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