includes/resourceloader/ResourceLoader.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  * @author Roan Kattouw
  20  * @author Trevor Parscal
  21  */
  22
  23 /**
  24  * Dynamic JavaScript and CSS resource loading system.
  25  *
  26  * Most of the documention is on the MediaWiki documentation wiki starting at:
  27  *    http://www.mediawiki.org/wiki/ResourceLoader
  28  */
  29 class ResourceLoader {
  30
  31         /* Protected Static Members */
  32
  33         /** Array: List of module name/ResourceLoaderModule object pairs */
  34         protected $modules = array();
  35         /** Associative array mapping module name to info associative array */
  36         protected $moduleInfos = array();
  37
  38         /* Protected Methods */
  39
  40         /**
  41          * Loads information stored in the database about modules.
  42          *
  43          * This method grabs modules dependencies from the database and updates modules
  44          * objects.
  45          *
  46          * This is not inside the module code because it is much faster to
  47          * request all of the information at once than it is to have each module
  48          * requests its own information. This sacrifice of modularity yields a substantial
  49          * performance improvement.
  50          *
  51          * @param $modules Array: List of module names to preload information for
  52          * @param $context ResourceLoaderContext: Context to load the information within
  53          */
  54         public function preloadModuleInfo( array $modules, ResourceLoaderContext $context ) {
  55                 if ( !count( $modules ) ) {
  56                         return; // or else Database*::select() will explode, plus it's cheaper!
  57                 }
  58                 $dbr = wfGetDB( DB_SLAVE );
  59                 $skin = $context->getSkin();
  60                 $lang = $context->getLanguage();
  61
  62                 // Get file dependency information
  63                 $res = $dbr->select( 'module_deps', array( 'md_module', 'md_deps' ), array(
  64                                 'md_module' => $modules,
  65                                 'md_skin' => $context->getSkin()
  66                         ), __METHOD__
  67                 );
  68
  69                 // Set modules' dependencies
  70                 $modulesWithDeps = array();
  71                 foreach ( $res as $row ) {
  72                         $this->getModule( $row->md_module )->setFileDependencies( $skin,
  73                                 FormatJson::decode( $row->md_deps, true )
  74                         );
  75                         $modulesWithDeps[] = $row->md_module;
  76                 }
  77
  78                 // Register the absence of a dependency row too
  79                 foreach ( array_diff( $modules, $modulesWithDeps ) as $name ) {
  80                         $this->getModule( $name )->setFileDependencies( $skin, array() );
  81                 }
  82
  83                 // Get message blob mtimes. Only do this for modules with messages
  84                 $modulesWithMessages = array();
  85                 foreach ( $modules as $name ) {
  86                         if ( count( $this->getModule( $name )->getMessages() ) ) {
  87                                 $modulesWithMessages[] = $name;
  88                         }
  89                 }
  90                 $modulesWithoutMessages = array_flip( $modules ); // Will be trimmed down by the loop below
  91                 if ( count( $modulesWithMessages ) ) {
  92                         $res = $dbr->select( 'msg_resource', array( 'mr_resource', 'mr_timestamp' ), array(
  93                                         'mr_resource' => $modulesWithMessages,
  94                                         'mr_lang' => $lang
  95                                 ), __METHOD__
  96                         );
  97                         foreach ( $res as $row ) {
  98                                 $this->getModule( $row->mr_resource )->setMsgBlobMtime( $lang, $row->mr_timestamp );
  99                                 unset( $modulesWithoutMessages[$row->mr_resource] );
 100                         }
 101                 }
 102                 foreach ( array_keys( $modulesWithoutMessages ) as $name ) {
 103                         $this->getModule( $name )->setMsgBlobMtime( $lang, 0 );
 104                 }
 105         }
 106
 107         /**
 108          * Runs JavaScript or CSS data through a filter, caching the filtered result for future calls.
 109          *
 110          * Available filters are:
 111          *  - minify-js \see JSMin::minify
 112          *  - minify-css \see CSSMin::minify
 113          *
 114          * If $data is empty, only contains whitespace or the filter was unknown,
 115          * $data is returned unmodified.
 116          *
 117          * @param $filter String: Name of filter to run
 118          * @param $data String: Text to filter, such as JavaScript or CSS text
 119          * @return String: Filtered data, or a comment containing an error message
 120          */
 121         protected function filter( $filter, $data ) {
 122                 wfProfileIn( __METHOD__ );
 123
 124                 // For empty/whitespace-only data or for unknown filters, don't perform
 125                 // any caching or processing
 126                 if ( trim( $data ) === ''
 127                         || !in_array( $filter, array( 'minify-js', 'minify-css' ) ) )
 128                 {
 129                         wfProfileOut( __METHOD__ );
 130                         return $data;
 131                 }
 132
 133                 // Try for cache hit
 134                 // Use CACHE_ANYTHING since filtering is very slow compared to DB queries
 135                 $key = wfMemcKey( 'resourceloader', 'filter', $filter, md5( $data ) );
 136                 $cache = wfGetCache( CACHE_ANYTHING );
 137                 $cacheEntry = $cache->get( $key );
 138                 if ( is_string( $cacheEntry ) ) {
 139                         wfProfileOut( __METHOD__ );
 140                         return $cacheEntry;
 141                 }
 142
 143                 // Run the filter - we've already verified one of these will work
 144                 try {
 145                         switch ( $filter ) {
 146                                 case 'minify-js':
 147                                         $result = JSMin::minify( $data );
 148                                         break;
 149                                 case 'minify-css':
 150                                         $result = CSSMin::minify( $data );
 151                                         break;
 152                         }
 153
 154                         // Save filtered text to Memcached
 155                         $cache->set( $key, $result );
 156                 } catch ( Exception $exception ) {
 157                         // Return exception as a comment
 158                         $result = "/*\n{$exception->__toString()}\n*/";
 159                 }
 160
 161                 wfProfileOut( __METHOD__ );
 162
 163                 return $result;
 164         }
 165
 166         /* Methods */
 167
 168         /**
 169          * Registers core modules and runs registration hooks.
 170          */
 171         public function __construct() {
 172                 global $IP, $wgResourceModules;
 173
 174                 wfProfileIn( __METHOD__ );
 175
 176                 // Register core modules
 177                 $this->register( include( "$IP/resources/Resources.php" ) );
 178                 // Register extension modules
 179                 wfRunHooks( 'ResourceLoaderRegisterModules', array( &$this ) );
 180                 $this->register( $wgResourceModules );
 181
 182                 wfProfileOut( __METHOD__ );
 183         }
 184
 185         /**
 186          * Registers a module with the ResourceLoader system.
 187          *
 188          * @param $name Mixed: Name of module as a string or List of name/object pairs as an array
 189          * @param $info Module info array. For backwards compatibility with 1.17alpha,
 190          *   this may also be a ResourceLoaderModule object. Optional when using
 191          *   multiple-registration calling style.
 192          * @throws MWException: If a duplicate module registration is attempted
 193          * @throws MWException: If something other than a ResourceLoaderModule is being registered
 194          * @return Boolean: False if there were any errors, in which case one or more modules were not
 195          *     registered
 196          */
 197         public function register( $name, $info = null ) {
 198                 wfProfileIn( __METHOD__ );
 199
 200                 // Allow multiple modules to be registered in one call
 201                 if ( is_array( $name ) ) {
 202                         foreach ( $name as $key => $value ) {
 203                                 $this->register( $key, $value );
 204                         }
 205                         return;
 206                 }
 207
 208                 // Disallow duplicate registrations
 209                 if ( isset( $this->moduleInfos[$name] ) ) {
 210                         // A module has already been registered by this name
 211                         throw new MWException(
 212                                 'ResourceLoader duplicate registration error. ' .
 213                                 'Another module has already been registered as ' . $name
 214                         );
 215                 }
 216
 217                 // Attach module
 218                 if ( is_object( $info ) ) {
 219                         // Old calling convention
 220                         // Validate the input
 221                         if ( !( $info instanceof ResourceLoaderModule ) ) {
 222                                 throw new MWException( 'ResourceLoader invalid module error. ' .
 223                                         'Instances of ResourceLoaderModule expected.' );
 224                         }
 225
 226                         $this->moduleInfos[$name] = array( 'object' => $info );
 227                         $info->setName( $name );
 228                         $this->modules[$name] = $info;
 229                 } else {
 230                         // New calling convention
 231                         $this->moduleInfos[$name] = $info;
 232                 }
 233
 234                 wfProfileOut( __METHOD__ );
 235         }
 236
 237         /**
 238          * Get a list of module names
 239          *
 240          * @return Array: List of module names
 241          */
 242         public function getModuleNames() {
 243                 return array_keys( $this->moduleInfos );
 244         }
 245
 246         /**
 247          * Get the ResourceLoaderModule object for a given module name.
 248          *
 249          * @param $name String: Module name
 250          * @return Mixed: ResourceLoaderModule if module has been registered, null otherwise
 251          */
 252         public function getModule( $name ) {
 253                 if ( !isset( $this->modules[$name] ) ) {
 254                         if ( !isset( $this->moduleInfos[$name] ) ) {
 255                                 // No such module
 256                                 return null;
 257                         }
 258                         // Construct the requested object
 259                         $info = $this->moduleInfos[$name];
 260                         if ( isset( $info['object'] ) ) {
 261                                 // Object given in info array
 262                                 $object = $info['object'];
 263                         } else {
 264                                 if ( !isset( $info['class'] ) ) {
 265                                         $class = 'ResourceLoaderFileModule';
 266                                 } else {
 267                                         $class = $info['class'];
 268                                 }
 269                                 $object = new $class( $info );
 270                         }
 271                         $object->setName( $name );
 272                         $this->modules[$name] = $object;
 273                 }
 274
 275                 return $this->modules[$name];
 276         }
 277
 278         /**
 279          * Outputs a response to a resource load-request, including a content-type header.
 280          *
 281          * @param $context ResourceLoaderContext: Context in which a response should be formed
 282          */
 283         public function respond( ResourceLoaderContext $context ) {
 284                 global $wgResourceLoaderMaxage, $wgCacheEpoch;
 285
 286                 // Buffer output to catch warnings. Normally we'd use ob_clean() on the
 287                 // top-level output buffer to clear warnings, but that breaks when ob_gzhandler
 288                 // is used: ob_clean() will clear the GZIP header in that case and it won't come
 289                 // back for subsequent output, resulting in invalid GZIP. So we have to wrap
 290                 // the whole thing in our own output buffer to be sure the active buffer
 291                 // doesn't use ob_gzhandler.
 292                 // See http://bugs.php.net/bug.php?id=36514
 293                 ob_start();
 294
 295                 wfProfileIn( __METHOD__ );
 296                 $response = '';
 297
 298                 // Split requested modules into two groups, modules and missing
 299                 $modules = array();
 300                 $missing = array();
 301                 foreach ( $context->getModules() as $name ) {
 302                         if ( isset( $this->moduleInfos[$name] ) ) {
 303                                 $modules[$name] = $this->getModule( $name );
 304                         } else {
 305                                 $missing[] = $name;
 306                         }
 307                 }
 308
 309                 // If a version wasn't specified we need a shorter expiry time for updates
 310                 // to propagate to clients quickly
 311                 if ( is_null( $context->getVersion() ) ) {
 312                         $maxage  = $wgResourceLoaderMaxage['unversioned']['client'];
 313                         $smaxage = $wgResourceLoaderMaxage['unversioned']['server'];
 314                 }
 315                 // If a version was specified we can use a longer expiry time since changing
 316                 // version numbers causes cache misses
 317                 else {
 318                         $maxage  = $wgResourceLoaderMaxage['versioned']['client'];
 319                         $smaxage = $wgResourceLoaderMaxage['versioned']['server'];
 320                 }
 321
 322                 // Preload information needed to the mtime calculation below
 323                 try {
 324                         $this->preloadModuleInfo( array_keys( $modules ), $context );
 325                 } catch( Exception $e ) {
 326                         // Add exception to the output as a comment
 327                         $response .= "/*\n{$e->__toString()}\n*/";
 328                 }
 329
 330                 wfProfileIn( __METHOD__.'-getModifiedTime' );
 331
 332                 // To send Last-Modified and support If-Modified-Since, we need to detect
 333                 // the last modified time
 334                 $mtime = wfTimestamp( TS_UNIX, $wgCacheEpoch );
 335                 foreach ( $modules as $module ) {
 336                         try {
 337                                 // Bypass squid cache if the request includes any private modules
 338                                 if ( $module->getGroup() === 'private' ) {
 339                                         $smaxage = 0;
 340                                 }
 341                                 // Calculate maximum modified time
 342                                 $mtime = max( $mtime, $module->getModifiedTime( $context ) );
 343                         } catch ( Exception $e ) {
 344                                 // Add exception to the output as a comment
 345                                 $response .= "/*\n{$e->__toString()}\n*/";
 346                         }
 347                 }
 348
 349                 wfProfileOut( __METHOD__.'-getModifiedTime' );
 350
 351                 if ( $context->getOnly() === 'styles' ) {
 352                         header( 'Content-Type: text/css' );
 353                 } else {
 354                         header( 'Content-Type: text/javascript' );
 355                 }
 356                 header( 'Last-Modified: ' . wfTimestamp( TS_RFC2822, $mtime ) );
 357                 if ( $context->getDebug() ) {
 358                         header( 'Cache-Control: must-revalidate' );
 359                 } else {
 360                         header( "Cache-Control: public, max-age=$maxage, s-maxage=$smaxage" );
 361                         header( 'Expires: ' . wfTimestamp( TS_RFC2822, min( $maxage, $smaxage ) + time() ) );
 362                 }
 363
 364                 // If there's an If-Modified-Since header, respond with a 304 appropriately
 365                 // Some clients send "timestamp;length=123". Strip the part after the first ';'
 366                 // so we get a valid timestamp.
 367                 $ims = $context->getRequest()->getHeader( 'If-Modified-Since' );
 368                 if ( $ims !== false ) {
 369                         $imsTS = strtok( $ims, ';' );
 370                         if ( $mtime <= wfTimestamp( TS_UNIX, $imsTS ) ) {
 371                                 // There's another bug in ob_gzhandler (see also the comment at
 372                                 // the top of this function) that causes it to gzip even empty
 373                                 // responses, meaning it's impossible to produce a truly empty
 374                                 // response (because the gzip header is always there). This is
 375                                 // a problem because 304 responses have to be completely empty
 376                                 // per the HTTP spec, and Firefox behaves buggily when they're not.
 377                                 // See also http://bugs.php.net/bug.php?id=51579
 378                                 // To work around this, we tear down all output buffering before
 379                                 // sending the 304.
 380                                 while ( ob_get_level() > 0 ) {
 381                                         ob_end_clean();
 382                                 }
 383
 384                                 header( 'HTTP/1.0 304 Not Modified' );
 385                                 header( 'Status: 304 Not Modified' );
 386                                 wfProfileOut( __METHOD__ );
 387                                 return;
 388                         }
 389                 }
 390
 391                 // Generate a response
 392                 $response .= $this->makeModuleResponse( $context, $modules, $missing );
 393
 394                 // Capture any PHP warnings from the output buffer and append them to the
 395                 // response in a comment if we're in debug mode.
 396                 if ( $context->getDebug() && strlen( $warnings = ob_get_contents() ) ) {
 397                         $response .= "/*\n$warnings\n*/";
 398                 }
 399
 400                 // Remove the output buffer and output the response
 401                 ob_end_clean();
 402                 echo $response;
 403
 404                 wfProfileOut( __METHOD__ );
 405         }
 406
 407         /**
 408          * Generates code for a response
 409          *
 410          * @param $context ResourceLoaderContext: Context in which to generate a response
 411          * @param $modules Array: List of module objects keyed by module name
 412          * @param $missing Array: List of unavailable modules (optional)
 413          * @return String: Response data
 414          */
 415         public function makeModuleResponse( ResourceLoaderContext $context,
 416                 array $modules, $missing = array() )
 417         {
 418                 $out = '';
 419                 if ( $modules === array() && $missing === array() ) {
 420                         return '/* No modules requested. Max made me put this here */';
 421                 }
 422
 423                 // Pre-fetch blobs
 424                 if ( $context->shouldIncludeMessages() ) {
 425                         //try {
 426                                 $blobs = MessageBlobStore::get( $this, $modules, $context->getLanguage() );
 427                         //} catch ( Exception $e ) {
 428                                 // Add exception to the output as a comment
 429                         //      $out .= "/*\n{$e->__toString()}\n*/";
 430                         //}
 431                 } else {
 432                         $blobs = array();
 433                 }
 434
 435                 // Generate output
 436                 foreach ( $modules as $name => $module ) {
 437                         wfProfileIn( __METHOD__ . '-' . $name );
 438                         try {
 439                                 // Scripts
 440                                 $scripts = '';
 441                                 if ( $context->shouldIncludeScripts() ) {
 442                                         $scripts .= $module->getScript( $context ) . "\n";
 443                                 }
 444
 445                                 // Styles
 446                                 $styles = array();
 447                                 if ( $context->shouldIncludeStyles() ) {
 448                                         $styles = $module->getStyles( $context );
 449                                 }
 450
 451                                 // Messages
 452                                 $messagesBlob = isset( $blobs[$name] ) ? $blobs[$name] : '{}';
 453
 454                                 // Append output
 455                                 switch ( $context->getOnly() ) {
 456                                         case 'scripts':
 457                                                 $out .= $scripts;
 458                                                 break;
 459                                         case 'styles':
 460                                                 $out .= self::makeCombinedStyles( $styles );
 461                                                 break;
 462                                         case 'messages':
 463                                                 $out .= self::makeMessageSetScript( new XmlJsCode( $messagesBlob ) );
 464                                                 break;
 465                                         default:
 466                                                 // Minify CSS before embedding in mediaWiki.loader.implement call
 467                                                 // (unless in debug mode)
 468                                                 if ( !$context->getDebug() ) {
 469                                                         foreach ( $styles as $media => $style ) {
 470                                                                 $styles[$media] = $this->filter( 'minify-css', $style );
 471                                                         }
 472                                                 }
 473                                                 $out .= self::makeLoaderImplementScript( $name, $scripts, $styles,
 474                                                         new XmlJsCode( $messagesBlob ) );
 475                                                 break;
 476                                 }
 477                         } catch ( Exception $e ) {
 478                                 // Add exception to the output as a comment
 479                                 $out .= "/*\n{$e->__toString()}\n*/";
 480
 481                                 // Register module as missing
 482                                 $missing[] = $name;
 483                                 unset( $modules[$name] );
 484                         }
 485                         wfProfileOut( __METHOD__ . '-' . $name );
 486                 }
 487
 488                 // Update module states
 489                 if ( $context->shouldIncludeScripts() ) {
 490                         // Set the state of modules loaded as only scripts to ready
 491                         if ( count( $modules ) && $context->getOnly() === 'scripts'
 492                                 && !isset( $modules['startup'] ) )
 493                         {
 494                                 $out .= self::makeLoaderStateScript(
 495                                         array_fill_keys( array_keys( $modules ), 'ready' ) );
 496                         }
 497                         // Set the state of modules which were requested but unavailable as missing
 498                         if ( is_array( $missing ) && count( $missing ) ) {
 499                                 $out .= self::makeLoaderStateScript( array_fill_keys( $missing, 'missing' ) );
 500                         }
 501                 }
 502
 503                 if ( $context->getDebug() ) {
 504                         return $out;
 505                 } else {
 506                         if ( $context->getOnly() === 'styles' ) {
 507                                 return $this->filter( 'minify-css', $out );
 508                         } else {
 509                                 return $this->filter( 'minify-js', $out );
 510                         }
 511                 }
 512         }
 513
 514         /* Static Methods */
 515
 516         /**
 517          * Returns JS code to call to mediaWiki.loader.implement for a module with
 518          * given properties.
 519          *
 520          * @param $name Module name
 521          * @param $scripts Array: List of JavaScript code snippets to be executed after the
 522          *     module is loaded
 523          * @param $styles Array: List of CSS strings keyed by media type
 524          * @param $messages Mixed: List of messages associated with this module. May either be an
 525          *     associative array mapping message key to value, or a JSON-encoded message blob containing
 526          *     the same data, wrapped in an XmlJsCode object.
 527          */
 528         public static function makeLoaderImplementScript( $name, $scripts, $styles, $messages ) {
 529                 if ( is_array( $scripts ) ) {
 530                         $scripts = implode( $scripts, "\n" );
 531                 }
 532                 return Xml::encodeJsCall(
 533                         'mediaWiki.loader.implement',
 534                         array(
 535                                 $name,
 536                                 new XmlJsCode( "function() {{$scripts}}" ),
 537                                 (object)$styles,
 538                                 (object)$messages
 539                         ) );
 540         }
 541
 542         /**
 543          * Returns JS code which, when called, will register a given list of messages.
 544          *
 545          * @param $messages Mixed: Either an associative array mapping message key to value, or a
 546          *     JSON-encoded message blob containing the same data, wrapped in an XmlJsCode object.
 547          */
 548         public static function makeMessageSetScript( $messages ) {
 549                 return Xml::encodeJsCall( 'mediaWiki.messages.set', array( (object)$messages ) );
 550         }
 551
 552         /**
 553          * Combines an associative array mapping media type to CSS into a
 554          * single stylesheet with @media blocks.
 555          *
 556          * @param $styles Array: List of CSS strings keyed by media type
 557          */
 558         public static function makeCombinedStyles( array $styles ) {
 559                 $out = '';
 560                 foreach ( $styles as $media => $style ) {
 561                         $out .= "@media $media {\n" . str_replace( "\n", "\n\t", "\t" . $style ) . "\n}\n";
 562                 }
 563                 return $out;
 564         }
 565
 566         /**
 567          * Returns a JS call to mediaWiki.loader.state, which sets the state of a
 568          * module or modules to a given value. Has two calling conventions:
 569          *
 570          *    - ResourceLoader::makeLoaderStateScript( $name, $state ):
 571          *         Set the state of a single module called $name to $state
 572          *
 573          *    - ResourceLoader::makeLoaderStateScript( array( $name => $state, ... ) ):
 574          *         Set the state of modules with the given names to the given states
 575          */
 576         public static function makeLoaderStateScript( $name, $state = null ) {
 577                 if ( is_array( $name ) ) {
 578                         return Xml::encodeJsCall( 'mediaWiki.loader.state', array( $name ) );
 579                 } else {
 580                         return Xml::encodeJsCall( 'mediaWiki.loader.state', array( $name, $state ) );
 581                 }
 582         }
 583
 584         /**
 585          * Returns JS code which calls the script given by $script. The script will
 586          * be called with local variables name, version, dependencies and group,
 587          * which will have values corresponding to $name, $version, $dependencies
 588          * and $group as supplied.
 589          *
 590          * @param $name String: Module name
 591          * @param $version Integer: Module version number as a timestamp
 592          * @param $dependencies Array: List of module names on which this module depends
 593          * @param $group String: Group which the module is in.
 594          * @param $script String: JavaScript code
 595          */
 596         public static function makeCustomLoaderScript( $name, $version, $dependencies, $group, $script ) {
 597                 $script = str_replace( "\n", "\n\t", trim( $script ) );
 598                 return Xml::encodeJsCall(
 599                         "( function( name, version, dependencies, group ) {\n\t$script\n} )",
 600                         array( $name, $version, $dependencies, $group ) );
 601         }
 602
 603         /**
 604          * Returns JS code which calls mediaWiki.loader.register with the given
 605          * parameters. Has three calling conventions:
 606          *
 607          *   - ResourceLoader::makeLoaderRegisterScript( $name, $version, $dependencies, $group ):
 608          *       Register a single module.
 609          *
 610          *   - ResourceLoader::makeLoaderRegisterScript( array( $name1, $name2 ) ):
 611          *       Register modules with the given names.
 612          *
 613          *   - ResourceLoader::makeLoaderRegisterScript( array(
 614          *        array( $name1, $version1, $dependencies1, $group1 ),
 615          *        array( $name2, $version2, $dependencies1, $group2 ),
 616          *        ...
 617          *     ) ):
 618          *        Registers modules with the given names and parameters.
 619          *
 620          * @param $name String: Module name
 621          * @param $version Integer: Module version number as a timestamp
 622          * @param $dependencies Array: List of module names on which this module depends
 623          * @param $group String: group which the module is in.
 624          */
 625         public static function makeLoaderRegisterScript( $name, $version = null,
 626                 $dependencies = null, $group = null )
 627         {
 628                 if ( is_array( $name ) ) {
 629                         return Xml::encodeJsCall( 'mediaWiki.loader.register', array( $name ) );
 630                 } else {
 631                         $version = (int) $version > 1 ? (int) $version : 1;
 632                         return Xml::encodeJsCall( 'mediaWiki.loader.register',
 633                                 array( $name, $version, $dependencies, $group ) );
 634                 }
 635         }
 636
 637         /**
 638          * Returns JS code which runs given JS code if the client-side framework is
 639          * present.
 640          *
 641          * @param $script String: JavaScript code
 642          */
 643         public static function makeLoaderConditionalScript( $script ) {
 644                 $script = str_replace( "\n", "\n\t", trim( $script ) );
 645                 return "if ( window.mediaWiki ) {\n\t$script\n}\n";
 646         }
 647
 648         /**
 649          * Returns JS code which will set the MediaWiki configuration array to
 650          * the given value.
 651          *
 652          * @param $configuration Array: List of configuration values keyed by variable name
 653          */
 654         public static function makeConfigSetScript( array $configuration ) {
 655                 return Xml::encodeJsCall( 'mediaWiki.config.set', array( $configuration ) );
 656         }
 657
 658         /**
 659          * Determine whether debug mode was requested
 660          * Order of priority is 1) request param, 2) cookie, 3) $wg setting
 661          * @return bool
 662          */
 663         public static function inDebugMode() {
 664                 global $wgRequest, $wgResourceLoaderDebug;
 665                 static $retval = null;
 666                 if ( !is_null( $retval ) )
 667                         return $retval;
 668                 return $retval = $wgRequest->getFuzzyBool( 'debug',
 669                         $wgRequest->getCookie( 'resourceLoaderDebug', '', $wgResourceLoaderDebug ) );
 670         }
 671 }