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