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_MESSAGES = 'messages';
  33         const TYPE_COMBINED = 'combined';
  34
  35         # sitewide core module like a skin file or jQuery component
  36         const ORIGIN_CORE_SITEWIDE = 1;
  37
  38         # per-user module generated by the software
  39         const ORIGIN_CORE_INDIVIDUAL = 2;
  40
  41         # sitewide module generated from user-editable files, like MediaWiki:Common.js, or
  42         # modules accessible to multiple users, such as those generated by the Gadgets extension.
  43         const ORIGIN_USER_SITEWIDE = 3;
  44
  45         # per-user module generated from user-editable files, like User:Me/vector.js
  46         const ORIGIN_USER_INDIVIDUAL = 4;
  47
  48         # an access constant; make sure this is kept as the largest number in this group
  49         const ORIGIN_ALL = 10;
  50
  51         # script and style modules form a hierarchy of trustworthiness, with core modules like
  52         # skins and jQuery as most trustworthy, and user scripts as least trustworthy.  We can
  53         # limit the types of scripts and styles we allow to load on, say, sensitive special
  54         # pages like Special:UserLogin and Special:Preferences
  55         protected $origin = self::ORIGIN_CORE_SITEWIDE;
  56
  57         /* Protected Members */
  58
  59         protected $name = null;
  60         protected $targets = array( 'desktop' );
  61
  62         // In-object cache for file dependencies
  63         protected $fileDeps = array();
  64         // In-object cache for message blob mtime
  65         protected $msgBlobMtime = array();
  66
  67         /**
  68          * @var Config
  69          */
  70         protected $config;
  71
  72         /* Methods */
  73
  74         /**
  75          * Get this module's name. This is set when the module is registered
  76          * with ResourceLoader::register()
  77          *
  78          * @return string|null Name (string) or null if no name was set
  79          */
  80         public function getName() {
  81                 return $this->name;
  82         }
  83
  84         /**
  85          * Set this module's name. This is called by ResourceLoader::register()
  86          * when registering the module. Other code should not call this.
  87          *
  88          * @param string $name Name
  89          */
  90         public function setName( $name ) {
  91                 $this->name = $name;
  92         }
  93
  94         /**
  95          * Get this module's origin. This is set when the module is registered
  96          * with ResourceLoader::register()
  97          *
  98          * @return int ResourceLoaderModule class constant, the subclass default
  99          *     if not set manually
 100          */
 101         public function getOrigin() {
 102                 return $this->origin;
 103         }
 104
 105         /**
 106          * Set this module's origin. This is called by ResourceLoader::register()
 107          * when registering the module. Other code should not call this.
 108          *
 109          * @param int $origin Origin
 110          */
 111         public function setOrigin( $origin ) {
 112                 $this->origin = $origin;
 113         }
 114
 115         /**
 116          * @param ResourceLoaderContext $context
 117          * @return bool
 118          */
 119         public function getFlip( $context ) {
 120                 global $wgContLang;
 121
 122                 return $wgContLang->getDir() !== $context->getDirection();
 123         }
 124
 125         /**
 126          * Get all JS for this module for a given language and skin.
 127          * Includes all relevant JS except loader scripts.
 128          *
 129          * @param ResourceLoaderContext $context
 130          * @return string JavaScript code
 131          */
 132         public function getScript( ResourceLoaderContext $context ) {
 133                 // Stub, override expected
 134                 return '';
 135         }
 136
 137         /**
 138          * @return Config
 139          * @since 1.24
 140          */
 141         public function getConfig() {
 142                 if ( $this->config === null ) {
 143                         // Ugh, fall back to default
 144                         $this->config = ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
 145                 }
 146
 147                 return $this->config;
 148         }
 149
 150         /**
 151          * @param Config $config
 152          * @since 1.24
 153          */
 154         public function setConfig( Config $config ) {
 155                 $this->config = $config;
 156         }
 157
 158         /**
 159          * Get the URL or URLs to load for this module's JS in debug mode.
 160          * The default behavior is to return a load.php?only=scripts URL for
 161          * the module, but file-based modules will want to override this to
 162          * load the files directly.
 163          *
 164          * This function is called only when 1) we're in debug mode, 2) there
 165          * is no only= parameter and 3) supportsURLLoading() returns true.
 166          * #2 is important to prevent an infinite loop, therefore this function
 167          * MUST return either an only= URL or a non-load.php URL.
 168          *
 169          * @param ResourceLoaderContext $context
 170          * @return array Array of URLs
 171          */
 172         public function getScriptURLsForDebug( ResourceLoaderContext $context ) {
 173                 $resourceLoader = $context->getResourceLoader();
 174                 $derivative = new DerivativeResourceLoaderContext( $context );
 175                 $derivative->setModules( array( $this->getName() ) );
 176                 $derivative->setOnly( 'scripts' );
 177                 $derivative->setDebug( true );
 178
 179                 $url = $resourceLoader->createLoaderURL(
 180                         $this->getSource(),
 181                         $derivative
 182                 );
 183
 184                 return array( $url );
 185         }
 186
 187         /**
 188          * Whether this module supports URL loading. If this function returns false,
 189          * getScript() will be used even in cases (debug mode, no only param) where
 190          * getScriptURLsForDebug() would normally be used instead.
 191          * @return bool
 192          */
 193         public function supportsURLLoading() {
 194                 return true;
 195         }
 196
 197         /**
 198          * Get all CSS for this module for a given skin.
 199          *
 200          * @param ResourceLoaderContext $context
 201          * @return array List of CSS strings or array of CSS strings keyed by media type.
 202          *  like array( 'screen' => '.foo { width: 0 }' );
 203          *  or array( 'screen' => array( '.foo { width: 0 }' ) );
 204          */
 205         public function getStyles( ResourceLoaderContext $context ) {
 206                 // Stub, override expected
 207                 return array();
 208         }
 209
 210         /**
 211          * Get the URL or URLs to load for this module's CSS in debug mode.
 212          * The default behavior is to return a load.php?only=styles URL for
 213          * the module, but file-based modules will want to override this to
 214          * load the files directly. See also getScriptURLsForDebug()
 215          *
 216          * @param ResourceLoaderContext $context
 217          * @return array Array( mediaType => array( URL1, URL2, ... ), ... )
 218          */
 219         public function getStyleURLsForDebug( ResourceLoaderContext $context ) {
 220                 $resourceLoader = $context->getResourceLoader();
 221                 $derivative = new DerivativeResourceLoaderContext( $context );
 222                 $derivative->setModules( array( $this->getName() ) );
 223                 $derivative->setOnly( 'styles' );
 224                 $derivative->setDebug( true );
 225
 226                 $url = $resourceLoader->createLoaderURL(
 227                         $this->getSource(),
 228                         $derivative
 229                 );
 230
 231                 return array( 'all' => array( $url ) );
 232         }
 233
 234         /**
 235          * Get the messages needed for this module.
 236          *
 237          * To get a JSON blob with messages, use MessageBlobStore::get()
 238          *
 239          * @return array List of message keys. Keys may occur more than once
 240          */
 241         public function getMessages() {
 242                 // Stub, override expected
 243                 return array();
 244         }
 245
 246         /**
 247          * Get the group this module is in.
 248          *
 249          * @return string Group name
 250          */
 251         public function getGroup() {
 252                 // Stub, override expected
 253                 return null;
 254         }
 255
 256         /**
 257          * Get the origin of this module. Should only be overridden for foreign modules.
 258          *
 259          * @return string Origin name, 'local' for local modules
 260          */
 261         public function getSource() {
 262                 // Stub, override expected
 263                 return 'local';
 264         }
 265
 266         /**
 267          * Where on the HTML page should this module's JS be loaded?
 268          *  - 'top': in the "<head>"
 269          *  - 'bottom': at the bottom of the "<body>"
 270          *
 271          * @return string
 272          */
 273         public function getPosition() {
 274                 return 'bottom';
 275         }
 276
 277         /**
 278          * Whether this module's JS expects to work without the client-side ResourceLoader module.
 279          * Returning true from this function will prevent mw.loader.state() call from being
 280          * appended to the bottom of the script.
 281          *
 282          * @return bool
 283          */
 284         public function isRaw() {
 285                 return false;
 286         }
 287
 288         /**
 289          * Get the loader JS for this module, if set.
 290          *
 291          * @return mixed JavaScript loader code as a string or boolean false if no custom loader set
 292          */
 293         public function getLoaderScript() {
 294                 // Stub, override expected
 295                 return false;
 296         }
 297
 298         /**
 299          * Get a list of modules this module depends on.
 300          *
 301          * Dependency information is taken into account when loading a module
 302          * on the client side.
 303          *
 304          * To add dependencies dynamically on the client side, use a custom
 305          * loader script, see getLoaderScript()
 306          * @return array List of module names as strings
 307          */
 308         public function getDependencies() {
 309                 // Stub, override expected
 310                 return array();
 311         }
 312
 313         /**
 314          * Get target(s) for the module, eg ['desktop'] or ['desktop', 'mobile']
 315          *
 316          * @return array Array of strings
 317          */
 318         public function getTargets() {
 319                 return $this->targets;
 320         }
 321
 322         /**
 323          * Get the skip function.
 324          *
 325          * Modules that provide fallback functionality can provide a "skip function". This
 326          * function, if provided, will be passed along to the module registry on the client.
 327          * When this module is loaded (either directly or as a dependency of another module),
 328          * then this function is executed first. If the function returns true, the module will
 329          * instantly be considered "ready" without requesting the associated module resources.
 330          *
 331          * The value returned here must be valid javascript for execution in a private function.
 332          * It must not contain the "function () {" and "}" wrapper though.
 333          *
 334          * @return string|null A JavaScript function body returning a boolean value, or null
 335          */
 336         public function getSkipFunction() {
 337                 return null;
 338         }
 339
 340         /**
 341          * Get the files this module depends on indirectly for a given skin.
 342          * Currently these are only image files referenced by the module's CSS.
 343          *
 344          * @param string $skin Skin name
 345          * @return array List of files
 346          */
 347         public function getFileDependencies( $skin ) {
 348                 // Try in-object cache first
 349                 if ( isset( $this->fileDeps[$skin] ) ) {
 350                         return $this->fileDeps[$skin];
 351                 }
 352
 353                 $dbr = wfGetDB( DB_SLAVE );
 354                 $deps = $dbr->selectField( 'module_deps', 'md_deps', array(
 355                                 'md_module' => $this->getName(),
 356                                 'md_skin' => $skin,
 357                         ), __METHOD__
 358                 );
 359                 if ( !is_null( $deps ) ) {
 360                         $this->fileDeps[$skin] = (array)FormatJson::decode( $deps, true );
 361                 } else {
 362                         $this->fileDeps[$skin] = array();
 363                 }
 364                 return $this->fileDeps[$skin];
 365         }
 366
 367         /**
 368          * Set preloaded file dependency information. Used so we can load this
 369          * information for all modules at once.
 370          * @param string $skin Skin name
 371          * @param array $deps Array of file names
 372          */
 373         public function setFileDependencies( $skin, $deps ) {
 374                 $this->fileDeps[$skin] = $deps;
 375         }
 376
 377         /**
 378          * Get the last modification timestamp of the message blob for this
 379          * module in a given language.
 380          * @param string $lang Language code
 381          * @return int UNIX timestamp, or 0 if the module doesn't have messages
 382          */
 383         public function getMsgBlobMtime( $lang ) {
 384                 if ( !isset( $this->msgBlobMtime[$lang] ) ) {
 385                         if ( !count( $this->getMessages() ) ) {
 386                                 return 0;
 387                         }
 388
 389                         $dbr = wfGetDB( DB_SLAVE );
 390                         $msgBlobMtime = $dbr->selectField( 'msg_resource', 'mr_timestamp', array(
 391                                         'mr_resource' => $this->getName(),
 392                                         'mr_lang' => $lang
 393                                 ), __METHOD__
 394                         );
 395                         // If no blob was found, but the module does have messages, that means we need
 396                         // to regenerate it. Return NOW
 397                         if ( $msgBlobMtime === false ) {
 398                                 $msgBlobMtime = wfTimestampNow();
 399                         }
 400                         $this->msgBlobMtime[$lang] = wfTimestamp( TS_UNIX, $msgBlobMtime );
 401                 }
 402                 return $this->msgBlobMtime[$lang];
 403         }
 404
 405         /**
 406          * Set a preloaded message blob last modification timestamp. Used so we
 407          * can load this information for all modules at once.
 408          * @param string $lang Language code
 409          * @param int $mtime UNIX timestamp or 0 if there is no such blob
 410          */
 411         public function setMsgBlobMtime( $lang, $mtime ) {
 412                 $this->msgBlobMtime[$lang] = $mtime;
 413         }
 414
 415         /* Abstract Methods */
 416
 417         /**
 418          * Get this module's last modification timestamp for a given
 419          * combination of language, skin and debug mode flag. This is typically
 420          * the highest of each of the relevant components' modification
 421          * timestamps. Whenever anything happens that changes the module's
 422          * contents for these parameters, the mtime should increase.
 423          *
 424          * NOTE: The mtime of the module's messages is NOT automatically included.
 425          * If you want this to happen, you'll need to call getMsgBlobMtime()
 426          * yourself and take its result into consideration.
 427          *
 428          * NOTE: The mtime of the module's hash is NOT automatically included.
 429          * If your module provides a getModifiedHash() method, you'll need to call getHashMtime()
 430          * yourself and take its result into consideration.
 431          *
 432          * @param ResourceLoaderContext $context Context object
 433          * @return int UNIX timestamp
 434          */
 435         public function getModifiedTime( ResourceLoaderContext $context ) {
 436                 // 0 would mean now
 437                 return 1;
 438         }
 439
 440         /**
 441          * Helper method for calculating when the module's hash (if it has one) changed.
 442          *
 443          * @param ResourceLoaderContext $context
 444          * @return int UNIX timestamp or 0 if no hash was provided
 445          *  by getModifiedHash()
 446          */
 447         public function getHashMtime( ResourceLoaderContext $context ) {
 448                 $hash = $this->getModifiedHash( $context );
 449                 if ( !is_string( $hash ) ) {
 450                         return 0;
 451                 }
 452
 453                 $cache = wfGetCache( CACHE_ANYTHING );
 454                 $key = wfMemcKey( 'resourceloader', 'modulemodifiedhash', $this->getName(), $hash );
 455
 456                 $data = $cache->get( $key );
 457                 if ( is_array( $data ) && $data['hash'] === $hash ) {
 458                         // Hash is still the same, re-use the timestamp of when we first saw this hash.
 459                         return $data['timestamp'];
 460                 }
 461
 462                 $timestamp = wfTimestamp();
 463                 $cache->set( $key, array(
 464                         'hash' => $hash,
 465                         'timestamp' => $timestamp,
 466                 ) );
 467
 468                 return $timestamp;
 469         }
 470
 471         /**
 472          * Get the hash for whatever this module may contain.
 473          *
 474          * This is the method subclasses should implement if they want to make
 475          * use of getHashMTime() inside getModifiedTime().
 476          *
 477          * @param ResourceLoaderContext $context
 478          * @return string|null Hash
 479          */
 480         public function getModifiedHash( ResourceLoaderContext $context ) {
 481                 return null;
 482         }
 483
 484         /**
 485          * Helper method for calculating when this module's definition summary was last changed.
 486          *
 487          * @since 1.23
 488          *
 489          * @return int UNIX timestamp or 0 if no definition summary was provided
 490          *  by getDefinitionSummary()
 491          */
 492         public function getDefinitionMtime( ResourceLoaderContext $context ) {
 493                 wfProfileIn( __METHOD__ );
 494                 $summary = $this->getDefinitionSummary( $context );
 495                 if ( $summary === null ) {
 496                         wfProfileOut( __METHOD__ );
 497                         return 0;
 498                 }
 499
 500                 $hash = md5( json_encode( $summary ) );
 501
 502                 $cache = wfGetCache( CACHE_ANYTHING );
 503
 504                 // Embed the hash itself in the cache key. This allows for a few nifty things:
 505                 // - During deployment, servers with old and new versions of the code communicating
 506                 //   with the same memcached will not override the same key repeatedly increasing
 507                 //   the timestamp.
 508                 // - In case of the definition changing and then changing back in a short period of time
 509                 //   (e.g. in case of a revert or a corrupt server) the old timestamp and client-side cache
 510                 //   url will be re-used.
 511                 // - If different context-combinations (e.g. same skin, same language or some combination
 512                 //   thereof) result in the same definition, they will use the same hash and timestamp.
 513                 $key = wfMemcKey( 'resourceloader', 'moduledefinition', $this->getName(), $hash );
 514
 515                 $data = $cache->get( $key );
 516                 if ( is_int( $data ) && $data > 0 ) {
 517                         // We've seen this hash before, re-use the timestamp of when we first saw it.
 518                         wfProfileOut( __METHOD__ );
 519                         return $data;
 520                 }
 521
 522                 wfDebugLog( 'resourceloader', __METHOD__ . ": New definition hash for module "
 523                         . "{$this->getName()} in context {$context->getHash()}: $hash." );
 524
 525                 $timestamp = time();
 526                 $cache->set( $key, $timestamp );
 527
 528                 wfProfileOut( __METHOD__ );
 529                 return $timestamp;
 530         }
 531
 532         /**
 533          * Get the definition summary for this module.
 534          *
 535          * This is the method subclasses should implement if they want to make
 536          * use of getDefinitionMTime() inside getModifiedTime().
 537          *
 538          * Return an array containing values from all significant properties of this
 539          * module's definition. Be sure to include things that are explicitly ordered,
 540          * in their actaul order (bug 37812).
 541          *
 542          * Avoid including things that are insiginificant (e.g. order of message
 543          * keys is insignificant and should be sorted to avoid unnecessary cache
 544          * invalidation).
 545          *
 546          * Avoid including things already considered by other methods inside your
 547          * getModifiedTime(), such as file mtime timestamps.
 548          *
 549          * Serialisation is done using json_encode, which means object state is not
 550          * taken into account when building the hash. This data structure must only
 551          * contain arrays and scalars as values (avoid object instances) which means
 552          * it requires abstraction.
 553          *
 554          * @since 1.23
 555          *
 556          * @return array|null
 557          */
 558         public function getDefinitionSummary( ResourceLoaderContext $context ) {
 559                 return array(
 560                         'class' => get_class( $this ),
 561                 );
 562         }
 563
 564         /**
 565          * Check whether this module is known to be empty. If a child class
 566          * has an easy and cheap way to determine that this module is
 567          * definitely going to be empty, it should override this method to
 568          * return true in that case. Callers may optimize the request for this
 569          * module away if this function returns true.
 570          * @param ResourceLoaderContext $context
 571          * @return bool
 572          */
 573         public function isKnownEmpty( ResourceLoaderContext $context ) {
 574                 return false;
 575         }
 576
 577         /** @var JSParser Lazy-initialized; use self::javaScriptParser() */
 578         private static $jsParser;
 579         private static $parseCacheVersion = 1;
 580
 581         /**
 582          * Validate a given script file; if valid returns the original source.
 583          * If invalid, returns replacement JS source that throws an exception.
 584          *
 585          * @param string $fileName
 586          * @param string $contents
 587          * @return string JS with the original, or a replacement error
 588          */
 589         protected function validateScriptFile( $fileName, $contents ) {
 590                 if ( $this->getConfig()->get( 'ResourceLoaderValidateJS' ) ) {
 591                         // Try for cache hit
 592                         // Use CACHE_ANYTHING since filtering is very slow compared to DB queries
 593                         $key = wfMemcKey( 'resourceloader', 'jsparse', self::$parseCacheVersion, md5( $contents ) );
 594                         $cache = wfGetCache( CACHE_ANYTHING );
 595                         $cacheEntry = $cache->get( $key );
 596                         if ( is_string( $cacheEntry ) ) {
 597                                 return $cacheEntry;
 598                         }
 599
 600                         $parser = self::javaScriptParser();
 601                         try {
 602                                 $parser->parse( $contents, $fileName, 1 );
 603                                 $result = $contents;
 604                         } catch ( Exception $e ) {
 605                                 // We'll save this to cache to avoid having to validate broken JS over and over...
 606                                 $err = $e->getMessage();
 607                                 $result = "throw new Error(" . Xml::encodeJsVar( "JavaScript parse error: $err" ) . ");";
 608                         }
 609
 610                         $cache->set( $key, $result );
 611                         return $result;
 612                 } else {
 613                         return $contents;
 614                 }
 615         }
 616
 617         /**
 618          * @return JSParser
 619          */
 620         protected static function javaScriptParser() {
 621                 if ( !self::$jsParser ) {
 622                         self::$jsParser = new JSParser();
 623                 }
 624                 return self::$jsParser;
 625         }
 626
 627         /**
 628          * Safe version of filemtime(), which doesn't throw a PHP warning if the file doesn't exist
 629          * but returns 1 instead.
 630          * @param string $filename File name
 631          * @return int UNIX timestamp, or 1 if the file doesn't exist
 632          */
 633         protected static function safeFilemtime( $filename ) {
 634                 if ( file_exists( $filename ) ) {
 635                         return filemtime( $filename );
 636                 } else {
 637                         // We only ever map this function on an array if we're gonna call max() after,
 638                         // so return our standard minimum timestamps here. This is 1, not 0, because
 639                         // wfTimestamp(0) == NOW
 640                         return 1;
 641                 }
 642         }
 643 }