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