuration has changed significantly since bootstrap time, e.g.
 143          * during the installation process or during testing.
 144          *
 145          * @warning Calling resetGlobalInstance() may leave the application in an inconsistent
 146          * state. Calling this is only safe under the ASSUMPTION that NO REFERENCE to
 147          * any of the services managed by MediaWikiServices exist. If any service objects
 148          * managed by the old MediaWikiServices instance remain in use, they may INTERFERE
 149          * with the operation of the services managed by the new MediaWikiServices.
 150          * Operating with a mix of services created by the old and the new
 151          * MediaWikiServices instance may lead to INCONSISTENCIES and even DATA LOSS!
 152          * Any class implementing LAZY LOADING is especially prone to this problem,
 153          * since instances would typically retain a reference to a storage layer service.
 154          *
 155          * @see forceGlobalInstance()
 156          * @see resetGlobalInstance()
 157          * @see resetBetweenTest()
 158          *
 159          * @param Config|null $bootstrapConfig The Config object to be registered as the
 160          *        'BootstrapConfig' service. This has to contain at least the information
 161          *        needed to set up the 'ConfigFactory' service. If not given, the bootstrap
 162          *        config of the old instance of MediaWikiServices will be re-used. If there
 163          *        was no previous instance, a new GlobalVarConfig object will be used to
 164          *        bootstrap the services.
 165          *
 166          * @param string $quick Set this to "quick" to allow expensive resources to be re-used.
 167          * See SalvageableService for details.
 168          *
 169          * @throws MWException If called after MW_SERVICE_BOOTSTRAP_COMPLETE has been defined in
 170          *         Setup.php (unless MW_PHPUNIT_TEST or MEDIAWIKI_INSTALL or RUN_MAINTENANCE_IF_MAIN
 171          *          is defined).
 172          */
 173         public static function resetGlobalInstance( Config $bootstrapConfig = null, $quick = '' ) {
 174                 if ( self::$instance === null ) {
 175                         // no global instance yet, nothing to reset
 176                         return;
 177                 }
 178
 179                 self::failIfResetNotAllowed( __METHOD__ );
 180
 181                 if ( $bootstrapConfig === null ) {
 182                         $bootstrapConfig = self::$instance->getBootstrapConfig();
 183                 }
 184
 185                 $oldInstance = self::$instance;
 186
 187                 self::$instance = self::newInstance( $bootstrapConfig, 'load' );
 188                 self::$instance->importWiring( $oldInstance, [ 'BootstrapConfig' ] );
 189
 190                 if ( $quick === 'quick' ) {
 191                         self::$instance->salvage( $oldInstance );
 192                 } else {
 193                         $oldInstance->destroy();
 194                 }
 195         }
 196
 197         /**
 198          * Salvages the state of any salvageable service instances in $other.
 199          *
 200          * @note $other will have been destroyed when salvage() returns.
 201          *
 202          * @param MediaWikiServices $other
 203          */
 204         private function salvage( self $other ) {
 205                 foreach ( $this->getServiceNames() as $name ) {
 206                         // The service could be new in the new instance and not registered in the
 207                         // other instance (e.g. an extension that was loaded after the instantiation of
 208                         // the other instance. Skip this service in this case. See T143974
 209                         try {
 210                                 $oldService = $other->peekService( $name );
 211                         } catch ( NoSuchServiceException $e ) {
 212                                 continue;
 213                         }
 214
 215                         if ( $oldService instanceof SalvageableService ) {
 216                                 /** @var SalvageableService $newService */
 217                                 $newService = $this->getService( $name );
 218                                 $newService->salvage( $oldService );
 219                         }
 220                 }
 221
 222                 $other->destroy();
 223         }
 224
 225         /**
 226          * Creates a new MediaWikiServices instance and initializes it according to the
 227          * given $bootstrapConfig. In particular, all wiring files defined in the
 228          * ServiceWiringFiles setting are loaded, and the MediaWikiServices hook is called.
 229          *
 230          * @param Config|null $bootstrapConfig The Config object to be registered as the
 231          *        'BootstrapConfig' service.
 232          *
 233          * @param string $loadWiring set this to 'load' to load the wiring files specified
 234          *        in the 'ServiceWiringFiles' setting in $bootstrapConfig.
 235          *
 236          * @return MediaWikiServices
 237          * @throws MWException
 238          * @throws \FatalError
 239          */
 240         private static function newInstance( Config $bootstrapConfig, $loadWiring = '' ) {
 241                 $instance = new self( $bootstrapConfig );
 242
 243                 // Load the default wiring from the specified files.
 244                 if ( $loadWiring === 'load' ) {
 245                         $wiringFiles = $bootstrapConfig->get( 'ServiceWiringFiles' );
 246                         $instance->loadWiringFiles( $wiringFiles );
 247                 }
 248
 249                 // Provide a traditional hook point to allow extensions to configure services.
 250                 Hooks::run( 'MediaWikiServices', [ $instance ] );
 251
 252                 return $instance;
 253         }
 254
 255         /**
 256          * Disables all storage layer services. After calling this, any attempt to access the
 257          * storage layer will result in an error. Use resetGlobalInstance() to restore normal
 258          * operation.
 259          *
 260          * @since 1.28
 261          *
 262          * @warning This is intended for extreme situations only and should never be used
 263          * while serving normal web requests. Legitimate use cases for this method include
 264          * the installation process. Test fixtures may also use this, if the fixture relies
 265          * on globalState.
 266          *
 267          * @see resetGlobalInstance()
 268          * @see resetChildProcessServices()
 269          */
 270         public static function disableStorageBackend() {
 271                 // TODO: also disable some Caches, JobQueues, etc
 272                 $destroy = [ 'DBLoadBalancer', 'DBLoadBalancerFactory' ];
 273                 $services = self::getInstance();
 274
 275                 foreach ( $destroy as $name ) {
 276                         $services->disableService( $name );
 277                 }
 278
 279                 ObjectCache::clear();
 280         }
 281
 282         /**
 283          * Resets any services that may have become stale after a child process
 284          * returns from after pcntl_fork(). It's also safe, but generally unnecessary,
 285          * to call this method from the parent process.
 286          *
 287          * @since 1.28
 288          *
 289          * @note This is intended for use in the context of process forking only!
 290          *
 291          * @see resetGlobalInstance()
 292          * @see disableStorageBackend()
 293          */
 294         public static function resetChildProcessServices() {
 295                 // NOTE: for now, just reset everything. Since we don't know the interdependencies
 296                 // between services, we can't do this more selectively at this time.
 297                 self::resetGlobalInstance();
 298
 299                 // Child, reseed because there is no bug in PHP:
 300                 // https://bugs.php.net/bug.php?id=42465
 301                 mt_srand( getmypid() );
 302         }
 303
 304         /**
 305          * Resets the given service for testing purposes.
 306          *
 307          * @since 1.28
 308          *
 309          * @warning This is generally unsafe! Other services may still retain references
 310          * to the stale service instance, leading to failures and inconsistencies. Subclasses
 311          * may use this method to reset specific services under specific instances, but
 312          * it should not be exposed to application logic.
 313          *
 314          * @note With proper dependency injection used throughout the codebase, this method
 315          * should not be needed. It is provided to allow tests that pollute global service
 316          * instances to clean up.
 317          *
 318          * @param string $name
 319          * @param bool $destroy Whether the service instance should be destroyed if it exists.
 320          *        When set to false, any existing service instance will effectively be detached
 321          *        from the container.
 322          *
 323          * @throws MWException if called outside of PHPUnit tests.
 324          */
 325         public function resetServiceForTesting( $name, $destroy = true ) {
 326                 if ( !defined( 'MW_PHPUNIT_TEST' ) && !defined( 'MW_PARSER_TEST' ) ) {
 327                         throw new MWException( 'resetServiceForTesting() must not be used outside unit tests.' );
 328                 }
 329
 330                 $this->resetService( $name, $destroy );
 331         }
 332
 333         /**
 334          * Convenience method that throws an exception unless it is called during a phase in which
 335          * resetting of global services is allowed. In general, services should not be reset
 336          * individually, since that may introduce inconsistencies.
 337          *
 338          * @since 1.28
 339          *
 340          * This method will throw an exception if:
 341          *
 342          * - self::$resetInProgress is false (to allow all services to be reset together
 343          *   via resetGlobalInstance)
 344          * - and MEDIAWIKI_INSTALL is not defined (to allow services to be reset during installation)
 345          * - and MW_PHPUNIT_TEST is not defined (to allow services to be reset during testing)
 346          *
 347          * This method is intended to be used to safeguard against accidentally resetting
 348          * global service instances that are not yet managed by MediaWikiServices. It is
 349          * defined here in the MediaWikiServices services class to have a central place
 350          * for managing service bootstrapping and resetting.
 351          *
 352          * @param string $method the name of the caller method, as given by __METHOD__.
 353          *
 354          * @throws MWException if called outside bootstrap mode.
 355          *
 356          * @see resetGlobalInstance()
 357          * @see forceGlobalInstance()
 358          * @see disableStorageBackend()
 359          */
 360         public static function failIfResetNotAllowed( $method ) {
 361                 if ( !defined( 'MW_PHPUNIT_TEST' )
 362                         && !defined( 'MW_PARSER_TEST' )
 363                         && !defined( 'MEDIAWIKI_INSTALL' )
 364                         && !defined( 'RUN_MAINTENANCE_IF_MAIN' )
 365                         && defined( 'MW_SERVICE_BOOTSTRAP_COMPLETE' )
 366                 ) {
 367                         throw new MWException( $method . ' may only be called during bootstrapping and unit tests!' );
 368                 }
 369         }
 370
 371         /**
 372          * @param Config $config The Config object to be registered as the 'BootstrapConfig' service.
 373          *        This has to contain at least the information needed to set up the 'ConfigFactory'
 374          *        service.
 375          */
 376         public function __construct( Config $config ) {
 377                 parent::__construct();
 378
 379                 // Register the given Config object as the bootstrap config service.
 380                 $this->defineService( 'BootstrapConfig', function() use ( $config ) {
 381                         return $config;
 382                 } );
 383         }
 384
 385         // CONVENIENCE GETTERS ////////////////////////////////////////////////////
 386
 387         /**
 388          * Returns the Config object containing the bootstrap configuration.
 389          * Bootstrap configuration would typically include database credentials
 390          * and other information that may be needed before the ConfigFactory
 391          * service can be instantiated.
 392          *
 393          * @note This should only be used during bootstrapping, in particular
 394          * when creating the MainConfig service. Application logic should
 395          * use getMainConfig() to get a Config instances.
 396          *
 397          * @since 1.27
 398          * @return Config
 399          */
 400         public function getBootstrapConfig() {
 401                 return $this->getService( 'BootstrapConfig' );
 402         }
 403
 404         /**
 405          * @since 1.27
 406          * @return ConfigFactory
 407          */
 408         public function getConfigFactory() {
 409                 return $this->getService( 'ConfigFactory' );
 410         }
 411
 412         /**
 413          * Returns the Config object that provides configuration for MediaWiki core.
 414          * This may or may not be the same object that is returned by getBootstrapConfig().
 415          *
 416          * @since 1.27
 417          * @return Config
 418          */
 419         public function getMainConfig() {
 420                 return $this->getService( 'MainConfig' );
 421         }
 422
 423         /**
 424          * @since 1.27
 425          * @return SiteLookup
 426          */
 427         public function getSiteLookup() {
 428                 return $this->getService( 'SiteLookup' );
 429         }
 430
 431         /**
 432          * @since 1.27
 433          * @return SiteStore
 434          */
 435         public function getSiteStore() {
 436                 return $this->getService( 'SiteStore' );
 437         }
 438
 439         /**
 440          * @since 1.28
 441          * @return InterwikiLookup
 442          */
 443         public function getInterwikiLookup() {
 444                 return $this->getService( 'InterwikiLookup' );
 445         }
 446
 447         /**
 448          * @since 1.27
 449          * @return StatsdDataFactory
 450          */
 451         public function getStatsdDataFactory() {
 452                 return $this->getService( 'StatsdDataFactory' );
 453         }
 454
 455         /**
 456          * @since 1.27
 457          * @return EventRelayerGroup
 458          */
 459         public function getEventRelayerGroup() {
 460                 return $this->getService( 'EventRelayerGroup' );
 461         }
 462
 463         /**
 464          * @since 1.27
 465          * @return SearchEngine
 466          */
 467         public function newSearchEngine() {
 468                 // New engine object every time, since they keep state
 469                 return $this->getService( 'SearchEngineFactory' )->create();
 470         }
 471
 472         /**
 473          * @since 1.27
 474          * @return SearchEngineFactory
 475          */
 476         public function getSearchEngineFactory() {
 477                 return $this->getService( 'SearchEngineFactory' );
 478         }
 479
 480         /**
 481          * @since 1.27
 482          * @return SearchEngineConfig
 483          */
 484         public function getSearchEngineConfig() {
 485                 return $this->getService( 'SearchEngineConfig' );
 486         }
 487
 488         /**
 489          * @since 1.27
 490          * @return SkinFactory
 491          */
 492         public function getSkinFactory() {
 493                 return $this->getService( 'SkinFactory' );
 494         }
 495
 496         /**
 497          * @since 1.28
 498          * @return LBFactory
 499          */
 500         public function getDBLoadBalancerFactory() {
 501                 return $this->getService( 'DBLoadBalancerFactory' );
 502         }
 503
 504         /**
 505          * @since 1.28
 506          * @return LoadBalancer The main DB load balancer for the local wiki.
 507          */
 508         public function getDBLoadBalancer() {
 509                 return $this->getService( 'DBLoadBalancer' );
 510         }
 511
 512         /**
 513          * @since 1.28
 514          * @return WatchedItemStore
 515          */
 516         public function getWatchedItemStore() {
 517                 return $this->getService( 'WatchedItemStore' );
 518         }
 519
 520         /**
 521          * @since 1.28
 522          * @return WatchedItemQueryService
 523          */
 524         public function getWatchedItemQueryService() {
 525                 return $this->getService( 'WatchedItemQueryService' );
 526         }
 527
 528         /**
 529          * @since 1.28
 530          * @return CryptRand
 531          */
 532         public function getCryptRand() {
 533                 return $this->getService( 'CryptRand' );
 534         }
 535
 536         /**
 537          * @since 1.28
 538          * @return CryptHKDF
 539          */
 540         public function getCryptHKDF() {
 541                 return $this->getService( 'CryptHKDF' );
 542         }
 543
 544         /**
 545          * @since 1.28
 546          * @return MediaHandlerFactory
 547          */
 548         public function getMediaHandlerFactory() {
 549                 return $this->getService( 'MediaHandlerFactory' );
 550         }
 551
 552         /**
 553          * @since 1.28
 554          * @return MimeAnalyzer
 555          */
 556         public function getMimeAnalyzer() {
 557                 return $this->getService( 'MimeAnalyzer' );
 558         }
 559
 560         /**
 561          * @since 1.28
 562          * @return ProxyLookup
 563          */
 564         public function getProxyLookup() {
 565                 return $this->getService( 'ProxyLookup' );
 566         }
 567
 568         /**
 569          * @since 1.29
 570          * @return Parser
 571          */
 572         public function getParser() {
 573                 return $this->getService( 'Parser' );
 574         }
 575
 576         /**
 577          * @since 1.28
 578          * @return GenderCache
 579          */
 580         public function getGenderCache() {
 581                 return $this->getService( 'GenderCache' );
 582         }
 583
 584         /**
 585          * @since 1.28
 586          * @return LinkCache
 587          */
 588         public function getLinkCache() {
 589                 return $this->getService( 'LinkCache' );
 590         }
 591
 592         /**
 593          * @since 1.28
 594          * @return LinkRendererFactory
 595          */
 596         public function getLinkRendererFactory() {
 597                 return $this->getService( 'LinkRendererFactory' );
 598         }
 599
 600         /**
 601          * LinkRenderer instance that can be used
 602          * if no custom options are needed
 603          *
 604          * @since 1.28
 605          * @return LinkRenderer
 606          */
 607         public function getLinkRenderer() {
 608                 return $this->getService( 'LinkRenderer' );
 609         }
 610
 611         /**
 612          * @since 1.28
 613          * @return TitleFormatter
 614          */
 615         public function getTitleFormatter() {
 616                 return $this->getService( 'TitleFormatter' );
 617         }
 618
 619         /**
 620          * @since 1.28
 621          * @return TitleParser
 622          */
 623         public function getTitleParser() {
 624                 return $this->getService( 'TitleParser' );
 625         }
 626
 627         /**
 628          * @since 1.28
 629          * @return \BagOStuff
 630          */
 631         public function getMainObjectStash() {
 632                 return $this->getService( 'MainObjectStash' );
 633         }
 634
 635         /**
 636          * @since 1.28
 637          * @return \WANObjectCache
 638          */
 639         public function getMainWANObjectCache() {
 640                 return $this->getService( 'MainWANObjectCache' );
 641         }
 642
 643         /**
 644          * @since 1.28
 645          * @return \BagOStuff
 646          */
 647         public function getLocalServerObjectCache() {
 648                 return $this->getService( 'LocalServerObjectCache' );
 649         }
 650
 651         /**
 652          * @since 1.28
 653          * @return VirtualRESTServiceClient
 654          */
 655         public function getVirtualRESTServiceClient() {
 656                 return $this->getService( 'VirtualRESTServiceClient' );
 657         }
 658
 659         ///////////////////////////////////////////////////////////////////////////
 660         // NOTE: When adding a service getter here, don't forget to add a test
 661         // case for it in MediaWikiServicesTest::provideGetters() and in
 662         // MediaWikiServicesTest::provideGetService()!
 663         ///////////////////////////////////////////////////////////////////////////
 664
 665 }