includes/resourceloader/ResourceLoader.php

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