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