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