includes/resourceloader/ResourceLoader.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  * @author Roan Kattouw
  20  * @author Trevor Parscal
  21  */
  22
  23 use MediaWiki\MediaWikiServices;
  24 use Psr\Log\LoggerAwareInterface;
  25 use Psr\Log\LoggerInterface;
  26 use Psr\Log\NullLogger;
  27 use Wikimedia\Rdbms\DBConnectionError;
  28 use Wikimedia\WrappedString;
  29
  30 /**
  31  * @defgroup ResourceLoader ResourceLoader
  32  *
  33  * For higher level documentation, see <https://www.mediawiki.org/wiki/ResourceLoader/Architecture>.
  34  */
  35
  36 /**
  37  * ResourceLoader is a loading system for JavaScript and CSS resources.
  38  *
  39  * For higher level documentation, see <https://www.mediawiki.org/wiki/ResourceLoader/Architecture>.
  40  *
  41  * @ingroup ResourceLoader
  42  * @since 1.17
  43  */
  44 class ResourceLoader implements LoggerAwareInterface {
  45         /** @var Config */
  46         protected $config;
  47         /** @var MessageBlobStore */
  48         protected $blobStore;
  49
  50         /** @var LoggerInterface */
  51         private $logger;
  52
  53         /** @var ResourceLoaderModule[] Map of (module name => ResourceLoaderModule) */
  54         protected $modules = [];
  55         /** @var array[] Map of (module name => associative info array) */
  56         protected $moduleInfos = [];
  57         /**
  58          * Associative array mapping framework ids to a list of names of test suite modules
  59          * like [ 'qunit' => [ 'mediawiki.tests.qunit.suites', 'ext.foo.tests', ... ], ... ]
  60          * @var array
  61          */
  62         protected $testModuleNames = [];
  63         /** @var string[] List of module names that contain QUnit test suites */
  64         protected $testSuiteModuleNames = [];
  65
  66         /** @var array Map of (source => path); E.g. [ 'source-id' => 'http://.../load.php' ] */
  67         protected $sources = [];
  68         /** @var array Errors accumulated during current respond() call */
  69         protected $errors = [];
  70         /** @var string[] Extra HTTP response headers from modules loaded in makeModuleResponse() */
  71         protected $extraHeaders = [];
  72
  73         /** @var bool */
  74         protected static $debugMode = null;
  75
  76         /** @var int */
  77         const CACHE_VERSION = 8;
  78
  79         /** @var string JavaScript / CSS pragma to disable minification. * */
  80         const FILTER_NOMIN = '/*@nomin*/';
  81
  82         /**
  83          * Load information stored in the database about modules.
  84          *
  85          * This method grabs modules dependencies from the database and updates modules
  86          * objects.
  87          *
  88          * This is not inside the module code because it is much faster to
  89          * request all of the information at once than it is to have each module
  90          * requests its own information. This sacrifice of modularity yields a substantial
  91          * performance improvement.
  92          *
  93          * @param array $moduleNames List of module names to preload information for
  94          * @param ResourceLoaderContext $context Context to load the information within
  95          */
  96         public function preloadModuleInfo( array $moduleNames, ResourceLoaderContext $context ) {
  97                 if ( !$moduleNames ) {
  98                         // Or else Database*::select() will explode, plus it's cheaper!
  99                         return;
 100                 }
 101                 $dbr = wfGetDB( DB_REPLICA );
 102                 $lang = $context->getLanguage();
 103
 104                 // Batched version of ResourceLoaderModule::getFileDependencies
 105                 $vary = ResourceLoaderModule::getVary( $context );
 106                 $res = $dbr->select( 'module_deps', [ 'md_module', 'md_deps' ], [
 107                                 'md_module' => $moduleNames,
 108                                 'md_skin' => $vary,
 109                         ], __METHOD__
 110                 );
 111
 112                 // Prime in-object cache for file dependencies
 113                 $modulesWithDeps = [];
 114                 foreach ( $res as $row ) {
 115                         $module = $this->getModule( $row->md_module );
 116                         if ( $module ) {
 117                                 $module->setFileDependencies( $context, ResourceLoaderModule::expandRelativePaths(
 118                                         json_decode( $row->md_deps, true )
 119                                 ) );
 120                                 $modulesWithDeps[] = $row->md_module;
 121                         }
 122                 }
 123                 // Register the absence of a dependency row too
 124                 foreach ( array_diff( $moduleNames, $modulesWithDeps ) as $name ) {
 125                         $module = $this->getModule( $name );
 126                         if ( $module ) {
 127                                 $this->getModule( $name )->setFileDependencies( $context, [] );
 128                         }
 129                 }
 130
 131                 // Batched version of ResourceLoaderWikiModule::getTitleInfo
 132                 ResourceLoaderWikiModule::preloadTitleInfo( $context, $dbr, $moduleNames );
 133
 134                 // Prime in-object cache for message blobs for modules with messages
 135                 $modules = [];
 136                 foreach ( $moduleNames as $name ) {
 137                         $module = $this->getModule( $name );
 138                         if ( $module && $module->getMessages() ) {
 139                                 $modules[$name] = $module;
 140                         }
 141                 }
 142                 $store = $this->getMessageBlobStore();
 143                 $blobs = $store->getBlobs( $modules, $lang );
 144                 foreach ( $blobs as $name => $blob ) {
 145                         $modules[$name]->setMessageBlob( $blob, $lang );
 146                 }
 147         }
 148
 149         /**
 150          * Run JavaScript or CSS data through a filter, caching the filtered result for future calls.
 151          *
 152          * Available filters are:
 153          *
 154          *    - minify-js \see JavaScriptMinifier::minify
 155          *    - minify-css \see CSSMin::minify
 156          *
 157          * If $data is empty, only contains whitespace or the filter was unknown,
 158          * $data is returned unmodified.
 159          *
 160          * @param string $filter Name of filter to run
 161          * @param string $data Text to filter, such as JavaScript or CSS text
 162          * @param array $options Keys:
 163          *  - (bool) cache: Whether to allow caching this data. Default: true.
 164          * @return string Filtered data, or a comment containing an error message
 165          */
 166         public static function filter( $filter, $data, array $options = [] ) {
 167                 if ( strpos( $data, self::FILTER_NOMIN ) !== false ) {
 168                         return $data;
 169                 }
 170
 171                 if ( isset( $options['cache'] ) && $options['cache'] === false ) {
 172                         return self::applyFilter( $filter, $data );
 173                 }
 174
 175                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 176                 $cache = ObjectCache::getLocalServerInstance( CACHE_ANYTHING );
 177
 178                 $key = $cache->makeGlobalKey(
 179                         'resourceloader-filter',
 180                         $filter,
 181                         self::CACHE_VERSION,
 182                         md5( $data )
 183                 );
 184
 185                 $result = $cache->get( $key );
 186                 if ( $result === false ) {
 187                         $stats->increment( "resourceloader_cache.$filter.miss" );
 188                         $result = self::applyFilter( $filter, $data );
 189                         $cache->set( $key, $result, 24 * 3600 );
 190                 } else {
 191                         $stats->increment( "resourceloader_cache.$filter.hit" );
 192                 }
 193                 if ( $result === null ) {
 194                         // Cached failure
 195                         $result = $data;
 196                 }
 197
 198                 return $result;
 199         }
 200
 201         private static function applyFilter( $filter, $data ) {
 202                 $data = trim( $data );
 203                 if ( $data ) {
 204                         try {
 205                                 $data = ( $filter === 'minify-css' )
 206                                         ? CSSMin::minify( $data )
 207                                         : JavaScriptMinifier::minify( $data );
 208                         } catch ( Exception $e ) {
 209                                 MWExceptionHandler::logException( $e );
 210                                 return null;
 211                         }
 212                 }
 213                 return $data;
 214         }
 215
 216         /**
 217          * Register core modules and runs registration hooks.
 218          * @param Config|null $config
 219          * @param LoggerInterface|null $logger [optional]
 220          */
 221         public function __construct( Config $config = null, LoggerInterface $logger = null ) {
 222                 $this->logger = $logger ?: new NullLogger();
 223
 224                 if ( !$config ) {
 225                         wfDeprecated( __METHOD__ . ' without a Config instance', '1.34' );
 226                         $config = MediaWikiServices::getInstance()->getMainConfig();
 227                 }
 228                 $this->config = $config;
 229
 230                 // Add 'local' source first
 231                 $this->addSource( 'local', $config->get( 'LoadScript' ) );
 232
 233                 // Special module that always exists
 234                 $this->register( 'startup', [ 'class' => ResourceLoaderStartUpModule::class ] );
 235
 236                 $this->setMessageBlobStore( new MessageBlobStore( $this, $this->logger ) );
 237         }
 238
 239         /**
 240          * @return Config
 241          */
 242         public function getConfig() {
 243                 return $this->config;
 244         }
 245
 246         /**
 247          * @since 1.26
 248          * @param LoggerInterface $logger
 249          */
 250         public function setLogger( LoggerInterface $logger ) {
 251                 $this->logger = $logger;
 252         }
 253
 254         /**
 255          * @since 1.27
 256          * @return LoggerInterface
 257          */
 258         public function getLogger() {
 259                 return $this->logger;
 260         }
 261
 262         /**
 263          * @since 1.26
 264          * @return MessageBlobStore
 265          */
 266         public function getMessageBlobStore() {
 267                 return $this->blobStore;
 268         }
 269
 270         /**
 271          * @since 1.25
 272          * @param MessageBlobStore $blobStore
 273          */
 274         public function setMessageBlobStore( MessageBlobStore $blobStore ) {
 275                 $this->blobStore = $blobStore;
 276         }
 277
 278         /**
 279          * Register a module with the ResourceLoader system.
 280          *
 281          * @param string|array[] $name Module name as a string or, array of module info arrays
 282          *  keyed by name.
 283          * @param array|null $info Module info array. When using the first parameter to register
 284          *  multiple modules at once, this parameter is optional.
 285          * @throws MWException If a duplicate module registration is attempted
 286          * @throws MWException If a module name contains illegal characters (pipes or commas)
 287          * @throws InvalidArgumentException If the module info is not an array
 288          */
 289         public function register( $name, $info = null ) {
 290                 $moduleSkinStyles = $this->config->get( 'ResourceModuleSkinStyles' );
 291
 292                 // Allow multiple modules to be registered in one call
 293                 $registrations = is_array( $name ) ? $name : [ $name => $info ];
 294                 foreach ( $registrations as $name => $info ) {
 295                         // Warn on duplicate registrations
 296                         if ( isset( $this->moduleInfos[$name] ) ) {
 297                                 // A module has already been registered by this name
 298                                 $this->logger->warning(
 299                                         'ResourceLoader duplicate registration warning. ' .
 300                                         'Another module has already been registered as ' . $name
 301                                 );
 302                         }
 303
 304                         // Check validity
 305                         if ( !self::isValidModuleName( $name ) ) {
 306                                 throw new MWException( "ResourceLoader module name '$name' is invalid, "
 307                                         . "see ResourceLoader::isValidModuleName()" );
 308                         }
 309                         if ( !is_array( $info ) ) {
 310                                 throw new InvalidArgumentException(
 311                                         'Invalid module info for "' . $name . '": expected array, got ' . gettype( $info )
 312                                 );
 313                         }
 314
 315                         // Attach module
 316                         $this->moduleInfos[$name] = $info;
 317
 318                         // Last-minute changes
 319                         // Apply custom skin-defined styles to existing modules.
 320                         if ( $this->isFileModule( $name ) ) {
 321                                 foreach ( $moduleSkinStyles as $skinName => $skinStyles ) {
 322                                         // If this module already defines skinStyles for this skin, ignore $wgResourceModuleSkinStyles.
 323                                         if ( isset( $this->moduleInfos[$name]['skinStyles'][$skinName] ) ) {
 324                                                 continue;
 325                                         }
 326
 327                                         // If $name is preceded with a '+', the defined style files will be added to 'default'
 328                                         // skinStyles, otherwise 'default' will be ignored as it normally would be.
 329                                         if ( isset( $skinStyles[$name] ) ) {
 330                                                 $paths = (array)$skinStyles[$name];
 331                                                 $styleFiles = [];
 332                                         } elseif ( isset( $skinStyles['+' . $name] ) ) {
 333                                                 $paths = (array)$skinStyles['+' . $name];
 334                                                 $styleFiles = isset( $this->moduleInfos[$name]['skinStyles']['default'] ) ?
 335                                                         (array)$this->moduleInfos[$name]['skinStyles']['default'] :
 336                                                         [];
 337                                         } else {
 338                                                 continue;
 339                                         }
 340
 341                                         // Add new file paths, remapping them to refer to our directories and not use settings
 342                                         // from the module we're modifying, which come from the base definition.
 343                                         list( $localBasePath, $remoteBasePath ) =
 344                                                 ResourceLoaderFileModule::extractBasePaths( $skinStyles );
 345
 346                                         foreach ( $paths as $path ) {
 347                                                 $styleFiles[] = new ResourceLoaderFilePath( $path, $localBasePath, $remoteBasePath );
 348                                         }
 349
 350                                         $this->moduleInfos[$name]['skinStyles'][$skinName] = $styleFiles;
 351                                 }
 352                         }
 353                 }
 354         }
 355
 356         /**
 357          * @internal For use by ServiceWiring only
 358          * @codeCoverageIgnore
 359          */
 360         public function registerTestModules() {
 361                 global $IP;
 362
 363                 if ( $this->config->get( 'EnableJavaScriptTest' ) !== true ) {
 364                         throw new MWException( 'Attempt to register JavaScript test modules '
 365                                 . 'but <code>$wgEnableJavaScriptTest</code> is false. '
 366                                 . 'Edit your <code>LocalSettings.php</code> to enable it.' );
 367                 }
 368
 369                 // This has a 'qunit' key for compat with the below hook.
 370                 $testModulesMeta = [ 'qunit' => [] ];
 371
 372                 // Get test suites from extensions
 373                 // Avoid PHP 7.1 warning from passing $this by reference
 374                 $rl = $this;
 375                 Hooks::run( 'ResourceLoaderTestModules', [ &$testModulesMeta, &$rl ] );
 376                 $extRegistry = ExtensionRegistry::getInstance();
 377                 // In case of conflict, the deprecated hook has precedence.
 378                 $testModules = $testModulesMeta['qunit'] + $extRegistry->getAttribute( 'QUnitTestModules' );
 379
 380                 $testSuiteModuleNames = [];
 381                 foreach ( $testModules as $name => &$module ) {
 382                         // Turn any single-module dependency into an array
 383                         if ( isset( $module['dependencies'] ) && is_string( $module['dependencies'] ) ) {
 384                                 $module['dependencies'] = [ $module['dependencies'] ];
 385                         }
 386
 387                         // Ensure the testrunner loads before any test suites
 388                         $module['dependencies'][] = 'test.mediawiki.qunit.testrunner';
 389
 390                         // Keep track of the test suites to load on SpecialJavaScriptTest
 391                         $testSuiteModuleNames[] = $name;
 392                 }
 393
 394                 // Core test suites (their names have further precedence).
 395                 $testModules = ( include "$IP/tests/qunit/QUnitTestResources.php" ) + $testModules;
 396                 $testSuiteModuleNames[] = 'test.mediawiki.qunit.suites';
 397
 398                 $this->register( $testModules );
 399                 $this->testSuiteModuleNames = $testSuiteModuleNames;
 400         }
 401
 402         /**
 403          * Add a foreign source of modules.
 404          *
 405          * Source IDs are typically the same as the Wiki ID or database name (e.g. lowercase a-z).
 406          *
 407          * @param array|string $id Source ID (string), or [ id1 => loadUrl, id2 => loadUrl, ... ]
 408          * @param string|array|null $loadUrl load.php url (string), or array with loadUrl key for
 409          *  backwards-compatibility.
 410          * @throws MWException
 411          */
 412         public function addSource( $id, $loadUrl = null ) {
 413                 // Allow multiple sources to be registered in one call
 414                 if ( is_array( $id ) ) {
 415                         foreach ( $id as $key => $value ) {
 416                                 $this->addSource( $key, $value );
 417                         }
 418                         return;
 419                 }
 420
 421                 // Disallow duplicates
 422                 if ( isset( $this->sources[$id] ) ) {
 423                         throw new MWException(
 424                                 'ResourceLoader duplicate source addition error. ' .
 425                                 'Another source has already been registered as ' . $id
 426                         );
 427                 }
 428
 429                 // Pre 1.24 backwards-compatibility
 430                 if ( is_array( $loadUrl ) ) {
 431                         if ( !isset( $loadUrl['loadScript'] ) ) {
 432                                 throw new MWException(
 433                                         __METHOD__ . ' was passed an array with no "loadScript" key.'
 434                                 );
 435                         }
 436
 437                         $loadUrl = $loadUrl['loadScript'];
 438                 }
 439
 440                 $this->sources[$id] = $loadUrl;
 441         }
 442
 443         /**
 444          * Get a list of module names.
 445          *
 446          * @return array List of module names
 447          */
 448         public function getModuleNames() {
 449                 return array_keys( $this->moduleInfos );
 450         }
 451
 452         /**
 453          * Get a list of module names with QUnit test suites.
 454          *
 455          * @internal For use by SpecialJavaScriptTest only
 456          * @return array
 457          * @codeCoverageIgnore
 458          */
 459         public function getTestSuiteModuleNames() {
 460                 return $this->testSuiteModuleNames;
 461         }
 462
 463         /**
 464          * Check whether a ResourceLoader module is registered
 465          *
 466          * @since 1.25
 467          * @param string $name
 468          * @return bool
 469          */
 470         public function isModuleRegistered( $name ) {
 471                 return isset( $this->moduleInfos[$name] );
 472         }
 473
 474         /**
 475          * Get the ResourceLoaderModule object for a given module name.
 476          *
 477          * If an array of module parameters exists but a ResourceLoaderModule object has not
 478          * yet been instantiated, this method will instantiate and cache that object such that
 479          * subsequent calls simply return the same object.
 480          *
 481          * @param string $name Module name
 482          * @return ResourceLoaderModule|null If module has been registered, return a
 483          *  ResourceLoaderModule instance. Otherwise, return null.
 484          */
 485         public function getModule( $name ) {
 486                 if ( !isset( $this->modules[$name] ) ) {
 487                         if ( !isset( $this->moduleInfos[$name] ) ) {
 488                                 // No such module
 489                                 return null;
 490                         }
 491                         // Construct the requested module object
 492                         $info = $this->moduleInfos[$name];
 493                         if ( isset( $info['factory'] ) ) {
 494                                 /** @var ResourceLoaderModule $object */
 495                                 $object = call_user_func( $info['factory'], $info );
 496                         } else {
 497                                 $class = $info['class'] ?? ResourceLoaderFileModule::class;
 498                                 /** @var ResourceLoaderModule $object */
 499                                 $object = new $class( $info );
 500                         }
 501                         $object->setConfig( $this->getConfig() );
 502                         $object->setLogger( $this->logger );
 503                         $object->setName( $name );
 504                         $this->modules[$name] = $object;
 505                 }
 506
 507                 return $this->modules[$name];
 508         }
 509
 510         /**
 511          * Whether the module is a ResourceLoaderFileModule (including subclasses).
 512          *
 513          * @param string $name Module name
 514          * @return bool
 515          */
 516         protected function isFileModule( $name ) {
 517                 if ( !isset( $this->moduleInfos[$name] ) ) {
 518                         return false;
 519                 }
 520                 $info = $this->moduleInfos[$name];
 521                 return !isset( $info['factory'] ) && (
 522                         // The implied default for 'class' is ResourceLoaderFileModule
 523                         !isset( $info['class'] ) ||
 524                         // Explicit default
 525                         $info['class'] === ResourceLoaderFileModule::class ||
 526                         is_subclass_of( $info['class'], ResourceLoaderFileModule::class )
 527                 );
 528         }
 529
 530         /**
 531          * Get the list of sources.
 532          *
 533          * @return array Like [ id => load.php url, ... ]
 534          */
 535         public function getSources() {
 536                 return $this->sources;
 537         }
 538
 539         /**
 540          * Get the URL to the load.php endpoint for the given
 541          * ResourceLoader source
 542          *
 543          * @since 1.24
 544          * @param string $source
 545          * @throws MWException On an invalid $source name
 546          * @return string
 547          */
 548         public function getLoadScript( $source ) {
 549                 if ( !isset( $this->sources[$source] ) ) {
 550                         throw new MWException( "The $source source was never registered in ResourceLoader." );
 551                 }
 552                 return $this->sources[$source];
 553         }
 554
 555         /**
 556          * @internal For use by ResourceLoaderStartUpModule only.
 557          */
 558         const HASH_LENGTH = 5;
 559
 560         /**
 561          * Create a hash for module versioning purposes.
 562          *
 563          * This hash is used in three ways:
 564          *
 565          * - To differentiate between the current version and a past version
 566          *   of a module by the same name.
 567          *
 568          *   In the cache key of localStorage in the browser (mw.loader.store).
 569          *   This store keeps only one version of any given module. As long as the
 570          *   next version the client encounters has a different hash from the last
 571          *   version it saw, it will correctly discard it in favour of a network fetch.
 572          *
 573          *   A browser may evict a site's storage container for any reason (e.g. when
 574          *   the user hasn't visited a site for some time, and/or when the device is
 575          *   low on storage space). Anecdotally it seems devices rarely keep unused
 576          *   storage beyond 2 weeks on mobile devices and 4 weeks on desktop.
 577          *   But, there is no hard limit or expiration on localStorage.
 578          *   ResourceLoader's Client also clears localStorage when the user changes
 579          *   their language preference or when they (temporarily) use Debug Mode.
 580          *
 581          *   The only hard factors that reduce the range of possible versions are
 582          *   1) the name and existence of a given module, and
 583          *   2) the TTL for mw.loader.store, and
 584          *   3) the `$wgResourceLoaderStorageVersion` configuration variable.
 585          *
 586          * - To identify a batch response of modules from load.php in an HTTP cache.
 587          *
 588          *   When fetching modules in a batch from load.php, a combined hash
 589          *   is created by the JS code, and appended as query parameter.
 590          *
 591          *   In cache proxies (e.g. Varnish, Nginx) and in the browser's HTTP cache,
 592          *   these urls are used to identify other previously cached responses.
 593          *   The range of possible versions a given version has to be unique amongst
 594          *   is determined by the maximum duration each response is stored for, which
 595          *   is controlled by `$wgResourceLoaderMaxage['versioned']`.
 596          *
 597          * - To detect race conditions between multiple web servers in a MediaWiki
 598          *   deployment of which some have the newer version and some still the older
 599          *   version.
 600          *
 601          *   An HTTP request from a browser for the Startup manifest may be responded
 602          *   to by a server with the newer version. The browser may then use that to
 603          *   request a given module, which may then be responded to by a server with
 604          *   the older version. To avoid caching this for too long (which would pollute
 605          *   all other users without repairing itself), the combined hash that the JS
 606          *   client adds to the url is verified by the server (in ::sendResponseHeaders).
 607          *   If they don't match, we instruct cache proxies and clients to not cache
 608          *   this response as long as they normally would. This is also the reason
 609          *   that the algorithm used here in PHP must match the one used in JS.
 610          *
 611          * The fnv132 digest creates a 32-bit integer, which goes upto 4 Giga and
 612          * needs up to 7 chars in base 36.
 613          * Within 7 characters, base 36 can count up to 78,364,164,096 (78 Giga),
 614          * (but with fnv132 we'd use very little of this range, mostly padding).
 615          * Within 6 characters, base 36 can count up to 2,176,782,336 (2 Giga).
 616          * Within 5 characters, base 36 can count up to 60,466,176 (60 Mega).
 617          *
 618          * @since 1.26
 619          * @param string $value
 620          * @return string Hash
 621          */
 622         public static function makeHash( $value ) {
 623                 $hash = hash( 'fnv132', $value );
 624                 // The base_convert will pad it (if too short),
 625                 // then substr() will trim it (if too long).
 626                 return substr(
 627                         Wikimedia\base_convert( $hash, 16, 36, self::HASH_LENGTH ),
 628                         0,
 629                         self::HASH_LENGTH
 630                 );
 631         }
 632
 633         /**
 634          * Add an error to the 'errors' array and log it.
 635          *
 636          * @private For internal use by ResourceLoader and ResourceLoaderStartUpModule.
 637          * @since 1.29
 638          * @param Exception $e
 639          * @param string $msg
 640          * @param array $context
 641          */
 642         public function outputErrorAndLog( Exception $e, $msg, array $context = [] ) {
 643                 MWExceptionHandler::logException( $e );
 644                 $this->logger->warning(
 645                         $msg,
 646                         $context + [ 'exception' => $e ]
 647                 );
 648                 $this->errors[] = self::formatExceptionNoComment( $e );
 649         }
 650
 651         /**
 652          * Helper method to get and combine versions of multiple modules.
 653          *
 654          * @since 1.26
 655          * @param ResourceLoaderContext $context
 656          * @param string[] $moduleNames List of known module names
 657          * @return string Hash
 658          */
 659         public function getCombinedVersion( ResourceLoaderContext $context, array $moduleNames ) {
 660                 if ( !$moduleNames ) {
 661                         return '';
 662                 }
 663                 $hashes = array_map( function ( $module ) use ( $context ) {
 664                         try {
 665                                 return $this->getModule( $module )->getVersionHash( $context );
 666                         } catch ( Exception $e ) {
 667                                 // If modules fail to compute a version, don't fail the request (T152266)
 668                                 // and still compute versions of other modules.
 669                                 $this->outputErrorAndLog( $e,
 670                                         'Calculating version for "{module}" failed: {exception}',
 671                                         [
 672                                                 'module' => $module,
 673                                         ]
 674                                 );
 675                                 return '';
 676                         }
 677                 }, $moduleNames );
 678                 return self::makeHash( implode( '', $hashes ) );
 679         }
 680
 681         /**
 682          * Get the expected value of the 'version' query parameter.
 683          *
 684          * This is used by respond() to set a short Cache-Control header for requests with
 685          * information newer than the current server has. This avoids pollution of edge caches.
 686          * Typically during deployment. (T117587)
 687          *
 688          * This MUST match return value of `mw.loader#getCombinedVersion()` client-side.
 689          *
 690          * @since 1.28
 691          * @param ResourceLoaderContext $context
 692          * @param string[]|null $modules
 693          * @return string Hash
 694          */
 695         public function makeVersionQuery( ResourceLoaderContext $context, array $modules = null ) {
 696                 if ( $modules === null ) {
 697                         wfDeprecated( __METHOD__ . ' without $modules', '1.34' );
 698                         $modules = $context->getModules();
 699                 }
 700                 // As of MediaWiki 1.28, the server and client use the same algorithm for combining
 701                 // version hashes. There is no technical reason for this to be same, and for years the
 702                 // implementations differed. If getCombinedVersion in PHP (used for StartupModule and
 703                 // E-Tag headers) differs in the future from getCombinedVersion in JS (used for 'version'
 704                 // query parameter), then this method must continue to match the JS one.
 705                 $filtered = [];
 706                 foreach ( $modules as $name ) {
 707                         if ( !$this->getModule( $name ) ) {
 708                                 // If a versioned request contains a missing module, the version is a mismatch
 709                                 // as the client considered a module (and version) we don't have.
 710                                 return '';
 711                         }
 712                         $filtered[] = $name;
 713                 }
 714                 return $this->getCombinedVersion( $context, $filtered );
 715         }
 716
 717         /**
 718          * Output a response to a load request, including the content-type header.
 719          *
 720          * @param ResourceLoaderContext $context Context in which a response should be formed
 721          */
 722         public function respond( ResourceLoaderContext $context ) {
 723                 // Buffer output to catch warnings. Normally we'd use ob_clean() on the
 724                 // top-level output buffer to clear warnings, but that breaks when ob_gzhandler
 725                 // is used: ob_clean() will clear the GZIP header in that case and it won't come
 726                 // back for subsequent output, resulting in invalid GZIP. So we have to wrap
 727                 // the whole thing in our own output buffer to be sure the active buffer
 728                 // doesn't use ob_gzhandler.
 729                 // See https://bugs.php.net/bug.php?id=36514
 730                 ob_start();
 731
 732                 $this->measureResponseTime( RequestContext::getMain()->getTiming() );
 733
 734                 // Find out which modules are missing and instantiate the others
 735                 $modules = [];
 736                 $missing = [];
 737                 foreach ( $context->getModules() as $name ) {
 738                         $module = $this->getModule( $name );
 739                         if ( $module ) {
 740                                 // Do not allow private modules to be loaded from the web.
 741                                 // This is a security issue, see T36907.
 742                                 if ( $module->getGroup() === 'private' ) {
 743                                         // Not a serious error, just means something is trying to access it (T101806)
 744                                         $this->logger->debug( "Request for private module '$name' denied" );
 745                                         $this->errors[] = "Cannot build private module \"$name\"";
 746                                         continue;
 747                                 }
 748                                 $modules[$name] = $module;
 749                         } else {
 750                                 $missing[] = $name;
 751                         }
 752                 }
 753
 754                 try {
 755                         // Preload for getCombinedVersion() and for batch makeModuleResponse()
 756                         $this->preloadModuleInfo( array_keys( $modules ), $context );
 757                 } catch ( Exception $e ) {
 758                         $this->outputErrorAndLog( $e, 'Preloading module info failed: {exception}' );
 759                 }
 760
 761                 // Combine versions to propagate cache invalidation
 762                 $versionHash = '';
 763                 try {
 764                         $versionHash = $this->getCombinedVersion( $context, array_keys( $modules ) );
 765                 } catch ( Exception $e ) {
 766                         $this->outputErrorAndLog( $e, 'Calculating version hash failed: {exception}' );
 767                 }
 768
 769                 // See RFC 2616 § 3.11 Entity Tags
 770                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.11
 771                 $etag = 'W/"' . $versionHash . '"';
 772
 773                 // Try the client-side cache first
 774                 if ( $this->tryRespondNotModified( $context, $etag ) ) {
 775                         return; // output handled (buffers cleared)
 776                 }
 777
 778                 // Use file cache if enabled and available...
 779                 if ( $this->config->get( 'UseFileCache' ) ) {
 780                         $fileCache = ResourceFileCache::newFromContext( $context );
 781                         if ( $this->tryRespondFromFileCache( $fileCache, $context, $etag ) ) {
 782                                 return; // output handled
 783                         }
 784                 } else {
 785                         $fileCache = null;
 786                 }
 787
 788                 // Generate a response
 789                 $response = $this->makeModuleResponse( $context, $modules, $missing );
 790
 791                 // Capture any PHP warnings from the output buffer and append them to the
 792                 // error list if we're in debug mode.
 793                 if ( $context->getDebug() ) {
 794                         $warnings = ob_get_contents();
 795                         if ( strlen( $warnings ) ) {
 796                                 $this->errors[] = $warnings;
 797                         }
 798                 }
 799
 800                 // Consider saving the response to file cache (unless there are errors).
 801                 if ( $fileCache &&
 802                         !$this->errors &&
 803                         $missing === [] &&
 804                         ResourceFileCache::useFileCache( $context )
 805                 ) {
 806                         if ( $fileCache->isCacheWorthy() ) {
 807                                 // There were enough hits, save the response to the cache
 808                                 $fileCache->saveText( $response );
 809                         } else {
 810                                 $fileCache->incrMissesRecent( $context->getRequest() );
 811                         }
 812                 }
 813
 814                 $this->sendResponseHeaders( $context, $etag, (bool)$this->errors, $this->extraHeaders );
 815
 816                 // Remove the output buffer and output the response
 817                 ob_end_clean();
 818
 819                 if ( $context->getImageObj() && $this->errors ) {
 820                         // We can't show both the error messages and the response when it's an image.
 821                         $response = implode( "\n\n", $this->errors );
 822                 } elseif ( $this->errors ) {
 823                         $errorText = implode( "\n\n", $this->errors );
 824                         $errorResponse = self::makeComment( $errorText );
 825                         if ( $context->shouldIncludeScripts() ) {
 826                                 $errorResponse .= 'if (window.console && console.error) { console.error('
 827                                         . self::encodeJsonForScript( $errorText )
 828                                         . "); }\n";
 829                         }
 830
 831                         // Prepend error info to the response
 832                         $response = $errorResponse . $response;
 833                 }
 834
 835                 $this->errors = [];
 836                 echo $response;
 837         }
 838
 839         protected function measureResponseTime( Timing $timing ) {
 840                 DeferredUpdates::addCallableUpdate( function () use ( $timing ) {
 841                         $measure = $timing->measure( 'responseTime', 'requestStart', 'requestShutdown' );
 842                         if ( $measure !== false ) {
 843                                 $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
 844                                 $stats->timing( 'resourceloader.responseTime', $measure['duration'] * 1000 );
 845                         }
 846                 } );
 847         }
 848
 849         /**
 850          * Send main response headers to the client.
 851          *
 852          * Deals with Content-Type, CORS (for stylesheets), and caching.
 853          *
 854          * @param ResourceLoaderContext $context
 855          * @param string $etag ETag header value
 856          * @param bool $errors Whether there are errors in the response
 857          * @param string[] $extra Array of extra HTTP response headers
 858          * @return void
 859          */
 860         protected function sendResponseHeaders(
 861                 ResourceLoaderContext $context, $etag, $errors, array $extra = []
 862         ) {
 863                 \MediaWiki\HeaderCallback::warnIfHeadersSent();
 864                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 865                 // Use a short cache expiry so that updates propagate to clients quickly, if:
 866                 // - No version specified (shared resources, e.g. stylesheets)
 867                 // - There were errors (recover quickly)
 868                 // - Version mismatch (T117587, T47877)
 869                 if ( is_null( $context->getVersion() )
 870                         || $errors
 871                         || $context->getVersion() !== $this->makeVersionQuery( $context, $context->getModules() )
 872                 ) {
 873                         $maxage = $rlMaxage['unversioned']['client'];
 874                         $smaxage = $rlMaxage['unversioned']['server'];
 875                 // If a version was specified we can use a longer expiry time since changing
 876                 // version numbers causes cache misses
 877                 } else {
 878                         $maxage = $rlMaxage['versioned']['client'];
 879                         $smaxage = $rlMaxage['versioned']['server'];
 880                 }
 881                 if ( $context->getImageObj() ) {
 882                         // Output different headers if we're outputting textual errors.
 883                         if ( $errors ) {
 884                                 header( 'Content-Type: text/plain; charset=utf-8' );
 885                         } else {
 886                                 $context->getImageObj()->sendResponseHeaders( $context );
 887                         }
 888                 } elseif ( $context->getOnly() === 'styles' ) {
 889                         header( 'Content-Type: text/css; charset=utf-8' );
 890                         header( 'Access-Control-Allow-Origin: *' );
 891                 } else {
 892                         header( 'Content-Type: text/javascript; charset=utf-8' );
 893                 }
 894                 // See RFC 2616 § 14.19 ETag
 895                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.19
 896                 header( 'ETag: ' . $etag );
 897                 if ( $context->getDebug() ) {
 898                         // Do not cache debug responses
 899                         header( 'Cache-Control: private, no-cache, must-revalidate' );
 900                         header( 'Pragma: no-cache' );
 901                 } else {
 902                         header( "Cache-Control: public, max-age=$maxage, s-maxage=$smaxage" );
 903                         $exp = min( $maxage, $smaxage );
 904                         header( 'Expires: ' . wfTimestamp( TS_RFC2822, $exp + time() ) );
 905                 }
 906                 foreach ( $extra as $header ) {
 907                         header( $header );
 908                 }
 909         }
 910
 911         /**
 912          * Respond with HTTP 304 Not Modified if appropiate.
 913          *
 914          * If there's an If-None-Match header, respond with a 304 appropriately
 915          * and clear out the output buffer. If the client cache is too old then do nothing.
 916          *
 917          * @param ResourceLoaderContext $context
 918          * @param string $etag ETag header value
 919          * @return bool True if HTTP 304 was sent and output handled
 920          */
 921         protected function tryRespondNotModified( ResourceLoaderContext $context, $etag ) {
 922                 // See RFC 2616 § 14.26 If-None-Match
 923                 // https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.26
 924                 $clientKeys = $context->getRequest()->getHeader( 'If-None-Match', WebRequest::GETHEADER_LIST );
 925                 // Never send 304s in debug mode
 926                 if ( $clientKeys !== false && !$context->getDebug() && in_array( $etag, $clientKeys ) ) {
 927                         // There's another bug in ob_gzhandler (see also the comment at
 928                         // the top of this function) that causes it to gzip even empty
 929                         // responses, meaning it's impossible to produce a truly empty
 930                         // response (because the gzip header is always there). This is
 931                         // a problem because 304 responses have to be completely empty
 932                         // per the HTTP spec, and Firefox behaves buggily when they're not.
 933                         // See also https://bugs.php.net/bug.php?id=51579
 934                         // To work around this, we tear down all output buffering before
 935                         // sending the 304.
 936                         wfResetOutputBuffers( /* $resetGzipEncoding = */ true );
 937
 938                         HttpStatus::header( 304 );
 939
 940                         $this->sendResponseHeaders( $context, $etag, false );
 941                         return true;
 942                 }
 943                 return false;
 944         }
 945
 946         /**
 947          * Send out code for a response from file cache if possible.
 948          *
 949          * @param ResourceFileCache $fileCache Cache object for this request URL
 950          * @param ResourceLoaderContext $context Context in which to generate a response
 951          * @param string $etag ETag header value
 952          * @return bool If this found a cache file and handled the response
 953          */
 954         protected function tryRespondFromFileCache(
 955                 ResourceFileCache $fileCache,
 956                 ResourceLoaderContext $context,
 957                 $etag
 958         ) {
 959                 $rlMaxage = $this->config->get( 'ResourceLoaderMaxage' );
 960                 // Buffer output to catch warnings.
 961                 ob_start();
 962                 // Get the maximum age the cache can be
 963                 $maxage = is_null( $context->getVersion() )
 964                         ? $rlMaxage['unversioned']['server']
 965                         : $rlMaxage['versioned']['server'];
 966                 // Minimum timestamp the cache file must have
 967                 $good = $fileCache->isCacheGood( wfTimestamp( TS_MW, time() - $maxage ) );
 968                 if ( !$good ) {
 969                         try { // RL always hits the DB on file cache miss...
 970                                 wfGetDB( DB_REPLICA );
 971                         } catch ( DBConnectionError $e ) { // ...check if we need to fallback to cache
 972                                 $good = $fileCache->isCacheGood(); // cache existence check
 973                         }
 974                 }
 975                 if ( $good ) {
 976                         $ts = $fileCache->cacheTimestamp();
 977                         // Send content type and cache headers
 978                         $this->sendResponseHeaders( $context, $etag, false );
 979                         $response = $fileCache->fetchText();
 980                         // Capture any PHP warnings from the output buffer and append them to the
 981                         // response in a comment if we're in debug mode.
 982                         if ( $context->getDebug() ) {
 983                                 $warnings = ob_get_contents();
 984                                 if ( strlen( $warnings ) ) {
 985                                         $response = self::makeComment( $warnings ) . $response;
 986                                 }
 987                         }
 988                         // Remove the output buffer and output the response
 989                         ob_end_clean();
 990                         echo $response . "\n/* Cached {$ts} */";
 991                         return true; // cache hit
 992                 }
 993                 // Clear buffer
 994                 ob_end_clean();
 995
 996                 return false; // cache miss
 997         }
 998
 999         /**
1000          * Generate a CSS or JS comment block.
1001          *
1002          * Only use this for public data, not error message details.
1003          *
1004          * @param string $text
1005          * @return string
1006          */
1007         public static function makeComment( $text ) {
1008                 $encText = str_replace( '*/', '* /', $text );
1009                 return "/*\n$encText\n*/\n";
1010         }
1011
1012         /**
1013          * Handle exception display.
1014          *
1015          * @param Exception $e Exception to be shown to the user
1016          * @return string Sanitized text in a CSS/JS comment that can be returned to the user
1017          */
1018         public static function formatException( $e ) {
1019                 return self::makeComment( self::formatExceptionNoComment( $e ) );
1020         }
1021
1022         /**
1023          * Handle exception display.
1024          *
1025          * @since 1.25
1026          * @param Exception $e Exception to be shown to the user
1027          * @return string Sanitized text that can be returned to the user
1028          */
1029         protected static function formatExceptionNoComment( $e ) {
1030                 global $wgShowExceptionDetails;
1031
1032                 if ( !$wgShowExceptionDetails ) {
1033                         return MWExceptionHandler::getPublicLogMessage( $e );
1034                 }
1035
1036                 return MWExceptionHandler::getLogMessage( $e ) .
1037                         "\nBacktrace:\n" .
1038                         MWExceptionHandler::getRedactedTraceAsString( $e );
1039         }
1040
1041         /**
1042          * Generate code for a response.
1043          *
1044          * Calling this method also populates the `errors` and `headers` members,
1045          * later used by respond().
1046          *
1047          * @param ResourceLoaderContext $context Context in which to generate a response
1048          * @param ResourceLoaderModule[] $modules List of module objects keyed by module name
1049          * @param string[] $missing List of requested module names that are unregistered (optional)
1050          * @return string Response data
1051          */
1052         public function makeModuleResponse( ResourceLoaderContext $context,
1053                 array $modules, array $missing = []
1054         ) {
1055                 $out = '';
1056                 $states = [];
1057
1058                 if ( $modules === [] && $missing === [] ) {
1059                         return <<<MESSAGE
1060 /* This file is the Web entry point for MediaWiki's ResourceLoader:
1061    <https://www.mediawiki.org/wiki/ResourceLoader>. In this request,
1062    no modules were requested. Max made me put this here. */
1063 MESSAGE;
1064                 }
1065
1066                 $image = $context->getImageObj();
1067                 if ( $image ) {
1068                         $data = $image->getImageData( $context );
1069                         if ( $data === false ) {
1070                                 $data = '';
1071                                 $this->errors[] = 'Image generation failed';
1072                         }
1073                         return $data;
1074                 }
1075
1076                 foreach ( $missing as $name ) {
1077                         $states[$name] = 'missing';
1078                 }
1079
1080                 $filter = $context->getOnly() === 'styles' ? 'minify-css' : 'minify-js';
1081
1082                 foreach ( $modules as $name => $module ) {
1083                         try {
1084                                 $content = $module->getModuleContent( $context );
1085                                 $implementKey = $name . '@' . $module->getVersionHash( $context );
1086                                 $strContent = '';
1087
1088                                 if ( isset( $content['headers'] ) ) {
1089                                         $this->extraHeaders = array_merge( $this->extraHeaders, $content['headers'] );
1090                                 }
1091
1092                                 // Append output
1093                                 switch ( $context->getOnly() ) {
1094                                         case 'scripts':
1095                                                 $scripts = $content['scripts'];
1096                                                 if ( is_string( $scripts ) ) {
1097                                                         // Load scripts raw...
1098                                                         $strContent = $scripts;
1099                                                 } elseif ( is_array( $scripts ) ) {
1100                                                         // ...except when $scripts is an array of URLs or an associative array
1101                                                         $strContent = self::makeLoaderImplementScript( $implementKey, $scripts, [], [], [] );
1102                                                 }
1103                                                 break;
1104                                         case 'styles':
1105                                                 $styles = $content['styles'];
1106                                                 // We no longer separate into media, they are all combined now with
1107                                                 // custom media type groups into @media .. {} sections as part of the css string.
1108                                                 // Module returns either an empty array or a numerical array with css strings.
1109                                                 $strContent = isset( $styles['css'] ) ? implode( '', $styles['css'] ) : '';
1110                                                 break;
1111                                         default:
1112                                                 $scripts = $content['scripts'] ?? '';
1113                                                 if ( is_string( $scripts ) ) {
1114                                                         if ( $name === 'site' || $name === 'user' ) {
1115                                                                 // Legacy scripts that run in the global scope without a closure.
1116                                                                 // mw.loader.implement will use globalEval if scripts is a string.
1117                                                                 // Minify manually here, because general response minification is
1118                                                                 // not effective due it being a string literal, not a function.
1119                                                                 if ( !$context->getDebug() ) {
1120                                                                         $scripts = self::filter( 'minify-js', $scripts ); // T107377
1121                                                                 }
1122                                                         } else {
1123                                                                 $scripts = new XmlJsCode( $scripts );
1124                                                         }
1125                                                 }
1126                                                 $strContent = self::makeLoaderImplementScript(
1127                                                         $implementKey,
1128                                                         $scripts,
1129                                                         $content['styles'] ?? [],
1130                                                         isset( $content['messagesBlob'] ) ? new XmlJsCode( $content['messagesBlob'] ) : [],
1131                                                         $content['templates'] ?? []
1132                                                 );
1133                                                 break;
1134                                 }
1135
1136                                 if ( !$context->getDebug() ) {
1137                                         $strContent = self::filter( $filter, $strContent );
1138                                 } else {
1139                                         // In debug mode, separate each response by a new line.
1140                                         // For example, between 'mw.loader.implement();' statements.
1141                                         $strContent = $this->ensureNewline( $strContent );
1142                                 }
1143
1144                                 if ( $context->getOnly() === 'scripts' ) {
1145                                         // Use a linebreak between module scripts (T162719)
1146                                         $out .= $this->ensureNewline( $strContent );
1147                                 } else {
1148                                         $out .= $strContent;
1149                                 }
1150
1151                         } catch ( Exception $e ) {
1152                                 $this->outputErrorAndLog( $e, 'Generating module package failed: {exception}' );
1153
1154                                 // Respond to client with error-state instead of module implementation
1155                                 $states[$name] = 'error';
1156                                 unset( $modules[$name] );
1157                         }
1158                 }
1159
1160                 // Update module states
1161                 if ( $context->shouldIncludeScripts() && !$context->getRaw() ) {
1162                         if ( $modules && $context->getOnly() === 'scripts' ) {
1163                                 // Set the state of modules loaded as only scripts to ready as
1164                                 // they don't have an mw.loader.implement wrapper that sets the state
1165                                 foreach ( $modules as $name => $module ) {
1166                                         $states[$name] = 'ready';
1167                                 }
1168                         }
1169
1170                         // Set the state of modules we didn't respond to with mw.loader.implement
1171                         if ( $states ) {
1172                                 $stateScript = self::makeLoaderStateScript( $states );
1173                                 if ( !$context->getDebug() ) {
1174                                         $stateScript = self::filter( 'minify-js', $stateScript );
1175                                 }
1176                                 // Use a linebreak between module script and state script (T162719)
1177                                 $out = $this->ensureNewline( $out ) . $stateScript;
1178                         }
1179                 } elseif ( $states ) {
1180                         $this->errors[] = 'Problematic modules: '
1181                                 . self::encodeJsonForScript( $states );
1182                 }
1183
1184                 return $out;
1185         }
1186
1187         /**
1188          * Ensure the string is either empty or ends in a line break
1189          * @param string $str
1190          * @return string
1191          */
1192         private function ensureNewline( $str ) {
1193                 $end = substr( $str, -1 );
1194                 if ( $end === false || $end === '' || $end === "\n" ) {
1195                         return $str;
1196                 }
1197                 return $str . "\n";
1198         }
1199
1200         /**
1201          * Get names of modules that use a certain message.
1202          *
1203          * @param string $messageKey
1204          * @return array List of module names
1205          */
1206         public function getModulesByMessage( $messageKey ) {
1207                 $moduleNames = [];
1208                 foreach ( $this->getModuleNames() as $moduleName ) {
1209                         $module = $this->getModule( $moduleName );
1210                         if ( in_array( $messageKey, $module->getMessages() ) ) {
1211                                 $moduleNames[] = $moduleName;
1212                         }
1213                 }
1214                 return $moduleNames;
1215         }
1216
1217         /**
1218          * Return JS code that calls mw.loader.implement with given module properties.
1219          *
1220          * @param string $name Module name or implement key (format "`[name]@[version]`")
1221          * @param XmlJsCode|array|string $scripts Code as XmlJsCode (to be wrapped in a closure),
1222          *  list of URLs to JavaScript files, string of JavaScript for `$.globalEval`, or array with
1223          *  'files' and 'main' properties (see ResourceLoaderModule::getScript())
1224          * @param mixed $styles Array of CSS strings keyed by media type, or an array of lists of URLs
1225          *   to CSS files keyed by media type
1226          * @param mixed $messages List of messages associated with this module. May either be an
1227          *   associative array mapping message key to value, or a JSON-encoded message blob containing
1228          *   the same data, wrapped in an XmlJsCode object.
1229          * @param array $templates Keys are name of templates and values are the source of
1230          *   the template.
1231          * @throws MWException
1232          * @return string JavaScript code
1233          */
1234         protected static function makeLoaderImplementScript(
1235                 $name, $scripts, $styles, $messages, $templates
1236         ) {
1237                 if ( $scripts instanceof XmlJsCode ) {
1238                         if ( $scripts->value === '' ) {
1239                                 $scripts = null;
1240                         } elseif ( self::inDebugMode() ) {
1241                                 $scripts = new XmlJsCode( "function ( $, jQuery, require, module ) {\n{$scripts->value}\n}" );
1242                         } else {
1243                                 $scripts = new XmlJsCode( 'function($,jQuery,require,module){' . $scripts->value . '}' );
1244                         }
1245                 } elseif ( is_array( $scripts ) && isset( $scripts['files'] ) ) {
1246                         $files = $scripts['files'];
1247                         foreach ( $files as $path => &$file ) {
1248                                 // $file is changed (by reference) from a descriptor array to the content of the file
1249                                 // All of these essentially do $file = $file['content'];, some just have wrapping around it
1250                                 if ( $file['type'] === 'script' ) {
1251                                         // Multi-file modules only get two parameters ($ and jQuery are being phased out)
1252                                         if ( self::inDebugMode() ) {
1253                                                 $file = new XmlJsCode( "function ( require, module ) {\n{$file['content']}\n}" );
1254                                         } else {
1255                                                 $file = new XmlJsCode( 'function(require,module){' . $file['content'] . '}' );
1256                                         }
1257                                 } else {
1258                                         $file = $file['content'];
1259                                 }
1260                         }
1261                         $scripts = XmlJsCode::encodeObject( [
1262                                 'main' => $scripts['main'],
1263                                 'files' => XmlJsCode::encodeObject( $files, self::inDebugMode() )
1264                         ], self::inDebugMode() );
1265                 } elseif ( !is_string( $scripts ) && !is_array( $scripts ) ) {
1266                         throw new MWException( 'Invalid scripts error. Array of URLs or string of code expected.' );
1267                 }
1268
1269                 // mw.loader.implement requires 'styles', 'messages' and 'templates' to be objects (not
1270                 // arrays). json_encode considers empty arrays to be numerical and outputs "[]" instead
1271                 // of "{}". Force them to objects.
1272                 $module = [
1273                         $name,
1274                         $scripts,
1275                         (object)$styles,
1276                         (object)$messages,
1277                         (object)$templates
1278                 ];
1279                 self::trimArray( $module );
1280
1281                 return Xml::encodeJsCall( 'mw.loader.implement', $module, self::inDebugMode() );
1282         }
1283
1284         /**
1285          * Returns JS code which, when called, will register a given list of messages.
1286          *
1287          * @param mixed $messages Associative array mapping message key to value.
1288          * @return string JavaScript code
1289          */
1290         public static function makeMessageSetScript( $messages ) {
1291                 return 'mw.messages.set('
1292                         . self::encodeJsonForScript( (object)$messages )
1293                         . ');';
1294         }
1295
1296         /**
1297          * Combines an associative array mapping media type to CSS into a
1298          * single stylesheet with "@media" blocks.
1299          *
1300          * @param array $stylePairs Array keyed by media type containing (arrays of) CSS strings
1301          * @return array
1302          */
1303         public static function makeCombinedStyles( array $stylePairs ) {
1304                 $out = [];
1305                 foreach ( $stylePairs as $media => $styles ) {
1306                         // ResourceLoaderFileModule::getStyle can return the styles
1307                         // as a string or an array of strings. This is to allow separation in
1308                         // the front-end.
1309                         $styles = (array)$styles;
1310                         foreach ( $styles as $style ) {
1311                                 $style = trim( $style );
1312                                 // Don't output an empty "@media print { }" block (T42498)
1313                                 if ( $style !== '' ) {
1314                                         // Transform the media type based on request params and config
1315                                         // The way that this relies on $wgRequest to propagate request params is slightly evil
1316                                         $media = OutputPage::transformCssMedia( $media );
1317
1318                                         if ( $media === '' || $media == 'all' ) {
1319                                                 $out[] = $style;
1320                                         } elseif ( is_string( $media ) ) {
1321                                                 $out[] = "@media $media {\n" . str_replace( "\n", "\n\t", "\t" . $style ) . "}";
1322                                         }
1323                                         // else: skip
1324                                 }
1325                         }
1326                 }
1327                 return $out;
1328         }
1329
1330         /**
1331          * Wrapper around json_encode that avoids needless escapes,
1332          * and pretty-prints in debug mode.
1333          *
1334          * @internal
1335          * @since 1.32
1336          * @param mixed $data
1337          * @return string|false JSON string, false on error
1338          */
1339         public static function encodeJsonForScript( $data ) {
1340                 // Keep output as small as possible by disabling needless escape modes
1341                 // that PHP uses by default.
1342                 // However, while most module scripts are only served on HTTP responses
1343                 // for JavaScript, some modules can also be embedded in the HTML as inline
1344                 // scripts. This, and the fact that we sometimes need to export strings
1345                 // containing user-generated content and labels that may genuinely contain
1346                 // a sequences like "</script>", we need to encode either '/' or '<'.
1347                 // By default PHP escapes '/'. Let's escape '<' instead which is less common
1348                 // and allows URLs to mostly remain readable.
1349                 $jsonFlags = JSON_UNESCAPED_SLASHES |
1350                         JSON_UNESCAPED_UNICODE |
1351                         JSON_HEX_TAG |
1352                         JSON_HEX_AMP;
1353                 if ( self::inDebugMode() ) {
1354                         $jsonFlags |= JSON_PRETTY_PRINT;
1355                 }
1356                 return json_encode( $data, $jsonFlags );
1357         }
1358
1359         /**
1360          * Returns a JS call to mw.loader.state, which sets the state of one
1361          * ore more modules to a given value. Has two calling conventions:
1362          *
1363          *    - ResourceLoader::makeLoaderStateScript( $name, $state ):
1364          *         Set the state of a single module called $name to $state
1365          *
1366          *    - ResourceLoader::makeLoaderStateScript( [ $name => $state, ... ] ):
1367          *         Set the state of modules with the given names to the given states
1368          *
1369          * @param array|string $states
1370          * @param string|null $state
1371          * @return string JavaScript code
1372          */
1373         public static function makeLoaderStateScript( $states, $state = null ) {
1374                 if ( !is_array( $states ) ) {
1375                         $states = [ $states => $state ];
1376                 }
1377                 return 'mw.loader.state('
1378                         . self::encodeJsonForScript( $states )
1379                         . ');';
1380         }
1381
1382         private static function isEmptyObject( stdClass $obj ) {
1383                 foreach ( $obj as $key => $value ) {
1384                         return false;
1385                 }
1386                 return true;
1387         }
1388
1389         /**
1390          * Remove empty values from the end of an array.
1391          *
1392          * Values considered empty:
1393          *
1394          * - null
1395          * - []
1396          * - new XmlJsCode( '{}' )
1397          * - new stdClass() // (object) []
1398          *
1399          * @param array $array
1400          */
1401         private static function trimArray( array &$array ) {
1402                 $i = count( $array );
1403                 while ( $i-- ) {
1404                         if ( $array[$i] === null
1405                                 || $array[$i] === []
1406                                 || ( $array[$i] instanceof XmlJsCode && $array[$i]->value === '{}' )
1407                                 || ( $array[$i] instanceof stdClass && self::isEmptyObject( $array[$i] ) )
1408                         ) {
1409                                 unset( $array[$i] );
1410                         } else {
1411                                 break;
1412                         }
1413                 }
1414         }
1415
1416         /**
1417          * Returns JS code which calls mw.loader.register with the given
1418          * parameter.
1419          *
1420          * @par Example
1421          * @code
1422          *
1423          *     ResourceLoader::makeLoaderRegisterScript( [
1424          *        [ $name1, $version1, $dependencies1, $group1, $source1, $skip1 ],
1425          *        [ $name2, $version2, $dependencies1, $group2, $source2, $skip2 ],
1426          *        ...
1427          *     ] ):
1428          * @endcode
1429          *
1430          * @internal
1431          * @since 1.32
1432          * @param array $modules Array of module registration arrays, each containing
1433          *  - string: module name
1434          *  - string: module version
1435          *  - array|null: List of dependencies (optional)
1436          *  - string|null: Module group (optional)
1437          *  - string|null: Name of foreign module source, or 'local' (optional)
1438          *  - string|null: Script body of a skip function (optional)
1439          * @return string JavaScript code
1440          */
1441         public static function makeLoaderRegisterScript( array $modules ) {
1442                 // Optimisation: Transform dependency names into indexes when possible
1443                 // to produce smaller output. They are expanded by mw.loader.register on
1444                 // the other end using resolveIndexedDependencies().
1445                 $index = [];
1446                 foreach ( $modules as $i => &$module ) {
1447                         // Build module name index
1448                         $index[$module[0]] = $i;
1449                 }
1450                 foreach ( $modules as &$module ) {
1451                         if ( isset( $module[2] ) ) {
1452                                 foreach ( $module[2] as &$dependency ) {
1453                                         if ( isset( $index[$dependency] ) ) {
1454                                                 // Replace module name in dependency list with index
1455                                                 $dependency = $index[$dependency];
1456                                         }
1457                                 }
1458                         }
1459                 }
1460
1461                 array_walk( $modules, [ self::class, 'trimArray' ] );
1462
1463                 return 'mw.loader.register('
1464                         . self::encodeJsonForScript( $modules )
1465                         . ');';
1466         }
1467
1468         /**
1469          * Returns JS code which calls mw.loader.addSource() with the given
1470          * parameters. Has two calling conventions:
1471          *
1472          *   - ResourceLoader::makeLoaderSourcesScript( $id, $properties ):
1473          *       Register a single source
1474          *
1475          *   - ResourceLoader::makeLoaderSourcesScript( [ $id1 => $loadUrl, $id2 => $loadUrl, ... ] );
1476          *       Register sources with the given IDs and properties.
1477          *
1478          * @param string|array $sources Source ID
1479          * @param string|null $loadUrl load.php url
1480          * @return string JavaScript code
1481          */
1482         public static function makeLoaderSourcesScript( $sources, $loadUrl = null ) {
1483                 if ( !is_array( $sources ) ) {
1484                         $sources = [ $sources => $loadUrl ];
1485                 }
1486                 return 'mw.loader.addSource('
1487                         . self::encodeJsonForScript( $sources )
1488                         . ');';
1489         }
1490
1491         /**
1492          * Wraps JavaScript code to run after the startup module.
1493          *
1494          * @param string $script JavaScript code
1495          * @return string JavaScript code
1496          */
1497         public static function makeLoaderConditionalScript( $script ) {
1498                 // Adds a function to lazy-created RLQ
1499                 return '(RLQ=window.RLQ||[]).push(function(){' .
1500                         trim( $script ) . '});';
1501         }
1502
1503         /**
1504          * Wraps JavaScript code to run after a required module.
1505          *
1506          * @since 1.32
1507          * @param string|string[] $modules Module name(s)
1508          * @param string $script JavaScript code
1509          * @return string JavaScript code
1510          */
1511         public static function makeInlineCodeWithModule( $modules, $script ) {
1512                 // Adds an array to lazy-created RLQ
1513                 return '(RLQ=window.RLQ||[]).push(['
1514                         . self::encodeJsonForScript( $modules ) . ','
1515                         . 'function(){' . trim( $script ) . '}'
1516                         . ']);';
1517         }
1518
1519         /**
1520          * Returns an HTML script tag that runs given JS code after startup and base modules.
1521          *
1522          * The code will be wrapped in a closure, and it will be executed by ResourceLoader's
1523          * startup module if the client has adequate support for MediaWiki JavaScript code.
1524          *
1525          * @param string $script JavaScript code
1526          * @param string|null $nonce [optional] Content-Security-Policy nonce
1527          *  (from OutputPage::getCSPNonce)
1528          * @return string|WrappedString HTML
1529          */
1530         public static function makeInlineScript( $script, $nonce = null ) {
1531                 $js = self::makeLoaderConditionalScript( $script );
1532                 $escNonce = '';
1533                 if ( $nonce === null ) {
1534                         wfWarn( __METHOD__ . " did not get nonce. Will break CSP" );
1535                 } elseif ( $nonce !== false ) {
1536                         // If it was false, CSP is disabled, so no nonce attribute.
1537                         // Nonce should be only base64 characters, so should be safe,
1538                         // but better to be safely escaped than sorry.
1539                         $escNonce = ' nonce="' . htmlspecialchars( $nonce ) . '"';
1540                 }
1541
1542                 return new WrappedString(
1543                         Html::inlineScript( $js, $nonce ),
1544                         "<script$escNonce>(RLQ=window.RLQ||[]).push(function(){",
1545                         '});</script>'
1546                 );
1547         }
1548
1549         /**
1550          * Returns JS code which will set the MediaWiki configuration array to
1551          * the given value.
1552          *
1553          * @param array $configuration List of configuration values keyed by variable name
1554          * @return string JavaScript code
1555          * @throws Exception
1556          */
1557         public static function makeConfigSetScript( array $configuration ) {
1558                 $json = self::encodeJsonForScript( $configuration );
1559                 if ( $json === false ) {
1560                         $e = new Exception(
1561                                 'JSON serialization of config data failed. ' .
1562                                 'This usually means the config data is not valid UTF-8.'
1563                         );
1564                         MWExceptionHandler::logException( $e );
1565                         return 'mw.log.error(' . self::encodeJsonForScript( $e->__toString() ) . ');';
1566                 }
1567                 return "mw.config.set($json);";
1568         }
1569
1570         /**
1571          * Convert an array of module names to a packed query string.
1572          *
1573          * For example, `[ 'foo.bar', 'foo.baz', 'bar.baz', 'bar.quux' ]`
1574          * becomes `'foo.bar,baz|bar.baz,quux'`.
1575          *
1576          * This process is reversed by ResourceLoader::expandModuleNames().
1577          * See also mw.loader#buildModulesString() which is a port of this, used
1578          * on the client-side.
1579          *
1580          * @param array $modules List of module names (strings)
1581          * @return string Packed query string
1582          */
1583         public static function makePackedModulesString( $modules ) {
1584                 $moduleMap = []; // [ prefix => [ suffixes ] ]
1585                 foreach ( $modules as $module ) {
1586                         $pos = strrpos( $module, '.' );
1587                         $prefix = $pos === false ? '' : substr( $module, 0, $pos );
1588                         $suffix = $pos === false ? $module : substr( $module, $pos + 1 );
1589                         $moduleMap[$prefix][] = $suffix;
1590                 }
1591
1592                 $arr = [];
1593                 foreach ( $moduleMap as $prefix => $suffixes ) {
1594                         $p = $prefix === '' ? '' : $prefix . '.';
1595                         $arr[] = $p . implode( ',', $suffixes );
1596                 }
1597                 return implode( '|', $arr );
1598         }
1599
1600         /**
1601          * Expand a string of the form `jquery.foo,bar|jquery.ui.baz,quux` to
1602          * an array of module names like `[ 'jquery.foo', 'jquery.bar',
1603          * 'jquery.ui.baz', 'jquery.ui.quux' ]`.
1604          *
1605          * This process is reversed by ResourceLoader::makePackedModulesString().
1606          *
1607          * @since 1.33
1608          * @param string $modules Packed module name list
1609          * @return array Array of module names
1610          */
1611         public static function expandModuleNames( $modules ) {
1612                 $retval = [];
1613                 $exploded = explode( '|', $modules );
1614                 foreach ( $exploded as $group ) {
1615                         if ( strpos( $group, ',' ) === false ) {
1616                                 // This is not a set of modules in foo.bar,baz notation
1617                                 // but a single module
1618                                 $retval[] = $group;
1619                         } else {
1620                                 // This is a set of modules in foo.bar,baz notation
1621                                 $pos = strrpos( $group, '.' );
1622                                 if ( $pos === false ) {
1623                                         // Prefixless modules, i.e. without dots
1624                                         $retval = array_merge( $retval, explode( ',', $group ) );
1625                                 } else {
1626                                         // We have a prefix and a bunch of suffixes
1627                                         $prefix = substr( $group, 0, $pos ); // 'foo'
1628                                         $suffixes = explode( ',', substr( $group, $pos + 1 ) ); // [ 'bar', 'baz' ]
1629                                         foreach ( $suffixes as $suffix ) {
1630                                                 $retval[] = "$prefix.$suffix";
1631                                         }
1632                                 }
1633                         }
1634                 }
1635                 return $retval;
1636         }
1637
1638         /**
1639          * Determine whether debug mode was requested
1640          * Order of priority is 1) request param, 2) cookie, 3) $wg setting
1641          * @return bool
1642          */
1643         public static function inDebugMode() {
1644                 if ( self::$debugMode === null ) {
1645                         global $wgRequest, $wgResourceLoaderDebug;
1646                         self::$debugMode = $wgRequest->getFuzzyBool( 'debug',
1647                                 $wgRequest->getCookie( 'resourceLoaderDebug', '', $wgResourceLoaderDebug )
1648                         );
1649                 }
1650                 return self::$debugMode;
1651         }
1652
1653         /**
1654          * Reset static members used for caching.
1655          *
1656          * Global state and $wgRequest are evil, but we're using it right
1657          * now and sometimes we need to be able to force ResourceLoader to
1658          * re-evaluate the context because it has changed (e.g. in the test suite).
1659          *
1660          * @internal For use by unit tests
1661          * @codeCoverageIgnore
1662          */
1663         public static function clearCache() {
1664                 self::$debugMode = null;
1665         }
1666
1667         /**
1668          * Build a load.php URL
1669          *
1670          * @since 1.24
1671          * @param string $source Name of the ResourceLoader source
1672          * @param ResourceLoaderContext $context
1673          * @param array $extraQuery
1674          * @return string URL to load.php. May be protocol-relative if $wgLoadScript is, too.
1675          */
1676         public function createLoaderURL( $source, ResourceLoaderContext $context,
1677                 $extraQuery = []
1678         ) {
1679                 $query = self::createLoaderQuery( $context, $extraQuery );
1680                 $script = $this->getLoadScript( $source );
1681
1682                 return wfAppendQuery( $script, $query );
1683         }
1684
1685         /**
1686          * Helper for createLoaderURL()
1687          *
1688          * @since 1.24
1689          * @see makeLoaderQuery
1690          * @param ResourceLoaderContext $context
1691          * @param array $extraQuery
1692          * @return array
1693          */
1694         protected static function createLoaderQuery( ResourceLoaderContext $context, $extraQuery = [] ) {
1695                 return self::makeLoaderQuery(
1696                         $context->getModules(),
1697                         $context->getLanguage(),
1698                         $context->getSkin(),
1699                         $context->getUser(),
1700                         $context->getVersion(),
1701                         $context->getDebug(),
1702                         $context->getOnly(),
1703                         $context->getRequest()->getBool( 'printable' ),
1704                         $context->getRequest()->getBool( 'handheld' ),
1705                         $extraQuery
1706                 );
1707         }
1708
1709         /**
1710          * Build a query array (array representation of query string) for load.php. Helper
1711          * function for createLoaderURL().
1712          *
1713          * @param array $modules
1714          * @param string $lang
1715          * @param string $skin
1716          * @param string|null $user
1717          * @param string|null $version
1718          * @param bool $debug
1719          * @param string|null $only
1720          * @param bool $printable
1721          * @param bool $handheld
1722          * @param array $extraQuery
1723          * @return array
1724          */
1725         public static function makeLoaderQuery( $modules, $lang, $skin, $user = null,
1726                 $version = null, $debug = false, $only = null, $printable = false,
1727                 $handheld = false, $extraQuery = []
1728         ) {
1729                 $query = [
1730                         'modules' => self::makePackedModulesString( $modules ),
1731                 ];
1732                 // Keep urls short by omitting query parameters that
1733                 // match the defaults assumed by ResourceLoaderContext.
1734                 // Note: This relies on the defaults either being insignificant or forever constant,
1735                 // as otherwise cached urls could change in meaning when the defaults change.
1736                 if ( $lang !== ResourceLoaderContext::DEFAULT_LANG ) {
1737                         $query['lang'] = $lang;
1738                 }
1739                 if ( $skin !== ResourceLoaderContext::DEFAULT_SKIN ) {
1740                         $query['skin'] = $skin;
1741                 }
1742                 if ( $debug === true ) {
1743                         $query['debug'] = 'true';
1744                 }
1745                 if ( $user !== null ) {
1746                         $query['user'] = $user;
1747                 }
1748                 if ( $version !== null ) {
1749                         $query['version'] = $version;
1750                 }
1751                 if ( $only !== null ) {
1752                         $query['only'] = $only;
1753                 }
1754                 if ( $printable ) {
1755                         $query['printable'] = 1;
1756                 }
1757                 if ( $handheld ) {
1758                         $query['handheld'] = 1;
1759                 }
1760                 $query += $extraQuery;
1761
1762                 // Make queries uniform in order
1763                 ksort( $query );
1764                 return $query;
1765         }
1766
1767         /**
1768          * Check a module name for validity.
1769          *
1770          * Module names may not contain pipes (|), commas (,) or exclamation marks (!) and can be
1771          * at most 255 bytes.
1772          *
1773          * @param string $moduleName Module name to check
1774          * @return bool Whether $moduleName is a valid module name
1775          */
1776         public static function isValidModuleName( $moduleName ) {
1777                 return strcspn( $moduleName, '!,|', 0, 255 ) === strlen( $moduleName );
1778         }
1779
1780         /**
1781          * Returns LESS compiler set up for use with MediaWiki
1782          *
1783          * @since 1.27
1784          * @param array $vars Associative array of variables that should be used
1785          *  for compilation. Since 1.32, this method no longer automatically includes
1786          *  global LESS vars from ResourceLoader::getLessVars (T191937).
1787          * @throws MWException
1788          * @return Less_Parser
1789          */
1790         public function getLessCompiler( $vars = [] ) {
1791                 global $IP;
1792                 // When called from the installer, it is possible that a required PHP extension
1793                 // is missing (at least for now; see T49564). If this is the case, throw an
1794                 // exception (caught by the installer) to prevent a fatal error later on.
1795                 if ( !class_exists( 'Less_Parser' ) ) {
1796                         throw new MWException( 'MediaWiki requires the less.php parser' );
1797                 }
1798
1799                 $parser = new Less_Parser;
1800                 $parser->ModifyVars( $vars );
1801                 $parser->SetImportDirs( [
1802                         "$IP/resources/src/mediawiki.less/" => '',
1803                 ] );
1804                 $parser->SetOption( 'relativeUrls', false );
1805
1806                 return $parser;
1807         }
1808
1809         /**
1810          * Get global LESS variables.
1811          *
1812          * @since 1.27
1813          * @deprecated since 1.32 Use ResourceLoderModule::getLessVars() instead.
1814          * @return array Map of variable names to string CSS values.
1815          */
1816         public function getLessVars() {
1817                 return [];
1818         }
1819 }