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