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