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