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