includes/resourceloader/ResourceLoader.php

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