includes/resourceloader/ResourceLoader.php

   1 <?php
   2 /**
   3  * Base class for resource loading system.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Roan Kattouw
  22  * @author Trevor Parscal
  23  */
  24
  25 use MediaWiki\MediaWikiServices;
  26 use Psr\Log\LoggerAwareInterface;
  27 use Psr\Log\LoggerInterface;
  28 use Psr\Log\NullLogger;
  29 use Wikimedia\Rdbms\DBConnectionError;
  30 use Wikimedia\WrappedString;
  31
  32 /**
  33  * Dynamic JavaScript and CSS resource loading system.
  34  *
  35  * Most of the documentation is on the MediaWiki documentation wiki starting at:
  36  *    https://www.mediawiki.org/wiki/ResourceLoader
  37  */
  38 class ResourceLoader implements LoggerAwareInterface {
  39         /** @var Config $config */
  40         protected $config;
  41         /** @var MessageBlobStore */
  42         protected $blobStore;
  43
  44         /** @var LoggerInterface */
  45         private $logger;
  46
  47         /** @var ResourceLoaderModule[] Map of (module name => ResourceLoaderModule) */
  48         protected $modules = [];
  49         /** @var array[] Map of (module name => associative info array) */
  50         protected $moduleInfos = [];
  51         /**
  52          * Associative array mapping framework ids to a list of names of test suite modules
  53          * like [ 'qunit' => [ 'mediawiki.tests.qunit.suites', 'ext.foo.tests', ... ], ... ]
  54          * @var array
  55          */
  56         protected $testModuleNames = [];
  57         /** @var string[] List of module names that contain QUnit test suites */
  58         protected $testSuiteModuleNames = [];
  59
  60         /** @var array Map of (source => path); E.g. [ 'source-id' => 'http://.../load.php' ] */
  61         protected $sources = [];
  62         /** @var array Errors accumulated during current respond() call */
  63         protected $errors = [];
  64         /** @var string[] Extra HTTP response headers from modules loaded in makeModuleResponse() */
  65         protected $extraHeaders = [];
  66
  67         /** @var bool */
  68         protected static $debugMode = null;
  69
  70         /** @var int */
  71         const CACHE_VERSION = 8;
  72
  73         /** @var string JavaScript / CSS pragma to disable minification. * */
  74         const FILTER_NOMIN = '/*@nomin*/';
  75
  76         /**
  77          * Load information stored in the database about modules.
  78          *
  79          * This method grabs modules dependencies from the database and updates modules
  80          * objects.
  81          *
  82          * This is not inside the module code because it is much faster to
  83          * request all of the information at once than it is to have each module
  84          * requests its own information. This sacrifice of modularity yields a substantial
  85          * performance improvement.
  86          *
  87          * @param array $moduleNames List of module names to preload information for
  88          * @param ResourceLoaderContext $context Context to load the information within
  89          */
  90         public function preloadModuleInfo( array $moduleNames, ResourceLoaderContext $context ) {
  91                 if ( !$moduleNames ) {
  92                         // Or else Database*::select() will explode, plus it's cheaper!
  93                         return;
  94                 }
  95                 $dbr = wfGetDB( DB_REPLICA );
  96                 $lang = $context->getLanguage();
  97
  98                 // Batched version of ResourceLoaderModule::getFileDependencies
  99                 $vary = ResourceLoaderModule::getVary( $context );
 100                 $res = $dbr->select( 'module_deps', [ 'md_module', 'md_deps' ], [
 101                                 'md_module' => $moduleNames,
 102                                 'md_skin' => $vary,
 103                         ], __METHOD__
 104                 );
 105
 106                 // Prime in-object cache for file dependencies
 107                 $modulesWithDeps = [];
 108                 foreach ( $res as $row ) {
 109                         $module = $this->getModule( $row->md_module );
 110                         if ( $module ) {
 111                                 $module->setFileDependencies( $context, ResourceLoaderModule::expandRelativePaths(
 112                                         json_decode( $row->md_deps, true )
 113                                 ) );
 114                                 $modulesWithDeps[] = $row->md_module;
 115                         }
 116                 }
 117                 // Register the absence of a dependency row too
 118                 foreach ( array_diff( $moduleNames, $modulesWithDeps ) as $name ) {
 119                         $module = $this->getModule( $name );
 120                         if ( $module ) {
 121                                 $this->getModule( $name )->setFileDependencies( $context, [] );
 122                         }
 123                 }
 124
 125                 // Batched version of ResourceLoaderWikiModule::getTitleInfo
 126                 ResourceLoaderWikiModule::preloadTitleInfo( $context, $dbr, $moduleNames );
 127
 128                 // Prime in-object cache for message blobs for modules with messages
 129                 $modules = [];
 130                 foreach ( $moduleNames as $name ) {
 131                         $module = $this->getModule( $name );
 132                         if ( $module && $module->getMessages() ) {
 133                                 $modules[$name] = $module;
 134                         }
 135                 }
 136                 $store = $this->getMessageBlobStore();
 137                 $blobs = $store->getBlobs( $modules, $lang );
 138                 foreach ( $blobs as $name => $blob ) {
 139                         $modules[$name]->setMessageBlob( $blob, $lang );
 140                 }
 141         }
 142
 143         /**
 144          * Run JavaScript or CSS data through a filter, caching the filtered result for future calls.
 145          *
 146          * Available filters are:
 147          *
 148          *    - minify-js \see JavaScriptMinifier::minify
 149          *    - minify-css \see CSSMin::minify
 150          *
 151          * If $data is empty, only contains whitespace or the filter was unknown,
 152          * $data is returned unmodified.
 153          *
 154          * @param string $filter Name of filter to run
 155          * @param string $data Text to filter, such as JavaScript or CSS text
 156          * @param array $options Keys:
 157          *  - (bool) cache: Whether to allow caching this data. Default: true.
 158          * @return string Filtered data, or a comment containing an error message
 159          */
 160         public static function filter( $filter, $data, array $options = [] ) {
 161                 if ( strpos( $data, self::FILTER_NOMIN ) !== false ) {
 162                         return $data;
 163                 }
 164
 165                 if ( isset( $options['cache'] ) && $options['cache'] === false ) {
 166                         return self::applyFilter( $filter, $data );
 167                 }
 168
 169                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 170                 $cache = ObjectCache::getLocalServerInstance( CACHE_ANYTHING );
 171
 172                 $key = $cache->makeGlobalKey(
 173                         'resourceloader-filter',
 174                         $filter,
 175                         self::CACHE_VERSION,
 176                         md5( $data )
 177                 );
 178
 179                 $result = $cache->get( $key );
 180                 if ( $result === false ) {
 181                         $stats->increment( "resourceloader_cache.$filter.miss" );
 182                         $result = self::applyFilter( $filter, $data );
 183                         $cache->set( $key, $result, 24 * 3600 );
 184                 } else {
 185                         $stats->increment( "resourceloader_cache.$filter.hit" );
 186                 }
 187                 if ( $result === null ) {
 188                         // Cached failure
 189                         $result = $data;
 190                 }
 191
 192                 return $result;
 193         }
 194
 195         private static function applyFilter( $filter, $data ) {
 196                 $data = trim( $data );
 197                 if ( $data ) {
 198                         try {
 199                                 $data = ( $filter === 'minify-css' )
 200                                         ? CSSMin::minify( $data )
 201                                         : JavaScriptMinifier::minify( $data );
 202                         } catch ( Exception $e ) {
 203                                 MWExceptionHandler::logException( $e );
 204                                 return null;
 205                         }
 206                 }
 207                 return $data;
 208         }
 209
 210         /**
 211          * Register core modules and runs registration hooks.
 212          * @param Config|null $config
 213          * @param LoggerInterface|null $logger [optional]
 214          */
 215         public function __construct( Config $config = null, LoggerInterface $logger = null ) {
 216                 $this->logger = $logger ?: new NullLogger();
 217
 218                 if ( !$config ) {
 219                         wfDeprecated( __METHOD__ . ' without a Config instance', '1.34' );
 220                         $config = MediaWikiServices::getInstance()->getMainConfig();
 221                 }
 222                 $this->config = $config;
 223
 224                 // Add 'local' source first
 225                 $this->addSource( 'local', $config->get( 'LoadScript' ) );
 226
 227                 // Special module that always exists
 228                 $this->register( 'startup', [ 'class' => ResourceLoaderStartUpModule::class ] );
 229
 230                 $this->setMessageBlobStore( new MessageBlobStore( $this, $this->logger ) );
 231         }
 232
 233         /**
 234          * @return Config
 235          */
 236         public function getConfig() {
 237                 return $this->config;
 238         }
 239
 240         /**
 241          * @since 1.26
 242          * @param LoggerInterface $logger
 243          */
 244         public function setLogger( LoggerInterface $logger ) {
 245                 $this->logger = $logger;
 246         }
 247
 248         /**
 249          * @since 1.27
 250          * @return LoggerInterface
 251          */
 252         public function getLogger() {
 253                 return $this->logger;
 254         }
 255
 256         /**
 257          * @since 1.26
 258          * @return MessageBlobStore
 259          */
 260         public function getMessageBlobStore() {
 261                 return $this->blobStore;
 262         }
 263
 264         /**
 265          * @since 1.25
 266          * @param MessageBlobStore $blobStore
 267          */
 268         public function setMessageBlobStore( MessageBlobStore $blobStore ) {
 269                 $this->blobStore = $blobStore;
 270         }
 271
 272         /**
 273          * Register a module with the ResourceLoader system.
 274          *
 275          * @param string|array[] $name Module name as a string or, array of module info arrays
 276          *  keyed by name.
 277          * @param array|null $info Module info array. When using the first parameter to register
 278          *  multiple modules at once, this parameter is optional.
 279          * @throws MWException If a duplicate module registration is attempted
 280          * @throws MWException If a module name contains illegal characters (pipes or commas)
 281          * @throws InvalidArgumentException If the module info is not an array
 282          */
 283         public function register( $name, $info = null ) {
 284                 $moduleSkinStyles = $this->config->get( 'ResourceModuleSkinStyles' );
 285
 286                 // Allow multiple modules to be registered in one call
 287                 $registrations = is_array( $name ) ? $name : [ $name => $info ];
 288                 foreach ( $registrations as $name => $info ) {
 289                         // Warn on duplicate registrations
 290                         if ( isset( $this->moduleInfos[$name] ) ) {
 291                                 // A module has already been registered by this name
 292                                 $this->logger->warning(
 293                                         'ResourceLoader duplicate registration warning. ' .
 294                                         'Another module has already been registered as ' . $name
 295                                 );
 296                         }
 297
 298                         // Check validity
 299                         if ( !self::isValidModuleName( $name ) ) {
 300                                 throw new MWException( "ResourceLoader module name '$name' is invalid, "
 301                                         . "see ResourceLoader::isValidModuleName()" );
 302                         }
 303                         if ( !is_array( $info ) ) {
 304                                 throw new InvalidArgumentException(
 305                                         'Invalid module info for "' . $name . '": expected array, got ' . gettype( $info )
 306                                 );
 307                         }
 308
 309                         // Attach module
 310                         $this->moduleInfos[$name] = $info;
 311
 312                         // Last-minute changes
 313                         // Apply custom skin-defined styles to existing modules.
 314                         if ( $this->isFileModule( $name ) ) {
 315                                 foreach ( $moduleSkinStyles as $skinName => $skinStyles ) {
 316                                         // If this module already defines skinStyles for this skin, ignore $wgResourceModuleSkinStyles.
 317                                         if ( isset( $this->moduleInfos[$name]['skinStyles'][$skinName] ) ) {
 318                                                 continue;
 319                                         }
 320
 321                                         // If $name is preceded with a '+', the defined style files will be added to 'default'
 322                                         // skinStyles, otherwise 'default' will be ignored as it normally would be.
 323                                         if ( isset( $skinStyles[$name] ) ) {
 324                                                 $paths = (array)$skinStyles[$name];
 325                                                 $styleFiles = [];
 326                                         } elseif ( isset( $skinStyles['+' . $name] ) ) {
 327                                                 $paths = (array)$skinStyles['+' . $name];
 328                                                 $styleFiles = isset( $this->moduleInfos[$name]['skinStyles']['default'] ) ?
 329                                                         (array)$this->moduleInfos[$name]['skinStyles']['default'] :
 330                                                         [];
 331                                         } else {
 332                                                 continue;
 333                                         }
 334
 335                                         // Add new file paths, remapping them to refer to our directories and not use settings
 336                                         // from the module we're modifying, which come from the base definition.
 337                                         list( $localBasePath, $remoteBasePath ) =
 338                                                 ResourceLoaderFileModule::extractBasePaths( $skinStyles );
 339
 340                                         foreach ( $paths as $path ) {
 341                                                 $styleFiles[] = new ResourceLoaderFilePath( $path, $localBasePath, $remoteBasePath );
 342                                         }
 343
 344                                         $this->moduleInfos[$name]['skinStyles'][$skinName] = $styleFiles;
 345                                 }
 346                         }
 347                 }
 348         }
 349
 350         /**
 351          * @internal For use by ServiceWiring only
 352          * @codeCoverageIgnore
 353          */
 354         public function registerTestModules() {
 355                 global $IP;
 356
 357                 if ( $this->config->get( 'EnableJavaScriptTest' ) !== true ) {
 358                         throw new MWException( 'Attempt to register JavaScript test modules '
 359                                 . 'but <code>$wgEnableJavaScriptTest</code> is false. '
 360                                 . 'Edit your <code>LocalSettings.php</code> to enable it.' );
 361                 }
 362
 363                 // This has a 'qunit' key for compat with the below hook.
 364                 $testModulesMeta = [ 'qunit' => [] ];
 365
 366                 // Get test suites from extensions
 367                 // Avoid PHP 7.1 warning from passing $this by reference
 368                 $rl = $this;
 369                 Hooks::run( 'ResourceLoaderTestModules', [ &$testModulesMeta, &$rl ] );
 370                 $extRegistry = ExtensionRegistry::getInstance();
 371                 // In case of conflict, the deprecated hook has precedence.
 372                 $testModules = $testModulesMeta['qunit'] + $extRegistry->getAttribute( 'QUnitTestModules' );
 373
 374                 $testSuiteModuleNames = [];
 375                 foreach ( $testModules as $name => &$module ) {
 376                         // Turn any single-module dependency into an array
 377                         if ( isset( $module['dependencies'] ) && is_string( $module['dependencies'] ) ) {
 378                                 $module['dependencies'] = [ $module['dependencies'] ];
 379                         }
 380
 381                         // Ensure the testrunner loads before any test suites
 382                         $module['dependencies'][] = 'test.mediawiki.qunit.testrunner';
 383
 384                         // Keep track of the test suites to load on SpecialJavaScriptTest
 385                         $testSuiteModuleNames[] = $name;
 386                 }
 387
 388                 // Core test suites (their names have further precedence).
 389                 $testModules = ( include "$IP/tests/qunit/QUnitTestResources.php" ) + $testModules;
 390                 $testSuiteModuleNames[] = 'test.mediawiki.qunit.suites';
 391
 392                 $this->register( $testModules );
 393                 $this->testSuiteModuleNames = $testSuiteModuleNames;
 394         }
 395
 396         /**
 397          * Add a foreign source of modules.
 398          *
 399          * Source IDs are typically the same as the Wiki ID or database name (e.g. lowercase a-z).
 400          *
 401          * @param array|string $id Source ID (string), or [ id1 => loadUrl, id2 => loadUrl, ... ]
 402          * @param string|array|null $loadUrl load.php url (string), or array with loadUrl key for
 403          *  backwards-compatibility.
 404          * @throws MWException
 405          */
 406         public function addSource( $id, $loadUrl = null ) {
 407                 // Allow multiple sources to be registered in one call
 408                 if ( is_array( $id ) ) {
 409                         foreach ( $id as $key => $value ) {
 410                                 $this->addSource( $key, $value );
 411                         }
 412                         return;
 413                 }
 414
 415                 // Disallow duplicates
 416                 if ( isset( $this->sources[$id] ) ) {
 417                         throw new MWException(
 418                                 'ResourceLoader duplicate source addition error. ' .
 419                                 'Another source has already been registered as ' . $id
 420                         );
 421                 }
 422
 423                 // Pre 1.24 backwards-compatibility
 424                 if ( is_array( $loadUrl ) ) {
 425                         if ( !isset( $loadUrl['loadScript'] ) ) {
 426                                 throw new MWException(
 427                                         __METHOD__ . ' was passed an array with no "loadScript" key.'
 428                                 );
 429                         }
 430
 431                         $loadUrl = $loadUrl['loadScript'];
 432                 }
 433
 434                 $this->sources[$id] = $loadUrl;
 435         }
 436
 437         /**
 438          * Get a list of module names.
 439          *
 440          * @return array List of module names
 441          */
 442         public function getModuleNames() {
 443                 return array_keys( $this->moduleInfos );
 444         }
 445
 446         /**
 447          * Get a list of module names with QUnit test suites.
 448          *
 449          * @internal For use by SpecialJavaScriptTest only
 450          * @return array
 451          * @codeCoverageIgnore
 452          */
 453         public function getTestSuiteModuleNames() {
 454                 return $this->testSuiteModuleNames;
 455         }
 456
 457         /**
 458          * Check whether a ResourceLoader module is registered
 459          *
 460          * @since 1.25
 461          * @param string $name
 462          * @return bool
 463          */
 464         public function isModuleRegistered( $name ) {
 465                 return isset( $this->moduleInfos[$name] );
 466         }
 467
 468         /**
 469          * Get the ResourceLoaderModule object for a given module name.
 470          *
 471          * If an array of module parameters exists but a ResourceLoaderModule object has not
 472          * yet been instantiated, this method will instantiate and cache that object such that
 473          * subsequent calls simply return the same object.
 474          *
 475          * @param string $name Module name
 476          * @return ResourceLoaderModule|null If module has been registered, return a
 477          *  ResourceLoaderModule instance. Otherwise, return null.
 478          */
 479         public function getModule( $name ) {
 480                 if ( !isset( $this->modules[$name] ) ) {
 481                         if ( !isset( $this->moduleInfos[$name] ) ) {
 482                                 // No such module
 483                                 return null;
 484                         }
 485                         // Construct the requested module object
 486                         $info = $this->moduleInfos[$name];
 487                         if ( isset( $info['factory'] ) ) {
 488                                 /** @var ResourceLoaderModule $object */
 489                                 $object = call_user_func( $info['factory'], $info );
 490                         } else {
 491                                 $class = $info['class'] ?? ResourceLoaderFileModule::class;
 492                                 /** @var ResourceLoaderModule $object */
 493                                 $object = new $class( $info );
 494                         }
 495                         $object->setConfig( $this->getConfig() );
 496                         $object->setLogger( $this->logger );
 497                         $object->setName( $name );
 498                         $this->modules[$name] = $object;
 499                 }
 500
 501                 return $this->modules[$name];
 502         }
 503
 504         /**
 505          * Whether the module is a ResourceLoaderFileModule (including subclasses).
 506          *
 507          * @param string $name Module name
 508          * @return bool
 509          */
 510         protected function isFileModule( $name ) {
 511                 if ( !isset( $this->moduleInfos[$name] ) ) {
 512                         return false;
 513                 }
 514                 $info = $this->moduleInfos[$name];
 515                 return !isset( $info['factory'] ) && (
 516                         // The implied default for 'class' is ResourceLoaderFileModule
 517                         !isset( $info['class'] ) ||
 518                         // Explicit default
 519                         $info['class'] === ResourceLoaderFileModule::class ||
 520                         is_subclass_of( $info['class'], ResourceLoaderFileModule::class )
 521                 );
 522         }
 523
 524         /**
 525          * Get the list of sources.
 526          *
 527          * @return array Like [ id => load.php url, ... ]
 528          */
 529         public function getSources() {
 530                 return $this->sources;
 531         }
 532
 533         /**
 534          * Get the URL to the load.php endpoint for the given
 535          * ResourceLoader source
 536          *
 537          * @since 1.24
 538          * @param string $source
 539          * @throws MWException On an invalid $source name
 540          * @return string
 541          */
 542         public function getLoadScript( $source ) {
 543                 if ( !isset( $this->sources[$source] ) ) {
 544                         throw new MWException( "The $source source was never registered in ResourceLoader." );
 545                 }
 546                 return $this->sources[$source];
 547         }
 548
 549         /**
 550          * @internal For use by ResourceLoaderStartUpModule only.
 551          */
 552         const HASH_LENGTH = 5;
 553
 554         /**
 555          * Create a hash for module versioning purposes.
 556          *
 557          * This hash is used in three ways:
 558          *
 559          * - To differentiate between the current version and a past version
 560          *   of a module by the same name.
 561          *
 562          *   In the cache key of localStorage in the browser (mw.loader.store).
 563          *   This store keeps only one version of any given module. As long as the
 564          *   next version the client encounters has a different hash from the last
 565          *   version it saw, it will correctly discard it in favour of a network fetch.
 566          *
 567          *   A browser may evict a site's storage container for any reason (e.g. when
 568          *   the user hasn't visited a site for some time, and/or when the device is
 569          *   low on storage space). Anecdotally it seems devices rarely keep unused
 570          *   storage beyond 2 weeks on mobile devices and 4 weeks on desktop.
 571          *   But, there is no hard limit or expiration on localStorage.
 572          *   ResourceLoader's Client also clears localStorage when the user changes
 573          *   their language preference or when they (temporarily) use Debug Mode.
 574          *
 575          *   The only hard factors that reduce the range of possible versions are
 576          *   1) the name and existence of a given module, and
 577          *   2) the TTL for mw.loader.store, and
 578          *   3) the `$wgResourceLoaderStorageVersion` configuration variable.
 579          *
 580          * - To identify a batch response of modules from load.php in an HTTP cache.
 581          *
 582          *   When fetching modules in a batch from load.php, a combined hash
 583          *   is created by the JS code, and appended as query parameter.
 584          *
 585          *   In cache proxies (e.g. Varnish, Nginx) and in the browser's HTTP cache,
 586          *   these urls are used to identify other previously cached responses.
 587          *   The range of possible versions a given version has to be unique amongst
 588          *   is determined by the maximum duration each response is stored for, which
 589          *   is controlled by `$wgResourceLoaderMaxage['versioned']`.
 590          *
 591          * - To detect race conditions between multiple web servers in a MediaWiki
 592          *   deployment of which some have the newer version and some still the older
 593          *   version.
 594          *
 595          *   An HTTP request from a browser for the Startup manifest may be responded
 596          *   to by a server with the newer version. The browser may then use that to
 597          *   request a given module, which may then be responded to by a server with
 598          *   the older version. To avoid caching this for too long (which would pollute
 599          *   all other users without repairing itself), the combined hash that the JS
 600          *   client adds to the url is verified by the server (in ::sendResponseHeaders).
 601          *   If they don't match, we instruct cache proxies and clients to not cache
 602          *   this response as long as they normally would. This is also the reason
 603          *   that the algorithm used here in PHP must match the one used in JS.
 604          *
 605          * The fnv132 digest creates a 32-bit integer, which goes upto 4 Giga and
 606          * needs up to 7 chars in base 36.
 607          * Within 7 characters, base 36 can count up to 78,364,164,096 (78 Giga),
 608          * (but with fnv132 we'd use very little of this range, mostly padding).
 609          * Within 6 characters, base 36 can count up to 2,176,782,336 (2 Giga).
 610          * Within 5 characters, base 36 can count up to 60,466,176 (60 Mega).
 611          *
 612          * @since 1.26
 613          * @param string $value
 614          * @return string Hash
 615          */
 616         public static function makeHash( $value ) {
 617                 $hash = hash( 'fnv132', $value );
 618                 // The base_convert will pad it (if too short),
 619                 // then substr() will trim it (if too long).
 620                 return substr(
 621                         Wikimedia\base_convert( $hash, 16, 36, self::HASH_LENGTH ),
 622                         0,
 623                         self::HASH_LENGTH
 624                 );
 625         }
 626
 627         /**
 628          * Add an error to the 'errors' array and log it.
 629          *
 630          * @private For internal use by ResourceLoader and ResourceLoaderStartUpModule.
 631          * @since 1.29
 632          * @param Exception $e
 633          * @param string $msg
 634          * @param array $context
 635          */
 636         public function outputErrorAndLog( Exception $e, $msg, array $context = [] ) {
 637                 MWExceptionHandler::logException( $e );
 638                 $this->logger->warning(
 639                         $msg,
 640                         $context + [ 'exception' => $e ]
 641                 );
 642                 $this->errors[] = self::formatExceptionNoComment( $e );
 643         }
 644
 645         /**
 646          * Helper method to get and combine versions of multiple modules.
 647          *
 648          * @since 1.26
 649          * @param ResourceLoaderContext $context
 650          * @param string[] $moduleNames List of known module names
 651          * @return string Hash
 652          */
 653         public function getCombinedVersion( ResourceLoaderContext $context, array $moduleNames ) {
 654                 if ( !$moduleNames ) {
 655                         return '';
 656                 }
 657                 $hashes = array_map( function ( $module ) use ( $context ) {
 658                         try {
 659                                 return $this->getModule( $module )->getVersionHash( $context );
 660                         } catch ( Exception $e ) {
 661                                 // If modules fail to compute a version, don't fail the request (T152266)
 662                                 // and still compute versions of other modules.
 663                                 $this->outputErrorAndLog( $e,
 664                                         'Calculating version for "{module}" failed: {exception}',
 665                                         [
 666                                                 'module' => $module,
 667                                         ]
 668                                 );
 669                                 return '';
 670                         }
 671                 }, $moduleNames );
 672                 return self::makeHash( implode( '', $hashes ) );
 673         }
 674
 675         /**
 676          * Get the expected value of the 'version' query parameter.
 677          *
 678          * This is used by respond() to set a short Cache-Control header for requests with
 679          * information newer than the current server has. This avoids pollution of edge caches.
 680          * Typically during deployment. (T117587)
 681          *
 682          * This MUST match return value of `mw.loader#getCombinedVersion()` client-side.
 683          *
 684          * @since 1.28
 685          * @param ResourceLoaderContext $context
 686          * @return string Hash
 687          */
 688         public function makeVersionQuery( ResourceLoaderContext $context ) {
 689                 // As of MediaWiki 1.28, the server and client use the same algorithm for combining
 690                 // version hashes. There is no technical reason for this to be same, and for years the
 691                 // implementations differed. If getCombinedVersion in PHP (used for StartupModule and
 692                 // E-Tag headers) differs in the future from getCombinedVersion in JS (used for 'version'
 693                 // query parameter), then this method must continue to match the JS one.
 694                 $moduleNames = [];
 695                 foreach ( $context->getModules() as $name ) {
 696                         if ( !$this->getModule( $name ) ) {
 697                                 // If a versioned request contains a missing module, the version is a mismatch
 698                                 // as the client considered a module (and version) we don't have.
 699                                 return '';
 700                         }
 701                         $moduleNames[] = $name;
 702                 }
 703                 return $this->getCombinedVersion( $context, $moduleNames );
 704         }
 705
 706         /**
 707          * Output a response to a load request, including the content-type header.
 708          *
 709          * @param ResourceLoaderContext $context Context in which a response should be formed
 710          */
 711         public function respond( ResourceLoaderContext $context ) {
 712                 // Buffer output to catch warnings. Normally we'd use ob_clean() on the
 713                 // top-level output buffer to clear warnings, but that breaks when ob_gzhandler
 714                 // is used: ob_clean() will clear the GZIP header in that case and it won't come
 715                 // back for subsequent output, resulting in invalid GZIP. So we have to wrap
 716                 // the whole thing in our own output buffer to be sure the active buffer
 717                 // doesn't use ob_gzhandler.
 718                 // See https://bugs.php.net/bug.php?id=36514
 719                 ob_start();
 720
 721                 $this->measureResponseTime( RequestContext::getMain()->getTiming() );
 722
 723                 // Find out which modules are missing and instantiate the others
 724                 $modules = [];
 725                 $missing = [];
 726                 foreach ( $context->getModules() as $name ) {
 727                         $module = $this->getModule( $name );
 728                         if ( $module ) {
 729                                 // Do not allow private modules to be loaded from the web.
 730                                 // This is a security issue, see T36907.
 731                                 if ( $module->getGroup() === 'private' ) {
 732                                         // Not a serious error, just means something is trying to access it (T101806)
 733                                         $this->logger->debug( "Request for private module '$name' denied" );
 734                                         $this->errors[] = "Cannot build private module \"$name\"";
 735                                         continue;
 736                                 }
 737                                 $modules[$name] = $module;
 738                         } else {
 739                                 $missing[] = $name;
 740                         }
 741                 }
 742
 743                 try {
 744                         // Preload for getCombinedVersion() and for batch makeModuleResponse()
 745                         $this->preloadModuleInfo( array_keys( $modules ), $context );
 746                 } catch ( Exception $e ) {
 747                         $this->outputErrorAndLog( $e, 'Preloading module info failed: {exception}' );
 748                 }
 749
 750                 // Combine versions to propagate cache invalidation
 751                 $versionHash = '';
 752                 try {
 753                         $versionHash = $this->getCombinedVersion( $context, array_keys( $modules ) );
 754                 } catch ( Exception $e ) {
 755                         $this->outputErrorAndLog( $e, 'Calculating version hash failed: {exception}' );
 756                 }
 757
 758                 // See RFC 2616 § 3.11 Entity Tags
 759                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.11
 760                 $etag = 'W/"' . $versionHash . '"';
 761
 762                 // Try the client-side cache first
 763                 if ( $this->tryRespondNotModified( $context, $etag ) ) {
 764                         return; // output handled (buffers cleared)
 765                 }
 766
 767                 // Use file cache if enabled and available...
 768                 if ( $this->config->get( 'UseFileCache' ) ) {
 769                         $fileCache = ResourceFileCache::newFromContext( $context );
 770                         if ( $this->tryRespondFromFileCache( $fileCache, $context, $etag ) ) {
 771                                 return; // output handled
 772                         }
 773                 } else {
 774                         $fileCache = null;
 775                 }
 776
 777                 // Generate a response
 778                 $response = $this->makeModuleResponse( $context, $modules, $missing );
 779
 780                 // Capture any PHP warnings from the output buffer and append them to the
 781                 // error list if we're in debug mode.
 782                 if ( $context->getDebug() ) {
 783                         $warnings = ob_get_contents();
 784                         if ( strlen( $warnings ) ) {
 785                                 $this->errors[] = $warnings;
 786                         }
 787                 }
 788
 789                 // Consider saving the response to file cache (unless there are errors).
 790                 if ( $fileCache &&
 791                         !$this->errors &&
 792                         $missing === [] &&
 793                         ResourceFileCache::useFileCache( $context )
 794                 ) {
 795                         if ( $fileCache->isCacheWorthy() ) {
 796                                 // There were enough hits, save the response to the cache
 797                                 $fileCache->saveText( $response );
 798                         } else {
 799                                 $fileCache->incrMissesRecent( $context->getRequest() );
 800                         }
 801                 }
 802
 803                 $this->sendResponseHeaders( $context, $etag, (bool)$this->errors, $this->extraHeaders );
 804
 805                 // Remove the output buffer and output the response
 806                 ob_end_clean();
 807
 808                 if ( $context->getImageObj() && $this->errors ) {
 809                         // We can't show both the error messages and the response when it's an image.
 810                         $response = implode( "\n\n", $this->errors );
 811                 } elseif ( $this->errors ) {
 812                         $errorText = implode( "\n\n", $this->errors );
 813                         $errorResponse = self::makeComment( $errorText );
 814                         if ( $context->shouldIncludeScripts() ) {
 815                                 $errorResponse .= 'if (window.console && console.error) { console.error('
 816                                         . self::encodeJsonForScript( $errorText )
 817                                         . "); }\n";
 818                         }
 819
 820                         // Prepend error info to the response
 821                         $response = $errorResponse . $response;
 822                 }
 823
 824                 $this->errors = [];
 825                 echo $response;
 826         }
 827
 828         protected function measureResponseTime( Timing $timing ) {
 829                 DeferredUpdates::addCallableUpdate( function () use ( $timing ) {
 830                         $measure = $timing->measure( 'responseTime', 'requestStart', 'requestShutdown' );
 831                         if ( $measure !== false ) {
 832                                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 833                                 $stats->timing( 'resourceloader.responseTime', $measure['duration'] * 1000 );
 834                         }
 835                 } );
 836         }
 837
 838         /**
 839          * Send main response headers to the client.
 840          *
 841          * Deals with Content-Type, CORS (for stylesheets), and caching.
 842          *
 843          * @param ResourceLoaderContext $context
 844          * @param string $etag ETag header value
 845          * @param bool $errors Whether there are errors in the response
 846          * @param string[] $extra Array of extra HTTP response headers
 847          * @return void
 848          */
 849         protected function sendResponseHeaders(
 850                 ResourceLoaderContext $context, $etag, $errors, array $extra = []
 851         ) {
 852                 \MediaWiki\HeaderCallback::warnIfHeadersSent();
 853                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 854                 // Use a short cache expiry so that updates propagate to clients quickly, if:
 855                 // - No version specified (shared resources, e.g. stylesheets)
 856                 // - There were errors (recover quickly)
 857                 // - Version mismatch (T117587, T47877)
 858                 if ( is_null( $context->getVersion() )
 859                         || $errors
 860                         || $context->getVersion() !== $this->makeVersionQuery( $context )
 861                 ) {
 862                         $maxage = $rlMaxage['unversioned']['client'];
 863                         $smaxage = $rlMaxage['unversioned']['server'];
 864                 // If a version was specified we can use a longer expiry time since changing
 865                 // version numbers causes cache misses
 866                 } else {
 867                         $maxage = $rlMaxage['versioned']['client'];
 868                         $smaxage = $rlMaxage['versioned']['server'];
 869                 }
 870                 if ( $context->getImageObj() ) {
 871                         // Output different headers if we're outputting textual errors.
 872                         if ( $errors ) {
 873                                 header( 'Content-Type: text/plain; charset=utf-8' );
 874                         } else {
 875                                 $context->getImageObj()->sendResponseHeaders( $context );
 876                         }
 877                 } elseif ( $context->getOnly() === 'styles' ) {
 878                         header( 'Content-Type: text/css; charset=utf-8' );
 879                         header( 'Access-Control-Allow-Origin: *' );
 880                 } else {
 881                         header( 'Content-Type: text/javascript; charset=utf-8' );
 882                 }
 883                 // See RFC 2616 § 14.19 ETag
 884                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.19
 885                 header( 'ETag: ' . $etag );
 886                 if ( $context->getDebug() ) {
 887                         // Do not cache debug responses
 888                         header( 'Cache-Control: private, no-cache, must-revalidate' );
 889                         header( 'Pragma: no-cache' );
 890                 } else {
 891                         header( "Cache-Control: public, max-age=$maxage, s-maxage=$smaxage" );
 892                         $exp = min( $maxage, $smaxage );
 893                         header( 'Expires: ' . wfTimestamp( TS_RFC2822, $exp + time() ) );
 894                 }
 895                 foreach ( $extra as $header ) {
 896                         header( $header );
 897                 }
 898         }
 899
 900         /**
 901          * Respond with HTTP 304 Not Modified if appropiate.
 902          *
 903          * If there's an If-None-Match header, respond with a 304 appropriately
 904          * and clear out the output buffer. If the client cache is too old then do nothing.
 905          *
 906          * @param ResourceLoaderContext $context
 907          * @param string $etag ETag header value
 908          * @return bool True if HTTP 304 was sent and output handled
 909          */
 910         protected function tryRespondNotModified( ResourceLoaderContext $context, $etag ) {
 911                 // See RFC 2616 § 14.26 If-None-Match
 912                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.26
 913                 $clientKeys = $context->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST );
 914                 // Never send 304s in debug mode
 915                 if ( $clientKeys !== false && !$context->getDebug() && in_array( $etag, $clientKeys ) ) {
 916                         // There's another bug in ob_gzhandler (see also the comment at
 917                         // the top of this function) that causes it to gzip even empty
 918                         // responses, meaning it's impossible to produce a truly empty
 919                         // response (because the gzip header is always there). This is
 920                         // a problem because 304 responses have to be completely empty
 921                         // per the HTTP spec, and Firefox behaves buggily when they're not.
 922                         // See also https://bugs.php.net/bug.php?id=51579
 923                         // To work around this, we tear down all output buffering before
 924                         // sending the 304.
 925                         wfResetOutputBuffers( /* $resetGzipEncoding = */ true );
 926
 927                         HttpStatus::header( 304 );
 928
 929                         $this->sendResponseHeaders( $context, $etag, false );
 930                         return true;
 931                 }
 932                 return false;
 933         }
 934
 935         /**
 936          * Send out code for a response from file cache if possible.
 937          *
 938          * @param ResourceFileCache $fileCache Cache object for this request URL
 939          * @param ResourceLoaderContext $context Context in which to generate a response
 940          * @param string $etag ETag header value
 941          * @return bool If this found a cache file and handled the response
 942          */
 943         protected function tryRespondFromFileCache(
 944                 ResourceFileCache $fileCache,
 945                 ResourceLoaderContext $context,
 946                 $etag
 947         ) {
 948                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 949                 // Buffer output to catch warnings.
 950                 ob_start();
 951                 // Get the maximum age the cache can be
 952                 $maxage = is_null( $context->getVersion() )
 953                         ? $rlMaxage['unversioned']['server']
 954                         : $rlMaxage['versioned']['server'];
 955                 // Minimum timestamp the cache file must have
 956                 $good = $fileCache->isCacheGood( wfTimestamp( TS_MW, time() - $maxage ) );
 957                 if ( !$good ) {
 958                         try { // RL always hits the DB on file cache miss...
 959                                 wfGetDB( DB_REPLICA );
 960                         } catch ( DBConnectionError $e ) { // ...check if we need to fallback to cache
 961                                 $good = $fileCache->isCacheGood(); // cache existence check
 962                         }
 963                 }
 964                 if ( $good ) {
 965                         $ts = $fileCache->cacheTimestamp();
 966                         // Send content type and cache headers
 967                         $this->sendResponseHeaders( $context, $etag, false );
 968                         $response = $fileCache->fetchText();
 969                         // Capture any PHP warnings from the output buffer and append them to the
 970                         // response in a comment if we're in debug mode.
 971                         if ( $context->getDebug() ) {
 972                                 $warnings = ob_get_contents();
 973                                 if ( strlen( $warnings ) ) {
 974                                         $response = self::makeComment( $warnings ) . $response;
 975                                 }
 976                         }
 977                         // Remove the output buffer and output the response
 978                         ob_end_clean();
 979                         echo $response . "\n/* Cached {$ts} */";
 980                         return true; // cache hit
 981                 }
 982                 // Clear buffer
 983                 ob_end_clean();
 984
 985                 return false; // cache miss
 986         }
 987
 988         /**
 989          * Generate a CSS or JS comment block.
 990          *
 991          * Only use this for public data, not error message details.
 992          *
 993          * @param string $text
 994          * @return string
 995          */
 996         public static function makeComment( $text ) {
 997                 $encText = str_replace( '*/', '* /', $text );
 998                 return "/*\n$encText\n*/\n";
 999         }
1000
1001         /**
1002          * Handle exception display.
1003          *
1004          * @param Exception $e Exception to be shown to the user
1005          * @return string Sanitized text in a CSS/JS comment that can be returned to the user
1006          */
1007         public static function formatException( $e ) {
1008                 return self::makeComment( self::formatExceptionNoComment( $e ) );
1009         }
1010
1011         /**
1012          * Handle exception display.
1013          *
1014          * @since 1.25
1015          * @param Exception $e Exception to be shown to the user
1016          * @return string Sanitized text that can be returned to the user
1017          */
1018         protected static function formatExceptionNoComment( $e ) {
1019                 global $wgShowExceptionDetails;
1020
1021                 if ( !$wgShowExceptionDetails ) {
1022                         return MWExceptionHandler::getPublicLogMessage( $e );
1023                 }
1024
1025                 return MWExceptionHandler::getLogMessage( $e ) .
1026                         "\nBacktrace:\n" .
1027                         MWExceptionHandler::getRedactedTraceAsString( $e );
1028         }
1029
1030         /**
1031          * Generate code for a response.
1032          *
1033          * Calling this method also populates the `errors` and `headers` members,
1034          * later used by respond().
1035          *
1036          * @param ResourceLoaderContext $context Context in which to generate a response
1037          * @param ResourceLoaderModule[] $modules List of module objects keyed by module name
1038          * @param string[] $missing List of requested module names that are unregistered (optional)
1039          * @return string Response data
1040          */
1041         public function makeModuleResponse( ResourceLoaderContext $context,
1042                 array $modules, array $missing = []
1043         ) {
1044                 $out = '';
1045                 $states = [];
1046
1047                 if ( $modules === [] && $missing === [] ) {
1048                         return <<<MESSAGE
1049 /* This file is the Web entry point for MediaWiki's ResourceLoader:
1050    <https://www.mediawiki.org/wiki/ResourceLoader>. In this request,
1051    no modules were requested. Max made me put this here. */
1052 MESSAGE;
1053                 }
1054
1055                 $image = $context->getImageObj();
1056                 if ( $image ) {
1057                         $data = $image->getImageData( $context );
1058                         if ( $data === false ) {
1059                                 $data = '';
1060                                 $this->errors[] = 'Image generation failed';
1061                         }
1062                         return $data;
1063                 }
1064
1065                 foreach ( $missing as $name ) {
1066                         $states[$name] = 'missing';
1067                 }
1068
1069                 $filter = $context->getOnly() === 'styles' ? 'minify-css' : 'minify-js';
1070
1071                 foreach ( $modules as $name => $module ) {
1072                         try {
1073                                 $content = $module->getModuleContent( $context );
1074                                 $implementKey = $name . '@' . $module->getVersionHash( $context );
1075                                 $strContent = '';
1076
1077                                 if ( isset( $content['headers'] ) ) {
1078                                         $this->extraHeaders = array_merge( $this->extraHeaders, $content['headers'] );
1079                                 }
1080
1081                                 // Append output
1082                                 switch ( $context->getOnly() ) {
1083                                         case 'scripts':
1084                                                 $scripts = $content['scripts'];
1085                                                 if ( is_string( $scripts ) ) {
1086                                                         // Load scripts raw...
1087                                                         $strContent = $scripts;
1088                                                 } elseif ( is_array( $scripts ) ) {
1089                                                         // ...except when $scripts is an array of URLs or an associative array
1090                                                         $strContent = self::makeLoaderImplementScript( $implementKey, $scripts, [], [], [] );
1091                                                 }
1092                                                 break;
1093                                         case 'styles':
1094                                                 $styles = $content['styles'];
1095                                                 // We no longer separate into media, they are all combined now with
1096                                                 // custom media type groups into @media .. {} sections as part of the css string.
1097                                                 // Module returns either an empty array or a numerical array with css strings.
1098                                                 $strContent = isset( $styles['css'] ) ? implode( '', $styles['css'] ) : '';
1099                                                 break;
1100                                         default:
1101                                                 $scripts = $content['scripts'] ?? '';
1102                                                 if ( is_string( $scripts ) ) {
1103                                                         if ( $name === 'site' || $name === 'user' ) {
1104                                                                 // Legacy scripts that run in the global scope without a closure.
1105                                                                 // mw.loader.implement will use globalEval if scripts is a string.
1106                                                                 // Minify manually here, because general response minification is
1107                                                                 // not effective due it being a string literal, not a function.
1108                                                                 if ( !$context->getDebug() ) {
1109                                                                         $scripts = self::filter( 'minify-js', $scripts ); // T107377
1110                                                                 }
1111                                                         } else {
1112                                                                 $scripts = new XmlJsCode( $scripts );
1113                                                         }
1114                                                 }
1115                                                 $strContent = self::makeLoaderImplementScript(
1116                                                         $implementKey,
1117                                                         $scripts,
1118                                                         $content['styles'] ?? [],
1119                                                         isset( $content['messagesBlob'] ) ? new XmlJsCode( $content['messagesBlob'] ) : [],
1120                                                         $content['templates'] ?? []
1121                                                 );
1122                                                 break;
1123                                 }
1124
1125                                 if ( !$context->getDebug() ) {
1126                                         $strContent = self::filter( $filter, $strContent );
1127                                 } else {
1128                                         // In debug mode, separate each response by a new line.
1129                                         // For example, between 'mw.loader.implement();' statements.
1130                                         $strContent = $this->ensureNewline( $strContent );
1131                                 }
1132
1133                                 if ( $context->getOnly() === 'scripts' ) {
1134                                         // Use a linebreak between module scripts (T162719)
1135                                         $out .= $this->ensureNewline( $strContent );
1136                                 } else {
1137                                         $out .= $strContent;
1138                                 }
1139
1140                         } catch ( Exception $e ) {
1141                                 $this->outputErrorAndLog( $e, 'Generating module package failed: {exception}' );
1142
1143                                 // Respond to client with error-state instead of module implementation
1144                                 $states[$name] = 'error';
1145                                 unset( $modules[$name] );
1146                         }
1147                 }
1148
1149                 // Update module states
1150                 if ( $context->shouldIncludeScripts() && !$context->getRaw() ) {
1151                         if ( $modules && $context->getOnly() === 'scripts' ) {
1152                                 // Set the state of modules loaded as only scripts to ready as
1153                                 // they don't have an mw.loader.implement wrapper that sets the state
1154                                 foreach ( $modules as $name => $module ) {
1155                                         $states[$name] = 'ready';
1156                                 }
1157                         }
1158
1159                         // Set the state of modules we didn't respond to with mw.loader.implement
1160                         if ( $states ) {
1161                                 $stateScript = self::makeLoaderStateScript( $states );
1162                                 if ( !$context->getDebug() ) {
1163                                         $stateScript = self::filter( 'minify-js', $stateScript );
1164                                 }
1165                                 // Use a linebreak between module script and state script (T162719)
1166                                 $out = $this->ensureNewline( $out ) . $stateScript;
1167                         }
1168                 } elseif ( $states ) {
1169                         $this->errors[] = 'Problematic modules: '
1170                                 . self::encodeJsonForScript( $states );
1171                 }
1172
1173                 return $out;
1174         }
1175
1176         /**
1177          * Ensure the string is either empty or ends in a line break
1178          * @param string $str
1179          * @return string
1180          */
1181         private function ensureNewline( $str ) {
1182                 $end = substr( $str, -1 );
1183                 if ( $end === false || $end === '' || $end === "\n" ) {
1184                         return $str;
1185                 }
1186                 return $str . "\n";
1187         }
1188
1189         /**
1190          * Get names of modules that use a certain message.
1191          *
1192          * @param string $messageKey
1193          * @return array List of module names
1194          */
1195         public function getModulesByMessage( $messageKey ) {
1196                 $moduleNames = [];
1197                 foreach ( $this->getModuleNames() as $moduleName ) {
1198                         $module = $this->getModule( $moduleName );
1199                         if ( in_array( $messageKey, $module->getMessages() ) ) {
1200                                 $moduleNames[] = $moduleName;
1201                         }
1202                 }
1203                 return $moduleNames;
1204         }
1205
1206         /**
1207          * Return JS code that calls mw.loader.implement with given module properties.
1208          *
1209          * @param string $name Module name or implement key (format "`[name]@[version]`")
1210          * @param XmlJsCode|array|string $scripts Code as XmlJsCode (to be wrapped in a closure),
1211          *  list of URLs to JavaScript files, string of JavaScript for `$.globalEval`, or array with
1212          *  'files' and 'main' properties (see ResourceLoaderModule::getScript())
1213          * @param mixed $styles Array of CSS strings keyed by media type, or an array of lists of URLs
1214          *   to CSS files keyed by media type
1215          * @param mixed $messages List of messages associated with this module. May either be an
1216          *   associative array mapping message key to value, or a JSON-encoded message blob containing
1217          *   the same data, wrapped in an XmlJsCode object.
1218          * @param array $templates Keys are name of templates and values are the source of
1219          *   the template.
1220          * @throws MWException
1221          * @return string JavaScript code
1222          */
1223         protected static function makeLoaderImplementScript(
1224                 $name, $scripts, $styles, $messages, $templates
1225         ) {
1226                 if ( $scripts instanceof XmlJsCode ) {
1227                         if ( $scripts->value === '' ) {
1228                                 $scripts = null;
1229                         } elseif ( self::inDebugMode() ) {
1230                                 $scripts = new XmlJsCode( "function ( $, jQuery, require, module ) {\n{$scripts->value}\n}" );
1231                         } else {
1232                                 $scripts = new XmlJsCode( 'function($,jQuery,require,module){' . $scripts->value . '}' );
1233                         }
1234                 } elseif ( is_array( $scripts ) && isset( $scripts['files'] ) ) {
1235                         $files = $scripts['files'];
1236                         foreach ( $files as $path => &$file ) {
1237                                 // $file is changed (by reference) from a descriptor array to the content of the file
1238                                 // All of these essentially do $file = $file['content'];, some just have wrapping around it
1239                                 if ( $file['type'] === 'script' ) {
1240                                         // Multi-file modules only get two parameters ($ and jQuery are being phased out)
1241                                         if ( self::inDebugMode() ) {
1242                                                 $file = new XmlJsCode( "function ( require, module ) {\n{$file['content']}\n}" );
1243                                         } else {
1244                                                 $file = new XmlJsCode( 'function(require,module){' . $file['content'] . '}' );
1245                                         }
1246                                 } else {
1247                                         $file = $file['content'];
1248                                 }
1249                         }
1250                         $scripts = XmlJsCode::encodeObject( [
1251                                 'main' => $scripts['main'],
1252                                 'files' => XmlJsCode::encodeObject( $files, self::inDebugMode() )
1253                         ], self::inDebugMode() );
1254                 } elseif ( !is_string( $scripts ) && !is_array( $scripts ) ) {
1255                         throw new MWException( 'Invalid scripts error. Array of URLs or string of code expected.' );
1256                 }
1257
1258                 // mw.loader.implement requires 'styles', 'messages' and 'templates' to be objects (not
1259                 // arrays). json_encode considers empty arrays to be numerical and outputs "[]" instead
1260                 // of "{}". Force them to objects.
1261                 $module = [
1262                         $name,
1263                         $scripts,
1264                         (object)$styles,
1265                         (object)$messages,
1266                         (object)$templates
1267                 ];
1268                 self::trimArray( $module );
1269
1270                 return Xml::encodeJsCall( 'mw.loader.implement', $module, self::inDebugMode() );
1271         }
1272
1273         /**
1274          * Returns JS code which, when called, will register a given list of messages.
1275          *
1276          * @param mixed $messages Associative array mapping message key to value.
1277          * @return string JavaScript code
1278          */
1279         public static function makeMessageSetScript( $messages ) {
1280                 return 'mw.messages.set('
1281                         . self::encodeJsonForScript( (object)$messages )
1282                         . ');';
1283         }
1284
1285         /**
1286          * Combines an associative array mapping media type to CSS into a
1287          * single stylesheet with "@media" blocks.
1288          *
1289          * @param array $stylePairs Array keyed by media type containing (arrays of) CSS strings
1290          * @return array
1291          */
1292         public static function makeCombinedStyles( array $stylePairs ) {
1293                 $out = [];
1294                 foreach ( $stylePairs as $media => $styles ) {
1295                         // ResourceLoaderFileModule::getStyle can return the styles
1296                         // as a string or an array of strings. This is to allow separation in
1297                         // the front-end.
1298                         $styles = (array)$styles;
1299                         foreach ( $styles as $style ) {
1300                                 $style = trim( $style );
1301                                 // Don't output an empty "@media print { }" block (T42498)
1302                                 if ( $style !== '' ) {
1303                                         // Transform the media type based on request params and config
1304                                         // The way that this relies on $wgRequest to propagate request params is slightly evil
1305                                         $media = OutputPage::transformCssMedia( $media );
1306
1307                                         if ( $media === '' || $media == 'all' ) {
1308                                                 $out[] = $style;
1309                                         } elseif ( is_string( $media ) ) {
1310                                                 $out[] = "@media $media {\n" . str_replace( "\n", "\n\t", "\t" . $style ) . "}";
1311                                         }
1312                                         // else: skip
1313                                 }
1314                         }
1315                 }
1316                 return $out;
1317         }
1318
1319         /**
1320          * Wrapper around json_encode that avoids needless escapes,
1321          * and pretty-prints in debug mode.
1322          *
1323          * @internal
1324          * @since 1.32
1325          * @param mixed $data
1326          * @return string|false JSON string, false on error
1327          */
1328         public static function encodeJsonForScript( $data ) {
1329                 // Keep output as small as possible by disabling needless escape modes
1330                 // that PHP uses by default.
1331                 // However, while most module scripts are only served on HTTP responses
1332                 // for JavaScript, some modules can also be embedded in the HTML as inline
1333                 // scripts. This, and the fact that we sometimes need to export strings
1334                 // containing user-generated content and labels that may genuinely contain
1335                 // a sequences like "</script>", we need to encode either '/' or '<'.
1336                 // By default PHP escapes '/'. Let's escape '<' instead which is less common
1337                 // and allows URLs to mostly remain readable.
1338                 $jsonFlags = JSON_UNESCAPED_SLASHES |
1339                         JSON_UNESCAPED_UNICODE |
1340                         JSON_HEX_TAG |
1341                         JSON_HEX_AMP;
1342                 if ( self::inDebugMode() ) {
1343                         $jsonFlags |= JSON_PRETTY_PRINT;
1344                 }
1345                 return json_encode( $data, $jsonFlags );
1346         }
1347
1348         /**
1349          * Returns a JS call to mw.loader.state, which sets the state of one
1350          * ore more modules to a given value. Has two calling conventions:
1351          *
1352          *    - ResourceLoader::makeLoaderStateScript( $name, $state ):
1353          *         Set the state of a single module called $name to $state
1354          *
1355          *    - ResourceLoader::makeLoaderStateScript( [ $name => $state, ... ] ):
1356          *         Set the state of modules with the given names to the given states
1357          *
1358          * @param array|string $states
1359          * @param string|null $state
1360          * @return string JavaScript code
1361          */
1362         public static function makeLoaderStateScript( $states, $state = null ) {
1363                 if ( !is_array( $states ) ) {
1364                         $states = [ $states => $state ];
1365                 }
1366                 return 'mw.loader.state('
1367                         . self::encodeJsonForScript( $states )
1368                         . ');';
1369         }
1370
1371         private static function isEmptyObject( stdClass $obj ) {
1372                 foreach ( $obj as $key => $value ) {
1373                         return false;
1374                 }
1375                 return true;
1376         }
1377
1378         /**
1379          * Remove empty values from the end of an array.
1380          *
1381          * Values considered empty:
1382          *
1383          * - null
1384          * - []
1385          * - new XmlJsCode( '{}' )
1386          * - new stdClass() // (object) []
1387          *
1388          * @param array $array
1389          */
1390         private static function trimArray( array &$array ) {
1391                 $i = count( $array );
1392                 while ( $i-- ) {
1393                         if ( $array[$i] === null
1394                                 || $array[$i] === []
1395                                 || ( $array[$i] instanceof XmlJsCode && $array[$i]->value === '{}' )
1396                                 || ( $array[$i] instanceof stdClass && self::isEmptyObject( $array[$i] ) )
1397                         ) {
1398                                 unset( $array[$i] );
1399                         } else {
1400                                 break;
1401                         }
1402                 }
1403         }
1404
1405         /**
1406          * Returns JS code which calls mw.loader.register with the given
1407          * parameter.
1408          *
1409          * @par Example
1410          * @code
1411          *
1412          *     ResourceLoader::makeLoaderRegisterScript( [
1413          *        [ $name1, $version1, $dependencies1, $group1, $source1, $skip1 ],
1414          *        [ $name2, $version2, $dependencies1, $group2, $source2, $skip2 ],
1415          *        ...
1416          *     ] ):
1417          * @endcode
1418          *
1419          * @internal
1420          * @since 1.32
1421          * @param array $modules Array of module registration arrays, each containing
1422          *  - string: module name
1423          *  - string: module version
1424          *  - array|null: List of dependencies (optional)
1425          *  - string|null: Module group (optional)
1426          *  - string|null: Name of foreign module source, or 'local' (optional)
1427          *  - string|null: Script body of a skip function (optional)
1428          * @return string JavaScript code
1429          */
1430         public static function makeLoaderRegisterScript( array $modules ) {
1431                 // Optimisation: Transform dependency names into indexes when possible
1432                 // to produce smaller output. They are expanded by mw.loader.register on
1433                 // the other end using resolveIndexedDependencies().
1434                 $index = [];
1435                 foreach ( $modules as $i => &$module ) {
1436                         // Build module name index
1437                         $index[$module[0]] = $i;
1438                 }
1439                 foreach ( $modules as &$module ) {
1440                         if ( isset( $module[2] ) ) {
1441                                 foreach ( $module[2] as &$dependency ) {
1442                                         if ( isset( $index[$dependency] ) ) {
1443                                                 // Replace module name in dependency list with index
1444                                                 $dependency = $index[$dependency];
1445                                         }
1446                                 }
1447                         }
1448                 }
1449
1450                 array_walk( $modules, [ self::class, 'trimArray' ] );
1451
1452                 return 'mw.loader.register('
1453                         . self::encodeJsonForScript( $modules )
1454                         . ');';
1455         }
1456
1457         /**
1458          * Returns JS code which calls mw.loader.addSource() with the given
1459          * parameters. Has two calling conventions:
1460          *
1461          *   - ResourceLoader::makeLoaderSourcesScript( $id, $properties ):
1462          *       Register a single source
1463          *
1464          *   - ResourceLoader::makeLoaderSourcesScript( [ $id1 => $loadUrl, $id2 => $loadUrl, ... ] );
1465          *       Register sources with the given IDs and properties.
1466          *
1467          * @param string|array $sources Source ID
1468          * @param string|null $loadUrl load.php url
1469          * @return string JavaScript code
1470          */
1471         public static function makeLoaderSourcesScript( $sources, $loadUrl = null ) {
1472                 if ( !is_array( $sources ) ) {
1473                         $sources = [ $sources => $loadUrl ];
1474                 }
1475                 return 'mw.loader.addSource('
1476                         . self::encodeJsonForScript( $sources )
1477                         . ');';
1478         }
1479
1480         /**
1481          * Wraps JavaScript code to run after the startup module.
1482          *
1483          * @param string $script JavaScript code
1484          * @return string JavaScript code
1485          */
1486         public static function makeLoaderConditionalScript( $script ) {
1487                 // Adds a function to lazy-created RLQ
1488                 return '(RLQ=window.RLQ||[]).push(function(){' .
1489                         trim( $script ) . '});';
1490         }
1491
1492         /**
1493          * Wraps JavaScript code to run after a required module.
1494          *
1495          * @since 1.32
1496          * @param string|string[] $modules Module name(s)
1497          * @param string $script JavaScript code
1498          * @return string JavaScript code
1499          */
1500         public static function makeInlineCodeWithModule( $modules, $script ) {
1501                 // Adds an array to lazy-created RLQ
1502                 return '(RLQ=window.RLQ||[]).push(['
1503                         . self::encodeJsonForScript( $modules ) . ','
1504                         . 'function(){' . trim( $script ) . '}'
1505                         . ']);';
1506         }
1507
1508         /**
1509          * Returns an HTML script tag that runs given JS code after startup and base modules.
1510          *
1511          * The code will be wrapped in a closure, and it will be executed by ResourceLoader's
1512          * startup module if the client has adequate support for MediaWiki JavaScript code.
1513          *
1514          * @param string $script JavaScript code
1515          * @param string|null $nonce [optional] Content-Security-Policy nonce
1516          *  (from OutputPage::getCSPNonce)
1517          * @return string|WrappedString HTML
1518          */
1519         public static function makeInlineScript( $script, $nonce = null ) {
1520                 $js = self::makeLoaderConditionalScript( $script );
1521                 $escNonce = '';
1522                 if ( $nonce === null ) {
1523                         wfWarn( __METHOD__ . " did not get nonce. Will break CSP" );
1524                 } elseif ( $nonce !== false ) {
1525                         // If it was false, CSP is disabled, so no nonce attribute.
1526                         // Nonce should be only base64 characters, so should be safe,
1527                         // but better to be safely escaped than sorry.
1528                         $escNonce = ' nonce="' . htmlspecialchars( $nonce ) . '"';
1529                 }
1530
1531                 return new WrappedString(
1532                         Html::inlineScript( $js, $nonce ),
1533                         "<script$escNonce>(RLQ=window.RLQ||[]).push(function(){",
1534                         '});</script>'
1535                 );
1536         }
1537
1538         /**
1539          * Returns JS code which will set the MediaWiki configuration array to
1540          * the given value.
1541          *
1542          * @param array $configuration List of configuration values keyed by variable name
1543          * @return string JavaScript code
1544          * @throws Exception
1545          */
1546         public static function makeConfigSetScript( array $configuration ) {
1547                 $json = self::encodeJsonForScript( $configuration );
1548                 if ( $json === false ) {
1549                         $e = new Exception(
1550                                 'JSON serialization of config data failed. ' .
1551                                 'This usually means the config data is not valid UTF-8.'
1552                         );
1553                         MWExceptionHandler::logException( $e );
1554                         return 'mw.log.error(' . self::encodeJsonForScript( $e->__toString() ) . ');';
1555                 }
1556                 return "mw.config.set($json);";
1557         }
1558
1559         /**
1560          * Convert an array of module names to a packed query string.
1561          *
1562          * For example, `[ 'foo.bar', 'foo.baz', 'bar.baz', 'bar.quux' ]`
1563          * becomes `'foo.bar,baz|bar.baz,quux'`.
1564          *
1565          * This process is reversed by ResourceLoader::expandModuleNames().
1566          * See also mw.loader#buildModulesString() which is a port of this, used
1567          * on the client-side.
1568          *
1569          * @param array $modules List of module names (strings)
1570          * @return string Packed query string
1571          */
1572         public static function makePackedModulesString( $modules ) {
1573                 $moduleMap = []; // [ prefix => [ suffixes ] ]
1574                 foreach ( $modules as $module ) {
1575                         $pos = strrpos( $module, '.' );
1576                         $prefix = $pos === false ? '' : substr( $module, 0, $pos );
1577                         $suffix = $pos === false ? $module : substr( $module, $pos + 1 );
1578                         $moduleMap[$prefix][] = $suffix;
1579                 }
1580
1581                 $arr = [];
1582                 foreach ( $moduleMap as $prefix => $suffixes ) {
1583                         $p = $prefix === '' ? '' : $prefix . '.';
1584                         $arr[] = $p . implode( ',', $suffixes );
1585                 }
1586                 return implode( '|', $arr );
1587         }
1588
1589         /**
1590          * Expand a string of the form `jquery.foo,bar|jquery.ui.baz,quux` to
1591          * an array of module names like `[ 'jquery.foo', 'jquery.bar',
1592          * 'jquery.ui.baz', 'jquery.ui.quux' ]`.
1593          *
1594          * This process is reversed by ResourceLoader::makePackedModulesString().
1595          *
1596          * @since 1.33
1597          * @param string $modules Packed module name list
1598          * @return array Array of module names
1599          */
1600         public static function expandModuleNames( $modules ) {
1601                 $retval = [];
1602                 $exploded = explode( '|', $modules );
1603                 foreach ( $exploded as $group ) {
1604                         if ( strpos( $group, ',' ) === false ) {
1605                                 // This is not a set of modules in foo.bar,baz notation
1606                                 // but a single module
1607                                 $retval[] = $group;
1608                         } else {
1609                                 // This is a set of modules in foo.bar,baz notation
1610                                 $pos = strrpos( $group, '.' );
1611                                 if ( $pos === false ) {
1612                                         // Prefixless modules, i.e. without dots
1613                                         $retval = array_merge( $retval, explode( ',', $group ) );
1614                                 } else {
1615                                         // We have a prefix and a bunch of suffixes
1616                                         $prefix = substr( $group, 0, $pos ); // 'foo'
1617                                         $suffixes = explode( ',', substr( $group, $pos + 1 ) ); // [ 'bar', 'baz' ]
1618                                         foreach ( $suffixes as $suffix ) {
1619                                                 $retval[] = "$prefix.$suffix";
1620                                         }
1621                                 }
1622                         }
1623                 }
1624                 return $retval;
1625         }
1626
1627         /**
1628          * Determine whether debug mode was requested
1629          * Order of priority is 1) request param, 2) cookie, 3) $wg setting
1630          * @return bool
1631          */
1632         public static function inDebugMode() {
1633                 if ( self::$debugMode === null ) {
1634                         global $wgRequest, $wgResourceLoaderDebug;
1635                         self::$debugMode = $wgRequest->getFuzzyBool( 'debug',
1636                                 $wgRequest->getCookie( 'resourceLoaderDebug', '', $wgResourceLoaderDebug )
1637                         );
1638                 }
1639                 return self::$debugMode;
1640         }
1641
1642         /**
1643          * Reset static members used for caching.
1644          *
1645          * Global state and $wgRequest are evil, but we're using it right
1646          * now and sometimes we need to be able to force ResourceLoader to
1647          * re-evaluate the context because it has changed (e.g. in the test suite).
1648          *
1649          * @internal For use by unit tests
1650          * @codeCoverageIgnore
1651          */
1652         public static function clearCache() {
1653                 self::$debugMode = null;
1654         }
1655
1656         /**
1657          * Build a load.php URL
1658          *
1659          * @since 1.24
1660          * @param string $source Name of the ResourceLoader source
1661          * @param ResourceLoaderContext $context
1662          * @param array $extraQuery
1663          * @return string URL to load.php. May be protocol-relative if $wgLoadScript is, too.
1664          */
1665         public function createLoaderURL( $source, ResourceLoaderContext $context,
1666                 $extraQuery = []
1667         ) {
1668                 $query = self::createLoaderQuery( $context, $extraQuery );
1669                 $script = $this->getLoadScript( $source );
1670
1671                 return wfAppendQuery( $script, $query );
1672         }
1673
1674         /**
1675          * Helper for createLoaderURL()
1676          *
1677          * @since 1.24
1678          * @see makeLoaderQuery
1679          * @param ResourceLoaderContext $context
1680          * @param array $extraQuery
1681          * @return array
1682          */
1683         protected static function createLoaderQuery( ResourceLoaderContext $context, $extraQuery = [] ) {
1684                 return self::makeLoaderQuery(
1685                         $context->getModules(),
1686                         $context->getLanguage(),
1687                         $context->getSkin(),
1688                         $context->getUser(),
1689                         $context->getVersion(),
1690                         $context->getDebug(),
1691                         $context->getOnly(),
1692                         $context->getRequest()->getBool( 'printable' ),
1693                         $context->getRequest()->getBool( 'handheld' ),
1694                         $extraQuery
1695                 );
1696         }
1697
1698         /**
1699          * Build a query array (array representation of query string) for load.php. Helper
1700          * function for createLoaderURL().
1701          *
1702          * @param array $modules
1703          * @param string $lang
1704          * @param string $skin
1705          * @param string|null $user
1706          * @param string|null $version
1707          * @param bool $debug
1708          * @param string|null $only
1709          * @param bool $printable
1710          * @param bool $handheld
1711          * @param array $extraQuery
1712          * @return array
1713          */
1714         public static function makeLoaderQuery( $modules, $lang, $skin, $user = null,
1715                 $version = null, $debug = false, $only = null, $printable = false,
1716                 $handheld = false, $extraQuery = []
1717         ) {
1718                 $query = [
1719                         'modules' => self::makePackedModulesString( $modules ),
1720                 ];
1721                 // Keep urls short by omitting query parameters that
1722                 // match the defaults assumed by ResourceLoaderContext.
1723                 // Note: This relies on the defaults either being insignificant or forever constant,
1724                 // as otherwise cached urls could change in meaning when the defaults change.
1725                 if ( $lang !== ResourceLoaderContext::DEFAULT_LANG ) {
1726                         $query['lang'] = $lang;
1727                 }
1728                 if ( $skin !== ResourceLoaderContext::DEFAULT_SKIN ) {
1729                         $query['skin'] = $skin;
1730                 }
1731                 if ( $debug === true ) {
1732                         $query['debug'] = 'true';
1733                 }
1734                 if ( $user !== null ) {
1735                         $query['user'] = $user;
1736                 }
1737                 if ( $version !== null ) {
1738                         $query['version'] = $version;
1739                 }
1740                 if ( $only !== null ) {
1741                         $query['only'] = $only;
1742                 }
1743                 if ( $printable ) {
1744                         $query['printable'] = 1;
1745                 }
1746                 if ( $handheld ) {
1747                         $query['handheld'] = 1;
1748                 }
1749                 $query += $extraQuery;
1750
1751                 // Make queries uniform in order
1752                 ksort( $query );
1753                 return $query;
1754         }
1755
1756         /**
1757          * Check a module name for validity.
1758          *
1759          * Module names may not contain pipes (|), commas (,) or exclamation marks (!) and can be
1760          * at most 255 bytes.
1761          *
1762          * @param string $moduleName Module name to check
1763          * @return bool Whether $moduleName is a valid module name
1764          */
1765         public static function isValidModuleName( $moduleName ) {
1766                 return strcspn( $moduleName, '!,|', 0, 255 ) === strlen( $moduleName );
1767         }
1768
1769         /**
1770          * Returns LESS compiler set up for use with MediaWiki
1771          *
1772          * @since 1.27
1773          * @param array $vars Associative array of variables that should be used
1774          *  for compilation. Since 1.32, this method no longer automatically includes
1775          *  global LESS vars from ResourceLoader::getLessVars (T191937).
1776          * @throws MWException
1777          * @return Less_Parser
1778          */
1779         public function getLessCompiler( $vars = [] ) {
1780                 global $IP;
1781                 // When called from the installer, it is possible that a required PHP extension
1782                 // is missing (at least for now; see T49564). If this is the case, throw an
1783                 // exception (caught by the installer) to prevent a fatal error later on.
1784                 if ( !class_exists( 'Less_Parser' ) ) {
1785                         throw new MWException( 'MediaWiki requires the less.php parser' );
1786                 }
1787
1788                 $parser = new Less_Parser;
1789                 $parser->ModifyVars( $vars );
1790                 $parser->SetImportDirs( [
1791                         "$IP/resources/src/mediawiki.less/" => '',
1792                 ] );
1793                 $parser->SetOption( 'relativeUrls', false );
1794
1795                 return $parser;
1796         }
1797
1798         /**
1799          * Get global LESS variables.
1800          *
1801          * @since 1.27
1802          * @deprecated since 1.32 Use ResourceLoderModule::getLessVars() instead.
1803          * @return array Map of variable names to string CSS values.
1804          */
1805         public function getLessVars() {
1806                 return [];
1807         }
1808 }