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