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                         wfDebugLog( 'resourceloader', __METHOD__ . ": minification failed: $e" );
 178                         $this->hasErrors = true;
 179                         // Return exception as a comment
 180                         $result = $this->makeComment( $exception->__toString() );
 181                 }
 182
 183                 wfProfileOut( __METHOD__ );
 184
 185                 return $result;
 186         }
 187
 188         /* Methods */
 189
 190         /**
 191          * Registers core modules and runs registration hooks.
 192          */
 193         public function __construct() {
 194                 global $IP, $wgResourceModules, $wgResourceLoaderSources, $wgLoadScript, $wgEnableJavaScriptTest;
 195
 196                 wfProfileIn( __METHOD__ );
 197
 198                 // Add 'local' source first
 199                 $this->addSource( 'local', array( 'loadScript' => $wgLoadScript, 'apiScript' => wfScript( 'api' ) ) );
 200
 201                 // Add other sources
 202                 $this->addSource( $wgResourceLoaderSources );
 203
 204                 // Register core modules
 205                 $this->register( include "$IP/resources/Resources.php" );
 206                 // Register extension modules
 207                 wfRunHooks( 'ResourceLoaderRegisterModules', array( &$this ) );
 208                 $this->register( $wgResourceModules );
 209
 210                 if ( $wgEnableJavaScriptTest === true ) {
 211                         $this->registerTestModules();
 212                 }
 213
 214                 wfProfileOut( __METHOD__ );
 215         }
 216
 217         /**
 218          * Registers a module with the ResourceLoader system.
 219          *
 220          * @param $name Mixed: Name of module as a string or List of name/object pairs as an array
 221          * @param array $info Module info array. For backwards compatibility with 1.17alpha,
 222          *   this may also be a ResourceLoaderModule object. Optional when using
 223          *   multiple-registration calling style.
 224          * @throws MWException: If a duplicate module registration is attempted
 225          * @throws MWException: If a module name contains illegal characters (pipes or commas)
 226          * @throws MWException: If something other than a ResourceLoaderModule is being registered
 227          * @return Boolean: False if there were any errors, in which case one or more modules were not
 228          *     registered
 229          */
 230         public function register( $name, $info = null ) {
 231                 wfProfileIn( __METHOD__ );
 232
 233                 // Allow multiple modules to be registered in one call
 234                 $registrations = is_array( $name ) ? $name : array( $name => $info );
 235                 foreach ( $registrations as $name => $info ) {
 236                         // Disallow duplicate registrations
 237                         if ( isset( $this->moduleInfos[$name] ) ) {
 238                                 wfProfileOut( __METHOD__ );
 239                                 // A module has already been registered by this name
 240                                 throw new MWException(
 241                                         'ResourceLoader duplicate registration error. ' .
 242                                         'Another module has already been registered as ' . $name
 243                                 );
 244                         }
 245
 246                         // Check $name for validity
 247                         if ( !self::isValidModuleName( $name ) ) {
 248                                 wfProfileOut( __METHOD__ );
 249                                 throw new MWException( "ResourceLoader module name '$name' is invalid, see ResourceLoader::isValidModuleName()" );
 250                         }
 251
 252                         // Attach module
 253                         if ( is_object( $info ) ) {
 254                                 // Old calling convention
 255                                 // Validate the input
 256                                 if ( !( $info instanceof ResourceLoaderModule ) ) {
 257                                         wfProfileOut( __METHOD__ );
 258                                         throw new MWException( 'ResourceLoader invalid module error. ' .
 259                                                 'Instances of ResourceLoaderModule expected.' );
 260                                 }
 261
 262                                 $this->moduleInfos[$name] = array( 'object' => $info );
 263                                 $info->setName( $name );
 264                                 $this->modules[$name] = $info;
 265                         } else {
 266                                 // New calling convention
 267                                 $this->moduleInfos[$name] = $info;
 268                         }
 269                 }
 270
 271                 wfProfileOut( __METHOD__ );
 272         }
 273
 274         /**
 275          */
 276         public function registerTestModules() {
 277                 global $IP, $wgEnableJavaScriptTest;
 278
 279                 if ( $wgEnableJavaScriptTest !== true ) {
 280                         throw new MWException( 'Attempt to register JavaScript test modules but <tt>$wgEnableJavaScriptTest</tt> is false. Edit your <tt>LocalSettings.php</tt> to enable it.' );
 281                 }
 282
 283                 wfProfileIn( __METHOD__ );
 284
 285                 // Get core test suites
 286                 $testModules = array();
 287                 $testModules['qunit'] = include "$IP/tests/qunit/QUnitTestResources.php";
 288                 // Get other test suites (e.g. from extensions)
 289                 wfRunHooks( 'ResourceLoaderTestModules', array( &$testModules, &$this ) );
 290
 291                 // Add the testrunner (which configures QUnit) to the dependencies.
 292                 // Since it must be ready before any of the test suites are executed.
 293                 foreach ( $testModules['qunit'] as &$module ) {
 294                         // Make sure all test modules are top-loading so that when QUnit starts
 295                         // on document-ready, it will run once and finish. If some tests arrive
 296                         // later (possibly after QUnit has already finished) they will be ignored.
 297                         $module['position'] = 'top';
 298                         $module['dependencies'][] = 'mediawiki.tests.qunit.testrunner';
 299                 }
 300
 301                 foreach ( $testModules as $id => $names ) {
 302                         // Register test modules
 303                         $this->register( $testModules[$id] );
 304
 305                         // Keep track of their names so that they can be loaded together
 306                         $this->testModuleNames[$id] = array_keys( $testModules[$id] );
 307                 }
 308
 309                 wfProfileOut( __METHOD__ );
 310         }
 311
 312         /**
 313          * Add a foreign source of modules.
 314          *
 315          * Source properties:
 316          * 'loadScript': URL (either fully-qualified or protocol-relative) of load.php for this source
 317          *
 318          * @param $id Mixed: source ID (string), or array( id1 => props1, id2 => props2, ... )
 319          * @param array $properties source properties
 320          * @throws MWException
 321          */
 322         public function addSource( $id, $properties = null ) {
 323                 // Allow multiple sources to be registered in one call
 324                 if ( is_array( $id ) ) {
 325                         foreach ( $id as $key => $value ) {
 326                                 $this->addSource( $key, $value );
 327                         }
 328                         return;
 329                 }
 330
 331                 // Disallow duplicates
 332                 if ( isset( $this->sources[$id] ) ) {
 333                         throw new MWException(
 334                                 'ResourceLoader duplicate source addition error. ' .
 335                                 'Another source has already been registered as ' . $id
 336                         );
 337                 }
 338
 339                 // Validate properties
 340                 foreach ( self::$requiredSourceProperties as $prop ) {
 341                         if ( !isset( $properties[$prop] ) ) {
 342                                 throw new MWException( "Required property $prop missing from source ID $id" );
 343                         }
 344                 }
 345
 346                 $this->sources[$id] = $properties;
 347         }
 348
 349         /**
 350          * Get a list of module names
 351          *
 352          * @return Array: List of module names
 353          */
 354         public function getModuleNames() {
 355                 return array_keys( $this->moduleInfos );
 356         }
 357
 358         /**
 359          * Get a list of test module names for one (or all) frameworks.
 360          * If the given framework id is unknkown, or if the in-object variable is not an array,
 361          * then it will return an empty array.
 362          *
 363          * @param string $framework Optional. Get only the test module names for one
 364          * particular framework.
 365          * @return Array
 366          */
 367         public function getTestModuleNames( $framework = 'all' ) {
 368                 /// @todo api siteinfo prop testmodulenames modulenames
 369                 if ( $framework == 'all' ) {
 370                         return $this->testModuleNames;
 371                 } elseif ( isset( $this->testModuleNames[$framework] ) && is_array( $this->testModuleNames[$framework] ) ) {
 372                         return $this->testModuleNames[$framework];
 373                 } else {
 374                         return array();
 375                 }
 376         }
 377
 378         /**
 379          * Get the ResourceLoaderModule object for a given module name.
 380          *
 381          * @param string $name Module name
 382          * @return ResourceLoaderModule if module has been registered, null otherwise
 383          */
 384         public function getModule( $name ) {
 385                 if ( !isset( $this->modules[$name] ) ) {
 386                         if ( !isset( $this->moduleInfos[$name] ) ) {
 387                                 // No such module
 388                                 return null;
 389                         }
 390                         // Construct the requested object
 391                         $info = $this->moduleInfos[$name];
 392                         if ( isset( $info['object'] ) ) {
 393                                 // Object given in info array
 394                                 $object = $info['object'];
 395                         } else {
 396                                 if ( !isset( $info['class'] ) ) {
 397                                         $class = 'ResourceLoaderFileModule';
 398                                 } else {
 399                                         $class = $info['class'];
 400                                 }
 401                                 $object = new $class( $info );
 402                         }
 403                         $object->setName( $name );
 404                         $this->modules[$name] = $object;
 405                 }
 406
 407                 return $this->modules[$name];
 408         }
 409
 410         /**
 411          * Get the list of sources
 412          *
 413          * @return Array: array( id => array of properties, .. )
 414          */
 415         public function getSources() {
 416                 return $this->sources;
 417         }
 418
 419         /**
 420          * Outputs a response to a resource load-request, including a content-type header.
 421          *
 422          * @param $context ResourceLoaderContext: Context in which a response should be formed
 423          */
 424         public function respond( ResourceLoaderContext $context ) {
 425                 global $wgCacheEpoch, $wgUseFileCache;
 426
 427                 // Use file cache if enabled and available...
 428                 if ( $wgUseFileCache ) {
 429                         $fileCache = ResourceFileCache::newFromContext( $context );
 430                         if ( $this->tryRespondFromFileCache( $fileCache, $context ) ) {
 431                                 return; // output handled
 432                         }
 433                 }
 434
 435                 // Buffer output to catch warnings. Normally we'd use ob_clean() on the
 436                 // top-level output buffer to clear warnings, but that breaks when ob_gzhandler
 437                 // is used: ob_clean() will clear the GZIP header in that case and it won't come
 438                 // back for subsequent output, resulting in invalid GZIP. So we have to wrap
 439                 // the whole thing in our own output buffer to be sure the active buffer
 440                 // doesn't use ob_gzhandler.
 441                 // See http://bugs.php.net/bug.php?id=36514
 442                 ob_start();
 443
 444                 wfProfileIn( __METHOD__ );
 445                 $errors = '';
 446                 $this->hasErrors = false;
 447
 448                 // Split requested modules into two groups, modules and missing
 449                 $modules = array();
 450                 $missing = array();
 451                 foreach ( $context->getModules() as $name ) {
 452                         if ( isset( $this->moduleInfos[$name] ) ) {
 453                                 $module = $this->getModule( $name );
 454                                 // Do not allow private modules to be loaded from the web.
 455                                 // This is a security issue, see bug 34907.
 456                                 if ( $module->getGroup() === 'private' ) {
 457                                         wfDebugLog( 'resourceloader', __METHOD__ . ": request for private module denied: $e" );
 458                                         $this->hasErrors = true;
 459                                         // Add exception to the output as a comment
 460                                         $errors .= $this->makeComment( "Cannot show private module \"$name\"" );
 461
 462                                         continue;
 463                                 }
 464                                 $modules[$name] = $module;
 465                         } else {
 466                                 $missing[] = $name;
 467                         }
 468                 }
 469
 470                 // Preload information needed to the mtime calculation below
 471                 try {
 472                         $this->preloadModuleInfo( array_keys( $modules ), $context );
 473                 } catch ( Exception $e ) {
 474                         wfDebugLog( 'resourceloader', __METHOD__ . ": preloading module info failed: $e" );
 475                         $this->hasErrors = true;
 476                         // Add exception to the output as a comment
 477                         $errors .= $this->makeComment( $e->__toString() );
 478                 }
 479
 480                 wfProfileIn( __METHOD__ . '-getModifiedTime' );
 481
 482                 // To send Last-Modified and support If-Modified-Since, we need to detect
 483                 // the last modified time
 484                 $mtime = wfTimestamp( TS_UNIX, $wgCacheEpoch );
 485                 foreach ( $modules as $module ) {
 486                         /**
 487                          * @var $module ResourceLoaderModule
 488                          */
 489                         try {
 490                                 // Calculate maximum modified time
 491                                 $mtime = max( $mtime, $module->getModifiedTime( $context ) );
 492                         } catch ( Exception $e ) {
 493                                 wfDebugLog( 'resourceloader', __METHOD__ . ": calculating maximum modified time failed: $e" );
 494                                 $this->hasErrors = true;
 495                                 // Add exception to the output as a comment
 496                                 $errors .= $this->makeComment( $e->__toString() );
 497                         }
 498                 }
 499
 500                 wfProfileOut( __METHOD__ . '-getModifiedTime' );
 501
 502                 // If there's an If-Modified-Since header, respond with a 304 appropriately
 503                 if ( $this->tryRespondLastModified( $context, $mtime ) ) {
 504                         wfProfileOut( __METHOD__ );
 505                         return; // output handled (buffers cleared)
 506                 }
 507
 508                 // Generate a response
 509                 $response = $this->makeModuleResponse( $context, $modules, $missing );
 510
 511                 // Prepend comments indicating exceptions
 512                 $response = $errors . $response;
 513
 514                 // Capture any PHP warnings from the output buffer and append them to the
 515                 // response in a comment if we're in debug mode.
 516                 if ( $context->getDebug() && strlen( $warnings = ob_get_contents() ) ) {
 517                         $response = $this->makeComment( $warnings ) . $response;
 518                         $this->hasErrors = true;
 519                 }
 520
 521                 // Save response to file cache unless there are errors
 522                 if ( isset( $fileCache ) && !$errors && !$missing ) {
 523                         // Cache single modules...and other requests if there are enough hits
 524                         if ( ResourceFileCache::useFileCache( $context ) ) {
 525                                 if ( $fileCache->isCacheWorthy() ) {
 526                                         $fileCache->saveText( $response );
 527                                 } else {
 528                                         $fileCache->incrMissesRecent( $context->getRequest() );
 529                                 }
 530                         }
 531                 }
 532
 533                 // Send content type and cache related headers
 534                 $this->sendResponseHeaders( $context, $mtime, $this->hasErrors );
 535
 536                 // Remove the output buffer and output the response
 537                 ob_end_clean();
 538                 echo $response;
 539
 540                 wfProfileOut( __METHOD__ );
 541         }
 542
 543         /**
 544          * Send content type and last modified headers to the client.
 545          * @param $context ResourceLoaderContext
 546          * @param string $mtime TS_MW timestamp to use for last-modified
 547          * @param bool $error Whether there are commented-out errors in the response
 548          * @return void
 549          */
 550         protected function sendResponseHeaders( ResourceLoaderContext $context, $mtime, $errors ) {
 551                 global $wgResourceLoaderMaxage;
 552                 // If a version wasn't specified we need a shorter expiry time for updates
 553                 // to propagate to clients quickly
 554                 // If there were errors, we also need a shorter expiry time so we can recover quickly
 555                 if ( is_null( $context->getVersion() ) || $errors ) {
 556                         $maxage = $wgResourceLoaderMaxage['unversioned']['client'];
 557                         $smaxage = $wgResourceLoaderMaxage['unversioned']['server'];
 558                 // If a version was specified we can use a longer expiry time since changing
 559                 // version numbers causes cache misses
 560                 } else {
 561                         $maxage = $wgResourceLoaderMaxage['versioned']['client'];
 562                         $smaxage = $wgResourceLoaderMaxage['versioned']['server'];
 563                 }
 564                 if ( $context->getOnly() === 'styles' ) {
 565                         header( 'Content-Type: text/css; charset=utf-8' );
 566                         header( 'Access-Control-Allow-Origin: *' );
 567                 } else {
 568                         header( 'Content-Type: text/javascript; charset=utf-8' );
 569                 }
 570                 header( 'Last-Modified: ' . wfTimestamp( TS_RFC2822, $mtime ) );
 571                 if ( $context->getDebug() ) {
 572                         // Do not cache debug responses
 573                         header( 'Cache-Control: private, no-cache, must-revalidate' );
 574                         header( 'Pragma: no-cache' );
 575                 } else {
 576                         header( "Cache-Control: public, max-age=$maxage, s-maxage=$smaxage" );
 577                         $exp = min( $maxage, $smaxage );
 578                         header( 'Expires: ' . wfTimestamp( TS_RFC2822, $exp + time() ) );
 579                 }
 580         }
 581
 582         /**
 583          * If there's an If-Modified-Since header, respond with a 304 appropriately
 584          * and clear out the output buffer. If the client cache is too old then do nothing.
 585          * @param $context ResourceLoaderContext
 586          * @param string $mtime The TS_MW timestamp to check the header against
 587          * @return bool True iff 304 header sent and output handled
 588          */
 589         protected function tryRespondLastModified( ResourceLoaderContext $context, $mtime ) {
 590                 // If there's an If-Modified-Since header, respond with a 304 appropriately
 591                 // Some clients send "timestamp;length=123". Strip the part after the first ';'
 592                 // so we get a valid timestamp.
 593                 $ims = $context->getRequest()->getHeader( 'If-Modified-Since' );
 594                 // Never send 304s in debug mode
 595                 if ( $ims !== false && !$context->getDebug() ) {
 596                         $imsTS = strtok( $ims, ';' );
 597                         if ( $mtime <= wfTimestamp( TS_UNIX, $imsTS ) ) {
 598                                 // There's another bug in ob_gzhandler (see also the comment at
 599                                 // the top of this function) that causes it to gzip even empty
 600                                 // responses, meaning it's impossible to produce a truly empty
 601                                 // response (because the gzip header is always there). This is
 602                                 // a problem because 304 responses have to be completely empty
 603                                 // per the HTTP spec, and Firefox behaves buggily when they're not.
 604                                 // See also http://bugs.php.net/bug.php?id=51579
 605                                 // To work around this, we tear down all output buffering before
 606                                 // sending the 304.
 607                                 // On some setups, ob_get_level() doesn't seem to go down to zero
 608                                 // no matter how often we call ob_get_clean(), so instead of doing
 609                                 // the more intuitive while ( ob_get_level() > 0 ) ob_get_clean();
 610                                 // we have to be safe here and avoid an infinite loop.
 611                                 // Caching the level is not an option, need to allow it to
 612                                 // shorten the loop on-the-fly (bug 46836)
 613                                 for ( $i = 0; $i < ob_get_level(); $i++ ) {
 614                                         ob_end_clean();
 615                                 }
 616
 617                                 header( 'HTTP/1.0 304 Not Modified' );
 618                                 header( 'Status: 304 Not Modified' );
 619                                 return true;
 620                         }
 621                 }
 622                 return false;
 623         }
 624
 625         /**
 626          * Send out code for a response from file cache if possible
 627          *
 628          * @param $fileCache ResourceFileCache: Cache object for this request URL
 629          * @param $context ResourceLoaderContext: Context in which to generate a response
 630          * @return bool If this found a cache file and handled the response
 631          */
 632         protected function tryRespondFromFileCache(
 633                 ResourceFileCache $fileCache, ResourceLoaderContext $context
 634         ) {
 635                 global $wgResourceLoaderMaxage;
 636                 // Buffer output to catch warnings.
 637                 ob_start();
 638                 // Get the maximum age the cache can be
 639                 $maxage = is_null( $context->getVersion() )
 640                         ? $wgResourceLoaderMaxage['unversioned']['server']
 641                         : $wgResourceLoaderMaxage['versioned']['server'];
 642                 // Minimum timestamp the cache file must have
 643                 $good = $fileCache->isCacheGood( wfTimestamp( TS_MW, time() - $maxage ) );
 644                 if ( !$good ) {
 645                         try { // RL always hits the DB on file cache miss...
 646                                 wfGetDB( DB_SLAVE );
 647                         } catch ( DBConnectionError $e ) { // ...check if we need to fallback to cache
 648                                 $good = $fileCache->isCacheGood(); // cache existence check
 649                         }
 650                 }
 651                 if ( $good ) {
 652                         $ts = $fileCache->cacheTimestamp();
 653                         // Send content type and cache headers
 654                         $this->sendResponseHeaders( $context, $ts, false );
 655                         // If there's an If-Modified-Since header, respond with a 304 appropriately
 656                         if ( $this->tryRespondLastModified( $context, $ts ) ) {
 657                                 return false; // output handled (buffers cleared)
 658                         }
 659                         $response = $fileCache->fetchText();
 660                         // Capture any PHP warnings from the output buffer and append them to the
 661                         // response in a comment if we're in debug mode.
 662                         if ( $context->getDebug() && strlen( $warnings = ob_get_contents() ) ) {
 663                                 $response = "/*\n$warnings\n*/\n" . $response;
 664                         }
 665                         // Remove the output buffer and output the response
 666                         ob_end_clean();
 667                         echo $response . "\n/* Cached {$ts} */";
 668                         return true; // cache hit
 669                 }
 670                 // Clear buffer
 671                 ob_end_clean();
 672
 673                 return false; // cache miss
 674         }
 675
 676         protected function makeComment( $text ) {
 677                 $encText = str_replace( '*/', '* /', $text );
 678                 return "/*\n$encText\n*/\n";
 679         }
 680
 681         /**
 682          * Generates code for a response
 683          *
 684          * @param $context ResourceLoaderContext: Context in which to generate a response
 685          * @param array $modules List of module objects keyed by module name
 686          * @param array $missing List of unavailable modules (optional)
 687          * @return String: Response data
 688          */
 689         public function makeModuleResponse( ResourceLoaderContext $context,
 690                 array $modules, $missing = array()
 691         ) {
 692                 $out = '';
 693                 $exceptions = '';
 694                 if ( $modules === array() && $missing === array() ) {
 695                         return '/* No modules requested. Max made me put this here */';
 696                 }
 697
 698                 wfProfileIn( __METHOD__ );
 699                 // Pre-fetch blobs
 700                 if ( $context->shouldIncludeMessages() ) {
 701                         try {
 702                                 $blobs = MessageBlobStore::get( $this, $modules, $context->getLanguage() );
 703                         } catch ( Exception $e ) {
 704                                 wfDebugLog( 'resourceloader', __METHOD__ . ": pre-fetching blobs from MessageBlobStore failed: $e" );
 705                                 $this->hasErrors = true;
 706                                 // Add exception to the output as a comment
 707                                 $exceptions .= $this->makeComment( $e->__toString() );
 708                         }
 709                 } else {
 710                         $blobs = array();
 711                 }
 712
 713                 // Generate output
 714                 $isRaw = false;
 715                 foreach ( $modules as $name => $module ) {
 716                         /**
 717                          * @var $module ResourceLoaderModule
 718                          */
 719
 720                         wfProfileIn( __METHOD__ . '-' . $name );
 721                         try {
 722                                 $scripts = '';
 723                                 if ( $context->shouldIncludeScripts() ) {
 724                                         // If we are in debug mode, we'll want to return an array of URLs if possible
 725                                         // However, we can't do this if the module doesn't support it
 726                                         // We also can't do this if there is an only= parameter, because we have to give
 727                                         // the module a way to return a load.php URL without causing an infinite loop
 728                                         if ( $context->getDebug() && !$context->getOnly() && $module->supportsURLLoading() ) {
 729                                                 $scripts = $module->getScriptURLsForDebug( $context );
 730                                         } else {
 731                                                 $scripts = $module->getScript( $context );
 732                                                 if ( is_string( $scripts ) && strlen( $scripts ) && substr( $scripts, -1 ) !== ';' ) {
 733                                                         // bug 27054: Append semicolon to prevent weird bugs
 734                                                         // caused by files not terminating their statements right
 735                                                         $scripts .= ";\n";
 736                                                 }
 737                                         }
 738                                 }
 739                                 // Styles
 740                                 $styles = array();
 741                                 if ( $context->shouldIncludeStyles() ) {
 742                                         // Don't create empty stylesheets like array( '' => '' ) for modules
 743                                         // that don't *have* any stylesheets (bug 38024).
 744                                         $stylePairs = $module->getStyles( $context );
 745                                         if ( count ( $stylePairs ) ) {
 746                                                 // If we are in debug mode without &only= set, we'll want to return an array of URLs
 747                                                 // See comment near shouldIncludeScripts() for more details
 748                                                 if ( $context->getDebug() && !$context->getOnly() && $module->supportsURLLoading() ) {
 749                                                         $styles = array(
 750                                                                 'url' => $module->getStyleURLsForDebug( $context )
 751                                                         );
 752                                                 } else {
 753                                                         // Minify CSS before embedding in mw.loader.implement call
 754                                                         // (unless in debug mode)
 755                                                         if ( !$context->getDebug() ) {
 756                                                                 foreach ( $stylePairs as $media => $style ) {
 757                                                                         // Can be either a string or an array of strings.
 758                                                                         if ( is_array( $style ) ) {
 759                                                                                 $stylePairs[$media] = array();
 760                                                                                 foreach ( $style as $cssText ) {
 761                                                                                         if ( is_string( $cssText ) ) {
 762                                                                                                 $stylePairs[$media][] = $this->filter( 'minify-css', $cssText );
 763                                                                                         }
 764                                                                                 }
 765                                                                         } elseif ( is_string( $style ) ) {
 766                                                                                 $stylePairs[$media] = $this->filter( 'minify-css', $style );
 767                                                                         }
 768                                                                 }
 769                                                         }
 770                                                         // Wrap styles into @media groups as needed and flatten into a numerical array
 771                                                         $styles = array(
 772                                                                 'css' => self::makeCombinedStyles( $stylePairs )
 773                                                         );
 774                                                 }
 775                                         }
 776                                 }
 777
 778                                 // Messages
 779                                 $messagesBlob = isset( $blobs[$name] ) ? $blobs[$name] : '{}';
 780
 781                                 // Append output
 782                                 switch ( $context->getOnly() ) {
 783                                         case 'scripts':
 784                                                 if ( is_string( $scripts ) ) {
 785                                                         // Load scripts raw...
 786                                                         $out .= $scripts;
 787                                                 } elseif ( is_array( $scripts ) ) {
 788                                                         // ...except when $scripts is an array of URLs
 789                                                         $out .= self::makeLoaderImplementScript( $name, $scripts, array(), array() );
 790                                                 }
 791                                                 break;
 792                                         case 'styles':
 793                                                 // We no longer seperate into media, they are all combined now with
 794                                                 // custom media type groups into @media .. {} sections as part of the css string.
 795                                                 // Module returns either an empty array or a numerical array with css strings.
 796                                                 $out .= isset( $styles['css'] ) ? implode( '', $styles['css'] ) : '';
 797                                                 break;
 798                                         case 'messages':
 799                                                 $out .= self::makeMessageSetScript( new XmlJsCode( $messagesBlob ) );
 800                                                 break;
 801                                         default:
 802                                                 $out .= self::makeLoaderImplementScript(
 803                                                         $name,
 804                                                         $scripts,
 805                                                         $styles,
 806                                                         new XmlJsCode( $messagesBlob )
 807                                                 );
 808                                                 break;
 809                                 }
 810                         } catch ( Exception $e ) {
 811                                 wfDebugLog( 'resourceloader', __METHOD__ . ": generating module package failed: $e" );
 812                                 $this->hasErrors = true;
 813                                 // Add exception to the output as a comment
 814                                 $exceptions .= $this->makeComment( $e->__toString() );
 815
 816                                 // Register module as missing
 817                                 $missing[] = $name;
 818                                 unset( $modules[$name] );
 819                         }
 820                         $isRaw |= $module->isRaw();
 821                         wfProfileOut( __METHOD__ . '-' . $name );
 822                 }
 823
 824                 // Update module states
 825                 if ( $context->shouldIncludeScripts() && !$context->getRaw() && !$isRaw ) {
 826                         // Set the state of modules loaded as only scripts to ready
 827                         if ( count( $modules ) && $context->getOnly() === 'scripts' ) {
 828                                 $out .= self::makeLoaderStateScript(
 829                                         array_fill_keys( array_keys( $modules ), 'ready' ) );
 830                         }
 831                         // Set the state of modules which were requested but unavailable as missing
 832                         if ( is_array( $missing ) && count( $missing ) ) {
 833                                 $out .= self::makeLoaderStateScript( array_fill_keys( $missing, 'missing' ) );
 834                         }
 835                 }
 836
 837                 if ( !$context->getDebug() ) {
 838                         if ( $context->getOnly() === 'styles' ) {
 839                                 $out = $this->filter( 'minify-css', $out );
 840                         } else {
 841                                 $out = $this->filter( 'minify-js', $out );
 842                         }
 843                 }
 844
 845                 wfProfileOut( __METHOD__ );
 846                 return $exceptions . $out;
 847         }
 848
 849         /* Static Methods */
 850
 851         /**
 852          * Returns JS code to call to mw.loader.implement for a module with
 853          * given properties.
 854          *
 855          * @param string $name Module name
 856          * @param $scripts Mixed: List of URLs to JavaScript files or String of JavaScript code
 857          * @param $styles Mixed: Array of CSS strings keyed by media type, or an array of lists of URLs to
 858          * CSS files keyed by media type
 859          * @param $messages Mixed: List of messages associated with this module. May either be an
 860          *     associative array mapping message key to value, or a JSON-encoded message blob containing
 861          *     the same data, wrapped in an XmlJsCode object.
 862          *
 863          * @throws MWException
 864          * @return string
 865          */
 866         public static function makeLoaderImplementScript( $name, $scripts, $styles, $messages ) {
 867                 if ( is_string( $scripts ) ) {
 868                         $scripts = new XmlJsCode( "function () {\n{$scripts}\n}" );
 869                 } elseif ( !is_array( $scripts ) ) {
 870                         throw new MWException( 'Invalid scripts error. Array of URLs or string of code expected.' );
 871                 }
 872                 return Xml::encodeJsCall(
 873                         'mw.loader.implement',
 874                         array(
 875                                 $name,
 876                                 $scripts,
 877                                 // Force objects. mw.loader.implement requires them to be javascript objects.
 878                                 // Although these variables are associative arrays, which become javascript
 879                                 // objects through json_encode. In many cases they will be empty arrays, and
 880                                 // PHP/json_encode() consider empty arrays to be numerical arrays and
 881                                 // output javascript "[]" instead of "{}". This fixes that.
 882                                 (object)$styles,
 883                                 (object)$messages
 884                         ),
 885                         ResourceLoader::inDebugMode()
 886                 );
 887         }
 888
 889         /**
 890          * Returns JS code which, when called, will register a given list of messages.
 891          *
 892          * @param $messages Mixed: Either an associative array mapping message key to value, or a
 893          *     JSON-encoded message blob containing the same data, wrapped in an XmlJsCode object.
 894          *
 895          * @return string
 896          */
 897         public static function makeMessageSetScript( $messages ) {
 898                 return Xml::encodeJsCall( 'mw.messages.set', array( (object)$messages ) );
 899         }
 900
 901         /**
 902          * Combines an associative array mapping media type to CSS into a
 903          * single stylesheet with "@media" blocks.
 904          *
 905          * @param array $stylePairs Array keyed by media type containing (arrays of) CSS strings.
 906          *
 907          * @return Array
 908          */
 909         private static function makeCombinedStyles( array $stylePairs ) {
 910                 $out = array();
 911                 foreach ( $stylePairs as $media => $styles ) {
 912                         // ResourceLoaderFileModule::getStyle can return the styles
 913                         // as a string or an array of strings. This is to allow separation in
 914                         // the front-end.
 915                         $styles = (array)$styles;
 916                         foreach ( $styles as $style ) {
 917                                 $style = trim( $style );
 918                                 // Don't output an empty "@media print { }" block (bug 40498)
 919                                 if ( $style !== '' ) {
 920                                         // Transform the media type based on request params and config
 921                                         // The way that this relies on $wgRequest to propagate request params is slightly evil
 922                                         $media = OutputPage::transformCssMedia( $media );
 923
 924                                         if ( $media === '' || $media == 'all' ) {
 925                                                 $out[] = $style;
 926                                         } elseif ( is_string( $media ) ) {
 927                                                 $out[] = "@media $media {\n" . str_replace( "\n", "\n\t", "\t" . $style ) . "}";
 928                                         }
 929                                         // else: skip
 930                                 }
 931                         }
 932                 }
 933                 return $out;
 934         }
 935
 936         /**
 937          * Returns a JS call to mw.loader.state, which sets the state of a
 938          * module or modules to a given value. Has two calling conventions:
 939          *
 940          *    - ResourceLoader::makeLoaderStateScript( $name, $state ):
 941          *         Set the state of a single module called $name to $state
 942          *
 943          *    - ResourceLoader::makeLoaderStateScript( array( $name => $state, ... ) ):
 944          *         Set the state of modules with the given names to the given states
 945          *
 946          * @param $name string
 947          * @param $state
 948          *
 949          * @return string
 950          */
 951         public static function makeLoaderStateScript( $name, $state = null ) {
 952                 if ( is_array( $name ) ) {
 953                         return Xml::encodeJsCall( 'mw.loader.state', array( $name ) );
 954                 } else {
 955                         return Xml::encodeJsCall( 'mw.loader.state', array( $name, $state ) );
 956                 }
 957         }
 958
 959         /**
 960          * Returns JS code which calls the script given by $script. The script will
 961          * be called with local variables name, version, dependencies and group,
 962          * which will have values corresponding to $name, $version, $dependencies
 963          * and $group as supplied.
 964          *
 965          * @param string $name Module name
 966          * @param $version Integer: Module version number as a timestamp
 967          * @param array $dependencies List of module names on which this module depends
 968          * @param string $group Group which the module is in.
 969          * @param string $source Source of the module, or 'local' if not foreign.
 970          * @param string $script JavaScript code
 971          *
 972          * @return string
 973          */
 974         public static function makeCustomLoaderScript( $name, $version, $dependencies, $group, $source, $script ) {
 975                 $script = str_replace( "\n", "\n\t", trim( $script ) );
 976                 return Xml::encodeJsCall(
 977                         "( function ( name, version, dependencies, group, source ) {\n\t$script\n} )",
 978                         array( $name, $version, $dependencies, $group, $source ) );
 979         }
 980
 981         /**
 982          * Returns JS code which calls mw.loader.register with the given
 983          * parameters. Has three calling conventions:
 984          *
 985          *   - ResourceLoader::makeLoaderRegisterScript( $name, $version, $dependencies, $group, $source ):
 986          *       Register a single module.
 987          *
 988          *   - ResourceLoader::makeLoaderRegisterScript( array( $name1, $name2 ) ):
 989          *       Register modules with the given names.
 990          *
 991          *   - ResourceLoader::makeLoaderRegisterScript( array(
 992          *        array( $name1, $version1, $dependencies1, $group1, $source1 ),
 993          *        array( $name2, $version2, $dependencies1, $group2, $source2 ),
 994          *        ...
 995          *     ) ):
 996          *        Registers modules with the given names and parameters.
 997          *
 998          * @param string $name Module name
 999          * @param $version Integer: Module version number as a timestamp
1000          * @param array $dependencies List of module names on which this module depends
1001          * @param string $group group which the module is in.
1002          * @param string $source source of the module, or 'local' if not foreign
1003          *
1004          * @return string
1005          */
1006         public static function makeLoaderRegisterScript( $name, $version = null,
1007                 $dependencies = null, $group = null, $source = null
1008         ) {
1009                 if ( is_array( $name ) ) {
1010                         return Xml::encodeJsCall( 'mw.loader.register', array( $name ) );
1011                 } else {
1012                         $version = (int)$version > 1 ? (int)$version : 1;
1013                         return Xml::encodeJsCall( 'mw.loader.register',
1014                                 array( $name, $version, $dependencies, $group, $source ) );
1015                 }
1016         }
1017
1018         /**
1019          * Returns JS code which calls mw.loader.addSource() with the given
1020          * parameters. Has two calling conventions:
1021          *
1022          *   - ResourceLoader::makeLoaderSourcesScript( $id, $properties ):
1023          *       Register a single source
1024          *
1025          *   - ResourceLoader::makeLoaderSourcesScript( array( $id1 => $props1, $id2 => $props2, ... ) );
1026          *       Register sources with the given IDs and properties.
1027          *
1028          * @param string $id source ID
1029          * @param array $properties source properties (see addSource())
1030          *
1031          * @return string
1032          */
1033         public static function makeLoaderSourcesScript( $id, $properties = null ) {
1034                 if ( is_array( $id ) ) {
1035                         return Xml::encodeJsCall( 'mw.loader.addSource', array( $id ) );
1036                 } else {
1037                         return Xml::encodeJsCall( 'mw.loader.addSource', array( $id, $properties ) );
1038                 }
1039         }
1040
1041         /**
1042          * Returns JS code which runs given JS code if the client-side framework is
1043          * present.
1044          *
1045          * @param string $script JavaScript code
1046          *
1047          * @return string
1048          */
1049         public static function makeLoaderConditionalScript( $script ) {
1050                 return "if(window.mw){\n" . trim( $script ) . "\n}";
1051         }
1052
1053         /**
1054          * Returns JS code which will set the MediaWiki configuration array to
1055          * the given value.
1056          *
1057          * @param array $configuration List of configuration values keyed by variable name
1058          *
1059          * @return string
1060          */
1061         public static function makeConfigSetScript( array $configuration ) {
1062                 return Xml::encodeJsCall( 'mw.config.set', array( $configuration ), ResourceLoader::inDebugMode() );
1063         }
1064
1065         /**
1066          * Convert an array of module names to a packed query string.
1067          *
1068          * For example, array( 'foo.bar', 'foo.baz', 'bar.baz', 'bar.quux' )
1069          * becomes 'foo.bar,baz|bar.baz,quux'
1070          * @param array $modules of module names (strings)
1071          * @return string Packed query string
1072          */
1073         public static function makePackedModulesString( $modules ) {
1074                 $groups = array(); // array( prefix => array( suffixes ) )
1075                 foreach ( $modules as $module ) {
1076                         $pos = strrpos( $module, '.' );
1077                         $prefix = $pos === false ? '' : substr( $module, 0, $pos );
1078                         $suffix = $pos === false ? $module : substr( $module, $pos + 1 );
1079                         $groups[$prefix][] = $suffix;
1080                 }
1081
1082                 $arr = array();
1083                 foreach ( $groups as $prefix => $suffixes ) {
1084                         $p = $prefix === '' ? '' : $prefix . '.';
1085                         $arr[] = $p . implode( ',', $suffixes );
1086                 }
1087                 $str = implode( '|', $arr );
1088                 return $str;
1089         }
1090
1091         /**
1092          * Determine whether debug mode was requested
1093          * Order of priority is 1) request param, 2) cookie, 3) $wg setting
1094          * @return bool
1095          */
1096         public static function inDebugMode() {
1097                 global $wgRequest, $wgResourceLoaderDebug;
1098                 static $retval = null;
1099                 if ( !is_null( $retval ) ) {
1100                         return $retval;
1101                 }
1102                 return $retval = $wgRequest->getFuzzyBool( 'debug',
1103                         $wgRequest->getCookie( 'resourceLoaderDebug', '', $wgResourceLoaderDebug ) );
1104         }
1105
1106         /**
1107          * Build a load.php URL
1108          * @param array $modules of module names (strings)
1109          * @param string $lang Language code
1110          * @param string $skin Skin name
1111          * @param string|null $user User name. If null, the &user= parameter is omitted
1112          * @param string|null $version Versioning timestamp
1113          * @param bool $debug Whether the request should be in debug mode
1114          * @param string|null $only &only= parameter
1115          * @param bool $printable Printable mode
1116          * @param bool $handheld Handheld mode
1117          * @param array $extraQuery Extra query parameters to add
1118          * @return string URL to load.php. May be protocol-relative (if $wgLoadScript is procol-relative)
1119          */
1120         public static function makeLoaderURL( $modules, $lang, $skin, $user = null, $version = null, $debug = false, $only = null,
1121                         $printable = false, $handheld = false, $extraQuery = array() ) {
1122                 global $wgLoadScript;
1123                 $query = self::makeLoaderQuery( $modules, $lang, $skin, $user, $version, $debug,
1124                         $only, $printable, $handheld, $extraQuery
1125                 );
1126
1127                 // Prevent the IE6 extension check from being triggered (bug 28840)
1128                 // by appending a character that's invalid in Windows extensions ('*')
1129                 return wfExpandUrl( wfAppendQuery( $wgLoadScript, $query ) . '&*', PROTO_RELATIVE );
1130         }
1131
1132         /**
1133          * Build a query array (array representation of query string) for load.php. Helper
1134          * function for makeLoaderURL().
1135          * @return array
1136          */
1137         public static function makeLoaderQuery( $modules, $lang, $skin, $user = null, $version = null, $debug = false, $only = null,
1138                         $printable = false, $handheld = false, $extraQuery = array() ) {
1139                 $query = array(
1140                         'modules' => self::makePackedModulesString( $modules ),
1141                         'lang' => $lang,
1142                         'skin' => $skin,
1143                         'debug' => $debug ? 'true' : 'false',
1144                 );
1145                 if ( $user !== null ) {
1146                         $query['user'] = $user;
1147                 }
1148                 if ( $version !== null ) {
1149                         $query['version'] = $version;
1150                 }
1151                 if ( $only !== null ) {
1152                         $query['only'] = $only;
1153                 }
1154                 if ( $printable ) {
1155                         $query['printable'] = 1;
1156                 }
1157                 if ( $handheld ) {
1158                         $query['handheld'] = 1;
1159                 }
1160                 $query += $extraQuery;
1161
1162                 // Make queries uniform in order
1163                 ksort( $query );
1164                 return $query;
1165         }
1166
1167         /**
1168          * Check a module name for validity.
1169          *
1170          * Module names may not contain pipes (|), commas (,) or exclamation marks (!) and can be
1171          * at most 255 bytes.
1172          *
1173          * @param string $moduleName Module name to check
1174          * @return bool Whether $moduleName is a valid module name
1175          */
1176         public static function isValidModuleName( $moduleName ) {
1177                 return !preg_match( '/[|,!]/', $moduleName ) && strlen( $moduleName ) <= 255;
1178         }
1179 }