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 /**
  26  * Dynamic JavaScript and CSS resource loading system.
  27  *
  28  * Most of the documentation is on the MediaWiki documentation wiki starting at:
  29  *    https://www.mediawiki.org/wiki/ResourceLoader
  30  */
  31 class ResourceLoader {
  32
  33         /**
  34          * @var int
  35          */
  36         protected static $filterCacheVersion = 7;
  37         /**
  38          * @var array
  39          */
  40         protected static $requiredSourceProperties = array( 'loadScript' );
  41
  42         /**
  43          * @var array Module name/ResourceLoaderModule object pairs
  44          */
  45         protected $modules = array();
  46
  47         /**
  48          * @var array Associative array mapping module name to info associative array
  49          */
  50         protected $moduleInfos = array();
  51
  52         /**
  53          * @var array Associative array mapping framework ids to a list of names of test suite modules
  54          *      like array( 'qunit' => array( 'mediawiki.tests.qunit.suites', 'ext.foo.tests', .. ), .. )
  55          */
  56         protected $testModuleNames = array();
  57
  58         /**
  59          * @var array e.g. array( 'source-id' => array( 'loadScript' => 'http://.../load.php' ) )
  60          */
  61         protected $sources = array();
  62
  63         /**
  64          * @var bool
  65          */
  66         protected $hasErrors = false;
  67
  68         /**
  69          * Load information stored in the database about modules.
  70          *
  71          * This method grabs modules dependencies from the database and updates modules
  72          * objects.
  73          *
  74          * This is not inside the module code because it is much faster to
  75          * request all of the information at once than it is to have each module
  76          * requests its own information. This sacrifice of modularity yields a substantial
  77          * performance improvement.
  78          *
  79          * @param array $modules List of module names to preload information for
  80          * @param ResourceLoaderContext $context Context to load the information within
  81          */
  82         public function preloadModuleInfo( array $modules, ResourceLoaderContext $context ) {
  83                 if ( !count( $modules ) ) {
  84                         // Or else Database*::select() will explode, plus it's cheaper!
  85                         return;
  86                 }
  87                 $dbr = wfGetDB( DB_SLAVE );
  88                 $skin = $context->getSkin();
  89                 $lang = $context->getLanguage();
  90
  91                 // Get file dependency information
  92                 $res = $dbr->select( 'module_deps', array( 'md_module', 'md_deps' ), array(
  93                                 'md_module' => $modules,
  94                                 'md_skin' => $skin
  95                         ), __METHOD__
  96                 );
  97
  98                 // Set modules' dependencies
  99                 $modulesWithDeps = array();
 100                 foreach ( $res as $row ) {
 101                         $module = $this->getModule( $row->md_module );
 102                         if ( $module ) {
 103                                 $module->setFileDependencies( $skin, FormatJson::decode( $row->md_deps, true ) );
 104                                 $modulesWithDeps[] = $row->md_module;
 105                         }
 106                 }
 107
 108                 // Register the absence of a dependency row too
 109                 foreach ( array_diff( $modules, $modulesWithDeps ) as $name ) {
 110                         $module = $this->getModule( $name );
 111                         if ( $module ) {
 112                                 $this->getModule( $name )->setFileDependencies( $skin, array() );
 113                         }
 114                 }
 115
 116                 // Get message blob mtimes. Only do this for modules with messages
 117                 $modulesWithMessages = array();
 118                 foreach ( $modules as $name ) {
 119                         $module = $this->getModule( $name );
 120                         if ( $module && count( $module->getMessages() ) ) {
 121                                 $modulesWithMessages[] = $name;
 122                         }
 123                 }
 124                 $modulesWithoutMessages = array_flip( $modules ); // Will be trimmed down by the loop below
 125                 if ( count( $modulesWithMessages ) ) {
 126                         $res = $dbr->select( 'msg_resource', array( 'mr_resource', 'mr_timestamp' ), array(
 127                                         'mr_resource' => $modulesWithMessages,
 128                                         'mr_lang' => $lang
 129                                 ), __METHOD__
 130                         );
 131                         foreach ( $res as $row ) {
 132                                 $module = $this->getModule( $row->mr_resource );
 133                                 if ( $module ) {
 134                                         $module->setMsgBlobMtime( $lang, wfTimestamp( TS_UNIX, $row->mr_timestamp ) );
 135                                         unset( $modulesWithoutMessages[$row->mr_resource] );
 136                                 }
 137                         }
 138                 }
 139                 foreach ( array_keys( $modulesWithoutMessages ) as $name ) {
 140                         $module = $this->getModule( $name );
 141                         if ( $module ) {
 142                                 $module->setMsgBlobMtime( $lang, 0 );
 143                         }
 144                 }
 145         }
 146
 147         /**
 148          * Run JavaScript or CSS data through a filter, caching the filtered result for future calls.
 149          *
 150          * Available filters are:
 151          *
 152          *    - minify-js \see JavaScriptMinifier::minify
 153          *    - minify-css \see CSSMin::minify
 154          *
 155          * If $data is empty, only contains whitespace or the filter was unknown,
 156          * $data is returned unmodified.
 157          *
 158          * @param string $filter Name of filter to run
 159          * @param string $data Text to filter, such as JavaScript or CSS text
 160          * @return string Filtered data, or a comment containing an error message
 161          */
 162         protected function filter( $filter, $data ) {
 163                 global $wgResourceLoaderMinifierStatementsOnOwnLine, $wgResourceLoaderMinifierMaxLineLength;
 164                 wfProfileIn( __METHOD__ );
 165
 166                 // For empty/whitespace-only data or for unknown filters, don't perform
 167                 // any caching or processing
 168                 if ( trim( $data ) === '' || !in_array( $filter, array( 'minify-js', 'minify-css' ) ) ) {
 169                         wfProfileOut( __METHOD__ );
 170                         return $data;
 171                 }
 172
 173                 // Try for cache hit
 174                 // Use CACHE_ANYTHING since filtering is very slow compared to DB queries
 175                 $key = wfMemcKey( 'resourceloader', 'filter', $filter, self::$filterCacheVersion, md5( $data ) );
 176                 $cache = wfGetCache( CACHE_ANYTHING );
 177                 $cacheEntry = $cache->get( $key );
 178                 if ( is_string( $cacheEntry ) ) {
 179                         wfIncrStats( "rl-$filter-cache-hits" );
 180                         wfProfileOut( __METHOD__ );
 181                         return $cacheEntry;
 182                 }
 183
 184                 $result = '';
 185                 // Run the filter - we've already verified one of these will work
 186                 try {
 187                         wfIncrStats( "rl-$filter-cache-misses" );
 188                         switch ( $filter ) {
 189                                 case 'minify-js':
 190                                         $result = JavaScriptMinifier::minify( $data,
 191                                                 $wgResourceLoaderMinifierStatementsOnOwnLine,
 192                                                 $wgResourceLoaderMinifierMaxLineLength
 193                                         );
 194                                         $result .= "\n/* cache key: $key */";
 195                                         break;
 196                                 case 'minify-css':
 197                                         $result = CSSMin::minify( $data );
 198                                         $result .= "\n/* cache key: $key */";
 199                                         break;
 200                         }
 201
 202                         // Save filtered text to Memcached
 203                         $cache->set( $key, $result );
 204                 } catch ( Exception $e ) {
 205                         MWExceptionHandler::logException( $e );
 206                         wfDebugLog( 'resourceloader', __METHOD__ . ": minification failed: $e" );
 207                         $this->hasErrors = true;
 208                         // Return exception as a comment
 209                         $result = self::formatException( $e );
 210                 }
 211
 212                 wfProfileOut( __METHOD__ );
 213
 214                 return $result;
 215         }
 216
 217         /* Methods */
 218
 219         /**
 220          * Register core modules and runs registration hooks.
 221          */
 222         public function __construct() {
 223                 global $IP, $wgResourceModules, $wgResourceLoaderSources, $wgLoadScript, $wgEnableJavaScriptTest;
 224
 225                 wfProfileIn( __METHOD__ );
 226
 227                 // Add 'local' source first
 228                 $this->addSource( 'local', array( 'loadScript' => $wgLoadScript, 'apiScript' => wfScript( 'api' ) ) );
 229
 230                 // Add other sources
 231                 $this->addSource( $wgResourceLoaderSources );
 232
 233                 // Register core modules
 234                 $this->register( include "$IP/resources/Resources.php" );
 235                 // Register extension modules
 236                 wfRunHooks( 'ResourceLoaderRegisterModules', array( &$this ) );
 237                 $this->register( $wgResourceModules );
 238
 239                 if ( $wgEnableJavaScriptTest === true ) {
 240                         $this->registerTestModules();
 241                 }
 242
 243                 wfProfileOut( __METHOD__ );
 244         }
 245
 246         /**
 247          * Register a module with the ResourceLoader system.
 248          *
 249          * @param mixed $name Name of module as a string or List of name/object pairs as an array
 250          * @param array $info Module info array. For backwards compatibility with 1.17alpha,
 251          *   this may also be a ResourceLoaderModule object. Optional when using
 252          *   multiple-registration calling style.
 253          * @throws MWException If a duplicate module registration is attempted
 254          * @throws MWException If a module name contains illegal characters (pipes or commas)
 255          * @throws MWException If something other than a ResourceLoaderModule is being registered
 256          * @return bool False if there were any errors, in which case one or more modules were
 257          *   not registered
 258          */
 259         public function register( $name, $info = null ) {
 260                 wfProfileIn( __METHOD__ );
 261
 262                 // Allow multiple modules to be registered in one call
 263                 $registrations = is_array( $name ) ? $name : array( $name => $info );
 264                 foreach ( $registrations as $name => $info ) {
 265                         // Disallow duplicate registrations
 266                         if ( isset( $this->moduleInfos[$name] ) ) {
 267                                 wfProfileOut( __METHOD__ );
 268                                 // A module has already been registered by this name
 269                                 throw new MWException(
 270                                         'ResourceLoader duplicate registration error. ' .
 271                                         'Another module has already been registered as ' . $name
 272                                 );
 273                         }
 274
 275                         // Check $name for validity
 276                         if ( !self::isValidModuleName( $name ) ) {
 277                                 wfProfileOut( __METHOD__ );
 278                                 throw new MWException( "ResourceLoader module name '$name' is invalid, see ResourceLoader::isValidModuleName()" );
 279                         }
 280
 281                         // Attach module
 282                         if ( $info instanceof ResourceLoaderModule ) {
 283                                 $this->moduleInfos[$name] = array( 'object' => $info );
 284                                 $info->setName( $name );
 285                                 $this->modules[$name] = $info;
 286                         } elseif ( is_array( $info ) ) {
 287                                 // New calling convention
 288                                 $this->moduleInfos[$name] = $info;
 289                         } else {
 290                                 wfProfileOut( __METHOD__ );
 291                                 throw new MWException(
 292                                         'ResourceLoader module info type error for module \'' . $name .
 293                                         '\': expected ResourceLoaderModule or array (got: ' . gettype( $info ) . ')'
 294                                 );
 295                         }
 296                 }
 297
 298                 wfProfileOut( __METHOD__ );
 299         }
 300
 301         /**
 302          */
 303         public function registerTestModules() {
 304                 global $IP, $wgEnableJavaScriptTest;
 305
 306                 if ( $wgEnableJavaScriptTest !== true ) {
 307                         throw new MWException( 'Attempt to register JavaScript test modules but <code>$wgEnableJavaScriptTest</code> is false. Edit your <code>LocalSettings.php</code> to enable it.' );
 308                 }
 309
 310                 wfProfileIn( __METHOD__ );
 311
 312                 // Get core test suites
 313                 $testModules = array();
 314                 $testModules['qunit'] = array();
 315                 // Get other test suites (e.g. from extensions)
 316                 wfRunHooks( 'ResourceLoaderTestModules', array( &$testModules, &$this ) );
 317
 318                 // Add the testrunner (which configures QUnit) to the dependencies.
 319                 // Since it must be ready before any of the test suites are executed.
 320                 foreach ( $testModules['qunit'] as &$module ) {
 321                         // Make sure all test modules are top-loading so that when QUnit starts
 322                         // on document-ready, it will run once and finish. If some tests arrive
 323                         // later (possibly after QUnit has already finished) they will be ignored.
 324                         $module['position'] = 'top';
 325                         $module['dependencies'][] = 'test.mediawiki.qunit.testrunner';
 326                 }
 327
 328                 $testModules['qunit'] = ( include "$IP/tests/qunit/QUnitTestResources.php" ) + $testModules['qunit'];
 329
 330                 foreach ( $testModules as $id => $names ) {
 331                         // Register test modules
 332                         $this->register( $testModules[$id] );
 333
 334                         // Keep track of their names so that they can be loaded together
 335                         $this->testModuleNames[$id] = array_keys( $testModules[$id] );
 336                 }
 337
 338                 wfProfileOut( __METHOD__ );
 339         }
 340
 341         /**
 342          * Add a foreign source of modules.
 343          *
 344          * Source properties:
 345          * 'loadScript': URL (either fully-qualified or protocol-relative) of load.php for this source
 346          *
 347          * @param mixed $id Source ID (string), or array( id1 => props1, id2 => props2, ... )
 348          * @param array $properties Source properties
 349          * @throws MWException
 350          */
 351         public function addSource( $id, $properties = null ) {
 352                 // Allow multiple sources to be registered in one call
 353                 if ( is_array( $id ) ) {
 354                         foreach ( $id as $key => $value ) {
 355                                 $this->addSource( $key, $value );
 356                         }
 357                         return;
 358                 }
 359
 360                 // Disallow duplicates
 361                 if ( isset( $this->sources[$id] ) ) {
 362                         throw new MWException(
 363                                 'ResourceLoader duplicate source addition error. ' .
 364                                 'Another source has already been registered as ' . $id
 365                         );
 366                 }
 367
 368                 // Validate properties
 369                 foreach ( self::$requiredSourceProperties as $prop ) {
 370                         if ( !isset( $properties[$prop] ) ) {
 371                                 throw new MWException( "Required property $prop missing from source ID $id" );
 372                         }
 373                 }
 374
 375                 $this->sources[$id] = $properties;
 376         }
 377
 378         /**
 379          * Get a list of module names.
 380          *
 381          * @return array List of module names
 382          */
 383         public function getModuleNames() {
 384                 return array_keys( $this->moduleInfos );
 385         }
 386
 387         /**
 388          * Get a list of test module names for one (or all) frameworks.
 389          *
 390          * If the given framework id is unknkown, or if the in-object variable is not an array,
 391          * then it will return an empty array.
 392          *
 393          * @param string $framework Get only the test module names for one
 394          *   particular framework (optional)
 395          * @return array
 396          */
 397         public function getTestModuleNames( $framework = 'all' ) {
 398                 /// @todo api siteinfo prop testmodulenames modulenames
 399                 if ( $framework == 'all' ) {
 400                         return $this->testModuleNames;
 401                 } elseif ( isset( $this->testModuleNames[$framework] ) && is_array( $this->testModuleNames[$framework] ) ) {
 402                         return $this->testModuleNames[$framework];
 403                 } else {
 404                         return array();
 405                 }
 406         }
 407
 408         /**
 409          * Get the ResourceLoaderModule object for a given module name.
 410          *
 411          * If an array of module parameters exists but a ResourceLoaderModule object has not
 412          * yet been instantiated, this method will instantiate and cache that object such that
 413          * subsequent calls simply return the same object.
 414          *
 415          * @param string $name Module name
 416          * @return ResourceLoaderModule|null If module has been registered, return a
 417          *  ResourceLoaderModule instance. Otherwise, return null.
 418          */
 419         public function getModule( $name ) {
 420                 if ( !isset( $this->modules[$name] ) ) {
 421                         if ( !isset( $this->moduleInfos[$name] ) ) {
 422                                 // No such module
 423                                 return null;
 424                         }
 425                         // Construct the requested object
 426                         $info = $this->moduleInfos[$name];
 427                         /** @var ResourceLoaderModule $object */
 428                         if ( isset( $info['object'] ) ) {
 429                                 // Object given in info array
 430                                 $object = $info['object'];
 431                         } else {
 432                                 if ( !isset( $info['class'] ) ) {
 433                                         $class = 'ResourceLoaderFileModule';
 434                                 } else {
 435                                         $class = $info['class'];
 436                                 }
 437                                 $object = new $class( $info );
 438                         }
 439                         $object->setName( $name );
 440                         $this->modules[$name] = $object;
 441                 }
 442
 443                 return $this->modules[$name];
 444         }
 445
 446         /**
 447          * Get the list of sources.
 448          *
 449          * @return array Like array( id => array of properties, .. )
 450          */
 451         public function getSources() {
 452                 return $this->sources;
 453         }
 454
 455         /**
 456          * Output a response to a load request, including the content-type header.
 457          *
 458          * @param ResourceLoaderContext $context Context in which a response should be formed
 459          */
 460         public function respond( ResourceLoaderContext $context ) {
 461                 global $wgCacheEpoch, $wgUseFileCache;
 462
 463                 // Use file cache if enabled and available...
 464                 if ( $wgUseFileCache ) {
 465                         $fileCache = ResourceFileCache::newFromContext( $context );
 466                         if ( $this->tryRespondFromFileCache( $fileCache, $context ) ) {
 467                                 return; // output handled
 468                         }
 469                 }
 470
 471                 // Buffer output to catch warnings. Normally we'd use ob_clean() on the
 472                 // top-level output buffer to clear warnings, but that breaks when ob_gzhandler
 473                 // is used: ob_clean() will clear the GZIP header in that case and it won't come
 474                 // back for subsequent output, resulting in invalid GZIP. So we have to wrap
 475                 // the whole thing in our own output buffer to be sure the active buffer
 476                 // doesn't use ob_gzhandler.
 477                 // See http://bugs.php.net/bug.php?id=36514
 478                 ob_start();
 479
 480                 wfProfileIn( __METHOD__ );
 481                 $errors = '';
 482
 483                 // Find out which modules are missing and instantiate the others
 484                 $modules = array();
 485                 $missing = array();
 486                 foreach ( $context->getModules() as $name ) {
 487                         $module = $this->getModule( $name );
 488                         if ( $module ) {
 489                                 // Do not allow private modules to be loaded from the web.
 490                                 // This is a security issue, see bug 34907.
 491                                 if ( $module->getGroup() === 'private' ) {
 492                                         wfDebugLog( 'resourceloader', __METHOD__ . ": request for private module '$name' denied" );
 493                                         $this->hasErrors = true;
 494                                         // Add exception to the output as a comment
 495                                         $errors .= self::makeComment( "Cannot show private module \"$name\"" );
 496
 497                                         continue;
 498                                 }
 499                                 $modules[$name] = $module;
 500                         } else {
 501                                 $missing[] = $name;
 502                         }
 503                 }
 504
 505                 // Preload information needed to the mtime calculation below
 506                 try {
 507                         $this->preloadModuleInfo( array_keys( $modules ), $context );
 508                 } catch ( Exception $e ) {
 509                         MWExceptionHandler::logException( $e );
 510                         wfDebugLog( 'resourceloader', __METHOD__ . ": preloading module info failed: $e" );
 511                         $this->hasErrors = true;
 512                         // Add exception to the output as a comment
 513                         $errors .= self::formatException( $e );
 514                 }
 515
 516                 wfProfileIn( __METHOD__ . '-getModifiedTime' );
 517
 518                 // To send Last-Modified and support If-Modified-Since, we need to detect
 519                 // the last modified time
 520                 $mtime = wfTimestamp( TS_UNIX, $wgCacheEpoch );
 521                 foreach ( $modules as $module ) {
 522                         /**
 523                          * @var $module ResourceLoaderModule
 524                          */
 525                         try {
 526                                 // Calculate maximum modified time
 527                                 $mtime = max( $mtime, $module->getModifiedTime( $context ) );
 528                         } catch ( Exception $e ) {
 529                                 MWExceptionHandler::logException( $e );
 530                                 wfDebugLog( 'resourceloader', __METHOD__ . ": calculating maximum modified time failed: $e" );
 531                                 $this->hasErrors = true;
 532                                 // Add exception to the output as a comment
 533                                 $errors .= self::formatException( $e );
 534                         }
 535                 }
 536
 537                 wfProfileOut( __METHOD__ . '-getModifiedTime' );
 538
 539                 // If there's an If-Modified-Since header, respond with a 304 appropriately
 540                 if ( $this->tryRespondLastModified( $context, $mtime ) ) {
 541                         wfProfileOut( __METHOD__ );
 542                         return; // output handled (buffers cleared)
 543                 }
 544
 545                 // Generate a response
 546                 $response = $this->makeModuleResponse( $context, $modules, $missing );
 547
 548                 // Prepend comments indicating exceptions
 549                 $response = $errors . $response;
 550
 551                 // Capture any PHP warnings from the output buffer and append them to the
 552                 // response in a comment if we're in debug mode.
 553                 if ( $context->getDebug() && strlen( $warnings = ob_get_contents() ) ) {
 554                         $response = self::makeComment( $warnings ) . $response;
 555                         $this->hasErrors = true;
 556                 }
 557
 558                 // Save response to file cache unless there are errors
 559                 if ( isset( $fileCache ) && !$errors && !count( $missing ) ) {
 560                         // Cache single modules...and other requests if there are enough hits
 561                         if ( ResourceFileCache::useFileCache( $context ) ) {
 562                                 if ( $fileCache->isCacheWorthy() ) {
 563                                         $fileCache->saveText( $response );
 564                                 } else {
 565                                         $fileCache->incrMissesRecent( $context->getRequest() );
 566                                 }
 567                         }
 568                 }
 569
 570                 // Send content type and cache related headers
 571                 $this->sendResponseHeaders( $context, $mtime, $this->hasErrors );
 572
 573                 // Remove the output buffer and output the response
 574                 ob_end_clean();
 575                 echo $response;
 576
 577                 wfProfileOut( __METHOD__ );
 578         }
 579
 580         /**
 581          * Send content type and last modified headers to the client.
 582          * @param ResourceLoaderContext $context
 583          * @param string $mtime TS_MW timestamp to use for last-modified
 584          * @param bool $errors Whether there are commented-out errors in the response
 585          * @return void
 586          */
 587         protected function sendResponseHeaders( ResourceLoaderContext $context, $mtime, $errors ) {
 588                 global $wgResourceLoaderMaxage;
 589                 // If a version wasn't specified we need a shorter expiry time for updates
 590                 // to propagate to clients quickly
 591                 // If there were errors, we also need a shorter expiry time so we can recover quickly
 592                 if ( is_null( $context->getVersion() ) || $errors ) {
 593                         $maxage = $wgResourceLoaderMaxage['unversioned']['client'];
 594                         $smaxage = $wgResourceLoaderMaxage['unversioned']['server'];
 595                 // If a version was specified we can use a longer expiry time since changing
 596                 // version numbers causes cache misses
 597                 } else {
 598                         $maxage = $wgResourceLoaderMaxage['versioned']['client'];
 599                         $smaxage = $wgResourceLoaderMaxage['versioned']['server'];
 600                 }
 601                 if ( $context->getOnly() === 'styles' ) {
 602                         header( 'Content-Type: text/css; charset=utf-8' );
 603                         header( 'Access-Control-Allow-Origin: *' );
 604                 } else {
 605                         header( 'Content-Type: text/javascript; charset=utf-8' );
 606                 }
 607                 header( 'Last-Modified: ' . wfTimestamp( TS_RFC2822, $mtime ) );
 608                 if ( $context->getDebug() ) {
 609                         // Do not cache debug responses
 610                         header( 'Cache-Control: private, no-cache, must-revalidate' );
 611                         header( 'Pragma: no-cache' );
 612                 } else {
 613                         header( "Cache-Control: public, max-age=$maxage, s-maxage=$smaxage" );
 614                         $exp = min( $maxage, $smaxage );
 615                         header( 'Expires: ' . wfTimestamp( TS_RFC2822, $exp + time() ) );
 616                 }
 617         }
 618
 619         /**
 620          * Respond with 304 Last Modified if appropiate.
 621          *
 622          * If there's an If-Modified-Since header, respond with a 304 appropriately
 623          * and clear out the output buffer. If the client cache is too old then do nothing.
 624          *
 625          * @param ResourceLoaderContext $context
 626          * @param string $mtime The TS_MW timestamp to check the header against
 627          * @return bool True if 304 header sent and output handled
 628          */
 629         protected function tryRespondLastModified( ResourceLoaderContext $context, $mtime ) {
 630                 // If there's an If-Modified-Since header, respond with a 304 appropriately
 631                 // Some clients send "timestamp;length=123". Strip the part after the first ';'
 632                 // so we get a valid timestamp.
 633                 $ims = $context->getRequest()->getHeader( 'If-Modified-Since' );
 634                 // Never send 304s in debug mode
 635                 if ( $ims !== false && !$context->getDebug() ) {
 636                         $imsTS = strtok( $ims, ';' );
 637                         if ( $mtime <= wfTimestamp( TS_UNIX, $imsTS ) ) {
 638                                 // There's another bug in ob_gzhandler (see also the comment at
 639                                 // the top of this function) that causes it to gzip even empty
 640                                 // responses, meaning it's impossible to produce a truly empty
 641                                 // response (because the gzip header is always there). This is
 642                                 // a problem because 304 responses have to be completely empty
 643                                 // per the HTTP spec, and Firefox behaves buggily when they're not.
 644                                 // See also http://bugs.php.net/bug.php?id=51579
 645                                 // To work around this, we tear down all output buffering before
 646                                 // sending the 304.
 647                                 wfResetOutputBuffers( /* $resetGzipEncoding = */ true );
 648
 649                                 header( 'HTTP/1.0 304 Not Modified' );
 650                                 header( 'Status: 304 Not Modified' );
 651                                 return true;
 652                         }
 653                 }
 654                 return false;
 655         }
 656
 657         /**
 658          * Send out code for a response from file cache if possible.
 659          *
 660          * @param ResourceFileCache $fileCache Cache object for this request URL
 661          * @param ResourceLoaderContext $context Context in which to generate a response
 662          * @return bool If this found a cache file and handled the response
 663          */
 664         protected function tryRespondFromFileCache(
 665                 ResourceFileCache $fileCache, ResourceLoaderContext $context
 666         ) {
 667                 global $wgResourceLoaderMaxage;
 668                 // Buffer output to catch warnings.
 669                 ob_start();
 670                 // Get the maximum age the cache can be
 671                 $maxage = is_null( $context->getVersion() )
 672                         ? $wgResourceLoaderMaxage['unversioned']['server']
 673                         : $wgResourceLoaderMaxage['versioned']['server'];
 674                 // Minimum timestamp the cache file must have
 675                 $good = $fileCache->isCacheGood( wfTimestamp( TS_MW, time() - $maxage ) );
 676                 if ( !$good ) {
 677                         try { // RL always hits the DB on file cache miss...
 678                                 wfGetDB( DB_SLAVE );
 679                         } catch ( DBConnectionError $e ) { // ...check if we need to fallback to cache
 680                                 $good = $fileCache->isCacheGood(); // cache existence check
 681                         }
 682                 }
 683                 if ( $good ) {
 684                         $ts = $fileCache->cacheTimestamp();
 685                         // Send content type and cache headers
 686                         $this->sendResponseHeaders( $context, $ts, false );
 687                         // If there's an If-Modified-Since header, respond with a 304 appropriately
 688                         if ( $this->tryRespondLastModified( $context, $ts ) ) {
 689                                 return false; // output handled (buffers cleared)
 690                         }
 691                         $response = $fileCache->fetchText();
 692                         // Capture any PHP warnings from the output buffer and append them to the
 693                         // response in a comment if we're in debug mode.
 694                         if ( $context->getDebug() && strlen( $warnings = ob_get_contents() ) ) {
 695                                 $response = "/*\n$warnings\n*/\n" . $response;
 696                         }
 697                         // Remove the output buffer and output the response
 698                         ob_end_clean();
 699                         echo $response . "\n/* Cached {$ts} */";
 700                         return true; // cache hit
 701                 }
 702                 // Clear buffer
 703                 ob_end_clean();
 704
 705                 return false; // cache miss
 706         }
 707
 708         /**
 709          * Generate a CSS or JS comment block.
 710          *
 711          * Only use this for public data, not error message details.
 712          *
 713          * @param string $text
 714          * @return string
 715          */
 716         public static function makeComment( $text ) {
 717                 $encText = str_replace( '*/', '* /', $text );
 718                 return "/*\n$encText\n*/\n";
 719         }
 720
 721         /**
 722          * Handle exception display.
 723          *
 724          * @param Exception $e Exception to be shown to the user
 725          * @return string Sanitized text that can be returned to the user
 726          */
 727         public static function formatException( $e ) {
 728                 global $wgShowExceptionDetails;
 729
 730                 if ( $wgShowExceptionDetails ) {
 731                         return self::makeComment( $e->__toString() );
 732                 } else {
 733                         return self::makeComment( wfMessage( 'internalerror' )->text() );
 734                 }
 735         }
 736
 737         /**
 738          * Generate code for a response.
 739          *
 740          * @param ResourceLoaderContext $context Context in which to generate a response
 741          * @param array $modules List of module objects keyed by module name
 742          * @param array $missing List of requested module names that are unregistered (optional)
 743          * @return string Response data
 744          */
 745         public function makeModuleResponse( ResourceLoaderContext $context,
 746                 array $modules, array $missing = array()
 747         ) {
 748                 $out = '';
 749                 $exceptions = '';
 750                 $states = array();
 751
 752                 if ( !count( $modules ) && !count( $missing ) ) {
 753                         return "/* This file is the Web entry point for MediaWiki's ResourceLoader:
 754    <https://www.mediawiki.org/wiki/ResourceLoader>. In this request,
 755    no modules were requested. Max made me put this here. */";
 756                 }
 757
 758                 wfProfileIn( __METHOD__ );
 759
 760                 // Pre-fetch blobs
 761                 if ( $context->shouldIncludeMessages() ) {
 762                         try {
 763                                 $blobs = MessageBlobStore::get( $this, $modules, $context->getLanguage() );
 764                         } catch ( Exception $e ) {
 765                                 MWExceptionHandler::logException( $e );
 766                                 wfDebugLog( 'resourceloader', __METHOD__ . ": pre-fetching blobs from MessageBlobStore failed: $e" );
 767                                 $this->hasErrors = true;
 768                                 // Add exception to the output as a comment
 769                                 $exceptions .= self::formatException( $e );
 770                         }
 771                 } else {
 772                         $blobs = array();
 773                 }
 774
 775                 foreach ( $missing as $name ) {
 776                         $states[$name] = 'missing';
 777                 }
 778
 779                 // Generate output
 780                 $isRaw = false;
 781                 foreach ( $modules as $name => $module ) {
 782                         /**
 783                          * @var $module ResourceLoaderModule
 784                          */
 785
 786                         wfProfileIn( __METHOD__ . '-' . $name );
 787                         try {
 788                                 $scripts = '';
 789                                 if ( $context->shouldIncludeScripts() ) {
 790                                         // If we are in debug mode, we'll want to return an array of URLs if possible
 791                                         // However, we can't do this if the module doesn't support it
 792                                         // We also can't do this if there is an only= parameter, because we have to give
 793                                         // the module a way to return a load.php URL without causing an infinite loop
 794                                         if ( $context->getDebug() && !$context->getOnly() && $module->supportsURLLoading() ) {
 795                                                 $scripts = $module->getScriptURLsForDebug( $context );
 796                                         } else {
 797                                                 $scripts = $module->getScript( $context );
 798                                                 // rtrim() because there are usually a few line breaks after the last ';'.
 799                                                 // A new line at EOF, a new line added by ResourceLoaderFileModule::readScriptFiles, etc.
 800                                                 if ( is_string( $scripts ) && strlen( $scripts ) && substr( rtrim( $scripts ), -1 ) !== ';' ) {
 801                                                         // Append semicolon to prevent weird bugs caused by files not
 802                                                         // terminating their statements right (bug 27054)
 803                                                         $scripts .= ";\n";
 804                                                 }
 805                                         }
 806                                 }
 807                                 // Styles
 808                                 $styles = array();
 809                                 if ( $context->shouldIncludeStyles() ) {
 810                                         // Don't create empty stylesheets like array( '' => '' ) for modules
 811                                         // that don't *have* any stylesheets (bug 38024).
 812                                         $stylePairs = $module->getStyles( $context );
 813                                         if ( count ( $stylePairs ) ) {
 814                                                 // If we are in debug mode without &only= set, we'll want to return an array of URLs
 815                                                 // See comment near shouldIncludeScripts() for more details
 816                                                 if ( $context->getDebug() && !$context->getOnly() && $module->supportsURLLoading() ) {
 817                                                         $styles = array(
 818                                                                 'url' => $module->getStyleURLsForDebug( $context )
 819                                                         );
 820                                                 } else {
 821                                                         // Minify CSS before embedding in mw.loader.implement call
 822                                                         // (unless in debug mode)
 823                                                         if ( !$context->getDebug() ) {
 824                                                                 foreach ( $stylePairs as $media => $style ) {
 825                                                                         // Can be either a string or an array of strings.
 826                                                                         if ( is_array( $style ) ) {
 827                                                                                 $stylePairs[$media] = array();
 828                                                                                 foreach ( $style as $cssText ) {
 829                                                                                         if ( is_string( $cssText ) ) {
 830                                                                                                 $stylePairs[$media][] = $this->filter( 'minify-css', $cssText );
 831                                                                                         }
 832                                                                                 }
 833                                                                         } elseif ( is_string( $style ) ) {
 834                                                                                 $stylePairs[$media] = $this->filter( 'minify-css', $style );
 835                                                                         }
 836                                                                 }
 837                                                         }
 838                                                         // Wrap styles into @media groups as needed and flatten into a numerical array
 839                                                         $styles = array(
 840                                                                 'css' => self::makeCombinedStyles( $stylePairs )
 841                                                         );
 842                                                 }
 843                                         }
 844                                 }
 845
 846                                 // Messages
 847                                 $messagesBlob = isset( $blobs[$name] ) ? $blobs[$name] : '{}';
 848
 849                                 // Append output
 850                                 switch ( $context->getOnly() ) {
 851                                         case 'scripts':
 852                                                 if ( is_string( $scripts ) ) {
 853                                                         // Load scripts raw...
 854                                                         $out .= $scripts;
 855                                                 } elseif ( is_array( $scripts ) ) {
 856                                                         // ...except when $scripts is an array of URLs
 857                                                         $out .= self::makeLoaderImplementScript( $name, $scripts, array(), array() );
 858                                                 }
 859                                                 break;
 860                                         case 'styles':
 861                                                 // We no longer seperate into media, they are all combined now with
 862                                                 // custom media type groups into @media .. {} sections as part of the css string.
 863                                                 // Module returns either an empty array or a numerical array with css strings.
 864                                                 $out .= isset( $styles['css'] ) ? implode( '', $styles['css'] ) : '';
 865                                                 break;
 866                                         case 'messages':
 867                                                 $out .= self::makeMessageSetScript( new XmlJsCode( $messagesBlob ) );
 868                                                 break;
 869                                         default:
 870                                                 $out .= self::makeLoaderImplementScript(
 871                                                         $name,
 872                                                         $scripts,
 873                                                         $styles,
 874                                                         new XmlJsCode( $messagesBlob )
 875                                                 );
 876                                                 break;
 877                                 }
 878                         } catch ( Exception $e ) {
 879                                 MWExceptionHandler::logException( $e );
 880                                 wfDebugLog( 'resourceloader', __METHOD__ . ": generating module package failed: $e" );
 881                                 $this->hasErrors = true;
 882                                 // Add exception to the output as a comment
 883                                 $exceptions .= self::formatException( $e );
 884
 885                                 // Respond to client with error-state instead of module implementation
 886                                 $states[$name] = 'error';
 887                                 unset( $modules[$name] );
 888                         }
 889                         $isRaw |= $module->isRaw();
 890                         wfProfileOut( __METHOD__ . '-' . $name );
 891                 }
 892
 893                 // Update module states
 894                 if ( $context->shouldIncludeScripts() && !$context->getRaw() && !$isRaw ) {
 895                         if ( count( $modules ) && $context->getOnly() === 'scripts' ) {
 896                                 // Set the state of modules loaded as only scripts to ready as
 897                                 // they don't have an mw.loader.implement wrapper that sets the state
 898                                 foreach ( $modules as $name => $module ) {
 899                                         $states[$name] = 'ready';
 900                                 }
 901                         }
 902
 903                         // Set the state of modules we didn't respond to with mw.loader.implement
 904                         if ( count( $states ) ) {
 905                                 $out .= self::makeLoaderStateScript( $states );
 906                         }
 907                 }
 908
 909                 if ( !$context->getDebug() ) {
 910                         if ( $context->getOnly() === 'styles' ) {
 911                                 $out = $this->filter( 'minify-css', $out );
 912                         } else {
 913                                 $out = $this->filter( 'minify-js', $out );
 914                         }
 915                 }
 916
 917                 wfProfileOut( __METHOD__ );
 918                 return $exceptions . $out;
 919         }
 920
 921         /* Static Methods */
 922
 923         /**
 924          * Return JS code that calls mw.loader.implement with given module properties.
 925          *
 926          * @param string $name Module name
 927          * @param mixed $scripts List of URLs to JavaScript files or String of JavaScript code
 928          * @param mixed $styles Array of CSS strings keyed by media type, or an array of lists of URLs
 929          *   to CSS files keyed by media type
 930          * @param mixed $messages List of messages associated with this module. May either be an
 931          *   associative array mapping message key to value, or a JSON-encoded message blob containing
 932          *   the same data, wrapped in an XmlJsCode object.
 933          * @throws MWException
 934          * @return string
 935          */
 936         public static function makeLoaderImplementScript( $name, $scripts, $styles, $messages ) {
 937                 if ( is_string( $scripts ) ) {
 938                         $scripts = new XmlJsCode( "function ( $, jQuery ) {\n{$scripts}\n}" );
 939                 } elseif ( !is_array( $scripts ) ) {
 940                         throw new MWException( 'Invalid scripts error. Array of URLs or string of code expected.' );
 941                 }
 942                 return Xml::encodeJsCall(
 943                         'mw.loader.implement',
 944                         array(
 945                                 $name,
 946                                 $scripts,
 947                                 // Force objects. mw.loader.implement requires them to be javascript objects.
 948                                 // Although these variables are associative arrays, which become javascript
 949                                 // objects through json_encode. In many cases they will be empty arrays, and
 950                                 // PHP/json_encode() consider empty arrays to be numerical arrays and
 951                                 // output javascript "[]" instead of "{}". This fixes that.
 952                                 (object)$styles,
 953                                 (object)$messages
 954                         ),
 955                         ResourceLoader::inDebugMode()
 956                 );
 957         }
 958
 959         /**
 960          * Returns JS code which, when called, will register a given list of messages.
 961          *
 962          * @param mixed $messages Either an associative array mapping message key to value, or a
 963          *   JSON-encoded message blob containing the same data, wrapped in an XmlJsCode object.
 964          * @return string
 965          */
 966         public static function makeMessageSetScript( $messages ) {
 967                 return Xml::encodeJsCall(
 968                         'mw.messages.set',
 969                         array( (object)$messages ),
 970                         ResourceLoader::inDebugMode()
 971                 );
 972         }
 973
 974         /**
 975          * Combines an associative array mapping media type to CSS into a
 976          * single stylesheet with "@media" blocks.
 977          *
 978          * @param array $stylePairs Array keyed by media type containing (arrays of) CSS strings
 979          * @return array
 980          */
 981         private static function makeCombinedStyles( array $stylePairs ) {
 982                 $out = array();
 983                 foreach ( $stylePairs as $media => $styles ) {
 984                         // ResourceLoaderFileModule::getStyle can return the styles
 985                         // as a string or an array of strings. This is to allow separation in
 986                         // the front-end.
 987                         $styles = (array)$styles;
 988                         foreach ( $styles as $style ) {
 989                                 $style = trim( $style );
 990                                 // Don't output an empty "@media print { }" block (bug 40498)
 991                                 if ( $style !== '' ) {
 992                                         // Transform the media type based on request params and config
 993                                         // The way that this relies on $wgRequest to propagate request params is slightly evil
 994                                         $media = OutputPage::transformCssMedia( $media );
 995
 996                                         if ( $media === '' || $media == 'all' ) {
 997                                                 $out[] = $style;
 998                                         } elseif ( is_string( $media ) ) {
 999                                                 $out[] = "@media $media {\n" . str_replace( "\n", "\n\t", "\t" . $style ) . "}";
1000                                         }
1001                                         // else: skip
1002                                 }
1003                         }
1004                 }
1005                 return $out;
1006         }
1007
1008         /**
1009          * Returns a JS call to mw.loader.state, which sets the state of a
1010          * module or modules to a given value. Has two calling conventions:
1011          *
1012          *    - ResourceLoader::makeLoaderStateScript( $name, $state ):
1013          *         Set the state of a single module called $name to $state
1014          *
1015          *    - ResourceLoader::makeLoaderStateScript( array( $name => $state, ... ) ):
1016          *         Set the state of modules with the given names to the given states
1017          *
1018          * @param string $name
1019          * @param string $state
1020          * @return string
1021          */
1022         public static function makeLoaderStateScript( $name, $state = null ) {
1023                 if ( is_array( $name ) ) {
1024                         return Xml::encodeJsCall(
1025                                 'mw.loader.state',
1026                                 array( $name ),
1027                                 ResourceLoader::inDebugMode()
1028                         );
1029                 } else {
1030                         return Xml::encodeJsCall(
1031                                 'mw.loader.state',
1032                                 array( $name, $state ),
1033                                 ResourceLoader::inDebugMode()
1034                         );
1035                 }
1036         }
1037
1038         /**
1039          * Returns JS code which calls the script given by $script. The script will
1040          * be called with local variables name, version, dependencies and group,
1041          * which will have values corresponding to $name, $version, $dependencies
1042          * and $group as supplied.
1043          *
1044          * @param string $name Module name
1045          * @param int $version Module version number as a timestamp
1046          * @param array $dependencies List of module names on which this module depends
1047          * @param string $group Group which the module is in.
1048          * @param string $source Source of the module, or 'local' if not foreign.
1049          * @param string $script JavaScript code
1050          * @return string
1051          */
1052         public static function makeCustomLoaderScript( $name, $version, $dependencies, $group, $source, $script ) {
1053                 $script = str_replace( "\n", "\n\t", trim( $script ) );
1054                 return Xml::encodeJsCall(
1055                         "( function ( name, version, dependencies, group, source ) {\n\t$script\n} )",
1056                         array( $name, $version, $dependencies, $group, $source ),
1057                         ResourceLoader::inDebugMode()
1058                 );
1059         }
1060
1061         /**
1062          * Returns JS code which calls mw.loader.register with the given
1063          * parameters. Has three calling conventions:
1064          *
1065          *   - ResourceLoader::makeLoaderRegisterScript( $name, $version, $dependencies, $group, $source ):
1066          *       Register a single module.
1067          *
1068          *   - ResourceLoader::makeLoaderRegisterScript( array( $name1, $name2 ) ):
1069          *       Register modules with the given names.
1070          *
1071          *   - ResourceLoader::makeLoaderRegisterScript( array(
1072          *        array( $name1, $version1, $dependencies1, $group1, $source1 ),
1073          *        array( $name2, $version2, $dependencies1, $group2, $source2 ),
1074          *        ...
1075          *     ) ):
1076          *        Registers modules with the given names and parameters.
1077          *
1078          * @param string $name Module name
1079          * @param int $version Module version number as a timestamp
1080          * @param array $dependencies List of module names on which this module depends
1081          * @param string $group Group which the module is in
1082          * @param string $source Source of the module, or 'local' if not foreign
1083          * @return string
1084          */
1085         public static function makeLoaderRegisterScript( $name, $version = null,
1086                 $dependencies = null, $group = null, $source = null
1087         ) {
1088                 if ( is_array( $name ) ) {
1089                         return Xml::encodeJsCall(
1090                                 'mw.loader.register',
1091                                 array( $name ),
1092                                 ResourceLoader::inDebugMode()
1093                         );
1094                 } else {
1095                         $version = (int)$version > 1 ? (int)$version : 1;
1096                         return Xml::encodeJsCall(
1097                                 'mw.loader.register',
1098                                 array( $name, $version, $dependencies, $group, $source ),
1099                                 ResourceLoader::inDebugMode()
1100                         );
1101                 }
1102         }
1103
1104         /**
1105          * Returns JS code which calls mw.loader.addSource() with the given
1106          * parameters. Has two calling conventions:
1107          *
1108          *   - ResourceLoader::makeLoaderSourcesScript( $id, $properties ):
1109          *       Register a single source
1110          *
1111          *   - ResourceLoader::makeLoaderSourcesScript( array( $id1 => $props1, $id2 => $props2, ... ) );
1112          *       Register sources with the given IDs and properties.
1113          *
1114          * @param string $id Source ID
1115          * @param array $properties Source properties (see addSource())
1116          * @return string
1117          */
1118         public static function makeLoaderSourcesScript( $id, $properties = null ) {
1119                 if ( is_array( $id ) ) {
1120                         return Xml::encodeJsCall(
1121                                 'mw.loader.addSource',
1122                                 array( $id ),
1123                                 ResourceLoader::inDebugMode()
1124                         );
1125                 } else {
1126                         return Xml::encodeJsCall(
1127                                 'mw.loader.addSource',
1128                                 array( $id, $properties ),
1129                                 ResourceLoader::inDebugMode()
1130                         );
1131                 }
1132         }
1133
1134         /**
1135          * Returns JS code which runs given JS code if the client-side framework is
1136          * present.
1137          *
1138          * @param string $script JavaScript code
1139          * @return string
1140          */
1141         public static function makeLoaderConditionalScript( $script ) {
1142                 return "if(window.mw){\n" . trim( $script ) . "\n}";
1143         }
1144
1145         /**
1146          * Returns JS code which will set the MediaWiki configuration array to
1147          * the given value.
1148          *
1149          * @param array $configuration List of configuration values keyed by variable name
1150          * @return string
1151          */
1152         public static function makeConfigSetScript( array $configuration ) {
1153                 return Xml::encodeJsCall(
1154                         'mw.config.set',
1155                         array( $configuration ),
1156                         ResourceLoader::inDebugMode()
1157                 );
1158         }
1159
1160         /**
1161          * Convert an array of module names to a packed query string.
1162          *
1163          * For example, array( 'foo.bar', 'foo.baz', 'bar.baz', 'bar.quux' )
1164          * becomes 'foo.bar,baz|bar.baz,quux'
1165          * @param array $modules List of module names (strings)
1166          * @return string Packed query string
1167          */
1168         public static function makePackedModulesString( $modules ) {
1169                 $groups = array(); // array( prefix => array( suffixes ) )
1170                 foreach ( $modules as $module ) {
1171                         $pos = strrpos( $module, '.' );
1172                         $prefix = $pos === false ? '' : substr( $module, 0, $pos );
1173                         $suffix = $pos === false ? $module : substr( $module, $pos + 1 );
1174                         $groups[$prefix][] = $suffix;
1175                 }
1176
1177                 $arr = array();
1178                 foreach ( $groups as $prefix => $suffixes ) {
1179                         $p = $prefix === '' ? '' : $prefix . '.';
1180                         $arr[] = $p . implode( ',', $suffixes );
1181                 }
1182                 $str = implode( '|', $arr );
1183                 return $str;
1184         }
1185
1186         /**
1187          * Determine whether debug mode was requested
1188          * Order of priority is 1) request param, 2) cookie, 3) $wg setting
1189          * @return bool
1190          */
1191         public static function inDebugMode() {
1192                 global $wgRequest, $wgResourceLoaderDebug;
1193                 static $retval = null;
1194                 if ( is_null( $retval ) ) {
1195                         $retval = $wgRequest->getFuzzyBool( 'debug',
1196                                 $wgRequest->getCookie( 'resourceLoaderDebug', '', $wgResourceLoaderDebug ) );
1197                 }
1198                 return $retval;
1199         }
1200
1201         /**
1202          * Build a load.php URL
1203          * @param array $modules Array of module names (strings)
1204          * @param string $lang Language code
1205          * @param string $skin Skin name
1206          * @param string|null $user User name. If null, the &user= parameter is omitted
1207          * @param string|null $version Versioning timestamp
1208          * @param bool $debug Whether the request should be in debug mode
1209          * @param string|null $only &only= parameter
1210          * @param bool $printable Printable mode
1211          * @param bool $handheld Handheld mode
1212          * @param array $extraQuery Extra query parameters to add
1213          * @return string URL to load.php. May be protocol-relative (if $wgLoadScript is procol-relative)
1214          */
1215         public static function makeLoaderURL( $modules, $lang, $skin, $user = null, $version = null, $debug = false, $only = null,
1216                         $printable = false, $handheld = false, $extraQuery = array() ) {
1217                 global $wgLoadScript;
1218                 $query = self::makeLoaderQuery( $modules, $lang, $skin, $user, $version, $debug,
1219                         $only, $printable, $handheld, $extraQuery
1220                 );
1221
1222                 // Prevent the IE6 extension check from being triggered (bug 28840)
1223                 // by appending a character that's invalid in Windows extensions ('*')
1224                 return wfExpandUrl( wfAppendQuery( $wgLoadScript, $query ) . '&*', PROTO_RELATIVE );
1225         }
1226
1227         /**
1228          * Build a query array (array representation of query string) for load.php. Helper
1229          * function for makeLoaderURL().
1230          *
1231          * @param array $modules
1232          * @param string $lang
1233          * @param string $skin
1234          * @param string $user
1235          * @param string $version
1236          * @param bool $debug
1237          * @param string $only
1238          * @param bool $printable
1239          * @param bool $handheld
1240          * @param array $extraQuery
1241          *
1242          * @return array
1243          */
1244         public static function makeLoaderQuery( $modules, $lang, $skin, $user = null, $version = null, $debug = false, $only = null,
1245                         $printable = false, $handheld = false, $extraQuery = array() ) {
1246                 $query = array(
1247                         'modules' => self::makePackedModulesString( $modules ),
1248                         'lang' => $lang,
1249                         'skin' => $skin,
1250                         'debug' => $debug ? 'true' : 'false',
1251                 );
1252                 if ( $user !== null ) {
1253                         $query['user'] = $user;
1254                 }
1255                 if ( $version !== null ) {
1256                         $query['version'] = $version;
1257                 }
1258                 if ( $only !== null ) {
1259                         $query['only'] = $only;
1260                 }
1261                 if ( $printable ) {
1262                         $query['printable'] = 1;
1263                 }
1264                 if ( $handheld ) {
1265                         $query['handheld'] = 1;
1266                 }
1267                 $query += $extraQuery;
1268
1269                 // Make queries uniform in order
1270                 ksort( $query );
1271                 return $query;
1272         }
1273
1274         /**
1275          * Check a module name for validity.
1276          *
1277          * Module names may not contain pipes (|), commas (,) or exclamation marks (!) and can be
1278          * at most 255 bytes.
1279          *
1280          * @param string $moduleName Module name to check
1281          * @return bool Whether $moduleName is a valid module name
1282          */
1283         public static function isValidModuleName( $moduleName ) {
1284                 return !preg_match( '/[|,!]/', $moduleName ) && strlen( $moduleName ) <= 255;
1285         }
1286
1287         /**
1288          * Returns LESS compiler set up for use with MediaWiki
1289          *
1290          * @since 1.22
1291          * @return lessc
1292          */
1293         public static function getLessCompiler() {
1294                 global $wgResourceLoaderLESSFunctions, $wgResourceLoaderLESSImportPaths;
1295
1296                 // When called from the installer, it is possible that a required PHP extension
1297                 // is missing (at least for now; see bug 47564). If this is the case, throw an
1298                 // exception (caught by the installer) to prevent a fatal error later on.
1299                 if ( !function_exists( 'ctype_digit' ) ) {
1300                         throw new MWException( 'lessc requires the Ctype extension' );
1301                 }
1302
1303                 $less = new lessc();
1304                 $less->setPreserveComments( true );
1305                 $less->setVariables( self::getLESSVars() );
1306                 $less->setImportDir( $wgResourceLoaderLESSImportPaths );
1307                 foreach ( $wgResourceLoaderLESSFunctions as $name => $func ) {
1308                         $less->registerFunction( $name, $func );
1309                 }
1310                 return $less;
1311         }
1312
1313         /**
1314          * Get global LESS variables.
1315          *
1316          * $since 1.22
1317          * @return array Map of variable names to string CSS values.
1318          */
1319         public static function getLESSVars() {
1320                 global $wgResourceLoaderLESSVars;
1321
1322                 $lessVars = $wgResourceLoaderLESSVars;
1323                 // Sort by key to ensure consistent hashing for cache lookups.
1324                 ksort( $lessVars );
1325                 return $lessVars;
1326         }
1327 }