includes/MediaWikiServices.php

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