includes/resourceloader/ResourceLoaderModule.php

   1 <?php
   2 /**
   3  * Abstraction for resource loader modules.
   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 Trevor Parscal
  22  * @author Roan Kattouw
  23  */
  24
  25 /**
  26  * Abstraction for resource loader modules, with name registration and maxage functionality.
  27  */
  28 abstract class ResourceLoaderModule {
  29         # Type of resource
  30         const TYPE_SCRIPTS = 'scripts';
  31         const TYPE_STYLES = 'styles';
  32         const TYPE_COMBINED = 'combined';
  33
  34         # sitewide core module like a skin file or jQuery component
  35         const ORIGIN_CORE_SITEWIDE = 1;
  36
  37         # per-user module generated by the software
  38         const ORIGIN_CORE_INDIVIDUAL = 2;
  39
  40         # sitewide module generated from user-editable files, like MediaWiki:Common.js, or
  41         # modules accessible to multiple users, such as those generated by the Gadgets extension.
  42         const ORIGIN_USER_SITEWIDE = 3;
  43
  44         # per-user module generated from user-editable files, like User:Me/vector.js
  45         const ORIGIN_USER_INDIVIDUAL = 4;
  46
  47         # an access constant; make sure this is kept as the largest number in this group
  48         const ORIGIN_ALL = 10;
  49
  50         # script and style modules form a hierarchy of trustworthiness, with core modules like
  51         # skins and jQuery as most trustworthy, and user scripts as least trustworthy.  We can
  52         # limit the types of scripts and styles we allow to load on, say, sensitive special
  53         # pages like Special:UserLogin and Special:Preferences
  54         protected $origin = self::ORIGIN_CORE_SITEWIDE;
  55
  56         /* Protected Members */
  57
  58         protected $name = null;
  59         protected $targets = array( 'desktop' );
  60
  61         // In-object cache for file dependencies
  62         protected $fileDeps = array();
  63         // In-object cache for message blob mtime
  64         protected $msgBlobMtime = array();
  65         // In-object cache for version hash
  66         protected $versionHash = array();
  67
  68         /**
  69          * @var Config
  70          */
  71         protected $config;
  72
  73         /* Methods */
  74
  75         /**
  76          * Get this module's name. This is set when the module is registered
  77          * with ResourceLoader::register()
  78          *
  79          * @return string|null Name (string) or null if no name was set
  80          */
  81         public function getName() {
  82                 return $this->name;
  83         }
  84
  85         /**
  86          * Set this module's name. This is called by ResourceLoader::register()
  87          * when registering the module. Other code should not call this.
  88          *
  89          * @param string $name Name
  90          */
  91         public function setName( $name ) {
  92                 $this->name = $name;
  93         }
  94
  95         /**
  96          * Get this module's origin. This is set when the module is registered
  97          * with ResourceLoader::register()
  98          *
  99          * @return int ResourceLoaderModule class constant, the subclass default
 100          *     if not set manually
 101          */
 102         public function getOrigin() {
 103                 return $this->origin;
 104         }
 105
 106         /**
 107          * Set this module's origin. This is called by ResourceLoader::register()
 108          * when registering the module. Other code should not call this.
 109          *
 110          * @param int $origin Origin
 111          */
 112         public function setOrigin( $origin ) {
 113                 $this->origin = $origin;
 114         }
 115
 116         /**
 117          * @param ResourceLoaderContext $context
 118          * @return bool
 119          */
 120         public function getFlip( $context ) {
 121                 global $wgContLang;
 122
 123                 return $wgContLang->getDir() !== $context->getDirection();
 124         }
 125
 126         /**
 127          * Get all JS for this module for a given language and skin.
 128          * Includes all relevant JS except loader scripts.
 129          *
 130          * @param ResourceLoaderContext $context
 131          * @return string JavaScript code
 132          */
 133         public function getScript( ResourceLoaderContext $context ) {
 134                 // Stub, override expected
 135                 return '';
 136         }
 137
 138         /**
 139          * Takes named templates by the module and returns an array mapping.
 140          *
 141          * @return array of templates mapping template alias to content
 142          */
 143         public function getTemplates() {
 144                 // Stub, override expected.
 145                 return array();
 146         }
 147
 148         /**
 149          * @return Config
 150          * @since 1.24
 151          */
 152         public function getConfig() {
 153                 if ( $this->config === null ) {
 154                         // Ugh, fall back to default
 155                         $this->config = ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
 156                 }
 157
 158                 return $this->config;
 159         }
 160
 161         /**
 162          * @param Config $config
 163          * @since 1.24
 164          */
 165         public function setConfig( Config $config ) {
 166                 $this->config = $config;
 167         }
 168
 169         /**
 170          * Get the URL or URLs to load for this module's JS in debug mode.
 171          * The default behavior is to return a load.php?only=scripts URL for
 172          * the module, but file-based modules will want to override this to
 173          * load the files directly.
 174          *
 175          * This function is called only when 1) we're in debug mode, 2) there
 176          * is no only= parameter and 3) supportsURLLoading() returns true.
 177          * #2 is important to prevent an infinite loop, therefore this function
 178          * MUST return either an only= URL or a non-load.php URL.
 179          *
 180          * @param ResourceLoaderContext $context
 181          * @return array Array of URLs
 182          */
 183         public function getScriptURLsForDebug( ResourceLoaderContext $context ) {
 184                 $resourceLoader = $context->getResourceLoader();
 185                 $derivative = new DerivativeResourceLoaderContext( $context );
 186                 $derivative->setModules( array( $this->getName() ) );
 187                 $derivative->setOnly( 'scripts' );
 188                 $derivative->setDebug( true );
 189
 190                 $url = $resourceLoader->createLoaderURL(
 191                         $this->getSource(),
 192                         $derivative
 193                 );
 194
 195                 return array( $url );
 196         }
 197
 198         /**
 199          * Whether this module supports URL loading. If this function returns false,
 200          * getScript() will be used even in cases (debug mode, no only param) where
 201          * getScriptURLsForDebug() would normally be used instead.
 202          * @return bool
 203          */
 204         public function supportsURLLoading() {
 205                 return true;
 206         }
 207
 208         /**
 209          * Get all CSS for this module for a given skin.
 210          *
 211          * @param ResourceLoaderContext $context
 212          * @return array List of CSS strings or array of CSS strings keyed by media type.
 213          *  like array( 'screen' => '.foo { width: 0 }' );
 214          *  or array( 'screen' => array( '.foo { width: 0 }' ) );
 215          */
 216         public function getStyles( ResourceLoaderContext $context ) {
 217                 // Stub, override expected
 218                 return array();
 219         }
 220
 221         /**
 222          * Get the URL or URLs to load for this module's CSS in debug mode.
 223          * The default behavior is to return a load.php?only=styles URL for
 224          * the module, but file-based modules will want to override this to
 225          * load the files directly. See also getScriptURLsForDebug()
 226          *
 227          * @param ResourceLoaderContext $context
 228          * @return array Array( mediaType => array( URL1, URL2, ... ), ... )
 229          */
 230         public function getStyleURLsForDebug( ResourceLoaderContext $context ) {
 231                 $resourceLoader = $context->getResourceLoader();
 232                 $derivative = new DerivativeResourceLoaderContext( $context );
 233                 $derivative->setModules( array( $this->getName() ) );
 234                 $derivative->setOnly( 'styles' );
 235                 $derivative->setDebug( true );
 236
 237                 $url = $resourceLoader->createLoaderURL(
 238                         $this->getSource(),
 239                         $derivative
 240                 );
 241
 242                 return array( 'all' => array( $url ) );
 243         }
 244
 245         /**
 246          * Get the messages needed for this module.
 247          *
 248          * To get a JSON blob with messages, use MessageBlobStore::get()
 249          *
 250          * @return array List of message keys. Keys may occur more than once
 251          */
 252         public function getMessages() {
 253                 // Stub, override expected
 254                 return array();
 255         }
 256
 257         /**
 258          * Get the group this module is in.
 259          *
 260          * @return string Group name
 261          */
 262         public function getGroup() {
 263                 // Stub, override expected
 264                 return null;
 265         }
 266
 267         /**
 268          * Get the origin of this module. Should only be overridden for foreign modules.
 269          *
 270          * @return string Origin name, 'local' for local modules
 271          */
 272         public function getSource() {
 273                 // Stub, override expected
 274                 return 'local';
 275         }
 276
 277         /**
 278          * Where on the HTML page should this module's JS be loaded?
 279          *  - 'top': in the "<head>"
 280          *  - 'bottom': at the bottom of the "<body>"
 281          *
 282          * @return string
 283          */
 284         public function getPosition() {
 285                 return 'bottom';
 286         }
 287
 288         /**
 289          * Whether this module's JS expects to work without the client-side ResourceLoader module.
 290          * Returning true from this function will prevent mw.loader.state() call from being
 291          * appended to the bottom of the script.
 292          *
 293          * @return bool
 294          */
 295         public function isRaw() {
 296                 return false;
 297         }
 298
 299         /**
 300          * Get the loader JS for this module, if set.
 301          *
 302          * @return mixed JavaScript loader code as a string or boolean false if no custom loader set
 303          */
 304         public function getLoaderScript() {
 305                 // Stub, override expected
 306                 return false;
 307         }
 308
 309         /**
 310          * Get a list of modules this module depends on.
 311          *
 312          * Dependency information is taken into account when loading a module
 313          * on the client side.
 314          *
 315          * To add dependencies dynamically on the client side, use a custom
 316          * loader script, see getLoaderScript()
 317          * @return array List of module names as strings
 318          */
 319         public function getDependencies() {
 320                 // Stub, override expected
 321                 return array();
 322         }
 323
 324         /**
 325          * Get target(s) for the module, eg ['desktop'] or ['desktop', 'mobile']
 326          *
 327          * @return array Array of strings
 328          */
 329         public function getTargets() {
 330                 return $this->targets;
 331         }
 332
 333         /**
 334          * Get the skip function.
 335          *
 336          * Modules that provide fallback functionality can provide a "skip function". This
 337          * function, if provided, will be passed along to the module registry on the client.
 338          * When this module is loaded (either directly or as a dependency of another module),
 339          * then this function is executed first. If the function returns true, the module will
 340          * instantly be considered "ready" without requesting the associated module resources.
 341          *
 342          * The value returned here must be valid javascript for execution in a private function.
 343          * It must not contain the "function () {" and "}" wrapper though.
 344          *
 345          * @return string|null A JavaScript function body returning a boolean value, or null
 346          */
 347         public function getSkipFunction() {
 348                 return null;
 349         }
 350
 351         /**
 352          * Get the files this module depends on indirectly for a given skin.
 353          * Currently these are only image files referenced by the module's CSS.
 354          *
 355          * @param string $skin Skin name
 356          * @return array List of files
 357          */
 358         public function getFileDependencies( $skin ) {
 359                 // Try in-object cache first
 360                 if ( isset( $this->fileDeps[$skin] ) ) {
 361                         return $this->fileDeps[$skin];
 362                 }
 363
 364                 $dbr = wfGetDB( DB_SLAVE );
 365                 $deps = $dbr->selectField( 'module_deps', 'md_deps', array(
 366                                 'md_module' => $this->getName(),
 367                                 'md_skin' => $skin,
 368                         ), __METHOD__
 369                 );
 370                 if ( !is_null( $deps ) ) {
 371                         $this->fileDeps[$skin] = (array)FormatJson::decode( $deps, true );
 372                 } else {
 373                         $this->fileDeps[$skin] = array();
 374                 }
 375                 return $this->fileDeps[$skin];
 376         }
 377
 378         /**
 379          * Set preloaded file dependency information. Used so we can load this
 380          * information for all modules at once.
 381          * @param string $skin Skin name
 382          * @param array $deps Array of file names
 383          */
 384         public function setFileDependencies( $skin, $deps ) {
 385                 $this->fileDeps[$skin] = $deps;
 386         }
 387
 388         /**
 389          * Get the last modification timestamp of the messages in this module for a given language.
 390          * @param string $lang Language code
 391          * @return int UNIX timestamp
 392          */
 393         public function getMsgBlobMtime( $lang ) {
 394                 if ( !isset( $this->msgBlobMtime[$lang] ) ) {
 395                         if ( !count( $this->getMessages() ) ) {
 396                                 return 1;
 397                         }
 398
 399                         $dbr = wfGetDB( DB_SLAVE );
 400                         $msgBlobMtime = $dbr->selectField( 'msg_resource', 'mr_timestamp', array(
 401                                         'mr_resource' => $this->getName(),
 402                                         'mr_lang' => $lang
 403                                 ), __METHOD__
 404                         );
 405                         // If no blob was found, but the module does have messages, that means we need
 406                         // to regenerate it. Return NOW
 407                         if ( $msgBlobMtime === false ) {
 408                                 $msgBlobMtime = wfTimestampNow();
 409                         }
 410                         $this->msgBlobMtime[$lang] = wfTimestamp( TS_UNIX, $msgBlobMtime );
 411                 }
 412                 return $this->msgBlobMtime[$lang];
 413         }
 414
 415         /**
 416          * Set a preloaded message blob last modification timestamp. Used so we
 417          * can load this information for all modules at once.
 418          * @param string $lang Language code
 419          * @param int $mtime UNIX timestamp
 420          */
 421         public function setMsgBlobMtime( $lang, $mtime ) {
 422                 $this->msgBlobMtime[$lang] = $mtime;
 423         }
 424
 425         /**
 426          * Get a string identifying the current version of this module in a given context.
 427          *
 428          * Whenever anything happens that changes the module's response (e.g. scripts, styles, and
 429          * messages) this value must change. This value is used to store module responses in cache.
 430          * (Both client-side and server-side.)
 431          *
 432          * It is not recommended to override this directly. Use getDefinitionSummary() instead.
 433          * If overridden, one must call the parent getVersionHash(), append data and re-hash.
 434          *
 435          * This method should be quick because it is frequently run by ResourceLoaderStartUpModule to
 436          * propagate changes to the client and effectively invalidate cache.
 437          *
 438          * For backward-compatibility, the following optional data providers are automatically included:
 439          *
 440          * - getModifiedTime()
 441          * - getModifiedHash()
 442          *
 443          * @since 1.26
 444          * @param ResourceLoaderContext $context
 445          * @return string Hash (should use ResourceLoader::makeHash)
 446          */
 447         public function getVersionHash( ResourceLoaderContext $context ) {
 448                 // Cache this somewhat expensive operation. Especially because some classes
 449                 // (e.g. startup module) iterate more than once over all modules to get versions.
 450                 $contextHash = $context->getHash();
 451                 if ( !array_key_exists( $contextHash, $this->versionHash ) ) {
 452
 453                         $summary = $this->getDefinitionSummary( $context );
 454                         if ( !isset( $summary['_cacheEpoch'] ) ) {
 455                                 throw new Exception( 'getDefinitionSummary must call parent method' );
 456                         }
 457                         $str = json_encode( $summary );
 458
 459                         $mtime = $this->getModifiedTime( $context );
 460                         if ( $mtime !== null ) {
 461                                 // Support: MediaWiki 1.25 and earlier
 462                                 $str .= strval( $mtime );
 463                         }
 464
 465                         $mhash = $this->getModifiedHash( $context );
 466                         if ( $mhash !== null ) {
 467                                 // Support: MediaWiki 1.25 and earlier
 468                                 $str .= strval( $mhash );
 469                         }
 470
 471                         $this->versionHash[ $contextHash ] = ResourceLoader::makeHash( $str );
 472                 }
 473                 return $this->versionHash[ $contextHash ];
 474         }
 475
 476         /**
 477          * Get the definition summary for this module.
 478          *
 479          * This is the method subclasses are recommended to use to track values in their
 480          * version hash. Call this in getVersionHash() and pass it to e.g. json_encode.
 481          *
 482          * Subclasses must call the parent getDefinitionSummary() and build on that.
 483          * It is recommended that each subclass appends its own new array. This prevents
 484          * clashes or accidental overwrites of existing keys and gives each subclass
 485          * its own scope for simple array keys.
 486          *
 487          * @code
 488          *     $summary = parent::getDefinitionSummary( $context );
 489          *     $summary[] = array(
 490          *         'foo' => 123,
 491          *         'bar' => 'quux',
 492          *     );
 493          *     return $summary;
 494          * @endcode
 495          *
 496          * Return an array containing values from all significant properties of this
 497          * module's definition.
 498          *
 499          * Be careful not to normalise too much. Especially preserve the order of things
 500          * that carry significance in getScript and getStyles (T39812).
 501          *
 502          * Avoid including things that are insiginificant (e.g. order of message keys is
 503          * insignificant and should be sorted to avoid unnecessary cache invalidation).
 504          *
 505          * This data structure must exclusively contain arrays and scalars as values (avoid
 506          * object instances) to allow simple serialisation using json_encode.
 507          *
 508          * If modules have a hash or timestamp from another source, that may be incuded as-is.
 509          *
 510          * A number of utility methods are available to help you gather data. These are not
 511          * called by default and must be included by the subclass' getDefinitionSummary().
 512          *
 513          * - getMsgBlobMtime()
 514          *
 515          * @since 1.23
 516          * @param ResourceLoaderContext $context
 517          * @return array|null
 518          */
 519         public function getDefinitionSummary( ResourceLoaderContext $context ) {
 520                 return array(
 521                         '_class' => get_class( $this ),
 522                         '_cacheEpoch' => $this->getConfig()->get( 'CacheEpoch' ),
 523                 );
 524         }
 525
 526         /**
 527          * Get this module's last modification timestamp for a given context.
 528          *
 529          * @deprecated since 1.26 Use getDefinitionSummary() instead
 530          * @param ResourceLoaderContext $context Context object
 531          * @return int|null UNIX timestamp
 532          */
 533         public function getModifiedTime( ResourceLoaderContext $context ) {
 534                 return null;
 535         }
 536
 537         /**
 538          * Helper method for providing a version hash to getVersionHash().
 539          *
 540          * @deprecated since 1.26 Use getDefinitionSummary() instead
 541          * @param ResourceLoaderContext $context
 542          * @return string|null Hash
 543          */
 544         public function getModifiedHash( ResourceLoaderContext $context ) {
 545                 return null;
 546         }
 547
 548         /**
 549          * Back-compat dummy for old subclass implementations of getModifiedTime().
 550          *
 551          * This method used to use ObjectCache to track when a hash was first seen. That principle
 552          * stems from a time that ResourceLoader could only identify module versions by timestamp.
 553          * That is no longer the case. Use getDefinitionSummary() directly.
 554          *
 555          * @deprecated since 1.26 Superseded by getVersionHash()
 556          * @param ResourceLoaderContext $context
 557          * @return int UNIX timestamp
 558          */
 559         public function getHashMtime( ResourceLoaderContext $context ) {
 560                 if ( !is_string( $this->getModifiedHash( $context ) ) ) {
 561                         return 1;
 562                 }
 563                 // Dummy that is > 1
 564                 return 2;
 565         }
 566
 567         /**
 568          * Back-compat dummy for old subclass implementations of getModifiedTime().
 569          *
 570          * @since 1.23
 571          * @deprecated since 1.26 Superseded by getVersionHash()
 572          * @param ResourceLoaderContext $context
 573          * @return int UNIX timestamp
 574          */
 575         public function getDefinitionMtime( ResourceLoaderContext $context ) {
 576                 if ( $this->getDefinitionSummary( $context ) === null ) {
 577                         return 1;
 578                 }
 579                 // Dummy that is > 1
 580                 return 2;
 581         }
 582
 583         /**
 584          * Check whether this module is known to be empty. If a child class
 585          * has an easy and cheap way to determine that this module is
 586          * definitely going to be empty, it should override this method to
 587          * return true in that case. Callers may optimize the request for this
 588          * module away if this function returns true.
 589          * @param ResourceLoaderContext $context
 590          * @return bool
 591          */
 592         public function isKnownEmpty( ResourceLoaderContext $context ) {
 593                 return false;
 594         }
 595
 596         /** @var JSParser Lazy-initialized; use self::javaScriptParser() */
 597         private static $jsParser;
 598         private static $parseCacheVersion = 1;
 599
 600         /**
 601          * Validate a given script file; if valid returns the original source.
 602          * If invalid, returns replacement JS source that throws an exception.
 603          *
 604          * @param string $fileName
 605          * @param string $contents
 606          * @return string JS with the original, or a replacement error
 607          */
 608         protected function validateScriptFile( $fileName, $contents ) {
 609                 if ( $this->getConfig()->get( 'ResourceLoaderValidateJS' ) ) {
 610                         // Try for cache hit
 611                         // Use CACHE_ANYTHING since filtering is very slow compared to DB queries
 612                         $key = wfMemcKey( 'resourceloader', 'jsparse', self::$parseCacheVersion, md5( $contents ) );
 613                         $cache = wfGetCache( CACHE_ANYTHING );
 614                         $cacheEntry = $cache->get( $key );
 615                         if ( is_string( $cacheEntry ) ) {
 616                                 return $cacheEntry;
 617                         }
 618
 619                         $parser = self::javaScriptParser();
 620                         try {
 621                                 $parser->parse( $contents, $fileName, 1 );
 622                                 $result = $contents;
 623                         } catch ( Exception $e ) {
 624                                 // We'll save this to cache to avoid having to validate broken JS over and over...
 625                                 $err = $e->getMessage();
 626                                 $result = "throw new Error(" . Xml::encodeJsVar( "JavaScript parse error: $err" ) . ");";
 627                         }
 628
 629                         $cache->set( $key, $result );
 630                         return $result;
 631                 } else {
 632                         return $contents;
 633                 }
 634         }
 635
 636         /**
 637          * @return JSParser
 638          */
 639         protected static function javaScriptParser() {
 640                 if ( !self::$jsParser ) {
 641                         self::$jsParser = new JSParser();
 642                 }
 643                 return self::$jsParser;
 644         }
 645
 646         /**
 647          * Safe version of filemtime(), which doesn't throw a PHP warning if the file doesn't exist
 648          * but returns 1 instead.
 649          * @param string $filename File name
 650          * @return int UNIX timestamp
 651          */
 652         protected static function safeFilemtime( $filename ) {
 653                 wfSuppressWarnings();
 654                 $mtime = filemtime( $filename ) ?: 1;
 655                 wfRestoreWarnings();
 656
 657                 return $mtime;
 658         }
 659 }