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