includes/resourceloader/ResourceLoader.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  * @author Roan Kattouw
  20  * @author Trevor Parscal
  21  */
  22
  23 use MediaWiki\MediaWikiServices;
  24 use Psr\Log\LoggerAwareInterface;
  25 use Psr\Log\LoggerInterface;
  26 use Psr\Log\NullLogger;
  27 use Wikimedia\Rdbms\DBConnectionError;
  28 use Wikimedia\WrappedString;
  29
  30 /**
  31  * @defgroup ResourceLoader ResourceLoader
  32  *
  33  * For higher level documentation, see <https://www.mediawiki.org/wiki/ResourceLoader/Architecture>.
  34  */
  35
  36 /**
  37  * ResourceLoader is a loading system for JavaScript and CSS resources.
  38  *
  39  * For higher level documentation, see <https://www.mediawiki.org/wiki/ResourceLoader/Architecture>.
  40  *
  41  * @ingroup ResourceLoader
  42  * @since 1.17
  43  */
  44 class ResourceLoader implements LoggerAwareInterface {
  45         /** @var Config */
  46         protected $config;
  47         /** @var MessageBlobStore */
  48         protected $blobStore;
  49
  50         /** @var LoggerInterface */
  51         private $logger;
  52
  53         /** @var ResourceLoaderModule[] Map of (module name => ResourceLoaderModule) */
  54         protected $modules = [];
  55         /** @var array[] Map of (module name => associative info array) */
  56         protected $moduleInfos = [];
  57         /**
  58          * Associative array mapping framework ids to a list of names of test suite modules
  59          * like [ 'qunit' => [ 'mediawiki.tests.qunit.suites', 'ext.foo.tests', ... ], ... ]
  60          * @var array
  61          */
  62         protected $testModuleNames = [];
  63         /** @var string[] List of module names that contain QUnit test suites */
  64         protected $testSuiteModuleNames = [];
  65
  66         /** @var array Map of (source => path); E.g. [ 'source-id' => 'http://.../load.php' ] */
  67         protected $sources = [];
  68         /** @var array Errors accumulated during current respond() call */
  69         protected $errors = [];
  70         /** @var string[] Extra HTTP response headers from modules loaded in makeModuleResponse() */
  71         protected $extraHeaders = [];
  72
  73         /** @var bool */
  74         protected static $debugMode = null;
  75
  76         /** @var int */
  77         const CACHE_VERSION = 8;
  78
  79         /** @var string JavaScript / CSS pragma to disable minification. * */
  80         const FILTER_NOMIN = '/*@nomin*/';
  81
  82         /**
  83          * Load information stored in the database about modules.
  84          *
  85          * This method grabs modules dependencies from the database and updates modules
  86          * objects.
  87          *
  88          * This is not inside the module code because it is much faster to
  89          * request all of the information at once than it is to have each module
  90          * requests its own information. This sacrifice of modularity yields a substantial
  91          * performance improvement.
  92          *
  93          * @param array $moduleNames List of module names to preload information for
  94          * @param ResourceLoaderContext $context Context to load the information within
  95          */
  96         public function preloadModuleInfo( array $moduleNames, ResourceLoaderContext $context ) {
  97                 if ( !$moduleNames ) {
  98                         // Or else Database*::select() will explode, plus it's cheaper!
  99                         return;
 100                 }
 101                 $dbr = wfGetDB( DB_REPLICA );
 102                 $lang = $context->getLanguage();
 103
 104                 // Batched version of ResourceLoaderModule::getFileDependencies
 105                 $vary = ResourceLoaderModule::getVary( $context );
 106                 $res = $dbr->select( 'module_deps', [ 'md_module', 'md_deps' ], [
 107                                 'md_module' => $moduleNames,
 108                                 'md_skin' => $vary,
 109                         ], __METHOD__
 110                 );
 111
 112                 // Prime in-object cache for file dependencies
 113                 $modulesWithDeps = [];
 114                 foreach ( $res as $row ) {
 115                         $module = $this->getModule( $row->md_module );
 116                         if ( $module ) {
 117                                 $module->setFileDependencies( $context, ResourceLoaderModule::expandRelativePaths(
 118                                         json_decode( $row->md_deps, true )
 119                                 ) );
 120                                 $modulesWithDeps[] = $row->md_module;
 121                         }
 122                 }
 123                 // Register the absence of a dependency row too
 124                 foreach ( array_diff( $moduleNames, $modulesWithDeps ) as $name ) {
 125                         $module = $this->getModule( $name );
 126                         if ( $module ) {
 127                                 $this->getModule( $name )->setFileDependencies( $context, [] );
 128                         }
 129                 }
 130
 131                 // Batched version of ResourceLoaderWikiModule::getTitleInfo
 132                 ResourceLoaderWikiModule::preloadTitleInfo( $context, $dbr, $moduleNames );
 133
 134                 // Prime in-object cache for message blobs for modules with messages
 135                 $modules = [];
 136                 foreach ( $moduleNames as $name ) {
 137                         $module = $this->getModule( $name );
 138                         if ( $module && $module->getMessages() ) {
 139                                 $modules[$name] = $module;
 140                         }
 141                 }
 142                 $store = $this->getMessageBlobStore();
 143                 $blobs = $store->getBlobs( $modules, $lang );
 144                 foreach ( $blobs as $name => $blob ) {
 145                         $modules[$name]->setMessageBlob( $blob, $lang );
 146                 }
 147         }
 148
 149         /**
 150          * Run JavaScript or CSS data through a filter, caching the filtered result for future calls.
 151          *
 152          * Available filters are:
 153          *
 154          *    - minify-js \see JavaScriptMinifier::minify
 155          *    - minify-css \see CSSMin::minify
 156          *
 157          * If $data is empty, only contains whitespace or the filter was unknown,
 158          * $data is returned unmodified.
 159          *
 160          * @param string $filter Name of filter to run
 161          * @param string $data Text to filter, such as JavaScript or CSS text
 162          * @param array $options Keys:
 163          *  - (bool) cache: Whether to allow caching this data. Default: true.
 164          * @return string Filtered data, or a comment containing an error message
 165          */
 166         public static function filter( $filter, $data, array $options = [] ) {
 167                 if ( strpos( $data, self::FILTER_NOMIN ) !== false ) {
 168                         return $data;
 169                 }
 170
 171                 if ( isset( $options['cache'] ) && $options['cache'] === false ) {
 172                         return self::applyFilter( $filter, $data );
 173                 }
 174
 175                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 176                 $cache = ObjectCache::getLocalServerInstance( CACHE_ANYTHING );
 177
 178                 $key = $cache->makeGlobalKey(
 179                         'resourceloader-filter',
 180                         $filter,
 181                         self::CACHE_VERSION,
 182                         md5( $data )
 183                 );
 184
 185                 $result = $cache->get( $key );
 186                 if ( $result === false ) {
 187                         $stats->increment( "resourceloader_cache.$filter.miss" );
 188                         $result = self::applyFilter( $filter, $data );
 189                         $cache->set( $key, $result, 24 * 3600 );
 190                 } else {
 191                         $stats->increment( "resourceloader_cache.$filter.hit" );
 192                 }
 193                 if ( $result === null ) {
 194                         // Cached failure
 195                         $result = $data;
 196                 }
 197
 198                 return $result;
 199         }
 200
 201         private static function applyFilter( $filter, $data ) {
 202                 $data = trim( $data );
 203                 if ( $data ) {
 204                         try {
 205                                 $data = ( $filter === 'minify-css' )
 206                                         ? CSSMin::minify( $data )
 207                                         : JavaScriptMinifier::minify( $data );
 208                         } catch ( Exception $e ) {
 209                                 MWExceptionHandler::logException( $e );
 210                                 return null;
 211                         }
 212                 }
 213                 return $data;
 214         }
 215
 216         /**
 217          * Register core modules and runs registration hooks.
 218          * @param Config|null $config
 219          * @param LoggerInterface|null $logger [optional]
 220          */
 221         public function __construct( Config $config = null, LoggerInterface $logger = null ) {
 222                 $this->logger = $logger ?: new NullLogger();
 223
 224                 if ( !$config ) {
 225                         wfDeprecated( __METHOD__ . ' without a Config instance', '1.34' );
 226                         $config = MediaWikiServices::getInstance()->getMainConfig();
 227                 }
 228                 $this->config = $config;
 229
 230                 // Add 'local' source first
 231                 $this->addSource( 'local', $config->get( 'LoadScript' ) );
 232
 233                 // Special module that always exists
 234                 $this->register( 'startup', [ 'class' => ResourceLoaderStartUpModule::class ] );
 235
 236                 $this->setMessageBlobStore( new MessageBlobStore( $this, $this->logger ) );
 237         }
 238
 239         /**
 240          * @return Config
 241          */
 242         public function getConfig() {
 243                 return $this->config;
 244         }
 245
 246         /**
 247          * @since 1.26
 248          * @param LoggerInterface $logger
 249          */
 250         public function setLogger( LoggerInterface $logger ) {
 251                 $this->logger = $logger;
 252         }
 253
 254         /**
 255          * @since 1.27
 256          * @return LoggerInterface
 257          */
 258         public function getLogger() {
 259                 return $this->logger;
 260         }
 261
 262         /**
 263          * @since 1.26
 264          * @return MessageBlobStore
 265          */
 266         public function getMessageBlobStore() {
 267                 return $this->blobStore;
 268         }
 269
 270         /**
 271          * @since 1.25
 272          * @param MessageBlobStore $blobStore
 273          */
 274         public function setMessageBlobStore( MessageBlobStore $blobStore ) {
 275                 $this->blobStore = $blobStore;
 276         }
 277
 278         /**
 279          * Register a module with the ResourceLoader system.
 280          *
 281          * @param string|array[] $name Module name as a string or, array of module info arrays
 282          *  keyed by name.
 283          * @param array|null $info Module info array. When using the first parameter to register
 284          *  multiple modules at once, this parameter is optional.
 285          * @throws MWException If a duplicate module registration is attempted
 286          * @throws MWException If a module name contains illegal characters (pipes or commas)
 287          * @throws InvalidArgumentException If the module info is not an array
 288          */
 289         public function register( $name, $info = null ) {
 290                 $moduleSkinStyles = $this->config->get( 'ResourceModuleSkinStyles' );
 291
 292                 // Allow multiple modules to be registered in one call
 293                 $registrations = is_array( $name ) ? $name : [ $name => $info ];
 294                 foreach ( $registrations as $name => $info ) {
 295                         // Warn on duplicate registrations
 296                         if ( isset( $this->moduleInfos[$name] ) ) {
 297                                 // A module has already been registered by this name
 298                                 $this->logger->warning(
 299                                         'ResourceLoader duplicate registration warning. ' .
 300                                         'Another module has already been registered as ' . $name
 301                                 );
 302                         }
 303
 304                         // Check validity
 305                         if ( !self::isValidModuleName( $name ) ) {
 306                                 throw new MWException( "ResourceLoader module name '$name' is invalid, "
 307                                         . "see ResourceLoader::isValidModuleName()" );
 308                         }
 309                         if ( !is_array( $info ) ) {
 310                                 throw new InvalidArgumentException(
 311                                         'Invalid module info for "' . $name . '": expected array, got ' . gettype( $info )
 312                                 );
 313                         }
 314
 315                         // Attach module
 316                         $this->moduleInfos[$name] = $info;
 317
 318                         // Last-minute changes
 319                         // Apply custom skin-defined styles to existing modules.
 320                         if ( $this->isFileModule( $name ) ) {
 321                                 foreach ( $moduleSkinStyles as $skinName => $skinStyles ) {
 322                                         // If this module already defines skinStyles for this skin, ignore $wgResourceModuleSkinStyles.
 323                                         if ( isset( $this->moduleInfos[$name]['skinStyles'][$skinName] ) ) {
 324                                                 continue;
 325                                         }
 326
 327                                         // If $name is preceded with a '+', the defined style files will be added to 'default'
 328                                         // skinStyles, otherwise 'default' will be ignored as it normally would be.
 329                                         if ( isset( $skinStyles[$name] ) ) {
 330                                                 $paths = (array)$skinStyles[$name];
 331                                                 $styleFiles = [];
 332                                         } elseif ( isset( $skinStyles['+' . $name] ) ) {
 333                                                 $paths = (array)$skinStyles['+' . $name];
 334                                                 $styleFiles = isset( $this->moduleInfos[$name]['skinStyles']['default'] ) ?
 335                                                         (array)$this->moduleInfos[$name]['skinStyles']['default'] :
 336                                                         [];
 337                                         } else {
 338                                                 continue;
 339                                         }
 340
 341                                         // Add new file paths, remapping them to refer to our directories and not use settings
 342                                         // from the module we're modifying, which come from the base definition.
 343                                         list( $localBasePath, $remoteBasePath ) =
 344                                                 ResourceLoaderFileModule::extractBasePaths( $skinStyles );
 345
 346                                         foreach ( $paths as $path ) {
 347                                                 $styleFiles[] = new ResourceLoaderFilePath( $path, $localBasePath, $remoteBasePath );
 348                                         }
 349
 350                                         $this->moduleInfos[$name]['skinStyles'][$skinName] = $styleFiles;
 351                                 }
 352                         }
 353                 }
 354         }
 355
 356         /**
 357          * @internal For use by ServiceWiring only
 358          * @codeCoverageIgnore
 359          */
 360         public function registerTestModules() {
 361                 global $IP;
 362
 363                 if ( $this->config->get( 'EnableJavaScriptTest' ) !== true ) {
 364                         throw new MWException( 'Attempt to register JavaScript test modules '
 365                                 . 'but <code>$wgEnableJavaScriptTest</code> is false. '
 366                                 . 'Edit your <code>LocalSettings.php</code> to enable it.' );
 367                 }
 368
 369                 // This has a 'qunit' key for compat with the below hook.
 370                 $testModulesMeta = [ 'qunit' => [] ];
 371
 372                 // Get test suites from extensions
 373                 // Avoid PHP 7.1 warning from passing $this by reference
 374                 $rl = $this;
 375                 Hooks::run( 'ResourceLoaderTestModules', [ &$testModulesMeta, &$rl ] );
 376                 $extRegistry = ExtensionRegistry::getInstance();
 377                 // In case of conflict, the deprecated hook has precedence.
 378                 $testModules = $testModulesMeta['qunit'] + $extRegistry->getAttribute( 'QUnitTestModules' );
 379
 380                 $testSuiteModuleNames = [];
 381                 foreach ( $testModules as $name => &$module ) {
 382                         // Turn any single-module dependency into an array
 383                         if ( isset( $module['dependencies'] ) && is_string( $module['dependencies'] ) ) {
 384                                 $module['dependencies'] = [ $module['dependencies'] ];
 385                         }
 386
 387                         // Ensure the testrunner loads before any test suites
 388                         $module['dependencies'][] = 'test.mediawiki.qunit.testrunner';
 389
 390                         // Keep track of the test suites to load on SpecialJavaScriptTest
 391                         $testSuiteModuleNames[] = $name;
 392                 }
 393
 394                 // Core test suites (their names have further precedence).
 395                 $testModules = ( include "$IP/tests/qunit/QUnitTestResources.php" ) + $testModules;
 396                 $testSuiteModuleNames[] = 'test.mediawiki.qunit.suites';
 397
 398                 $this->register( $testModules );
 399                 $this->testSuiteModuleNames = $testSuiteModuleNames;
 400         }
 401
 402         /**
 403          * Add a foreign source of modules.
 404          *
 405          * Source IDs are typically the same as the Wiki ID or database name (e.g. lowercase a-z).
 406          *
 407          * @param array|string $id Source ID (string), or [ id1 => loadUrl, id2 => loadUrl, ... ]
 408          * @param string|array|null $loadUrl load.php url (string), or array with loadUrl key for
 409          *  backwards-compatibility.
 410          * @throws MWException
 411          */
 412         public function addSource( $id, $loadUrl = null ) {
 413                 // Allow multiple sources to be registered in one call
 414                 if ( is_array( $id ) ) {
 415                         foreach ( $id as $key => $value ) {
 416                                 $this->addSource( $key, $value );
 417                         }
 418                         return;
 419                 }
 420
 421                 // Disallow duplicates
 422                 if ( isset( $this->sources[$id] ) ) {
 423                         throw new MWException(
 424                                 'ResourceLoader duplicate source addition error. ' .
 425                                 'Another source has already been registered as ' . $id
 426                         );
 427                 }
 428
 429                 // Pre 1.24 backwards-compatibility
 430                 if ( is_array( $loadUrl ) ) {
 431                         if ( !isset( $loadUrl['loadScript'] ) ) {
 432                                 throw new MWException(
 433                                         __METHOD__ . ' was passed an array with no "loadScript" key.'
 434                                 );
 435                         }
 436
 437                         $loadUrl = $loadUrl['loadScript'];
 438                 }
 439
 440                 $this->sources[$id] = $loadUrl;
 441         }
 442
 443         /**
 444          * Get a list of module names.
 445          *
 446          * @return array List of module names
 447          */
 448         public function getModuleNames() {
 449                 return array_keys( $this->moduleInfos );
 450         }
 451
 452         /**
 453          * Get a list of module names with QUnit test suites.
 454          *
 455          * @internal For use by SpecialJavaScriptTest only
 456          * @return array
 457          * @codeCoverageIgnore
 458          */
 459         public function getTestSuiteModuleNames() {
 460                 return $this->testSuiteModuleNames;
 461         }
 462
 463         /**
 464          * Check whether a ResourceLoader module is registered
 465          *
 466          * @since 1.25
 467          * @param string $name
 468          * @return bool
 469          */
 470         public function isModuleRegistered( $name ) {
 471                 return isset( $this->moduleInfos[$name] );
 472         }
 473
 474         /**
 475          * Get the ResourceLoaderModule object for a given module name.
 476          *
 477          * If an array of module parameters exists but a ResourceLoaderModule object has not
 478          * yet been instantiated, this method will instantiate and cache that object such that
 479          * subsequent calls simply return the same object.
 480          *
 481          * @param string $name Module name
 482          * @return ResourceLoaderModule|null If module has been registered, return a
 483          *  ResourceLoaderModule instance. Otherwise, return null.
 484          */
 485         public function getModule( $name ) {
 486                 if ( !isset( $this->modules[$name] ) ) {
 487                         if ( !isset( $this->moduleInfos[$name] ) ) {
 488                                 // No such module
 489                                 return null;
 490                         }
 491                         // Construct the requested module object
 492                         $info = $this->moduleInfos[$name];
 493                         if ( isset( $info['factory'] ) ) {
 494                                 /** @var ResourceLoaderModule $object */
 495                                 $object = call_user_func( $info['factory'], $info );
 496                         } else {
 497                                 $class = $info['class'] ?? ResourceLoaderFileModule::class;
 498                                 /** @var ResourceLoaderModule $object */
 499                                 $object = new $class( $info );
 500                         }
 501                         $object->setConfig( $this->getConfig() );
 502                         $object->setLogger( $this->logger );
 503                         $object->setName( $name );
 504                         $this->modules[$name] = $object;
 505                 }
 506
 507                 return $this->modules[$name];
 508         }
 509
 510         /**
 511          * Whether the module is a ResourceLoaderFileModule (including subclasses).
 512          *
 513          * @param string $name Module name
 514          * @return bool
 515          */
 516         protected function isFileModule( $name ) {
 517                 if ( !isset( $this->moduleInfos[$name] ) ) {
 518                         return false;
 519                 }
 520                 $info = $this->moduleInfos[$name];
 521                 return !isset( $info['factory'] ) && (
 522                         // The implied default for 'class' is ResourceLoaderFileModule
 523                         !isset( $info['class'] ) ||
 524                         // Explicit default
 525                         $info['class'] === ResourceLoaderFileModule::class ||
 526                         is_subclass_of( $info['class'], ResourceLoaderFileModule::class )
 527                 );
 528         }
 529
 530         /**
 531          * Get the list of sources.
 532          *
 533          * @return array Like [ id => load.php url, ... ]
 534          */
 535         public function getSources() {
 536                 return $this->sources;
 537         }
 538
 539         /**
 540          * Get the URL to the load.php endpoint for the given
 541          * ResourceLoader source
 542          *
 543          * @since 1.24
 544          * @param string $source
 545          * @throws MWException On an invalid $source name
 546          * @return string
 547          */
 548         public function getLoadScript( $source ) {
 549                 if ( !isset( $this->sources[$source] ) ) {
 550                         throw new MWException( "The $source source was never registered in ResourceLoader." );
 551                 }
 552                 return $this->sources[$source];
 553         }
 554
 555         /**
 556          * @internal For use by ResourceLoaderStartUpModule only.
 557          */
 558         const HASH_LENGTH = 5;
 559
 560         /**
 561          * Create a hash for module versioning purposes.
 562          *
 563          * This hash is used in three ways:
 564          *
 565          * - To differentiate between the current version and a past version
 566          *   of a module by the same name.
 567          *
 568          *   In the cache key of localStorage in the browser (mw.loader.store).
 569          *   This store keeps only one version of any given module. As long as the
 570          *   next version the client encounters has a different hash from the last
 571          *   version it saw, it will correctly discard it in favour of a network fetch.
 572          *
 573          *   A browser may evict a site's storage container for any reason (e.g. when
 574          *   the user hasn't visited a site for some time, and/or when the device is
 575          *   low on storage space). Anecdotally it seems devices rarely keep unused
 576          *   storage beyond 2 weeks on mobile devices and 4 weeks on desktop.
 577          *   But, there is no hard limit or expiration on localStorage.
 578          *   ResourceLoader's Client also clears localStorage when the user changes
 579          *   their language preference or when they (temporarily) use Debug Mode.
 580          *
 581          *   The only hard factors that reduce the range of possible versions are
 582          *   1) the name and existence of a given module, and
 583          *   2) the TTL for mw.loader.store, and
 584          *   3) the `$wgResourceLoaderStorageVersion` configuration variable.
 585          *
 586          * - To identify a batch response of modules from load.php in an HTTP cache.
 587          *
 588          *   When fetching modules in a batch from load.php, a combined hash
 589          *   is created by the JS code, and appended as query parameter.
 590          *
 591          *   In cache proxies (e.g. Varnish, Nginx) and in the browser's HTTP cache,
 592          *   these urls are used to identify other previously cached responses.
 593          *   The range of possible versions a given version has to be unique amongst
 594          *   is determined by the maximum duration each response is stored for, which
 595          *   is controlled by `$wgResourceLoaderMaxage['versioned']`.
 596          *
 597          * - To detect race conditions between multiple web servers in a MediaWiki
 598          *   deployment of which some have the newer version and some still the older
 599          *   version.
 600          *
 601          *   An HTTP request from a browser for the Startup manifest may be responded
 602          *   to by a server with the newer version. The browser may then use that to
 603          *   request a given module, which may then be responded to by a server with
 604          *   the older version. To avoid caching this for too long (which would pollute
 605          *   all other users without repairing itself), the combined hash that the JS
 606          *   client adds to the url is verified by the server (in ::sendResponseHeaders).
 607          *   If they don't match, we instruct cache proxies and clients to not cache
 608          *   this response as long as they normally would. This is also the reason
 609          *   that the algorithm used here in PHP must match the one used in JS.
 610          *
 611          * The fnv132 digest creates a 32-bit integer, which goes upto 4 Giga and
 612          * needs up to 7 chars in base 36.
 613          * Within 7 characters, base 36 can count up to 78,364,164,096 (78 Giga),
 614          * (but with fnv132 we'd use very little of this range, mostly padding).
 615          * Within 6 characters, base 36 can count up to 2,176,782,336 (2 Giga).
 616          * Within 5 characters, base 36 can count up to 60,466,176 (60 Mega).
 617          *
 618          * @since 1.26
 619          * @param string $value
 620          * @return string Hash
 621          */
 622         public static function makeHash( $value ) {
 623                 $hash = hash( 'fnv132', $value );
 624                 // The base_convert will pad it (if too short),
 625                 // then substr() will trim it (if too long).
 626                 return substr(
 627                         Wikimedia\base_convert( $hash, 16, 36, self::HASH_LENGTH ),
 628                         0,
 629                         self::HASH_LENGTH
 630                 );
 631         }
 632
 633         /**
 634          * Add an error to the 'errors' array and log it.
 635          *
 636          * @private For internal use by ResourceLoader and ResourceLoaderStartUpModule.
 637          * @since 1.29
 638          * @param Exception $e
 639          * @param string $msg
 640          * @param array $context
 641          */
 642         public function outputErrorAndLog( Exception $e, $msg, array $context = [] ) {
 643                 MWExceptionHandler::logException( $e );
 644                 $this->logger->warning(
 645                         $msg,
 646                         $context + [ 'exception' => $e ]
 647                 );
 648                 $this->errors[] = self::formatExceptionNoComment( $e );
 649         }
 650
 651         /**
 652          * Helper method to get and combine versions of multiple modules.
 653          *
 654          * @since 1.26
 655          * @param ResourceLoaderContext $context
 656          * @param string[] $moduleNames List of known module names
 657          * @return string Hash
 658          */
 659         public function getCombinedVersion( ResourceLoaderContext $context, array $moduleNames ) {
 660                 if ( !$moduleNames ) {
 661                         return '';
 662                 }
 663                 $hashes = array_map( function ( $module ) use ( $context ) {
 664                         try {
 665                                 return $this->getModule( $module )->getVersionHash( $context );
 666                         } catch ( Exception $e ) {
 667                                 // If modules fail to compute a version, don't fail the request (T152266)
 668                                 // and still compute versions of other modules.
 669                                 $this->outputErrorAndLog( $e,
 670                                         'Calculating version for "{module}" failed: {exception}',
 671                                         [
 672                                                 'module' => $module,
 673                                         ]
 674                                 );
 675                                 return '';
 676                         }
 677                 }, $moduleNames );
 678                 return self::makeHash( implode( '', $hashes ) );
 679         }
 680
 681         /**
 682          * Get the expected value of the 'version' query parameter.
 683          *
 684          * This is used by respond() to set a short Cache-Control header for requests with
 685          * information newer than the current server has. This avoids pollution of edge caches.
 686          * Typically during deployment. (T117587)
 687          *
 688          * This MUST match return value of `mw.loader#getCombinedVersion()` client-side.
 689          *
 690          * @since 1.28
 691          * @param ResourceLoaderContext $context
 692          * @return string Hash
 693          */
 694         public function makeVersionQuery( ResourceLoaderContext $context ) {
 695                 // As of MediaWiki 1.28, the server and client use the same algorithm for combining
 696                 // version hashes. There is no technical reason for this to be same, and for years the
 697                 // implementations differed. If getCombinedVersion in PHP (used for StartupModule and
 698                 // E-Tag headers) differs in the future from getCombinedVersion in JS (used for 'version'
 699                 // query parameter), then this method must continue to match the JS one.
 700                 $moduleNames = [];
 701                 foreach ( $context->getModules() as $name ) {
 702                         if ( !$this->getModule( $name ) ) {
 703                                 // If a versioned request contains a missing module, the version is a mismatch
 704                                 // as the client considered a module (and version) we don't have.
 705                                 return '';
 706                         }
 707                         $moduleNames[] = $name;
 708                 }
 709                 return $this->getCombinedVersion( $context, $moduleNames );
 710         }
 711
 712         /**
 713          * Output a response to a load request, including the content-type header.
 714          *
 715          * @param ResourceLoaderContext $context Context in which a response should be formed
 716          */
 717         public function respond( ResourceLoaderContext $context ) {
 718                 // Buffer output to catch warnings. Normally we'd use ob_clean() on the
 719                 // top-level output buffer to clear warnings, but that breaks when ob_gzhandler
 720                 // is used: ob_clean() will clear the GZIP header in that case and it won't come
 721                 // back for subsequent output, resulting in invalid GZIP. So we have to wrap
 722                 // the whole thing in our own output buffer to be sure the active buffer
 723                 // doesn't use ob_gzhandler.
 724                 // See https://bugs.php.net/bug.php?id=36514
 725                 ob_start();
 726
 727                 $this->measureResponseTime( RequestContext::getMain()->getTiming() );
 728
 729                 // Find out which modules are missing and instantiate the others
 730                 $modules = [];
 731                 $missing = [];
 732                 foreach ( $context->getModules() as $name ) {
 733                         $module = $this->getModule( $name );
 734                         if ( $module ) {
 735                                 // Do not allow private modules to be loaded from the web.
 736                                 // This is a security issue, see T36907.
 737                                 if ( $module->getGroup() === 'private' ) {
 738                                         // Not a serious error, just means something is trying to access it (T101806)
 739                                         $this->logger->debug( "Request for private module '$name' denied" );
 740                                         $this->errors[] = "Cannot build private module \"$name\"";
 741                                         continue;
 742                                 }
 743                                 $modules[$name] = $module;
 744                         } else {
 745                                 $missing[] = $name;
 746                         }
 747                 }
 748
 749                 try {
 750                         // Preload for getCombinedVersion() and for batch makeModuleResponse()
 751                         $this->preloadModuleInfo( array_keys( $modules ), $context );
 752                 } catch ( Exception $e ) {
 753                         $this->outputErrorAndLog( $e, 'Preloading module info failed: {exception}' );
 754                 }
 755
 756                 // Combine versions to propagate cache invalidation
 757                 $versionHash = '';
 758                 try {
 759                         $versionHash = $this->getCombinedVersion( $context, array_keys( $modules ) );
 760                 } catch ( Exception $e ) {
 761                         $this->outputErrorAndLog( $e, 'Calculating version hash failed: {exception}' );
 762                 }
 763
 764                 // See RFC 2616 § 3.11 Entity Tags
 765                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.11
 766                 $etag = 'W/"' . $versionHash . '"';
 767
 768                 // Try the client-side cache first
 769                 if ( $this->tryRespondNotModified( $context, $etag ) ) {
 770                         return; // output handled (buffers cleared)
 771                 }
 772
 773                 // Use file cache if enabled and available...
 774                 if ( $this->config->get( 'UseFileCache' ) ) {
 775                         $fileCache = ResourceFileCache::newFromContext( $context );
 776                         if ( $this->tryRespondFromFileCache( $fileCache, $context, $etag ) ) {
 777                                 return; // output handled
 778                         }
 779                 } else {
 780                         $fileCache = null;
 781                 }
 782
 783                 // Generate a response
 784                 $response = $this->makeModuleResponse( $context, $modules, $missing );
 785
 786                 // Capture any PHP warnings from the output buffer and append them to the
 787                 // error list if we're in debug mode.
 788                 if ( $context->getDebug() ) {
 789                         $warnings = ob_get_contents();
 790                         if ( strlen( $warnings ) ) {
 791                                 $this->errors[] = $warnings;
 792                         }
 793                 }
 794
 795                 // Consider saving the response to file cache (unless there are errors).
 796                 if ( $fileCache &&
 797                         !$this->errors &&
 798                         $missing === [] &&
 799                         ResourceFileCache::useFileCache( $context )
 800                 ) {
 801                         if ( $fileCache->isCacheWorthy() ) {
 802                                 // There were enough hits, save the response to the cache
 803                                 $fileCache->saveText( $response );
 804                         } else {
 805                                 $fileCache->incrMissesRecent( $context->getRequest() );
 806                         }
 807                 }
 808
 809                 $this->sendResponseHeaders( $context, $etag, (bool)$this->errors, $this->extraHeaders );
 810
 811                 // Remove the output buffer and output the response
 812                 ob_end_clean();
 813
 814                 if ( $context->getImageObj() && $this->errors ) {
 815                         // We can't show both the error messages and the response when it's an image.
 816                         $response = implode( "\n\n", $this->errors );
 817                 } elseif ( $this->errors ) {
 818                         $errorText = implode( "\n\n", $this->errors );
 819                         $errorResponse = self::makeComment( $errorText );
 820                         if ( $context->shouldIncludeScripts() ) {
 821                                 $errorResponse .= 'if (window.console && console.error) { console.error('
 822                                         . self::encodeJsonForScript( $errorText )
 823                                         . "); }\n";
 824                         }
 825
 826                         // Prepend error info to the response
 827                         $response = $errorResponse . $response;
 828                 }
 829
 830                 $this->errors = [];
 831                 echo $response;
 832         }
 833
 834         protected function measureResponseTime( Timing $timing ) {
 835                 DeferredUpdates::addCallableUpdate( function () use ( $timing ) {
 836                         $measure = $timing->measure( 'responseTime', 'requestStart', 'requestShutdown' );
 837                         if ( $measure !== false ) {
 838                                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 839                                 $stats->timing( 'resourceloader.responseTime', $measure['duration'] * 1000 );
 840                         }
 841                 } );
 842         }
 843
 844         /**
 845          * Send main response headers to the client.
 846          *
 847          * Deals with Content-Type, CORS (for stylesheets), and caching.
 848          *
 849          * @param ResourceLoaderContext $context
 850          * @param string $etag ETag header value
 851          * @param bool $errors Whether there are errors in the response
 852          * @param string[] $extra Array of extra HTTP response headers
 853          * @return void
 854          */
 855         protected function sendResponseHeaders(
 856                 ResourceLoaderContext $context, $etag, $errors, array $extra = []
 857         ) {
 858                 \MediaWiki\HeaderCallback::warnIfHeadersSent();
 859                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 860                 // Use a short cache expiry so that updates propagate to clients quickly, if:
 861                 // - No version specified (shared resources, e.g. stylesheets)
 862                 // - There were errors (recover quickly)
 863                 // - Version mismatch (T117587, T47877)
 864                 if ( is_null( $context->getVersion() )
 865                         || $errors
 866                         || $context->getVersion() !== $this->makeVersionQuery( $context )
 867                 ) {
 868                         $maxage = $rlMaxage['unversioned']['client'];
 869                         $smaxage = $rlMaxage['unversioned']['server'];
 870                 // If a version was specified we can use a longer expiry time since changing
 871                 // version numbers causes cache misses
 872                 } else {
 873                         $maxage = $rlMaxage['versioned']['client'];
 874                         $smaxage = $rlMaxage['versioned']['server'];
 875                 }
 876                 if ( $context->getImageObj() ) {
 877                         // Output different headers if we're outputting textual errors.
 878                         if ( $errors ) {
 879                                 header( 'Content-Type: text/plain; charset=utf-8' );
 880                         } else {
 881                                 $context->getImageObj()->sendResponseHeaders( $context );
 882                         }
 883                 } elseif ( $context->getOnly() === 'styles' ) {
 884                         header( 'Content-Type: text/css; charset=utf-8' );
 885                         header( 'Access-Control-Allow-Origin: *' );
 886                 } else {
 887                         header( 'Content-Type: text/javascript; charset=utf-8' );
 888                 }
 889                 // See RFC 2616 § 14.19 ETag
 890                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.19
 891                 header( 'ETag: ' . $etag );
 892                 if ( $context->getDebug() ) {
 893                         // Do not cache debug responses
 894                         header( 'Cache-Control: private, no-cache, must-revalidate' );
 895                         header( 'Pragma: no-cache' );
 896                 } else {
 897                         header( "Cache-Control: public, max-age=$maxage, s-maxage=$smaxage" );
 898                         $exp = min( $maxage, $smaxage );
 899                         header( 'Expires: ' . wfTimestamp( TS_RFC2822, $exp + time() ) );
 900                 }
 901                 foreach ( $extra as $header ) {
 902                         header( $header );
 903                 }
 904         }
 905
 906         /**
 907          * Respond with HTTP 304 Not Modified if appropiate.
 908          *
 909          * If there's an If-None-Match header, respond with a 304 appropriately
 910          * and clear out the output buffer. If the client cache is too old then do nothing.
 911          *
 912          * @param ResourceLoaderContext $context
 913          * @param string $etag ETag header value
 914          * @return bool True if HTTP 304 was sent and output handled
 915          */
 916         protected function tryRespondNotModified( ResourceLoaderContext $context, $etag ) {
 917                 // See RFC 2616 § 14.26 If-None-Match
 918                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.26
 919                 $clientKeys = $context->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST );
 920                 // Never send 304s in debug mode
 921                 if ( $clientKeys !== false && !$context->getDebug() && in_array( $etag, $clientKeys ) ) {
 922                         // There's another bug in ob_gzhandler (see also the comment at
 923                         // the top of this function) that causes it to gzip even empty
 924                         // responses, meaning it's impossible to produce a truly empty
 925                         // response (because the gzip header is always there). This is
 926                         // a problem because 304 responses have to be completely empty
 927                         // per the HTTP spec, and Firefox behaves buggily when they're not.
 928                         // See also https://bugs.php.net/bug.php?id=51579
 929                         // To work around this, we tear down all output buffering before
 930                         // sending the 304.
 931                         wfResetOutputBuffers( /* $resetGzipEncoding = */ true );
 932
 933                         HttpStatus::header( 304 );
 934
 935                         $this->sendResponseHeaders( $context, $etag, false );
 936                         return true;
 937                 }
 938                 return false;
 939         }
 940
 941         /**
 942          * Send out code for a response from file cache if possible.
 943          *
 944          * @param ResourceFileCache $fileCache Cache object for this request URL
 945          * @param ResourceLoaderContext $context Context in which to generate a response
 946          * @param string $etag ETag header value
 947          * @return bool If this found a cache file and handled the response
 948          */
 949         protected function tryRespondFromFileCache(
 950                 ResourceFileCache $fileCache,
 951                 ResourceLoaderContext $context,
 952                 $etag
 953         ) {
 954                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 955                 // Buffer output to catch warnings.
 956                 ob_start();
 957                 // Get the maximum age the cache can be
 958                 $maxage = is_null( $context->getVersion() )
 959                         ? $rlMaxage['unversioned']['server']
 960                         : $rlMaxage['versioned']['server'];
 961                 // Minimum timestamp the cache file must have
 962                 $good = $fileCache->isCacheGood( wfTimestamp( TS_MW, time() - $maxage ) );
 963                 if ( !$good ) {
 964                         try { // RL always hits the DB on file cache miss...
 965                                 wfGetDB( DB_REPLICA );
 966                         } catch ( DBConnectionError $e ) { // ...check if we need to fallback to cache
 967                                 $good = $fileCache->isCacheGood(); // cache existence check
 968                         }
 969                 }
 970                 if ( $good ) {
 971                         $ts = $fileCache->cacheTimestamp();
 972                         // Send content type and cache headers
 973                         $this->sendResponseHeaders( $context, $etag, false );
 974                         $response = $fileCache->fetchText();
 975                         // Capture any PHP warnings from the output buffer and append them to the
 976                         // response in a comment if we're in debug mode.
 977                         if ( $context->getDebug() ) {
 978                                 $warnings = ob_get_contents();
 979                                 if ( strlen( $warnings ) ) {
 980                                         $response = self::makeComment( $warnings ) . $response;
 981                                 }
 982                         }
 983                         // Remove the output buffer and output the response
 984                         ob_end_clean();
 985                         echo $response . "\n/* Cached {$ts} */";
 986                         return true; // cache hit
 987                 }
 988                 // Clear buffer
 989                 ob_end_clean();
 990
 991                 return false; // cache miss
 992         }
 993
 994         /**
 995          * Generate a CSS or JS comment block.
 996          *
 997          * Only use this for public data, not error message details.
 998          *
 999          * @param string $text
1000          * @return string
1001          */
1002         public static function makeComment( $text ) {
1003                 $encText = str_replace( '*/', '* /', $text );
1004                 return "/*\n$encText\n*/\n";
1005         }
1006
1007         /**
1008          * Handle exception display.
1009          *
1010          * @param Exception $e Exception to be shown to the user
1011          * @return string Sanitized text in a CSS/JS comment that can be returned to the user
1012          */
1013         public static function formatException( $e ) {
1014                 return self::makeComment( self::formatExceptionNoComment( $e ) );
1015         }
1016
1017         /**
1018          * Handle exception display.
1019          *
1020          * @since 1.25
1021          * @param Exception $e Exception to be shown to the user
1022          * @return string Sanitized text that can be returned to the user
1023          */
1024         protected static function formatExceptionNoComment( $e ) {
1025                 global $wgShowExceptionDetails;
1026
1027                 if ( !$wgShowExceptionDetails ) {
1028                         return MWExceptionHandler::getPublicLogMessage( $e );
1029                 }
1030
1031                 return MWExceptionHandler::getLogMessage( $e ) .
1032                         "\nBacktrace:\n" .
1033                         MWExceptionHandler::getRedactedTraceAsString( $e );
1034         }
1035
1036         /**
1037          * Generate code for a response.
1038          *
1039          * Calling this method also populates the `errors` and `headers` members,
1040          * later used by respond().
1041          *
1042          * @param ResourceLoaderContext $context Context in which to generate a response
1043          * @param ResourceLoaderModule[] $modules List of module objects keyed by module name
1044          * @param string[] $missing List of requested module names that are unregistered (optional)
1045          * @return string Response data
1046          */
1047         public function makeModuleResponse( ResourceLoaderContext $context,
1048                 array $modules, array $missing = []
1049         ) {
1050                 $out = '';
1051                 $states = [];
1052
1053                 if ( $modules === [] && $missing === [] ) {
1054                         return <<<MESSAGE
1055 /* This file is the Web entry point for MediaWiki's ResourceLoader:
1056    <https://www.mediawiki.org/wiki/ResourceLoader>. In this request,
1057    no modules were requested. Max made me put this here. */
1058 MESSAGE;
1059                 }
1060
1061                 $image = $context->getImageObj();
1062                 if ( $image ) {
1063                         $data = $image->getImageData( $context );
1064                         if ( $data === false ) {
1065                                 $data = '';
1066                                 $this->errors[] = 'Image generation failed';
1067                         }
1068                         return $data;
1069                 }
1070
1071                 foreach ( $missing as $name ) {
1072                         $states[$name] = 'missing';
1073                 }
1074
1075                 $filter = $context->getOnly() === 'styles' ? 'minify-css' : 'minify-js';
1076
1077                 foreach ( $modules as $name => $module ) {
1078                         try {
1079                                 $content = $module->getModuleContent( $context );
1080                                 $implementKey = $name . '@' . $module->getVersionHash( $context );
1081                                 $strContent = '';
1082
1083                                 if ( isset( $content['headers'] ) ) {
1084                                         $this->extraHeaders = array_merge( $this->extraHeaders, $content['headers'] );
1085                                 }
1086
1087                                 // Append output
1088                                 switch ( $context->getOnly() ) {
1089                                         case 'scripts':
1090                                                 $scripts = $content['scripts'];
1091                                                 if ( is_string( $scripts ) ) {
1092                                                         // Load scripts raw...
1093                                                         $strContent = $scripts;
1094                                                 } elseif ( is_array( $scripts ) ) {
1095                                                         // ...except when $scripts is an array of URLs or an associative array
1096                                                         $strContent = self::makeLoaderImplementScript( $implementKey, $scripts, [], [], [] );
1097                                                 }
1098                                                 break;
1099                                         case 'styles':
1100                                                 $styles = $content['styles'];
1101                                                 // We no longer separate into media, they are all combined now with
1102                                                 // custom media type groups into @media .. {} sections as part of the css string.
1103                                                 // Module returns either an empty array or a numerical array with css strings.
1104                                                 $strContent = isset( $styles['css'] ) ? implode( '', $styles['css'] ) : '';
1105                                                 break;
1106                                         default:
1107                                                 $scripts = $content['scripts'] ?? '';
1108                                                 if ( is_string( $scripts ) ) {
1109                                                         if ( $name === 'site' || $name === 'user' ) {
1110                                                                 // Legacy scripts that run in the global scope without a closure.
1111                                                                 // mw.loader.implement will use globalEval if scripts is a string.
1112                                                                 // Minify manually here, because general response minification is
1113                                                                 // not effective due it being a string literal, not a function.
1114                                                                 if ( !$context->getDebug() ) {
1115                                                                         $scripts = self::filter( 'minify-js', $scripts ); // T107377
1116                                                                 }
1117                                                         } else {
1118                                                                 $scripts = new XmlJsCode( $scripts );
1119                                                         }
1120                                                 }
1121                                                 $strContent = self::makeLoaderImplementScript(
1122                                                         $implementKey,
1123                                                         $scripts,
1124                                                         $content['styles'] ?? [],
1125                                                         isset( $content['messagesBlob'] ) ? new XmlJsCode( $content['messagesBlob'] ) : [],
1126                                                         $content['templates'] ?? []
1127                                                 );
1128                                                 break;
1129                                 }
1130
1131                                 if ( !$context->getDebug() ) {
1132                                         $strContent = self::filter( $filter, $strContent );
1133                                 } else {
1134                                         // In debug mode, separate each response by a new line.
1135                                         // For example, between 'mw.loader.implement();' statements.
1136                                         $strContent = $this->ensureNewline( $strContent );
1137                                 }
1138
1139                                 if ( $context->getOnly() === 'scripts' ) {
1140                                         // Use a linebreak between module scripts (T162719)
1141                                         $out .= $this->ensureNewline( $strContent );
1142                                 } else {
1143                                         $out .= $strContent;
1144                                 }
1145
1146                         } catch ( Exception $e ) {
1147                                 $this->outputErrorAndLog( $e, 'Generating module package failed: {exception}' );
1148
1149                                 // Respond to client with error-state instead of module implementation
1150                                 $states[$name] = 'error';
1151                                 unset( $modules[$name] );
1152                         }
1153                 }
1154
1155                 // Update module states
1156                 if ( $context->shouldIncludeScripts() && !$context->getRaw() ) {
1157                         if ( $modules && $context->getOnly() === 'scripts' ) {
1158                                 // Set the state of modules loaded as only scripts to ready as
1159                                 // they don't have an mw.loader.implement wrapper that sets the state
1160                                 foreach ( $modules as $name => $module ) {
1161                                         $states[$name] = 'ready';
1162                                 }
1163                         }
1164
1165                         // Set the state of modules we didn't respond to with mw.loader.implement
1166                         if ( $states ) {
1167                                 $stateScript = self::makeLoaderStateScript( $states );
1168                                 if ( !$context->getDebug() ) {
1169                                         $stateScript = self::filter( 'minify-js', $stateScript );
1170                                 }
1171                                 // Use a linebreak between module script and state script (T162719)
1172                                 $out = $this->ensureNewline( $out ) . $stateScript;
1173                         }
1174                 } elseif ( $states ) {
1175                         $this->errors[] = 'Problematic modules: '
1176                                 . self::encodeJsonForScript( $states );
1177                 }
1178
1179                 return $out;
1180         }
1181
1182         /**
1183          * Ensure the string is either empty or ends in a line break
1184          * @param string $str
1185          * @return string
1186          */
1187         private function ensureNewline( $str ) {
1188                 $end = substr( $str, -1 );
1189                 if ( $end === false || $end === '' || $end === "\n" ) {
1190                         return $str;
1191                 }
1192                 return $str . "\n";
1193         }
1194
1195         /**
1196          * Get names of modules that use a certain message.
1197          *
1198          * @param string $messageKey
1199          * @return array List of module names
1200          */
1201         public function getModulesByMessage( $messageKey ) {
1202                 $moduleNames = [];
1203                 foreach ( $this->getModuleNames() as $moduleName ) {
1204                         $module = $this->getModule( $moduleName );
1205                         if ( in_array( $messageKey, $module->getMessages() ) ) {
1206                                 $moduleNames[] = $moduleName;
1207                         }
1208                 }
1209                 return $moduleNames;
1210         }
1211
1212         /**
1213          * Return JS code that calls mw.loader.implement with given module properties.
1214          *
1215          * @param string $name Module name or implement key (format "`[name]@[version]`")
1216          * @param XmlJsCode|array|string $scripts Code as XmlJsCode (to be wrapped in a closure),
1217          *  list of URLs to JavaScript files, string of JavaScript for `$.globalEval`, or array with
1218          *  'files' and 'main' properties (see ResourceLoaderModule::getScript())
1219          * @param mixed $styles Array of CSS strings keyed by media type, or an array of lists of URLs
1220          *   to CSS files keyed by media type
1221          * @param mixed $messages List of messages associated with this module. May either be an
1222          *   associative array mapping message key to value, or a JSON-encoded message blob containing
1223          *   the same data, wrapped in an XmlJsCode object.
1224          * @param array $templates Keys are name of templates and values are the source of
1225          *   the template.
1226          * @throws MWException
1227          * @return string JavaScript code
1228          */
1229         protected static function makeLoaderImplementScript(
1230                 $name, $scripts, $styles, $messages, $templates
1231         ) {
1232                 if ( $scripts instanceof XmlJsCode ) {
1233                         if ( $scripts->value === '' ) {
1234                                 $scripts = null;
1235                         } elseif ( self::inDebugMode() ) {
1236                                 $scripts = new XmlJsCode( "function ( $, jQuery, require, module ) {\n{$scripts->value}\n}" );
1237                         } else {
1238                                 $scripts = new XmlJsCode( 'function($,jQuery,require,module){' . $scripts->value . '}' );
1239                         }
1240                 } elseif ( is_array( $scripts ) && isset( $scripts['files'] ) ) {
1241                         $files = $scripts['files'];
1242                         foreach ( $files as $path => &$file ) {
1243                                 // $file is changed (by reference) from a descriptor array to the content of the file
1244                                 // All of these essentially do $file = $file['content'];, some just have wrapping around it
1245                                 if ( $file['type'] === 'script' ) {
1246                                         // Multi-file modules only get two parameters ($ and jQuery are being phased out)
1247                                         if ( self::inDebugMode() ) {
1248                                                 $file = new XmlJsCode( "function ( require, module ) {\n{$file['content']}\n}" );
1249                                         } else {
1250                                                 $file = new XmlJsCode( 'function(require,module){' . $file['content'] . '}' );
1251                                         }
1252                                 } else {
1253                                         $file = $file['content'];
1254                                 }
1255                         }
1256                         $scripts = XmlJsCode::encodeObject( [
1257                                 'main' => $scripts['main'],
1258                                 'files' => XmlJsCode::encodeObject( $files, self::inDebugMode() )
1259                         ], self::inDebugMode() );
1260                 } elseif ( !is_string( $scripts ) && !is_array( $scripts ) ) {
1261                         throw new MWException( 'Invalid scripts error. Array of URLs or string of code expected.' );
1262                 }
1263
1264                 // mw.loader.implement requires 'styles', 'messages' and 'templates' to be objects (not
1265                 // arrays). json_encode considers empty arrays to be numerical and outputs "[]" instead
1266                 // of "{}". Force them to objects.
1267                 $module = [
1268                         $name,
1269                         $scripts,
1270                         (object)$styles,
1271                         (object)$messages,
1272                         (object)$templates
1273                 ];
1274                 self::trimArray( $module );
1275
1276                 return Xml::encodeJsCall( 'mw.loader.implement', $module, self::inDebugMode() );
1277         }
1278
1279         /**
1280          * Returns JS code which, when called, will register a given list of messages.
1281          *
1282          * @param mixed $messages Associative array mapping message key to value.
1283          * @return string JavaScript code
1284          */
1285         public static function makeMessageSetScript( $messages ) {
1286                 return 'mw.messages.set('
1287                         . self::encodeJsonForScript( (object)$messages )
1288                         . ');';
1289         }
1290
1291         /**
1292          * Combines an associative array mapping media type to CSS into a
1293          * single stylesheet with "@media" blocks.
1294          *
1295          * @param array $stylePairs Array keyed by media type containing (arrays of) CSS strings
1296          * @return array
1297          */
1298         public static function makeCombinedStyles( array $stylePairs ) {
1299                 $out = [];
1300                 foreach ( $stylePairs as $media => $styles ) {
1301                         // ResourceLoaderFileModule::getStyle can return the styles
1302                         // as a string or an array of strings. This is to allow separation in
1303                         // the front-end.
1304                         $styles = (array)$styles;
1305                         foreach ( $styles as $style ) {
1306                                 $style = trim( $style );
1307                                 // Don't output an empty "@media print { }" block (T42498)
1308                                 if ( $style !== '' ) {
1309                                         // Transform the media type based on request params and config
1310                                         // The way that this relies on $wgRequest to propagate request params is slightly evil
1311                                         $media = OutputPage::transformCssMedia( $media );
1312
1313                                         if ( $media === '' || $media == 'all' ) {
1314                                                 $out[] = $style;
1315                                         } elseif ( is_string( $media ) ) {
1316                                                 $out[] = "@media $media {\n" . str_replace( "\n", "\n\t", "\t" . $style ) . "}";
1317                                         }
1318                                         // else: skip
1319                                 }
1320                         }
1321                 }
1322                 return $out;
1323         }
1324
1325         /**
1326          * Wrapper around json_encode that avoids needless escapes,
1327          * and pretty-prints in debug mode.
1328          *
1329          * @internal
1330          * @since 1.32
1331          * @param mixed $data
1332          * @return string|false JSON string, false on error
1333          */
1334         public static function encodeJsonForScript( $data ) {
1335                 // Keep output as small as possible by disabling needless escape modes
1336                 // that PHP uses by default.
1337                 // However, while most module scripts are only served on HTTP responses
1338                 // for JavaScript, some modules can also be embedded in the HTML as inline
1339                 // scripts. This, and the fact that we sometimes need to export strings
1340                 // containing user-generated content and labels that may genuinely contain
1341                 // a sequences like "</script>", we need to encode either '/' or '<'.
1342                 // By default PHP escapes '/'. Let's escape '<' instead which is less common
1343                 // and allows URLs to mostly remain readable.
1344                 $jsonFlags = JSON_UNESCAPED_SLASHES |
1345                         JSON_UNESCAPED_UNICODE |
1346                         JSON_HEX_TAG |
1347                         JSON_HEX_AMP;
1348                 if ( self::inDebugMode() ) {
1349                         $jsonFlags |= JSON_PRETTY_PRINT;
1350                 }
1351                 return json_encode( $data, $jsonFlags );
1352         }
1353
1354         /**
1355          * Returns a JS call to mw.loader.state, which sets the state of one
1356          * ore more modules to a given value. Has two calling conventions:
1357          *
1358          *    - ResourceLoader::makeLoaderStateScript( $name, $state ):
1359          *         Set the state of a single module called $name to $state
1360          *
1361          *    - ResourceLoader::makeLoaderStateScript( [ $name => $state, ... ] ):
1362          *         Set the state of modules with the given names to the given states
1363          *
1364          * @param array|string $states
1365          * @param string|null $state
1366          * @return string JavaScript code
1367          */
1368         public static function makeLoaderStateScript( $states, $state = null ) {
1369                 if ( !is_array( $states ) ) {
1370                         $states = [ $states => $state ];
1371                 }
1372                 return 'mw.loader.state('
1373                         . self::encodeJsonForScript( $states )
1374                         . ');';
1375         }
1376
1377         private static function isEmptyObject( stdClass $obj ) {
1378                 foreach ( $obj as $key => $value ) {
1379                         return false;
1380                 }
1381                 return true;
1382         }
1383
1384         /**
1385          * Remove empty values from the end of an array.
1386          *
1387          * Values considered empty:
1388          *
1389          * - null
1390          * - []
1391          * - new XmlJsCode( '{}' )
1392          * - new stdClass() // (object) []
1393          *
1394          * @param array $array
1395          */
1396         private static function trimArray( array &$array ) {
1397                 $i = count( $array );
1398                 while ( $i-- ) {
1399                         if ( $array[$i] === null
1400                                 || $array[$i] === []
1401                                 || ( $array[$i] instanceof XmlJsCode && $array[$i]->value === '{}' )
1402                                 || ( $array[$i] instanceof stdClass && self::isEmptyObject( $array[$i] ) )
1403                         ) {
1404                                 unset( $array[$i] );
1405                         } else {
1406                                 break;
1407                         }
1408                 }
1409         }
1410
1411         /**
1412          * Returns JS code which calls mw.loader.register with the given
1413          * parameter.
1414          *
1415          * @par Example
1416          * @code
1417          *
1418          *     ResourceLoader::makeLoaderRegisterScript( [
1419          *        [ $name1, $version1, $dependencies1, $group1, $source1, $skip1 ],
1420          *        [ $name2, $version2, $dependencies1, $group2, $source2, $skip2 ],
1421          *        ...
1422          *     ] ):
1423          * @endcode
1424          *
1425          * @internal
1426          * @since 1.32
1427          * @param array $modules Array of module registration arrays, each containing
1428          *  - string: module name
1429          *  - string: module version
1430          *  - array|null: List of dependencies (optional)
1431          *  - string|null: Module group (optional)
1432          *  - string|null: Name of foreign module source, or 'local' (optional)
1433          *  - string|null: Script body of a skip function (optional)
1434          * @return string JavaScript code
1435          */
1436         public static function makeLoaderRegisterScript( array $modules ) {
1437                 // Optimisation: Transform dependency names into indexes when possible
1438                 // to produce smaller output. They are expanded by mw.loader.register on
1439                 // the other end using resolveIndexedDependencies().
1440                 $index = [];
1441                 foreach ( $modules as $i => &$module ) {
1442                         // Build module name index
1443                         $index[$module[0]] = $i;
1444                 }
1445                 foreach ( $modules as &$module ) {
1446                         if ( isset( $module[2] ) ) {
1447                                 foreach ( $module[2] as &$dependency ) {
1448                                         if ( isset( $index[$dependency] ) ) {
1449                                                 // Replace module name in dependency list with index
1450                                                 $dependency = $index[$dependency];
1451                                         }
1452                                 }
1453                         }
1454                 }
1455
1456                 array_walk( $modules, [ self::class, 'trimArray' ] );
1457
1458                 return 'mw.loader.register('
1459                         . self::encodeJsonForScript( $modules )
1460                         . ');';
1461         }
1462
1463         /**
1464          * Returns JS code which calls mw.loader.addSource() with the given
1465          * parameters. Has two calling conventions:
1466          *
1467          *   - ResourceLoader::makeLoaderSourcesScript( $id, $properties ):
1468          *       Register a single source
1469          *
1470          *   - ResourceLoader::makeLoaderSourcesScript( [ $id1 => $loadUrl, $id2 => $loadUrl, ... ] );
1471          *       Register sources with the given IDs and properties.
1472          *
1473          * @param string|array $sources Source ID
1474          * @param string|null $loadUrl load.php url
1475          * @return string JavaScript code
1476          */
1477         public static function makeLoaderSourcesScript( $sources, $loadUrl = null ) {
1478                 if ( !is_array( $sources ) ) {
1479                         $sources = [ $sources => $loadUrl ];
1480                 }
1481                 return 'mw.loader.addSource('
1482                         . self::encodeJsonForScript( $sources )
1483                         . ');';
1484         }
1485
1486         /**
1487          * Wraps JavaScript code to run after the startup module.
1488          *
1489          * @param string $script JavaScript code
1490          * @return string JavaScript code
1491          */
1492         public static function makeLoaderConditionalScript( $script ) {
1493                 // Adds a function to lazy-created RLQ
1494                 return '(RLQ=window.RLQ||[]).push(function(){' .
1495                         trim( $script ) . '});';
1496         }
1497
1498         /**
1499          * Wraps JavaScript code to run after a required module.
1500          *
1501          * @since 1.32
1502          * @param string|string[] $modules Module name(s)
1503          * @param string $script JavaScript code
1504          * @return string JavaScript code
1505          */
1506         public static function makeInlineCodeWithModule( $modules, $script ) {
1507                 // Adds an array to lazy-created RLQ
1508                 return '(RLQ=window.RLQ||[]).push(['
1509                         . self::encodeJsonForScript( $modules ) . ','
1510                         . 'function(){' . trim( $script ) . '}'
1511                         . ']);';
1512         }
1513
1514         /**
1515          * Returns an HTML script tag that runs given JS code after startup and base modules.
1516          *
1517          * The code will be wrapped in a closure, and it will be executed by ResourceLoader's
1518          * startup module if the client has adequate support for MediaWiki JavaScript code.
1519          *
1520          * @param string $script JavaScript code
1521          * @param string|null $nonce [optional] Content-Security-Policy nonce
1522          *  (from OutputPage::getCSPNonce)
1523          * @return string|WrappedString HTML
1524          */
1525         public static function makeInlineScript( $script, $nonce = null ) {
1526                 $js = self::makeLoaderConditionalScript( $script );
1527                 $escNonce = '';
1528                 if ( $nonce === null ) {
1529                         wfWarn( __METHOD__ . " did not get nonce. Will break CSP" );
1530                 } elseif ( $nonce !== false ) {
1531                         // If it was false, CSP is disabled, so no nonce attribute.
1532                         // Nonce should be only base64 characters, so should be safe,
1533                         // but better to be safely escaped than sorry.
1534                         $escNonce = ' nonce="' . htmlspecialchars( $nonce ) . '"';
1535                 }
1536
1537                 return new WrappedString(
1538                         Html::inlineScript( $js, $nonce ),
1539                         "<script$escNonce>(RLQ=window.RLQ||[]).push(function(){",
1540                         '});</script>'
1541                 );
1542         }
1543
1544         /**
1545          * Returns JS code which will set the MediaWiki configuration array to
1546          * the given value.
1547          *
1548          * @param array $configuration List of configuration values keyed by variable name
1549          * @return string JavaScript code
1550          * @throws Exception
1551          */
1552         public static function makeConfigSetScript( array $configuration ) {
1553                 $json = self::encodeJsonForScript( $configuration );
1554                 if ( $json === false ) {
1555                         $e = new Exception(
1556                                 'JSON serialization of config data failed. ' .
1557                                 'This usually means the config data is not valid UTF-8.'
1558                         );
1559                         MWExceptionHandler::logException( $e );
1560                         return 'mw.log.error(' . self::encodeJsonForScript( $e->__toString() ) . ');';
1561                 }
1562                 return "mw.config.set($json);";
1563         }
1564
1565         /**
1566          * Convert an array of module names to a packed query string.
1567          *
1568          * For example, `[ 'foo.bar', 'foo.baz', 'bar.baz', 'bar.quux' ]`
1569          * becomes `'foo.bar,baz|bar.baz,quux'`.
1570          *
1571          * This process is reversed by ResourceLoader::expandModuleNames().
1572          * See also mw.loader#buildModulesString() which is a port of this, used
1573          * on the client-side.
1574          *
1575          * @param array $modules List of module names (strings)
1576          * @return string Packed query string
1577          */
1578         public static function makePackedModulesString( $modules ) {
1579                 $moduleMap = []; // [ prefix => [ suffixes ] ]
1580                 foreach ( $modules as $module ) {
1581                         $pos = strrpos( $module, '.' );
1582                         $prefix = $pos === false ? '' : substr( $module, 0, $pos );
1583                         $suffix = $pos === false ? $module : substr( $module, $pos + 1 );
1584                         $moduleMap[$prefix][] = $suffix;
1585                 }
1586
1587                 $arr = [];
1588                 foreach ( $moduleMap as $prefix => $suffixes ) {
1589                         $p = $prefix === '' ? '' : $prefix . '.';
1590                         $arr[] = $p . implode( ',', $suffixes );
1591                 }
1592                 return implode( '|', $arr );
1593         }
1594
1595         /**
1596          * Expand a string of the form `jquery.foo,bar|jquery.ui.baz,quux` to
1597          * an array of module names like `[ 'jquery.foo', 'jquery.bar',
1598          * 'jquery.ui.baz', 'jquery.ui.quux' ]`.
1599          *
1600          * This process is reversed by ResourceLoader::makePackedModulesString().
1601          *
1602          * @since 1.33
1603          * @param string $modules Packed module name list
1604          * @return array Array of module names
1605          */
1606         public static function expandModuleNames( $modules ) {
1607                 $retval = [];
1608                 $exploded = explode( '|', $modules );
1609                 foreach ( $exploded as $group ) {
1610                         if ( strpos( $group, ',' ) === false ) {
1611                                 // This is not a set of modules in foo.bar,baz notation
1612                                 // but a single module
1613                                 $retval[] = $group;
1614                         } else {
1615                                 // This is a set of modules in foo.bar,baz notation
1616                                 $pos = strrpos( $group, '.' );
1617                                 if ( $pos === false ) {
1618                                         // Prefixless modules, i.e. without dots
1619                                         $retval = array_merge( $retval, explode( ',', $group ) );
1620                                 } else {
1621                                         // We have a prefix and a bunch of suffixes
1622                                         $prefix = substr( $group, 0, $pos ); // 'foo'
1623                                         $suffixes = explode( ',', substr( $group, $pos + 1 ) ); // [ 'bar', 'baz' ]
1624                                         foreach ( $suffixes as $suffix ) {
1625                                                 $retval[] = "$prefix.$suffix";
1626                                         }
1627                                 }
1628                         }
1629                 }
1630                 return $retval;
1631         }
1632
1633         /**
1634          * Determine whether debug mode was requested
1635          * Order of priority is 1) request param, 2) cookie, 3) $wg setting
1636          * @return bool
1637          */
1638         public static function inDebugMode() {
1639                 if ( self::$debugMode === null ) {
1640                         global $wgRequest, $wgResourceLoaderDebug;
1641                         self::$debugMode = $wgRequest->getFuzzyBool( 'debug',
1642                                 $wgRequest->getCookie( 'resourceLoaderDebug', '', $wgResourceLoaderDebug )
1643                         );
1644                 }
1645                 return self::$debugMode;
1646         }
1647
1648         /**
1649          * Reset static members used for caching.
1650          *
1651          * Global state and $wgRequest are evil, but we're using it right
1652          * now and sometimes we need to be able to force ResourceLoader to
1653          * re-evaluate the context because it has changed (e.g. in the test suite).
1654          *
1655          * @internal For use by unit tests
1656          * @codeCoverageIgnore
1657          */
1658         public static function clearCache() {
1659                 self::$debugMode = null;
1660         }
1661
1662         /**
1663          * Build a load.php URL
1664          *
1665          * @since 1.24
1666          * @param string $source Name of the ResourceLoader source
1667          * @param ResourceLoaderContext $context
1668          * @param array $extraQuery
1669          * @return string URL to load.php. May be protocol-relative if $wgLoadScript is, too.
1670          */
1671         public function createLoaderURL( $source, ResourceLoaderContext $context,
1672                 $extraQuery = []
1673         ) {
1674                 $query = self::createLoaderQuery( $context, $extraQuery );
1675                 $script = $this->getLoadScript( $source );
1676
1677                 return wfAppendQuery( $script, $query );
1678         }
1679
1680         /**
1681          * Helper for createLoaderURL()
1682          *
1683          * @since 1.24
1684          * @see makeLoaderQuery
1685          * @param ResourceLoaderContext $context
1686          * @param array $extraQuery
1687          * @return array
1688          */
1689         protected static function createLoaderQuery( ResourceLoaderContext $context, $extraQuery = [] ) {
1690                 return self::makeLoaderQuery(
1691                         $context->getModules(),
1692                         $context->getLanguage(),
1693                         $context->getSkin(),
1694                         $context->getUser(),
1695                         $context->getVersion(),
1696                         $context->getDebug(),
1697                         $context->getOnly(),
1698                         $context->getRequest()->getBool( 'printable' ),
1699                         $context->getRequest()->getBool( 'handheld' ),
1700                         $extraQuery
1701                 );
1702         }
1703
1704         /**
1705          * Build a query array (array representation of query string) for load.php. Helper
1706          * function for createLoaderURL().
1707          *
1708          * @param array $modules
1709          * @param string $lang
1710          * @param string $skin
1711          * @param string|null $user
1712          * @param string|null $version
1713          * @param bool $debug
1714          * @param string|null $only
1715          * @param bool $printable
1716          * @param bool $handheld
1717          * @param array $extraQuery
1718          * @return array
1719          */
1720         public static function makeLoaderQuery( $modules, $lang, $skin, $user = null,
1721                 $version = null, $debug = false, $only = null, $printable = false,
1722                 $handheld = false, $extraQuery = []
1723         ) {
1724                 $query = [
1725                         'modules' => self::makePackedModulesString( $modules ),
1726                 ];
1727                 // Keep urls short by omitting query parameters that
1728                 // match the defaults assumed by ResourceLoaderContext.
1729                 // Note: This relies on the defaults either being insignificant or forever constant,
1730                 // as otherwise cached urls could change in meaning when the defaults change.
1731                 if ( $lang !== ResourceLoaderContext::DEFAULT_LANG ) {
1732                         $query['lang'] = $lang;
1733                 }
1734                 if ( $skin !== ResourceLoaderContext::DEFAULT_SKIN ) {
1735                         $query['skin'] = $skin;
1736                 }
1737                 if ( $debug === true ) {
1738                         $query['debug'] = 'true';
1739                 }
1740                 if ( $user !== null ) {
1741                         $query['user'] = $user;
1742                 }
1743                 if ( $version !== null ) {
1744                         $query['version'] = $version;
1745                 }
1746                 if ( $only !== null ) {
1747                         $query['only'] = $only;
1748                 }
1749                 if ( $printable ) {
1750                         $query['printable'] = 1;
1751                 }
1752                 if ( $handheld ) {
1753                         $query['handheld'] = 1;
1754                 }
1755                 $query += $extraQuery;
1756
1757                 // Make queries uniform in order
1758                 ksort( $query );
1759                 return $query;
1760         }
1761
1762         /**
1763          * Check a module name for validity.
1764          *
1765          * Module names may not contain pipes (|), commas (,) or exclamation marks (!) and can be
1766          * at most 255 bytes.
1767          *
1768          * @param string $moduleName Module name to check
1769          * @return bool Whether $moduleName is a valid module name
1770          */
1771         public static function isValidModuleName( $moduleName ) {
1772                 return strcspn( $moduleName, '!,|', 0, 255 ) === strlen( $moduleName );
1773         }
1774
1775         /**
1776          * Returns LESS compiler set up for use with MediaWiki
1777          *
1778          * @since 1.27
1779          * @param array $vars Associative array of variables that should be used
1780          *  for compilation. Since 1.32, this method no longer automatically includes
1781          *  global LESS vars from ResourceLoader::getLessVars (T191937).
1782          * @throws MWException
1783          * @return Less_Parser
1784          */
1785         public function getLessCompiler( $vars = [] ) {
1786                 global $IP;
1787                 // When called from the installer, it is possible that a required PHP extension
1788                 // is missing (at least for now; see T49564). If this is the case, throw an
1789                 // exception (caught by the installer) to prevent a fatal error later on.
1790                 if ( !class_exists( 'Less_Parser' ) ) {
1791                         throw new MWException( 'MediaWiki requires the less.php parser' );
1792                 }
1793
1794                 $parser = new Less_Parser;
1795                 $parser->ModifyVars( $vars );
1796                 $parser->SetImportDirs( [
1797                         "$IP/resources/src/mediawiki.less/" => '',
1798                 ] );
1799                 $parser->SetOption( 'relativeUrls', false );
1800
1801                 return $parser;
1802         }
1803
1804         /**
1805          * Get global LESS variables.
1806          *
1807          * @since 1.27
1808          * @deprecated since 1.32 Use ResourceLoderModule::getLessVars() instead.
1809          * @return array Map of variable names to string CSS values.
1810          */
1811         public function getLessVars() {
1812                 return [];
1813         }
1814 }