includes/resourceloader/ResourceLoaderModule.php

   1 <?php
   2 /**
   3  * Abstraction for ResourceLoader modules.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Trevor Parscal
  22  * @author Roan Kattouw
  23  */
  24
  25 use MediaWiki\MediaWikiServices;
  26 use Psr\Log\LoggerAwareInterface;
  27 use Psr\Log\LoggerInterface;
  28 use Psr\Log\NullLogger;
  29 use Wikimedia\RelPath;
  30 use Wikimedia\ScopedCallback;
  31
  32 /**
  33  * Abstraction for ResourceLoader modules, with name registration and maxage functionality.
  34  */
  35 abstract class ResourceLoaderModule implements LoggerAwareInterface {
  36         # Type of resource
  37         const TYPE_SCRIPTS = 'scripts';
  38         const TYPE_STYLES = 'styles';
  39         const TYPE_COMBINED = 'combined';
  40
  41         # Desired load type
  42         // Module only has styles (loaded via <style> or <link rel=stylesheet>)
  43         const LOAD_STYLES = 'styles';
  44         // Module may have other resources (loaded via mw.loader from a script)
  45         const LOAD_GENERAL = 'general';
  46
  47         # sitewide core module like a skin file or jQuery component
  48         const ORIGIN_CORE_SITEWIDE = 1;
  49
  50         # per-user module generated by the software
  51         const ORIGIN_CORE_INDIVIDUAL = 2;
  52
  53         # sitewide module generated from user-editable files, like MediaWiki:Common.js, or
  54         # modules accessible to multiple users, such as those generated by the Gadgets extension.
  55         const ORIGIN_USER_SITEWIDE = 3;
  56
  57         # per-user module generated from user-editable files, like User:Me/vector.js
  58         const ORIGIN_USER_INDIVIDUAL = 4;
  59
  60         # an access constant; make sure this is kept as the largest number in this group
  61         const ORIGIN_ALL = 10;
  62
  63         # script and style modules form a hierarchy of trustworthiness, with core modules like
  64         # skins and jQuery as most trustworthy, and user scripts as least trustworthy.  We can
  65         # limit the types of scripts and styles we allow to load on, say, sensitive special
  66         # pages like Special:UserLogin and Special:Preferences
  67         protected $origin = self::ORIGIN_CORE_SITEWIDE;
  68
  69         protected $name = null;
  70         protected $targets = [ 'desktop' ];
  71
  72         // In-object cache for file dependencies
  73         protected $fileDeps = [];
  74         // In-object cache for message blob (keyed by language)
  75         protected $msgBlobs = [];
  76         // In-object cache for version hash
  77         protected $versionHash = [];
  78         // In-object cache for module content
  79         protected $contents = [];
  80
  81         /**
  82          * @var Config
  83          */
  84         protected $config;
  85
  86         /**
  87          * @var array|bool
  88          */
  89         protected $deprecated = false;
  90
  91         /**
  92          * @var LoggerInterface
  93          */
  94         protected $logger;
  95
  96         /**
  97          * Get this module's name. This is set when the module is registered
  98          * with ResourceLoader::register()
  99          *
 100          * @return string|null Name (string) or null if no name was set
 101          */
 102         public function getName() {
 103                 return $this->name;
 104         }
 105
 106         /**
 107          * Set this module's name. This is called by ResourceLoader::register()
 108          * when registering the module. Other code should not call this.
 109          *
 110          * @param string $name
 111          */
 112         public function setName( $name ) {
 113                 $this->name = $name;
 114         }
 115
 116         /**
 117          * Get this module's origin. This is set when the module is registered
 118          * with ResourceLoader::register()
 119          *
 120          * @return int ResourceLoaderModule class constant, the subclass default
 121          *     if not set manually
 122          */
 123         public function getOrigin() {
 124                 return $this->origin;
 125         }
 126
 127         /**
 128          * @param ResourceLoaderContext $context
 129          * @return bool
 130          */
 131         public function getFlip( $context ) {
 132                 return MediaWikiServices::getInstance()->getContentLanguage()->getDir() !==
 133                         $context->getDirection();
 134         }
 135
 136         /**
 137          * Get JS representing deprecation information for the current module if available
 138          *
 139          * @return string JavaScript code
 140          */
 141         public function getDeprecationInformation() {
 142                 $deprecationInfo = $this->deprecated;
 143                 if ( $deprecationInfo ) {
 144                         $name = $this->getName();
 145                         $warning = 'This page is using the deprecated ResourceLoader module "' . $name . '".';
 146                         if ( is_string( $deprecationInfo ) ) {
 147                                 $warning .= "\n" . $deprecationInfo;
 148                         }
 149                         return 'mw.log.warn(' . ResourceLoader::encodeJsonForScript( $warning ) . ');';
 150                 } else {
 151                         return '';
 152                 }
 153         }
 154
 155         /**
 156          * Get all JS for this module for a given language and skin.
 157          * Includes all relevant JS except loader scripts.
 158          *
 159          * For "plain" script modules, this should return a string with JS code. For multi-file modules
 160          * where require() is used to load one file from another file, this should return an array
 161          * structured as follows:
 162          * [
 163          *     'files' => [
 164          *         'file1.js' => [ 'type' => 'script', 'content' => 'JS code' ],
 165          *         'file2.js' => [ 'type' => 'script', 'content' => 'JS code' ],
 166          *         'data.json' => [ 'type' => 'data', 'content' => array ]
 167          *     ],
 168          *     'main' => 'file1.js'
 169          * ]
 170          *
 171          * @param ResourceLoaderContext $context
 172          * @return string|array JavaScript code (string), or multi-file structure described above (array)
 173          */
 174         public function getScript( ResourceLoaderContext $context ) {
 175                 // Stub, override expected
 176                 return '';
 177         }
 178
 179         /**
 180          * Takes named templates by the module and returns an array mapping.
 181          *
 182          * @return string[] Array of templates mapping template alias to content
 183          */
 184         public function getTemplates() {
 185                 // Stub, override expected.
 186                 return [];
 187         }
 188
 189         /**
 190          * @return Config
 191          * @since 1.24
 192          */
 193         public function getConfig() {
 194                 if ( $this->config === null ) {
 195                         // Ugh, fall back to default
 196                         $this->config = MediaWikiServices::getInstance()->getMainConfig();
 197                 }
 198
 199                 return $this->config;
 200         }
 201
 202         /**
 203          * @param Config $config
 204          * @since 1.24
 205          */
 206         public function setConfig( Config $config ) {
 207                 $this->config = $config;
 208         }
 209
 210         /**
 211          * @since 1.27
 212          * @param LoggerInterface $logger
 213          * @return null
 214          */
 215         public function setLogger( LoggerInterface $logger ) {
 216                 $this->logger = $logger;
 217         }
 218
 219         /**
 220          * @since 1.27
 221          * @return LoggerInterface
 222          */
 223         protected function getLogger() {
 224                 if ( !$this->logger ) {
 225                         $this->logger = new NullLogger();
 226                 }
 227                 return $this->logger;
 228         }
 229
 230         /**
 231          * Get the URL or URLs to load for this module's JS in debug mode.
 232          * The default behavior is to return a load.php?only=scripts URL for
 233          * the module, but file-based modules will want to override this to
 234          * load the files directly.
 235          *
 236          * This function is called only when 1) we're in debug mode, 2) there
 237          * is no only= parameter and 3) supportsURLLoading() returns true.
 238          * #2 is important to prevent an infinite loop, therefore this function
 239          * MUST return either an only= URL or a non-load.php URL.
 240          *
 241          * @param ResourceLoaderContext $context
 242          * @return array Array of URLs
 243          */
 244         public function getScriptURLsForDebug( ResourceLoaderContext $context ) {
 245                 $resourceLoader = $context->getResourceLoader();
 246                 $derivative = new DerivativeResourceLoaderContext( $context );
 247                 $derivative->setModules( [ $this->getName() ] );
 248                 $derivative->setOnly( 'scripts' );
 249                 $derivative->setDebug( true );
 250
 251                 $url = $resourceLoader->createLoaderURL(
 252                         $this->getSource(),
 253                         $derivative
 254                 );
 255
 256                 return [ $url ];
 257         }
 258
 259         /**
 260          * Whether this module supports URL loading. If this function returns false,
 261          * getScript() will be used even in cases (debug mode, no only param) where
 262          * getScriptURLsForDebug() would normally be used instead.
 263          * @return bool
 264          */
 265         public function supportsURLLoading() {
 266                 return true;
 267         }
 268
 269         /**
 270          * Get all CSS for this module for a given skin.
 271          *
 272          * @param ResourceLoaderContext $context
 273          * @return array List of CSS strings or array of CSS strings keyed by media type.
 274          *  like [ 'screen' => '.foo { width: 0 }' ];
 275          *  or [ 'screen' => [ '.foo { width: 0 }' ] ];
 276          */
 277         public function getStyles( ResourceLoaderContext $context ) {
 278                 // Stub, override expected
 279                 return [];
 280         }
 281
 282         /**
 283          * Get the URL or URLs to load for this module's CSS in debug mode.
 284          * The default behavior is to return a load.php?only=styles URL for
 285          * the module, but file-based modules will want to override this to
 286          * load the files directly. See also getScriptURLsForDebug()
 287          *
 288          * @param ResourceLoaderContext $context
 289          * @return array [ mediaType => [ URL1, URL2, ... ], ... ]
 290          */
 291         public function getStyleURLsForDebug( ResourceLoaderContext $context ) {
 292                 $resourceLoader = $context->getResourceLoader();
 293                 $derivative = new DerivativeResourceLoaderContext( $context );
 294                 $derivative->setModules( [ $this->getName() ] );
 295                 $derivative->setOnly( 'styles' );
 296                 $derivative->setDebug( true );
 297
 298                 $url = $resourceLoader->createLoaderURL(
 299                         $this->getSource(),
 300                         $derivative
 301                 );
 302
 303                 return [ 'all' => [ $url ] ];
 304         }
 305
 306         /**
 307          * Get the messages needed for this module.
 308          *
 309          * To get a JSON blob with messages, use MessageBlobStore::get()
 310          *
 311          * @return array List of message keys. Keys may occur more than once
 312          */
 313         public function getMessages() {
 314                 // Stub, override expected
 315                 return [];
 316         }
 317
 318         /**
 319          * Get the group this module is in.
 320          *
 321          * @return string Group name
 322          */
 323         public function getGroup() {
 324                 // Stub, override expected
 325                 return null;
 326         }
 327
 328         /**
 329          * Get the source of this module. Should only be overridden for foreign modules.
 330          *
 331          * @return string Source name, 'local' for local modules
 332          */
 333         public function getSource() {
 334                 // Stub, override expected
 335                 return 'local';
 336         }
 337
 338         /**
 339          * Get a list of modules this module depends on.
 340          *
 341          * Dependency information is taken into account when loading a module
 342          * on the client side.
 343          *
 344          * Note: It is expected that $context will be made non-optional in the near
 345          * future.
 346          *
 347          * @param ResourceLoaderContext|null $context
 348          * @return array List of module names as strings
 349          */
 350         public function getDependencies( ResourceLoaderContext $context = null ) {
 351                 // Stub, override expected
 352                 return [];
 353         }
 354
 355         /**
 356          * Get target(s) for the module, eg ['desktop'] or ['desktop', 'mobile']
 357          *
 358          * @return array Array of strings
 359          */
 360         public function getTargets() {
 361                 return $this->targets;
 362         }
 363
 364         /**
 365          * Get the module's load type.
 366          *
 367          * @since 1.28
 368          * @return string ResourceLoaderModule LOAD_* constant
 369          */
 370         public function getType() {
 371                 return self::LOAD_GENERAL;
 372         }
 373
 374         /**
 375          * Get the skip function.
 376          *
 377          * Modules that provide fallback functionality can provide a "skip function". This
 378          * function, if provided, will be passed along to the module registry on the client.
 379          * When this module is loaded (either directly or as a dependency of another module),
 380          * then this function is executed first. If the function returns true, the module will
 381          * instantly be considered "ready" without requesting the associated module resources.
 382          *
 383          * The value returned here must be valid javascript for execution in a private function.
 384          * It must not contain the "function () {" and "}" wrapper though.
 385          *
 386          * @return string|null A JavaScript function body returning a boolean value, or null
 387          */
 388         public function getSkipFunction() {
 389                 return null;
 390         }
 391
 392         /**
 393          * Get the files this module depends on indirectly for a given skin.
 394          *
 395          * These are only image files referenced by the module's stylesheet.
 396          *
 397          * @param ResourceLoaderContext $context
 398          * @return array List of files
 399          */
 400         protected function getFileDependencies( ResourceLoaderContext $context ) {
 401                 $vary = self::getVary( $context );
 402
 403                 // Try in-object cache first
 404                 if ( !isset( $this->fileDeps[$vary] ) ) {
 405                         $dbr = wfGetDB( DB_REPLICA );
 406                         $deps = $dbr->selectField( 'module_deps',
 407                                 'md_deps',
 408                                 [
 409                                         'md_module' => $this->getName(),
 410                                         'md_skin' => $vary,
 411                                 ],
 412                                 __METHOD__
 413                         );
 414
 415                         if ( !is_null( $deps ) ) {
 416                                 $this->fileDeps[$vary] = self::expandRelativePaths(
 417                                         (array)json_decode( $deps, true )
 418                                 );
 419                         } else {
 420                                 $this->fileDeps[$vary] = [];
 421                         }
 422                 }
 423                 return $this->fileDeps[$vary];
 424         }
 425
 426         /**
 427          * Set in-object cache for file dependencies.
 428          *
 429          * This is used to retrieve data in batches. See ResourceLoader::preloadModuleInfo().
 430          * To save the data, use saveFileDependencies().
 431          *
 432          * @param ResourceLoaderContext $context
 433          * @param string[] $files Array of file names
 434          */
 435         public function setFileDependencies( ResourceLoaderContext $context, $files ) {
 436                 $vary = self::getVary( $context );
 437                 $this->fileDeps[$vary] = $files;
 438         }
 439
 440         /**
 441          * Set the files this module depends on indirectly for a given skin.
 442          *
 443          * @since 1.27
 444          * @param ResourceLoaderContext $context
 445          * @param array $localFileRefs List of files
 446          */
 447         protected function saveFileDependencies( ResourceLoaderContext $context, $localFileRefs ) {
 448                 try {
 449                         // Related bugs and performance considerations:
 450                         // 1. Don't needlessly change the database value with the same list in a
 451                         //    different order or with duplicates.
 452                         // 2. Use relative paths to avoid ghost entries when $IP changes. (T111481)
 453                         // 3. Don't needlessly replace the database with the same value
 454                         //    just because $IP changed (e.g. when upgrading a wiki).
 455                         // 4. Don't create an endless replace loop on every request for this
 456                         //    module when '../' is used anywhere. Even though both are expanded
 457                         //    (one expanded by getFileDependencies from the DB, the other is
 458                         //    still raw as originally read by RL), the latter has not
 459                         //    been normalized yet.
 460
 461                         // Normalise
 462                         $localFileRefs = array_values( array_unique( $localFileRefs ) );
 463                         sort( $localFileRefs );
 464                         $localPaths = self::getRelativePaths( $localFileRefs );
 465                         $storedPaths = self::getRelativePaths( $this->getFileDependencies( $context ) );
 466
 467                         if ( $localPaths === $storedPaths ) {
 468                                 // Unchanged. Avoid needless database query (especially master conn!).
 469                                 return;
 470                         }
 471
 472                         // The file deps list has changed, we want to update it.
 473                         $vary = self::getVary( $context );
 474                         $cache = ObjectCache::getLocalClusterInstance();
 475                         $key = $cache->makeKey( __METHOD__, $this->getName(), $vary );
 476                         $scopeLock = $cache->getScopedLock( $key, 0 );
 477                         if ( !$scopeLock ) {
 478                                 // Another request appears to be doing this update already.
 479                                 // Avoid write slams (T124649).
 480                                 return;
 481                         }
 482
 483                         // No needless escaping as this isn't HTML output.
 484                         // Only stored in the database and parsed in PHP.
 485                         $deps = json_encode( $localPaths, JSON_UNESCAPED_SLASHES );
 486                         $dbw = wfGetDB( DB_MASTER );
 487                         $dbw->upsert( 'module_deps',
 488                                 [
 489                                         'md_module' => $this->getName(),
 490                                         'md_skin' => $vary,
 491                                         'md_deps' => $deps,
 492                                 ],
 493                                 [ [ 'md_module', 'md_skin' ] ],
 494                                 [
 495                                         'md_deps' => $deps,
 496                                 ],
 497                                 __METHOD__
 498                         );
 499
 500                         if ( $dbw->trxLevel() ) {
 501                                 $dbw->onTransactionResolution(
 502                                         function () use ( &$scopeLock ) {
 503                                                 ScopedCallback::consume( $scopeLock ); // release after commit
 504                                         },
 505                                         __METHOD__
 506                                 );
 507                         }
 508                 } catch ( Exception $e ) {
 509                         // Probably a DB failure. Either the read query from getFileDependencies(),
 510                         // or the write query above.
 511                         wfDebugLog( 'resourceloader', __METHOD__ . ": failed to update DB: $e" );
 512                 }
 513         }
 514
 515         /**
 516          * Make file paths relative to MediaWiki directory.
 517          *
 518          * This is used to make file paths safe for storing in a database without the paths
 519          * becoming stale or incorrect when MediaWiki is moved or upgraded (T111481).
 520          *
 521          * @since 1.27
 522          * @param array $filePaths
 523          * @return array
 524          */
 525         public static function getRelativePaths( array $filePaths ) {
 526                 global $IP;
 527                 return array_map( function ( $path ) use ( $IP ) {
 528                         return RelPath::getRelativePath( $path, $IP );
 529                 }, $filePaths );
 530         }
 531
 532         /**
 533          * Expand directories relative to $IP.
 534          *
 535          * @since 1.27
 536          * @param array $filePaths
 537          * @return array
 538          */
 539         public static function expandRelativePaths( array $filePaths ) {
 540                 global $IP;
 541                 return array_map( function ( $path ) use ( $IP ) {
 542                         return RelPath::joinPath( $IP, $path );
 543                 }, $filePaths );
 544         }
 545
 546         /**
 547          * Get the hash of the message blob.
 548          *
 549          * @since 1.27
 550          * @param ResourceLoaderContext $context
 551          * @return string|null JSON blob or null if module has no messages
 552          */
 553         protected function getMessageBlob( ResourceLoaderContext $context ) {
 554                 if ( !$this->getMessages() ) {
 555                         // Don't bother consulting MessageBlobStore
 556                         return null;
 557                 }
 558                 // Message blobs may only vary language, not by context keys
 559                 $lang = $context->getLanguage();
 560                 if ( !isset( $this->msgBlobs[$lang] ) ) {
 561                         $this->getLogger()->warning( 'Message blob for {module} should have been preloaded', [
 562                                 'module' => $this->getName(),
 563                         ] );
 564                         $store = $context->getResourceLoader()->getMessageBlobStore();
 565                         $this->msgBlobs[$lang] = $store->getBlob( $this, $lang );
 566                 }
 567                 return $this->msgBlobs[$lang];
 568         }
 569
 570         /**
 571          * Set in-object cache for message blobs.
 572          *
 573          * Used to allow fetching of message blobs in batches. See ResourceLoader::preloadModuleInfo().
 574          *
 575          * @since 1.27
 576          * @param string|null $blob JSON blob or null
 577          * @param string $lang Language code
 578          */
 579         public function setMessageBlob( $blob, $lang ) {
 580                 $this->msgBlobs[$lang] = $blob;
 581         }
 582
 583         /**
 584          * Get headers to send as part of a module web response.
 585          *
 586          * It is not supported to send headers through this method that are
 587          * required to be unique or otherwise sent once in an HTTP response
 588          * because clients may make batch requests for multiple modules (as
 589          * is the default behaviour for ResourceLoader clients).
 590          *
 591          * For exclusive or aggregated headers, see ResourceLoader::sendResponseHeaders().
 592          *
 593          * @since 1.30
 594          * @param ResourceLoaderContext $context
 595          * @return string[] Array of HTTP response headers
 596          */
 597         final public function getHeaders( ResourceLoaderContext $context ) {
 598                 $headers = [];
 599
 600                 $formattedLinks = [];
 601                 foreach ( $this->getPreloadLinks( $context ) as $url => $attribs ) {
 602                         $link = "<{$url}>;rel=preload";
 603                         foreach ( $attribs as $key => $val ) {
 604                                 $link .= ";{$key}={$val}";
 605                         }
 606                         $formattedLinks[] = $link;
 607                 }
 608                 if ( $formattedLinks ) {
 609                         $headers[] = 'Link: ' . implode( ',', $formattedLinks );
 610                 }
 611
 612                 return $headers;
 613         }
 614
 615         /**
 616          * Get a list of resources that web browsers may preload.
 617          *
 618          * Behaviour of rel=preload link is specified at <https://www.w3.org/TR/preload/>.
 619          *
 620          * Use case for ResourceLoader originally part of T164299.
 621          *
 622          * @par Example
 623          * @code
 624          *     protected function getPreloadLinks() {
 625          *         return [
 626          *             'https://example.org/script.js' => [ 'as' => 'script' ],
 627          *             'https://example.org/image.png' => [ 'as' => 'image' ],
 628          *         ];
 629          *     }
 630          * @endcode
 631          *
 632          * @par Example using HiDPI image variants
 633          * @code
 634          *     protected function getPreloadLinks() {
 635          *         return [
 636          *             'https://example.org/logo.png' => [
 637          *                 'as' => 'image',
 638          *                 'media' => 'not all and (min-resolution: 2dppx)',
 639          *             ],
 640          *             'https://example.org/logo@2x.png' => [
 641          *                 'as' => 'image',
 642          *                 'media' => '(min-resolution: 2dppx)',
 643          *             ],
 644          *         ];
 645          *     }
 646          * @endcode
 647          *
 648          * @see ResourceLoaderModule::getHeaders
 649          * @since 1.30
 650          * @param ResourceLoaderContext $context
 651          * @return array Keyed by url, values must be an array containing
 652          *  at least an 'as' key. Optionally a 'media' key as well.
 653          */
 654         protected function getPreloadLinks( ResourceLoaderContext $context ) {
 655                 return [];
 656         }
 657
 658         /**
 659          * Get module-specific LESS variables, if any.
 660          *
 661          * @since 1.27
 662          * @param ResourceLoaderContext $context
 663          * @return array Module-specific LESS variables.
 664          */
 665         protected function getLessVars( ResourceLoaderContext $context ) {
 666                 return [];
 667         }
 668
 669         /**
 670          * Get an array of this module's resources. Ready for serving to the web.
 671          *
 672          * @since 1.26
 673          * @param ResourceLoaderContext $context
 674          * @return array
 675          */
 676         public function getModuleContent( ResourceLoaderContext $context ) {
 677                 $contextHash = $context->getHash();
 678                 // Cache this expensive operation. This calls builds the scripts, styles, and messages
 679                 // content which typically involves filesystem and/or database access.
 680                 if ( !array_key_exists( $contextHash, $this->contents ) ) {
 681                         $this->contents[$contextHash] = $this->buildContent( $context );
 682                 }
 683                 return $this->contents[$contextHash];
 684         }
 685
 686         /**
 687          * Bundle all resources attached to this module into an array.
 688          *
 689          * @since 1.26
 690          * @param ResourceLoaderContext $context
 691          * @return array
 692          */
 693         final protected function buildContent( ResourceLoaderContext $context ) {
 694                 $rl = $context->getResourceLoader();
 695                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 696                 $statStart = microtime( true );
 697
 698                 // This MUST build both scripts and styles, regardless of whether $context->getOnly()
 699                 // is 'scripts' or 'styles' because the result is used by getVersionHash which
 700                 // must be consistent regardless of the 'only' filter on the current request.
 701                 // Also, when introducing new module content resources (e.g. templates, headers),
 702                 // these should only be included in the array when they are non-empty so that
 703                 // existing modules not using them do not get their cache invalidated.
 704                 $content = [];
 705
 706                 // Scripts
 707                 // If we are in debug mode, we'll want to return an array of URLs if possible
 708                 // However, we can't do this if the module doesn't support it.
 709                 // We also can't do this if there is an only= parameter, because we have to give
 710                 // the module a way to return a load.php URL without causing an infinite loop
 711                 if ( $context->getDebug() && !$context->getOnly() && $this->supportsURLLoading() ) {
 712                         $scripts = $this->getScriptURLsForDebug( $context );
 713                 } else {
 714                         $scripts = $this->getScript( $context );
 715                         // Make the script safe to concatenate by making sure there is at least one
 716                         // trailing new line at the end of the content. Previously, this looked for
 717                         // a semi-colon instead, but that breaks concatenation if the semicolon
 718                         // is inside a comment like "// foo();". Instead, simply use a
 719                         // line break as separator which matches JavaScript native logic for implicitly
 720                         // ending statements even if a semi-colon is missing.
 721                         // Bugs: T29054, T162719.
 722                         if ( is_string( $scripts )
 723                                 && strlen( $scripts )
 724                                 && substr( $scripts, -1 ) !== "\n"
 725                         ) {
 726                                 $scripts .= "\n";
 727                         }
 728                 }
 729                 $content['scripts'] = $scripts;
 730
 731                 $styles = [];
 732                 // Don't create empty stylesheets like [ '' => '' ] for modules
 733                 // that don't *have* any stylesheets (T40024).
 734                 $stylePairs = $this->getStyles( $context );
 735                 if ( count( $stylePairs ) ) {
 736                         // If we are in debug mode without &only= set, we'll want to return an array of URLs
 737                         // See comment near shouldIncludeScripts() for more details
 738                         if ( $context->getDebug() && !$context->getOnly() && $this->supportsURLLoading() ) {
 739                                 $styles = [
 740                                         'url' => $this->getStyleURLsForDebug( $context )
 741                                 ];
 742                         } else {
 743                                 // Minify CSS before embedding in mw.loader.implement call
 744                                 // (unless in debug mode)
 745                                 if ( !$context->getDebug() ) {
 746                                         foreach ( $stylePairs as $media => $style ) {
 747                                                 // Can be either a string or an array of strings.
 748                                                 if ( is_array( $style ) ) {
 749                                                         $stylePairs[$media] = [];
 750                                                         foreach ( $style as $cssText ) {
 751                                                                 if ( is_string( $cssText ) ) {
 752                                                                         $stylePairs[$media][] =
 753                                                                                 ResourceLoader::filter( 'minify-css', $cssText );
 754                                                                 }
 755                                                         }
 756                                                 } elseif ( is_string( $style ) ) {
 757                                                         $stylePairs[$media] = ResourceLoader::filter( 'minify-css', $style );
 758                                                 }
 759                                         }
 760                                 }
 761                                 // Wrap styles into @media groups as needed and flatten into a numerical array
 762                                 $styles = [
 763                                         'css' => $rl->makeCombinedStyles( $stylePairs )
 764                                 ];
 765                         }
 766                 }
 767                 $content['styles'] = $styles;
 768
 769                 // Messages
 770                 $blob = $this->getMessageBlob( $context );
 771                 if ( $blob ) {
 772                         $content['messagesBlob'] = $blob;
 773                 }
 774
 775                 $templates = $this->getTemplates();
 776                 if ( $templates ) {
 777                         $content['templates'] = $templates;
 778                 }
 779
 780                 $headers = $this->getHeaders( $context );
 781                 if ( $headers ) {
 782                         $content['headers'] = $headers;
 783                 }
 784
 785                 $statTiming = microtime( true ) - $statStart;
 786                 $statName = strtr( $this->getName(), '.', '_' );
 787                 $stats->timing( "resourceloader_build.all", 1000 * $statTiming );
 788                 $stats->timing( "resourceloader_build.$statName", 1000 * $statTiming );
 789
 790                 return $content;
 791         }
 792
 793         /**
 794          * Get a string identifying the current version of this module in a given context.
 795          *
 796          * Whenever anything happens that changes the module's response (e.g. scripts, styles, and
 797          * messages) this value must change. This value is used to store module responses in cache.
 798          * (Both client-side and server-side.)
 799          *
 800          * It is not recommended to override this directly. Use getDefinitionSummary() instead.
 801          * If overridden, one must call the parent getVersionHash(), append data and re-hash.
 802          *
 803          * This method should be quick because it is frequently run by ResourceLoaderStartUpModule to
 804          * propagate changes to the client and effectively invalidate cache.
 805          *
 806          * @since 1.26
 807          * @param ResourceLoaderContext $context
 808          * @return string Hash (should use ResourceLoader::makeHash)
 809          */
 810         public function getVersionHash( ResourceLoaderContext $context ) {
 811                 // Cache this somewhat expensive operation. Especially because some classes
 812                 // (e.g. startup module) iterate more than once over all modules to get versions.
 813                 $contextHash = $context->getHash();
 814                 if ( !array_key_exists( $contextHash, $this->versionHash ) ) {
 815                         if ( $this->enableModuleContentVersion() ) {
 816                                 // Detect changes directly by hashing the module contents.
 817                                 $str = json_encode( $this->getModuleContent( $context ) );
 818                         } else {
 819                                 // Infer changes based on definition and other metrics
 820                                 $summary = $this->getDefinitionSummary( $context );
 821                                 if ( !isset( $summary['_class'] ) ) {
 822                                         throw new LogicException( 'getDefinitionSummary must call parent method' );
 823                                 }
 824                                 $str = json_encode( $summary );
 825                         }
 826
 827                         $this->versionHash[$contextHash] = ResourceLoader::makeHash( $str );
 828                 }
 829                 return $this->versionHash[$contextHash];
 830         }
 831
 832         /**
 833          * Whether to generate version hash based on module content.
 834          *
 835          * If a module requires database or file system access to build the module
 836          * content, consider disabling this in favour of manually tracking relevant
 837          * aspects in getDefinitionSummary(). See getVersionHash() for how this is used.
 838          *
 839          * @return bool
 840          */
 841         public function enableModuleContentVersion() {
 842                 return false;
 843         }
 844
 845         /**
 846          * Get the definition summary for this module.
 847          *
 848          * This is the method subclasses are recommended to use to track values in their
 849          * version hash. Call this in getVersionHash() and pass it to e.g. json_encode.
 850          *
 851          * Subclasses must call the parent getDefinitionSummary() and build on that.
 852          * It is recommended that each subclass appends its own new array. This prevents
 853          * clashes or accidental overwrites of existing keys and gives each subclass
 854          * its own scope for simple array keys.
 855          *
 856          * @code
 857          *     $summary = parent::getDefinitionSummary( $context );
 858          *     $summary[] = [
 859          *         'foo' => 123,
 860          *         'bar' => 'quux',
 861          *     ];
 862          *     return $summary;
 863          * @endcode
 864          *
 865          * Return an array containing values from all significant properties of this
 866          * module's definition.
 867          *
 868          * Be careful not to normalise too much. Especially preserve the order of things
 869          * that carry significance in getScript and getStyles (T39812).
 870          *
 871          * Avoid including things that are insiginificant (e.g. order of message keys is
 872          * insignificant and should be sorted to avoid unnecessary cache invalidation).
 873          *
 874          * This data structure must exclusively contain arrays and scalars as values (avoid
 875          * object instances) to allow simple serialisation using json_encode.
 876          *
 877          * If modules have a hash or timestamp from another source, that may be incuded as-is.
 878          *
 879          * A number of utility methods are available to help you gather data. These are not
 880          * called by default and must be included by the subclass' getDefinitionSummary().
 881          *
 882          * - getMessageBlob()
 883          *
 884          * @since 1.23
 885          * @param ResourceLoaderContext $context
 886          * @return array|null
 887          */
 888         public function getDefinitionSummary( ResourceLoaderContext $context ) {
 889                 return [
 890                         '_class' => static::class,
 891                         // Make sure that when filter cache for minification is invalidated,
 892                         // we also change the HTTP urls and mw.loader.store keys (T176884).
 893                         '_cacheVersion' => ResourceLoader::CACHE_VERSION,
 894                 ];
 895         }
 896
 897         /**
 898          * Check whether this module is known to be empty. If a child class
 899          * has an easy and cheap way to determine that this module is
 900          * definitely going to be empty, it should override this method to
 901          * return true in that case. Callers may optimize the request for this
 902          * module away if this function returns true.
 903          * @param ResourceLoaderContext $context
 904          * @return bool
 905          */
 906         public function isKnownEmpty( ResourceLoaderContext $context ) {
 907                 return false;
 908         }
 909
 910         /**
 911          * Check whether this module should be embeded rather than linked
 912          *
 913          * Modules returning true here will be embedded rather than loaded by
 914          * ResourceLoaderClientHtml.
 915          *
 916          * @since 1.30
 917          * @param ResourceLoaderContext $context
 918          * @return bool
 919          */
 920         public function shouldEmbedModule( ResourceLoaderContext $context ) {
 921                 return $this->getGroup() === 'private';
 922         }
 923
 924         /** @var JSParser Lazy-initialized; use self::javaScriptParser() */
 925         private static $jsParser;
 926         private static $parseCacheVersion = 1;
 927
 928         /**
 929          * Validate a given script file; if valid returns the original source.
 930          * If invalid, returns replacement JS source that throws an exception.
 931          *
 932          * @param string $fileName
 933          * @param string $contents
 934          * @return string JS with the original, or a replacement error
 935          */
 936         protected function validateScriptFile( $fileName, $contents ) {
 937                 if ( !$this->getConfig()->get( 'ResourceLoaderValidateJS' ) ) {
 938                         return $contents;
 939                 }
 940                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
 941                 return $cache->getWithSetCallback(
 942                         $cache->makeGlobalKey(
 943                                 'resourceloader-jsparse',
 944                                 self::$parseCacheVersion,
 945                                 md5( $contents ),
 946                                 $fileName
 947                         ),
 948                         $cache::TTL_WEEK,
 949                         function () use ( $contents, $fileName ) {
 950                                 $parser = self::javaScriptParser();
 951                                 $err = null;
 952                                 try {
 953                                         Wikimedia\suppressWarnings();
 954                                         $parser->parse( $contents, $fileName, 1 );
 955                                 } catch ( Exception $e ) {
 956                                         $err = $e;
 957                                 } finally {
 958                                         Wikimedia\restoreWarnings();
 959                                 }
 960                                 if ( $err ) {
 961                                         // Send the error to the browser console client-side.
 962                                         // By returning this as replacement for the actual script,
 963                                         // we ensure modules are safe to load in a batch request,
 964                                         // without causing other unrelated modules to break.
 965                                         return 'mw.log.error(' .
 966                                                 Xml::encodeJsVar( 'JavaScript parse error: ' . $err->getMessage() ) .
 967                                                 ');';
 968                                 }
 969                                 return $contents;
 970                         }
 971                 );
 972         }
 973
 974         /**
 975          * @return JSParser
 976          */
 977         protected static function javaScriptParser() {
 978                 if ( !self::$jsParser ) {
 979                         self::$jsParser = new JSParser();
 980                 }
 981                 return self::$jsParser;
 982         }
 983
 984         /**
 985          * Safe version of filemtime(), which doesn't throw a PHP warning if the file doesn't exist.
 986          * Defaults to 1.
 987          *
 988          * @param string $filePath File path
 989          * @return int UNIX timestamp
 990          */
 991         protected static function safeFilemtime( $filePath ) {
 992                 Wikimedia\suppressWarnings();
 993                 $mtime = filemtime( $filePath ) ?: 1;
 994                 Wikimedia\restoreWarnings();
 995                 return $mtime;
 996         }
 997
 998         /**
 999          * Compute a non-cryptographic string hash of a file's contents.
1000          * If the file does not exist or cannot be read, returns an empty string.
1001          *
1002          * @since 1.26 Uses MD4 instead of SHA1.
1003          * @param string $filePath File path
1004          * @return string Hash
1005          */
1006         protected static function safeFileHash( $filePath ) {
1007                 return FileContentsHasher::getFileContentsHash( $filePath );
1008         }
1009
1010         /**
1011          * Get vary string.
1012          *
1013          * @internal For internal use only.
1014          * @param ResourceLoaderContext $context
1015          * @return string Vary string
1016          */
1017         public static function getVary( ResourceLoaderContext $context ) {
1018                 return implode( '|', [
1019                         $context->getSkin(),
1020                         $context->getLanguage(),
1021                 ] );
1022         }
1023 }