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 use Wikimedia\Rdbms\DBConnectionError;
  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         protected static $filterCacheVersion = 7;
  41
  42         /** @var bool */
  43         protected static $debugMode = null;
  44
  45         /** @var array */
  46         private $lessVars = null;
  47
  48         /**
  49          * Module name/ResourceLoaderModule object pairs
  50          * @var array
  51          */
  52         protected $modules = [];
  53
  54         /**
  55          * Associative array mapping module name to info associative array
  56          * @var array
  57          */
  58         protected $moduleInfos = [];
  59
  60         /** @var Config $config */
  61         protected $config;
  62
  63         /**
  64          * Associative array mapping framework ids to a list of names of test suite modules
  65          * like [ 'qunit' => [ 'mediawiki.tests.qunit.suites', 'ext.foo.tests', ... ], ... ]
  66          * @var array
  67          */
  68         protected $testModuleNames = [];
  69
  70         /**
  71          * E.g. [ 'source-id' => 'http://.../load.php' ]
  72          * @var array
  73          */
  74         protected $sources = [];
  75
  76         /**
  77          * Errors accumulated during current respond() call.
  78          * @var array
  79          */
  80         protected $errors = [];
  81
  82         /**
  83          * @var MessageBlobStore
  84          */
  85         protected $blobStore;
  86
  87         /**
  88          * @var LoggerInterface
  89          */
  90         private $logger;
  91
  92         /** @var string JavaScript / CSS pragma to disable minification. **/
  93         const FILTER_NOMIN = '/*@nomin*/';
  94
  95         /**
  96          * Load information stored in the database about modules.
  97          *
  98          * This method grabs modules dependencies from the database and updates modules
  99          * objects.
 100          *
 101          * This is not inside the module code because it is much faster to
 102          * request all of the information at once than it is to have each module
 103          * requests its own information. This sacrifice of modularity yields a substantial
 104          * performance improvement.
 105          *
 106          * @param array $moduleNames List of module names to preload information for
 107          * @param ResourceLoaderContext $context Context to load the information within
 108          */
 109         public function preloadModuleInfo( array $moduleNames, ResourceLoaderContext $context ) {
 110                 if ( !$moduleNames ) {
 111                         // Or else Database*::select() will explode, plus it's cheaper!
 112                         return;
 113                 }
 114                 $dbr = wfGetDB( DB_REPLICA );
 115                 $skin = $context->getSkin();
 116                 $lang = $context->getLanguage();
 117
 118                 // Batched version of ResourceLoaderModule::getFileDependencies
 119                 $vary = "$skin|$lang";
 120                 $res = $dbr->select( 'module_deps', [ 'md_module', 'md_deps' ], [
 121                                 'md_module' => $moduleNames,
 122                                 'md_skin' => $vary,
 123                         ], __METHOD__
 124                 );
 125
 126                 // Prime in-object cache for file dependencies
 127                 $modulesWithDeps = [];
 128                 foreach ( $res as $row ) {
 129                         $module = $this->getModule( $row->md_module );
 130                         if ( $module ) {
 131                                 $module->setFileDependencies( $context, ResourceLoaderModule::expandRelativePaths(
 132                                         FormatJson::decode( $row->md_deps, true )
 133                                 ) );
 134                                 $modulesWithDeps[] = $row->md_module;
 135                         }
 136                 }
 137                 // Register the absence of a dependency row too
 138                 foreach ( array_diff( $moduleNames, $modulesWithDeps ) as $name ) {
 139                         $module = $this->getModule( $name );
 140                         if ( $module ) {
 141                                 $this->getModule( $name )->setFileDependencies( $context, [] );
 142                         }
 143                 }
 144
 145                 // Batched version of ResourceLoaderWikiModule::getTitleInfo
 146                 ResourceLoaderWikiModule::preloadTitleInfo( $context, $dbr, $moduleNames );
 147
 148                 // Prime in-object cache for message blobs for modules with messages
 149                 $modules = [];
 150                 foreach ( $moduleNames as $name ) {
 151                         $module = $this->getModule( $name );
 152                         if ( $module && $module->getMessages() ) {
 153                                 $modules[$name] = $module;
 154                         }
 155                 }
 156                 $store = $this->getMessageBlobStore();
 157                 $blobs = $store->getBlobs( $modules, $lang );
 158                 foreach ( $blobs as $name => $blob ) {
 159                         $modules[$name]->setMessageBlob( $blob, $lang );
 160                 }
 161         }
 162
 163         /**
 164          * Run JavaScript or CSS data through a filter, caching the filtered result for future calls.
 165          *
 166          * Available filters are:
 167          *
 168          *    - minify-js \see JavaScriptMinifier::minify
 169          *    - minify-css \see CSSMin::minify
 170          *
 171          * If $data is empty, only contains whitespace or the filter was unknown,
 172          * $data is returned unmodified.
 173          *
 174          * @param string $filter Name of filter to run
 175          * @param string $data Text to filter, such as JavaScript or CSS text
 176          * @param array $options Keys:
 177          *  - (bool) cache: Whether to allow caching this data. Default: true.
 178          * @return string Filtered data, or a comment containing an error message
 179          */
 180         public static function filter( $filter, $data, array $options = [] ) {
 181                 if ( strpos( $data, ResourceLoader::FILTER_NOMIN ) !== false ) {
 182                         return $data;
 183                 }
 184
 185                 if ( isset( $options['cache'] ) && $options['cache'] === false ) {
 186                         return self::applyFilter( $filter, $data );
 187                 }
 188
 189                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 190                 $cache = ObjectCache::getLocalServerInstance( CACHE_ANYTHING );
 191
 192                 $key = $cache->makeGlobalKey(
 193                         'resourceloader',
 194                         'filter',
 195                         $filter,
 196                         self::$filterCacheVersion, md5( $data )
 197                 );
 198
 199                 $result = $cache->get( $key );
 200                 if ( $result === false ) {
 201                         $stats->increment( "resourceloader_cache.$filter.miss" );
 202                         $result = self::applyFilter( $filter, $data );
 203                         $cache->set( $key, $result, 24 * 3600 );
 204                 } else {
 205                         $stats->increment( "resourceloader_cache.$filter.hit" );
 206                 }
 207                 if ( $result === null ) {
 208                         // Cached failure
 209                         $result = $data;
 210                 }
 211
 212                 return $result;
 213         }
 214
 215         private static function applyFilter( $filter, $data ) {
 216                 $data = trim( $data );
 217                 if ( $data ) {
 218                         try {
 219                                 $data = ( $filter === 'minify-css' )
 220                                         ? CSSMin::minify( $data )
 221                                         : JavaScriptMinifier::minify( $data );
 222                         } catch ( Exception $e ) {
 223                                 MWExceptionHandler::logException( $e );
 224                                 return null;
 225                         }
 226                 }
 227                 return $data;
 228         }
 229
 230         /* Methods */
 231
 232         /**
 233          * Register core modules and runs registration hooks.
 234          * @param Config $config [optional]
 235          * @param LoggerInterface $logger [optional]
 236          */
 237         public function __construct( Config $config = null, LoggerInterface $logger = null ) {
 238                 global $IP;
 239
 240                 $this->logger = $logger ?: new NullLogger();
 241
 242                 if ( !$config ) {
 243                         $this->logger->debug( __METHOD__ . ' was called without providing a Config instance' );
 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                 // Add other sources
 252                 $this->addSource( $config->get( 'ResourceLoaderSources' ) );
 253
 254                 // Register core modules
 255                 $this->register( include "$IP/resources/Resources.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                         } elseif ( isset( $info['factory'] ) ) {
 544                                 $object = call_user_func( $info['factory'], $info );
 545                                 $object->setConfig( $this->getConfig() );
 546                                 $object->setLogger( $this->logger );
 547                         } else {
 548                                 if ( !isset( $info['class'] ) ) {
 549                                         $class = 'ResourceLoaderFileModule';
 550                                 } else {
 551                                         $class = $info['class'];
 552                                 }
 553                                 /** @var ResourceLoaderModule $object */
 554                                 $object = new $class( $info );
 555                                 $object->setConfig( $this->getConfig() );
 556                                 $object->setLogger( $this->logger );
 557                         }
 558                         $object->setName( $name );
 559                         $this->modules[$name] = $object;
 560                 }
 561
 562                 return $this->modules[$name];
 563         }
 564
 565         /**
 566          * Return whether the definition of a module corresponds to a simple ResourceLoaderFileModule.
 567          *
 568          * @param string $name Module name
 569          * @return bool
 570          */
 571         protected function isFileModule( $name ) {
 572                 if ( !isset( $this->moduleInfos[$name] ) ) {
 573                         return false;
 574                 }
 575                 $info = $this->moduleInfos[$name];
 576                 if (
 577                         isset( $info['object'] ) ||
 578                         // This special case is dumb, but we need $wgResourceModuleSkinStyles
 579                         // to work for 'oojs-ui-core.styles'. See T167042.
 580                         ( isset( $info['class'] ) && $info['class'] !== 'ResourceLoaderOOUIFileModule' )
 581                 ) {
 582                         return false;
 583                 }
 584                 return true;
 585         }
 586
 587         /**
 588          * Get the list of sources.
 589          *
 590          * @return array Like [ id => load.php url, ... ]
 591          */
 592         public function getSources() {
 593                 return $this->sources;
 594         }
 595
 596         /**
 597          * Get the URL to the load.php endpoint for the given
 598          * ResourceLoader source
 599          *
 600          * @since 1.24
 601          * @param string $source
 602          * @throws MWException On an invalid $source name
 603          * @return string
 604          */
 605         public function getLoadScript( $source ) {
 606                 if ( !isset( $this->sources[$source] ) ) {
 607                         throw new MWException( "The $source source was never registered in ResourceLoader." );
 608                 }
 609                 return $this->sources[$source];
 610         }
 611
 612         /**
 613          * @since 1.26
 614          * @param string $value
 615          * @return string Hash
 616          */
 617         public static function makeHash( $value ) {
 618                 $hash = hash( 'fnv132', $value );
 619                 return Wikimedia\base_convert( $hash, 16, 36, 7 );
 620         }
 621
 622         /**
 623          * Add an error to the 'errors' array and log it.
 624          *
 625          * Should only be called from within respond().
 626          *
 627          * @since 1.29
 628          * @param Exception $e
 629          * @param string $msg
 630          * @param array $context
 631          */
 632         protected function outputErrorAndLog( Exception $e, $msg, array $context = [] ) {
 633                 MWExceptionHandler::logException( $e );
 634                 $this->logger->warning(
 635                         $msg,
 636                         $context + [ 'exception' => $e ]
 637                 );
 638                 $this->errors[] = self::formatExceptionNoComment( $e );
 639         }
 640
 641         /**
 642          * Helper method to get and combine versions of multiple modules.
 643          *
 644          * @since 1.26
 645          * @param ResourceLoaderContext $context
 646          * @param string[] $modules List of known module names
 647          * @return string Hash
 648          */
 649         public function getCombinedVersion( ResourceLoaderContext $context, array $moduleNames ) {
 650                 if ( !$moduleNames ) {
 651                         return '';
 652                 }
 653                 $hashes = array_map( function ( $module ) use ( $context ) {
 654                         try {
 655                                 return $this->getModule( $module )->getVersionHash( $context );
 656                         } catch ( Exception $e ) {
 657                                 // If modules fail to compute a version, do still consider the versions
 658                                 // of other modules - don't set an empty string E-Tag for the whole request.
 659                                 // See also T152266 and StartupModule::getModuleRegistrations().
 660                                 $this->outputErrorAndLog( $e,
 661                                         'Calculating version for "{module}" failed: {exception}',
 662                                         [
 663                                                 'module' => $module,
 664                                         ]
 665                                 );
 666                                 return '';
 667                         }
 668                 }, $moduleNames );
 669                 return self::makeHash( implode( '', $hashes ) );
 670         }
 671
 672         /**
 673          * Get the expected value of the 'version' query parameter.
 674          *
 675          * This is used by respond() to set a short Cache-Control header for requests with
 676          * information newer than the current server has. This avoids pollution of edge caches.
 677          * Typically during deployment. (T117587)
 678          *
 679          * This MUST match return value of `mw.loader#getCombinedVersion()` client-side.
 680          *
 681          * @since 1.28
 682          * @param ResourceLoaderContext $context
 683          * @param string[] $modules List of module names
 684          * @return string Hash
 685          */
 686         public function makeVersionQuery( ResourceLoaderContext $context ) {
 687                 // As of MediaWiki 1.28, the server and client use the same algorithm for combining
 688                 // version hashes. There is no technical reason for this to be same, and for years the
 689                 // implementations differed. If getCombinedVersion in PHP (used for StartupModule and
 690                 // E-Tag headers) differs in the future from getCombinedVersion in JS (used for 'version'
 691                 // query parameter), then this method must continue to match the JS one.
 692                 $moduleNames = [];
 693                 foreach ( $context->getModules() as $name ) {
 694                         if ( !$this->getModule( $name ) ) {
 695                                 // If a versioned request contains a missing module, the version is a mismatch
 696                                 // as the client considered a module (and version) we don't have.
 697                                 return '';
 698                         }
 699                         $moduleNames[] = $name;
 700                 }
 701                 return $this->getCombinedVersion( $context, $moduleNames );
 702         }
 703
 704         /**
 705          * Output a response to a load request, including the content-type header.
 706          *
 707          * @param ResourceLoaderContext $context Context in which a response should be formed
 708          */
 709         public function respond( ResourceLoaderContext $context ) {
 710                 // Buffer output to catch warnings. Normally we'd use ob_clean() on the
 711                 // top-level output buffer to clear warnings, but that breaks when ob_gzhandler
 712                 // is used: ob_clean() will clear the GZIP header in that case and it won't come
 713                 // back for subsequent output, resulting in invalid GZIP. So we have to wrap
 714                 // the whole thing in our own output buffer to be sure the active buffer
 715                 // doesn't use ob_gzhandler.
 716                 // See https://bugs.php.net/bug.php?id=36514
 717                 ob_start();
 718
 719                 // Find out which modules are missing and instantiate the others
 720                 $modules = [];
 721                 $missing = [];
 722                 foreach ( $context->getModules() as $name ) {
 723                         $module = $this->getModule( $name );
 724                         if ( $module ) {
 725                                 // Do not allow private modules to be loaded from the web.
 726                                 // This is a security issue, see T36907.
 727                                 if ( $module->getGroup() === 'private' ) {
 728                                         $this->logger->debug( "Request for private module '$name' denied" );
 729                                         $this->errors[] = "Cannot show private module \"$name\"";
 730                                         continue;
 731                                 }
 732                                 $modules[$name] = $module;
 733                         } else {
 734                                 $missing[] = $name;
 735                         }
 736                 }
 737
 738                 try {
 739                         // Preload for getCombinedVersion() and for batch makeModuleResponse()
 740                         $this->preloadModuleInfo( array_keys( $modules ), $context );
 741                 } catch ( Exception $e ) {
 742                         $this->outputErrorAndLog( $e, 'Preloading module info failed: {exception}' );
 743                 }
 744
 745                 // Combine versions to propagate cache invalidation
 746                 $versionHash = '';
 747                 try {
 748                         $versionHash = $this->getCombinedVersion( $context, array_keys( $modules ) );
 749                 } catch ( Exception $e ) {
 750                         $this->outputErrorAndLog( $e, 'Calculating version hash failed: {exception}' );
 751                 }
 752
 753                 // See RFC 2616 § 3.11 Entity Tags
 754                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.11
 755                 $etag = 'W/"' . $versionHash . '"';
 756
 757                 // Try the client-side cache first
 758                 if ( $this->tryRespondNotModified( $context, $etag ) ) {
 759                         return; // output handled (buffers cleared)
 760                 }
 761
 762                 // Use file cache if enabled and available...
 763                 if ( $this->config->get( 'UseFileCache' ) ) {
 764                         $fileCache = ResourceFileCache::newFromContext( $context );
 765                         if ( $this->tryRespondFromFileCache( $fileCache, $context, $etag ) ) {
 766                                 return; // output handled
 767                         }
 768                 }
 769
 770                 // Generate a response
 771                 $response = $this->makeModuleResponse( $context, $modules, $missing );
 772
 773                 // Capture any PHP warnings from the output buffer and append them to the
 774                 // error list if we're in debug mode.
 775                 if ( $context->getDebug() ) {
 776                         $warnings = ob_get_contents();
 777                         if ( strlen( $warnings ) ) {
 778                                 $this->errors[] = $warnings;
 779                         }
 780                 }
 781
 782                 // Save response to file cache unless there are errors
 783                 if ( isset( $fileCache ) && !$this->errors && !count( $missing ) ) {
 784                         // Cache single modules and images...and other requests if there are enough hits
 785                         if ( ResourceFileCache::useFileCache( $context ) ) {
 786                                 if ( $fileCache->isCacheWorthy() ) {
 787                                         $fileCache->saveText( $response );
 788                                 } else {
 789                                         $fileCache->incrMissesRecent( $context->getRequest() );
 790                                 }
 791                         }
 792                 }
 793
 794                 $this->sendResponseHeaders( $context, $etag, (bool)$this->errors );
 795
 796                 // Remove the output buffer and output the response
 797                 ob_end_clean();
 798
 799                 if ( $context->getImageObj() && $this->errors ) {
 800                         // We can't show both the error messages and the response when it's an image.
 801                         $response = implode( "\n\n", $this->errors );
 802                 } elseif ( $this->errors ) {
 803                         $errorText = implode( "\n\n", $this->errors );
 804                         $errorResponse = self::makeComment( $errorText );
 805                         if ( $context->shouldIncludeScripts() ) {
 806                                 $errorResponse .= 'if (window.console && console.error) {'
 807                                         . Xml::encodeJsCall( 'console.error', [ $errorText ] )
 808                                         . "}\n";
 809                         }
 810
 811                         // Prepend error info to the response
 812                         $response = $errorResponse . $response;
 813                 }
 814
 815                 $this->errors = [];
 816                 echo $response;
 817         }
 818
 819         /**
 820          * Send main response headers to the client.
 821          *
 822          * Deals with Content-Type, CORS (for stylesheets), and caching.
 823          *
 824          * @param ResourceLoaderContext $context
 825          * @param string $etag ETag header value
 826          * @param bool $errors Whether there are errors in the response
 827          * @return void
 828          */
 829         protected function sendResponseHeaders( ResourceLoaderContext $context, $etag, $errors ) {
 830                 \MediaWiki\HeaderCallback::warnIfHeadersSent();
 831                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 832                 // Use a short cache expiry so that updates propagate to clients quickly, if:
 833                 // - No version specified (shared resources, e.g. stylesheets)
 834                 // - There were errors (recover quickly)
 835                 // - Version mismatch (T117587, T47877)
 836                 if ( is_null( $context->getVersion() )
 837                         || $errors
 838                         || $context->getVersion() !== $this->makeVersionQuery( $context )
 839                 ) {
 840                         $maxage = $rlMaxage['unversioned']['client'];
 841                         $smaxage = $rlMaxage['unversioned']['server'];
 842                 // If a version was specified we can use a longer expiry time since changing
 843                 // version numbers causes cache misses
 844                 } else {
 845                         $maxage = $rlMaxage['versioned']['client'];
 846                         $smaxage = $rlMaxage['versioned']['server'];
 847                 }
 848                 if ( $context->getImageObj() ) {
 849                         // Output different headers if we're outputting textual errors.
 850                         if ( $errors ) {
 851                                 header( 'Content-Type: text/plain; charset=utf-8' );
 852                         } else {
 853                                 $context->getImageObj()->sendResponseHeaders( $context );
 854                         }
 855                 } elseif ( $context->getOnly() === 'styles' ) {
 856                         header( 'Content-Type: text/css; charset=utf-8' );
 857                         header( 'Access-Control-Allow-Origin: *' );
 858                 } else {
 859                         header( 'Content-Type: text/javascript; charset=utf-8' );
 860                 }
 861                 // See RFC 2616 § 14.19 ETag
 862                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.19
 863                 header( 'ETag: ' . $etag );
 864                 if ( $context->getDebug() ) {
 865                         // Do not cache debug responses
 866                         header( 'Cache-Control: private, no-cache, must-revalidate' );
 867                         header( 'Pragma: no-cache' );
 868                 } else {
 869                         header( "Cache-Control: public, max-age=$maxage, s-maxage=$smaxage" );
 870                         $exp = min( $maxage, $smaxage );
 871                         header( 'Expires: ' . wfTimestamp( TS_RFC2822, $exp + time() ) );
 872                 }
 873         }
 874
 875         /**
 876          * Respond with HTTP 304 Not Modified if appropiate.
 877          *
 878          * If there's an If-None-Match header, respond with a 304 appropriately
 879          * and clear out the output buffer. If the client cache is too old then do nothing.
 880          *
 881          * @param ResourceLoaderContext $context
 882          * @param string $etag ETag header value
 883          * @return bool True if HTTP 304 was sent and output handled
 884          */
 885         protected function tryRespondNotModified( ResourceLoaderContext $context, $etag ) {
 886                 // See RFC 2616 § 14.26 If-None-Match
 887                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.26
 888                 $clientKeys = $context->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST );
 889                 // Never send 304s in debug mode
 890                 if ( $clientKeys !== false && !$context->getDebug() && in_array( $etag, $clientKeys ) ) {
 891                         // There's another bug in ob_gzhandler (see also the comment at
 892                         // the top of this function) that causes it to gzip even empty
 893                         // responses, meaning it's impossible to produce a truly empty
 894                         // response (because the gzip header is always there). This is
 895                         // a problem because 304 responses have to be completely empty
 896                         // per the HTTP spec, and Firefox behaves buggily when they're not.
 897                         // See also https://bugs.php.net/bug.php?id=51579
 898                         // To work around this, we tear down all output buffering before
 899                         // sending the 304.
 900                         wfResetOutputBuffers( /* $resetGzipEncoding = */ true );
 901
 902                         HttpStatus::header( 304 );
 903
 904                         $this->sendResponseHeaders( $context, $etag, false );
 905                         return true;
 906                 }
 907                 return false;
 908         }
 909
 910         /**
 911          * Send out code for a response from file cache if possible.
 912          *
 913          * @param ResourceFileCache $fileCache Cache object for this request URL
 914          * @param ResourceLoaderContext $context Context in which to generate a response
 915          * @param string $etag ETag header value
 916          * @return bool If this found a cache file and handled the response
 917          */
 918         protected function tryRespondFromFileCache(
 919                 ResourceFileCache $fileCache,
 920                 ResourceLoaderContext $context,
 921                 $etag
 922         ) {
 923                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 924                 // Buffer output to catch warnings.
 925                 ob_start();
 926                 // Get the maximum age the cache can be
 927                 $maxage = is_null( $context->getVersion() )
 928                         ? $rlMaxage['unversioned']['server']
 929                         : $rlMaxage['versioned']['server'];
 930                 // Minimum timestamp the cache file must have
 931                 $good = $fileCache->isCacheGood( wfTimestamp( TS_MW, time() - $maxage ) );
 932                 if ( !$good ) {
 933                         try { // RL always hits the DB on file cache miss...
 934                                 wfGetDB( DB_REPLICA );
 935                         } catch ( DBConnectionError $e ) { // ...check if we need to fallback to cache
 936                                 $good = $fileCache->isCacheGood(); // cache existence check
 937                         }
 938                 }
 939                 if ( $good ) {
 940                         $ts = $fileCache->cacheTimestamp();
 941                         // Send content type and cache headers
 942                         $this->sendResponseHeaders( $context, $etag, false );
 943                         $response = $fileCache->fetchText();
 944                         // Capture any PHP warnings from the output buffer and append them to the
 945                         // response in a comment if we're in debug mode.
 946                         if ( $context->getDebug() ) {
 947                                 $warnings = ob_get_contents();
 948                                 if ( strlen( $warnings ) ) {
 949                                         $response = self::makeComment( $warnings ) . $response;
 950                                 }
 951                         }
 952                         // Remove the output buffer and output the response
 953                         ob_end_clean();
 954                         echo $response . "\n/* Cached {$ts} */";
 955                         return true; // cache hit
 956                 }
 957                 // Clear buffer
 958                 ob_end_clean();
 959
 960                 return false; // cache miss
 961         }
 962
 963         /**
 964          * Generate a CSS or JS comment block.
 965          *
 966          * Only use this for public data, not error message details.
 967          *
 968          * @param string $text
 969          * @return string
 970          */
 971         public static function makeComment( $text ) {
 972                 $encText = str_replace( '*/', '* /', $text );
 973                 return "/*\n$encText\n*/\n";
 974         }
 975
 976         /**
 977          * Handle exception display.
 978          *
 979          * @param Exception $e Exception to be shown to the user
 980          * @return string Sanitized text in a CSS/JS comment that can be returned to the user
 981          */
 982         public static function formatException( $e ) {
 983                 return self::makeComment( self::formatExceptionNoComment( $e ) );
 984         }
 985
 986         /**
 987          * Handle exception display.
 988          *
 989          * @since 1.25
 990          * @param Exception $e Exception to be shown to the user
 991          * @return string Sanitized text that can be returned to the user
 992          */
 993         protected static function formatExceptionNoComment( $e ) {
 994                 global $wgShowExceptionDetails;
 995
 996                 if ( !$wgShowExceptionDetails ) {
 997                         return MWExceptionHandler::getPublicLogMessage( $e );
 998                 }
 999
1000                 return MWExceptionHandler::getLogMessage( $e ) .
1001                         "\nBacktrace:\n" .
1002                         MWExceptionHandler::getRedactedTraceAsString( $e );
1003         }
1004
1005         /**
1006          * Generate code for a response.
1007          *
1008          * @param ResourceLoaderContext $context Context in which to generate a response
1009          * @param ResourceLoaderModule[] $modules List of module objects keyed by module name
1010          * @param string[] $missing List of requested module names that are unregistered (optional)
1011          * @return string Response data
1012          */
1013         public function makeModuleResponse( ResourceLoaderContext $context,
1014                 array $modules, array $missing = []
1015         ) {
1016                 $out = '';
1017                 $states = [];
1018
1019                 if ( !count( $modules ) && !count( $missing ) ) {
1020                         return <<<MESSAGE
1021 /* This file is the Web entry point for MediaWiki's ResourceLoader:
1022    <https://www.mediawiki.org/wiki/ResourceLoader>. In this request,
1023    no modules were requested. Max made me put this here. */
1024 MESSAGE;
1025                 }
1026
1027                 $image = $context->getImageObj();
1028                 if ( $image ) {
1029                         $data = $image->getImageData( $context );
1030                         if ( $data === false ) {
1031                                 $data = '';
1032                                 $this->errors[] = 'Image generation failed';
1033                         }
1034                         return $data;
1035                 }
1036
1037                 foreach ( $missing as $name ) {
1038                         $states[$name] = 'missing';
1039                 }
1040
1041                 // Generate output
1042                 $isRaw = false;
1043
1044                 $filter = $context->getOnly() === 'styles' ? 'minify-css' : 'minify-js';
1045
1046                 foreach ( $modules as $name => $module ) {
1047                         try {
1048                                 $content = $module->getModuleContent( $context );
1049                                 $implementKey = $name . '@' . $module->getVersionHash( $context );
1050                                 $strContent = '';
1051
1052                                 // Append output
1053                                 switch ( $context->getOnly() ) {
1054                                         case 'scripts':
1055                                                 $scripts = $content['scripts'];
1056                                                 if ( is_string( $scripts ) ) {
1057                                                         // Load scripts raw...
1058                                                         $strContent = $scripts;
1059                                                 } elseif ( is_array( $scripts ) ) {
1060                                                         // ...except when $scripts is an array of URLs
1061                                                         $strContent = self::makeLoaderImplementScript( $implementKey, $scripts, [], [], [] );
1062                                                 }
1063                                                 break;
1064                                         case 'styles':
1065                                                 $styles = $content['styles'];
1066                                                 // We no longer seperate into media, they are all combined now with
1067                                                 // custom media type groups into @media .. {} sections as part of the css string.
1068                                                 // Module returns either an empty array or a numerical array with css strings.
1069                                                 $strContent = isset( $styles['css'] ) ? implode( '', $styles['css'] ) : '';
1070                                                 break;
1071                                         default:
1072                                                 $scripts = isset( $content['scripts'] ) ? $content['scripts'] : '';
1073                                                 if ( is_string( $scripts ) ) {
1074                                                         if ( $name === 'site' || $name === 'user' ) {
1075                                                                 // Legacy scripts that run in the global scope without a closure.
1076                                                                 // mw.loader.implement will use globalEval if scripts is a string.
1077                                                                 // Minify manually here, because general response minification is
1078                                                                 // not effective due it being a string literal, not a function.
1079                                                                 if ( !ResourceLoader::inDebugMode() ) {
1080                                                                         $scripts = self::filter( 'minify-js', $scripts ); // T107377
1081                                                                 }
1082                                                         } else {
1083                                                                 $scripts = new XmlJsCode( $scripts );
1084                                                         }
1085                                                 }
1086                                                 $strContent = self::makeLoaderImplementScript(
1087                                                         $implementKey,
1088                                                         $scripts,
1089                                                         isset( $content['styles'] ) ? $content['styles'] : [],
1090                                                         isset( $content['messagesBlob'] ) ? new XmlJsCode( $content['messagesBlob'] ) : [],
1091                                                         isset( $content['templates'] ) ? $content['templates'] : []
1092                                                 );
1093                                                 break;
1094                                 }
1095
1096                                 if ( !$context->getDebug() ) {
1097                                         $strContent = self::filter( $filter, $strContent );
1098                                 }
1099
1100                                 $out .= $strContent;
1101
1102                         } catch ( Exception $e ) {
1103                                 $this->outputErrorAndLog( $e, 'Generating module package failed: {exception}' );
1104
1105                                 // Respond to client with error-state instead of module implementation
1106                                 $states[$name] = 'error';
1107                                 unset( $modules[$name] );
1108                         }
1109                         $isRaw |= $module->isRaw();
1110                 }
1111
1112                 // Update module states
1113                 if ( $context->shouldIncludeScripts() && !$context->getRaw() && !$isRaw ) {
1114                         if ( count( $modules ) && $context->getOnly() === 'scripts' ) {
1115                                 // Set the state of modules loaded as only scripts to ready as
1116                                 // they don't have an mw.loader.implement wrapper that sets the state
1117                                 foreach ( $modules as $name => $module ) {
1118                                         $states[$name] = 'ready';
1119                                 }
1120                         }
1121
1122                         // Set the state of modules we didn't respond to with mw.loader.implement
1123                         if ( count( $states ) ) {
1124                                 $stateScript = self::makeLoaderStateScript( $states );
1125                                 if ( !$context->getDebug() ) {
1126                                         $stateScript = self::filter( 'minify-js', $stateScript );
1127                                 }
1128                                 $out .= $stateScript;
1129                         }
1130                 } else {
1131                         if ( count( $states ) ) {
1132                                 $this->errors[] = 'Problematic modules: ' .
1133                                         FormatJson::encode( $states, ResourceLoader::inDebugMode() );
1134                         }
1135                 }
1136
1137                 return $out;
1138         }
1139
1140         /**
1141          * Get names of modules that use a certain message.
1142          *
1143          * @param string $messageKey
1144          * @return array List of module names
1145          */
1146         public function getModulesByMessage( $messageKey ) {
1147                 $moduleNames = [];
1148                 foreach ( $this->getModuleNames() as $moduleName ) {
1149                         $module = $this->getModule( $moduleName );
1150                         if ( in_array( $messageKey, $module->getMessages() ) ) {
1151                                 $moduleNames[] = $moduleName;
1152                         }
1153                 }
1154                 return $moduleNames;
1155         }
1156
1157         /* Static Methods */
1158
1159         /**
1160          * Return JS code that calls mw.loader.implement with given module properties.
1161          *
1162          * @param string $name Module name or implement key (format "`[name]@[version]`")
1163          * @param XmlJsCode|array|string $scripts Code as XmlJsCode (to be wrapped in a closure),
1164          *  list of URLs to JavaScript files, or a string of JavaScript for `$.globalEval`.
1165          * @param mixed $styles Array of CSS strings keyed by media type, or an array of lists of URLs
1166          *   to CSS files keyed by media type
1167          * @param mixed $messages List of messages associated with this module. May either be an
1168          *   associative array mapping message key to value, or a JSON-encoded message blob containing
1169          *   the same data, wrapped in an XmlJsCode object.
1170          * @param array $templates Keys are name of templates and values are the source of
1171          *   the template.
1172          * @throws MWException
1173          * @return string JavaScript code
1174          */
1175         protected static function makeLoaderImplementScript(
1176                 $name, $scripts, $styles, $messages, $templates
1177         ) {
1178                 if ( $scripts instanceof XmlJsCode ) {
1179                         $scripts = new XmlJsCode( "function ( $, jQuery, require, module ) {\n{$scripts->value}\n}" );
1180                 } elseif ( !is_string( $scripts ) && !is_array( $scripts ) ) {
1181                         throw new MWException( 'Invalid scripts error. Array of URLs or string of code expected.' );
1182                 }
1183                 // mw.loader.implement requires 'styles', 'messages' and 'templates' to be objects (not
1184                 // arrays). json_encode considers empty arrays to be numerical and outputs "[]" instead
1185                 // of "{}". Force them to objects.
1186                 $module = [
1187                         $name,
1188                         $scripts,
1189                         (object)$styles,
1190                         (object)$messages,
1191                         (object)$templates,
1192                 ];
1193                 self::trimArray( $module );
1194
1195                 return Xml::encodeJsCall( 'mw.loader.implement', $module, ResourceLoader::inDebugMode() );
1196         }
1197
1198         /**
1199          * Returns JS code which, when called, will register a given list of messages.
1200          *
1201          * @param mixed $messages Either an associative array mapping message key to value, or a
1202          *   JSON-encoded message blob containing the same data, wrapped in an XmlJsCode object.
1203          * @return string JavaScript code
1204          */
1205         public static function makeMessageSetScript( $messages ) {
1206                 return Xml::encodeJsCall(
1207                         'mw.messages.set',
1208                         [ (object)$messages ],
1209                         ResourceLoader::inDebugMode()
1210                 );
1211         }
1212
1213         /**
1214          * Combines an associative array mapping media type to CSS into a
1215          * single stylesheet with "@media" blocks.
1216          *
1217          * @param array $stylePairs Array keyed by media type containing (arrays of) CSS strings
1218          * @return array
1219          */
1220         public static function makeCombinedStyles( array $stylePairs ) {
1221                 $out = [];
1222                 foreach ( $stylePairs as $media => $styles ) {
1223                         // ResourceLoaderFileModule::getStyle can return the styles
1224                         // as a string or an array of strings. This is to allow separation in
1225                         // the front-end.
1226                         $styles = (array)$styles;
1227                         foreach ( $styles as $style ) {
1228                                 $style = trim( $style );
1229                                 // Don't output an empty "@media print { }" block (T42498)
1230                                 if ( $style !== '' ) {
1231                                         // Transform the media type based on request params and config
1232                                         // The way that this relies on $wgRequest to propagate request params is slightly evil
1233                                         $media = OutputPage::transformCssMedia( $media );
1234
1235                                         if ( $media === '' || $media == 'all' ) {
1236                                                 $out[] = $style;
1237                                         } elseif ( is_string( $media ) ) {
1238                                                 $out[] = "@media $media {\n" . str_replace( "\n", "\n\t", "\t" . $style ) . "}";
1239                                         }
1240                                         // else: skip
1241                                 }
1242                         }
1243                 }
1244                 return $out;
1245         }
1246
1247         /**
1248          * Returns a JS call to mw.loader.state, which sets the state of a
1249          * module or modules to a given value. Has two calling conventions:
1250          *
1251          *    - ResourceLoader::makeLoaderStateScript( $name, $state ):
1252          *         Set the state of a single module called $name to $state
1253          *
1254          *    - ResourceLoader::makeLoaderStateScript( [ $name => $state, ... ] ):
1255          *         Set the state of modules with the given names to the given states
1256          *
1257          * @param string $name
1258          * @param string $state
1259          * @return string JavaScript code
1260          */
1261         public static function makeLoaderStateScript( $name, $state = null ) {
1262                 if ( is_array( $name ) ) {
1263                         return Xml::encodeJsCall(
1264                                 'mw.loader.state',
1265                                 [ $name ],
1266                                 ResourceLoader::inDebugMode()
1267                         );
1268                 } else {
1269                         return Xml::encodeJsCall(
1270                                 'mw.loader.state',
1271                                 [ $name, $state ],
1272                                 ResourceLoader::inDebugMode()
1273                         );
1274                 }
1275         }
1276
1277         /**
1278          * Returns JS code which calls the script given by $script. The script will
1279          * be called with local variables name, version, dependencies and group,
1280          * which will have values corresponding to $name, $version, $dependencies
1281          * and $group as supplied.
1282          *
1283          * @param string $name Module name
1284          * @param string $version Module version hash
1285          * @param array $dependencies List of module names on which this module depends
1286          * @param string $group Group which the module is in.
1287          * @param string $source Source of the module, or 'local' if not foreign.
1288          * @param string $script JavaScript code
1289          * @return string JavaScript code
1290          */
1291         public static function makeCustomLoaderScript( $name, $version, $dependencies,
1292                 $group, $source, $script
1293         ) {
1294                 $script = str_replace( "\n", "\n\t", trim( $script ) );
1295                 return Xml::encodeJsCall(
1296                         "( function ( name, version, dependencies, group, source ) {\n\t$script\n} )",
1297                         [ $name, $version, $dependencies, $group, $source ],
1298                         ResourceLoader::inDebugMode()
1299                 );
1300         }
1301
1302         private static function isEmptyObject( stdClass $obj ) {
1303                 foreach ( $obj as $key => $value ) {
1304                         return false;
1305                 }
1306                 return true;
1307         }
1308
1309         /**
1310          * Remove empty values from the end of an array.
1311          *
1312          * Values considered empty:
1313          *
1314          * - null
1315          * - []
1316          * - new XmlJsCode( '{}' )
1317          * - new stdClass() // (object) []
1318          *
1319          * @param Array $array
1320          */
1321         private static function trimArray( array &$array ) {
1322                 $i = count( $array );
1323                 while ( $i-- ) {
1324                         if ( $array[$i] === null
1325                                 || $array[$i] === []
1326                                 || ( $array[$i] instanceof XmlJsCode && $array[$i]->value === '{}' )
1327                                 || ( $array[$i] instanceof stdClass && self::isEmptyObject( $array[$i] ) )
1328                         ) {
1329                                 unset( $array[$i] );
1330                         } else {
1331                                 break;
1332                         }
1333                 }
1334         }
1335
1336         /**
1337          * Returns JS code which calls mw.loader.register with the given
1338          * parameters. Has three calling conventions:
1339          *
1340          *   - ResourceLoader::makeLoaderRegisterScript( $name, $version,
1341          *        $dependencies, $group, $source, $skip
1342          *     ):
1343          *        Register a single module.
1344          *
1345          *   - ResourceLoader::makeLoaderRegisterScript( [ $name1, $name2 ] ):
1346          *        Register modules with the given names.
1347          *
1348          *   - ResourceLoader::makeLoaderRegisterScript( [
1349          *        [ $name1, $version1, $dependencies1, $group1, $source1, $skip1 ],
1350          *        [ $name2, $version2, $dependencies1, $group2, $source2, $skip2 ],
1351          *        ...
1352          *     ] ):
1353          *        Registers modules with the given names and parameters.
1354          *
1355          * @param string $name Module name
1356          * @param string $version Module version hash
1357          * @param array $dependencies List of module names on which this module depends
1358          * @param string $group Group which the module is in
1359          * @param string $source Source of the module, or 'local' if not foreign
1360          * @param string $skip Script body of the skip function
1361          * @return string JavaScript code
1362          */
1363         public static function makeLoaderRegisterScript( $name, $version = null,
1364                 $dependencies = null, $group = null, $source = null, $skip = null
1365         ) {
1366                 if ( is_array( $name ) ) {
1367                         // Build module name index
1368                         $index = [];
1369                         foreach ( $name as $i => &$module ) {
1370                                 $index[$module[0]] = $i;
1371                         }
1372
1373                         // Transform dependency names into indexes when possible, they will be resolved by
1374                         // mw.loader.register on the other end
1375                         foreach ( $name as &$module ) {
1376                                 if ( isset( $module[2] ) ) {
1377                                         foreach ( $module[2] as &$dependency ) {
1378                                                 if ( isset( $index[$dependency] ) ) {
1379                                                         $dependency = $index[$dependency];
1380                                                 }
1381                                         }
1382                                 }
1383                         }
1384
1385                         array_walk( $name, [ 'self', 'trimArray' ] );
1386
1387                         return Xml::encodeJsCall(
1388                                 'mw.loader.register',
1389                                 [ $name ],
1390                                 ResourceLoader::inDebugMode()
1391                         );
1392                 } else {
1393                         $registration = [ $name, $version, $dependencies, $group, $source, $skip ];
1394                         self::trimArray( $registration );
1395                         return Xml::encodeJsCall(
1396                                 'mw.loader.register',
1397                                 $registration,
1398                                 ResourceLoader::inDebugMode()
1399                         );
1400                 }
1401         }
1402
1403         /**
1404          * Returns JS code which calls mw.loader.addSource() with the given
1405          * parameters. Has two calling conventions:
1406          *
1407          *   - ResourceLoader::makeLoaderSourcesScript( $id, $properties ):
1408          *       Register a single source
1409          *
1410          *   - ResourceLoader::makeLoaderSourcesScript( [ $id1 => $loadUrl, $id2 => $loadUrl, ... ] );
1411          *       Register sources with the given IDs and properties.
1412          *
1413          * @param string $id Source ID
1414          * @param string $loadUrl load.php url
1415          * @return string JavaScript code
1416          */
1417         public static function makeLoaderSourcesScript( $id, $loadUrl = null ) {
1418                 if ( is_array( $id ) ) {
1419                         return Xml::encodeJsCall(
1420                                 'mw.loader.addSource',
1421                                 [ $id ],
1422                                 ResourceLoader::inDebugMode()
1423                         );
1424                 } else {
1425                         return Xml::encodeJsCall(
1426                                 'mw.loader.addSource',
1427                                 [ $id, $loadUrl ],
1428                                 ResourceLoader::inDebugMode()
1429                         );
1430                 }
1431         }
1432
1433         /**
1434          * Returns JS code which runs given JS code if the client-side framework is
1435          * present.
1436          *
1437          * @deprecated since 1.25; use makeInlineScript instead
1438          * @param string $script JavaScript code
1439          * @return string JavaScript code
1440          */
1441         public static function makeLoaderConditionalScript( $script ) {
1442                 return '(window.RLQ=window.RLQ||[]).push(function(){' .
1443                         trim( $script ) . '});';
1444         }
1445
1446         /**
1447          * Construct an inline script tag with given JS code.
1448          *
1449          * The code will be wrapped in a closure, and it will be executed by ResourceLoader
1450          * only if the client has adequate support for MediaWiki JavaScript code.
1451          *
1452          * @param string $script JavaScript code
1453          * @return WrappedString HTML
1454          */
1455         public static function makeInlineScript( $script ) {
1456                 $js = self::makeLoaderConditionalScript( $script );
1457                 return new WrappedString(
1458                         Html::inlineScript( $js ),
1459                         '<script>(window.RLQ=window.RLQ||[]).push(function(){',
1460                         '});</script>'
1461                 );
1462         }
1463
1464         /**
1465          * Returns JS code which will set the MediaWiki configuration array to
1466          * the given value.
1467          *
1468          * @param array $configuration List of configuration values keyed by variable name
1469          * @return string JavaScript code
1470          */
1471         public static function makeConfigSetScript( array $configuration ) {
1472                 return Xml::encodeJsCall(
1473                         'mw.config.set',
1474                         [ $configuration ],
1475                         ResourceLoader::inDebugMode()
1476                 );
1477         }
1478
1479         /**
1480          * Convert an array of module names to a packed query string.
1481          *
1482          * For example, [ 'foo.bar', 'foo.baz', 'bar.baz', 'bar.quux' ]
1483          * becomes 'foo.bar,baz|bar.baz,quux'
1484          * @param array $modules List of module names (strings)
1485          * @return string Packed query string
1486          */
1487         public static function makePackedModulesString( $modules ) {
1488                 $groups = []; // [ prefix => [ suffixes ] ]
1489                 foreach ( $modules as $module ) {
1490                         $pos = strrpos( $module, '.' );
1491                         $prefix = $pos === false ? '' : substr( $module, 0, $pos );
1492                         $suffix = $pos === false ? $module : substr( $module, $pos + 1 );
1493                         $groups[$prefix][] = $suffix;
1494                 }
1495
1496                 $arr = [];
1497                 foreach ( $groups as $prefix => $suffixes ) {
1498                         $p = $prefix === '' ? '' : $prefix . '.';
1499                         $arr[] = $p . implode( ',', $suffixes );
1500                 }
1501                 $str = implode( '|', $arr );
1502                 return $str;
1503         }
1504
1505         /**
1506          * Determine whether debug mode was requested
1507          * Order of priority is 1) request param, 2) cookie, 3) $wg setting
1508          * @return bool
1509          */
1510         public static function inDebugMode() {
1511                 if ( self::$debugMode === null ) {
1512                         global $wgRequest, $wgResourceLoaderDebug;
1513                         self::$debugMode = $wgRequest->getFuzzyBool( 'debug',
1514                                 $wgRequest->getCookie( 'resourceLoaderDebug', '', $wgResourceLoaderDebug )
1515                         );
1516                 }
1517                 return self::$debugMode;
1518         }
1519
1520         /**
1521          * Reset static members used for caching.
1522          *
1523          * Global state and $wgRequest are evil, but we're using it right
1524          * now and sometimes we need to be able to force ResourceLoader to
1525          * re-evaluate the context because it has changed (e.g. in the test suite).
1526          */
1527         public static function clearCache() {
1528                 self::$debugMode = null;
1529         }
1530
1531         /**
1532          * Build a load.php URL
1533          *
1534          * @since 1.24
1535          * @param string $source Name of the ResourceLoader source
1536          * @param ResourceLoaderContext $context
1537          * @param array $extraQuery
1538          * @return string URL to load.php. May be protocol-relative if $wgLoadScript is, too.
1539          */
1540         public function createLoaderURL( $source, ResourceLoaderContext $context,
1541                 $extraQuery = []
1542         ) {
1543                 $query = self::createLoaderQuery( $context, $extraQuery );
1544                 $script = $this->getLoadScript( $source );
1545
1546                 return wfAppendQuery( $script, $query );
1547         }
1548
1549         /**
1550          * Helper for createLoaderURL()
1551          *
1552          * @since 1.24
1553          * @see makeLoaderQuery
1554          * @param ResourceLoaderContext $context
1555          * @param array $extraQuery
1556          * @return array
1557          */
1558         protected static function createLoaderQuery( ResourceLoaderContext $context, $extraQuery = [] ) {
1559                 return self::makeLoaderQuery(
1560                         $context->getModules(),
1561                         $context->getLanguage(),
1562                         $context->getSkin(),
1563                         $context->getUser(),
1564                         $context->getVersion(),
1565                         $context->getDebug(),
1566                         $context->getOnly(),
1567                         $context->getRequest()->getBool( 'printable' ),
1568                         $context->getRequest()->getBool( 'handheld' ),
1569                         $extraQuery
1570                 );
1571         }
1572
1573         /**
1574          * Build a query array (array representation of query string) for load.php. Helper
1575          * function for createLoaderURL().
1576          *
1577          * @param array $modules
1578          * @param string $lang
1579          * @param string $skin
1580          * @param string $user
1581          * @param string $version
1582          * @param bool $debug
1583          * @param string $only
1584          * @param bool $printable
1585          * @param bool $handheld
1586          * @param array $extraQuery
1587          *
1588          * @return array
1589          */
1590         public static function makeLoaderQuery( $modules, $lang, $skin, $user = null,
1591                 $version = null, $debug = false, $only = null, $printable = false,
1592                 $handheld = false, $extraQuery = []
1593         ) {
1594                 $query = [
1595                         'modules' => self::makePackedModulesString( $modules ),
1596                         'lang' => $lang,
1597                         'skin' => $skin,
1598                         'debug' => $debug ? 'true' : 'false',
1599                 ];
1600                 if ( $user !== null ) {
1601                         $query['user'] = $user;
1602                 }
1603                 if ( $version !== null ) {
1604                         $query['version'] = $version;
1605                 }
1606                 if ( $only !== null ) {
1607                         $query['only'] = $only;
1608                 }
1609                 if ( $printable ) {
1610                         $query['printable'] = 1;
1611                 }
1612                 if ( $handheld ) {
1613                         $query['handheld'] = 1;
1614                 }
1615                 $query += $extraQuery;
1616
1617                 // Make queries uniform in order
1618                 ksort( $query );
1619                 return $query;
1620         }
1621
1622         /**
1623          * Check a module name for validity.
1624          *
1625          * Module names may not contain pipes (|), commas (,) or exclamation marks (!) and can be
1626          * at most 255 bytes.
1627          *
1628          * @param string $moduleName Module name to check
1629          * @return bool Whether $moduleName is a valid module name
1630          */
1631         public static function isValidModuleName( $moduleName ) {
1632                 return strcspn( $moduleName, '!,|', 0, 255 ) === strlen( $moduleName );
1633         }
1634
1635         /**
1636          * Returns LESS compiler set up for use with MediaWiki
1637          *
1638          * @since 1.27
1639          * @param array $extraVars Associative array of extra (i.e., other than the
1640          *   globally-configured ones) that should be used for compilation.
1641          * @throws MWException
1642          * @return Less_Parser
1643          */
1644         public function getLessCompiler( $extraVars = [] ) {
1645                 // When called from the installer, it is possible that a required PHP extension
1646                 // is missing (at least for now; see T49564). If this is the case, throw an
1647                 // exception (caught by the installer) to prevent a fatal error later on.
1648                 if ( !class_exists( 'Less_Parser' ) ) {
1649                         throw new MWException( 'MediaWiki requires the less.php parser' );
1650                 }
1651
1652                 $parser = new Less_Parser;
1653                 $parser->ModifyVars( array_merge( $this->getLessVars(), $extraVars ) );
1654                 $parser->SetImportDirs(
1655                         array_fill_keys( $this->config->get( 'ResourceLoaderLESSImportPaths' ), '' )
1656                 );
1657                 $parser->SetOption( 'relativeUrls', false );
1658
1659                 return $parser;
1660         }
1661
1662         /**
1663          * Get global LESS variables.
1664          *
1665          * @since 1.27
1666          * @return array Map of variable names to string CSS values.
1667          */
1668         public function getLessVars() {
1669                 if ( !$this->lessVars ) {
1670                         $lessVars = $this->config->get( 'ResourceLoaderLESSVars' );
1671                         Hooks::run( 'ResourceLoaderGetLessVars', [ &$lessVars ] );
1672                         $this->lessVars = $lessVars;
1673                 }
1674                 return $this->lessVars;
1675         }
1676 }