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