includes/Exception.php

   1 <?php
   2 /**
   3  * Exception class and handler.
   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  */
  22
  23 /**
  24  * @defgroup Exception Exception
  25  */
  26
  27 /**
  28  * MediaWiki exception
  29  *
  30  * @ingroup Exception
  31  */
  32 class MWException extends Exception {
  33         var $logId;
  34
  35         /**
  36          * Should the exception use $wgOut to output the error?
  37          *
  38          * @return bool
  39          */
  40         function useOutputPage() {
  41                 return $this->useMessageCache() &&
  42                         !empty( $GLOBALS['wgFullyInitialised'] ) &&
  43                         !empty( $GLOBALS['wgOut'] ) &&
  44                         !empty( $GLOBALS['wgTitle'] );
  45         }
  46
  47         /**
  48          * Can the extension use wfMsg() to get i18n messages?
  49          *
  50          * @return bool
  51          */
  52         function useMessageCache() {
  53                 global $wgLang;
  54
  55                 foreach ( $this->getTrace() as $frame ) {
  56                         if ( isset( $frame['class'] ) && $frame['class'] === 'LocalisationCache' ) {
  57                                 return false;
  58                         }
  59                 }
  60
  61                 return $wgLang instanceof Language;
  62         }
  63
  64         /**
  65          * Run hook to allow extensions to modify the text of the exception
  66          *
  67          * @param $name string: class name of the exception
  68          * @param $args array: arguments to pass to the callback functions
  69          * @return string|null string to output or null if any hook has been called
  70          */
  71         function runHooks( $name, $args = array() ) {
  72                 global $wgExceptionHooks;
  73
  74                 if ( !isset( $wgExceptionHooks ) || !is_array( $wgExceptionHooks ) ) {
  75                         return null; // Just silently ignore
  76                 }
  77
  78                 if ( !array_key_exists( $name, $wgExceptionHooks ) || !is_array( $wgExceptionHooks[ $name ] ) ) {
  79                         return null;
  80                 }
  81
  82                 $hooks = $wgExceptionHooks[ $name ];
  83                 $callargs = array_merge( array( $this ), $args );
  84
  85                 foreach ( $hooks as $hook ) {
  86                         if ( is_string( $hook ) || ( is_array( $hook ) && count( $hook ) >= 2 && is_string( $hook[0] ) ) ) {    // 'function' or array( 'class', hook' )
  87                                 $result = call_user_func_array( $hook, $callargs );
  88                         } else {
  89                                 $result = null;
  90                         }
  91
  92                         if ( is_string( $result ) ) {
  93                                 return $result;
  94                         }
  95                 }
  96                 return null;
  97         }
  98
  99         /**
 100          * Get a message from i18n
 101          *
 102          * @param $key string: message name
 103          * @param $fallback string: default message if the message cache can't be
 104          *                  called by the exception
 105          * The function also has other parameters that are arguments for the message
 106          * @return string message with arguments replaced
 107          */
 108         function msg( $key, $fallback /*[, params...] */ ) {
 109                 $args = array_slice( func_get_args(), 2 );
 110
 111                 if ( $this->useMessageCache() ) {
 112                         return wfMsgNoTrans( $key, $args );
 113                 } else {
 114                         return wfMsgReplaceArgs( $fallback, $args );
 115                 }
 116         }
 117
 118         /**
 119          * If $wgShowExceptionDetails is true, return a HTML message with a
 120          * backtrace to the error, otherwise show a message to ask to set it to true
 121          * to show that information.
 122          *
 123          * @return string html to output
 124          */
 125         function getHTML() {
 126                 global $wgShowExceptionDetails;
 127
 128                 if ( $wgShowExceptionDetails ) {
 129                         return '<p>' . nl2br( htmlspecialchars( $this->getMessage() ) ) .
 130                                 '</p><p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
 131                                 "</p>\n";
 132                 } else {
 133                         return
 134                                 "<div class=\"errorbox\">" .
 135                                 '[' . $this->getLogId() . '] ' .
 136                                 gmdate( 'Y-m-d H:i:s' ) .
 137                                 ": Fatal exception of type " . get_class( $this ) . "</div>\n" .
 138                                 "<!-- Set \$wgShowExceptionDetails = true; " .
 139                                 "at the bottom of LocalSettings.php to show detailed " .
 140                                 "debugging information. -->";
 141                 }
 142         }
 143
 144         /**
 145          * Get the text to display when reporting the error on the command line.
 146          * If $wgShowExceptionDetails is true, return a text message with a
 147          * backtrace to the error.
 148          *
 149          * @return string
 150          */
 151         function getText() {
 152                 global $wgShowExceptionDetails;
 153
 154                 if ( $wgShowExceptionDetails ) {
 155                         return $this->getMessage() .
 156                                 "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
 157                 } else {
 158                         return "Set \$wgShowExceptionDetails = true; " .
 159                                 "in LocalSettings.php to show detailed debugging information.\n";
 160                 }
 161         }
 162
 163         /**
 164          * Return the title of the page when reporting this error in a HTTP response.
 165          *
 166          * @return string
 167          */
 168         function getPageTitle() {
 169                 return $this->msg( 'internalerror', "Internal error" );
 170         }
 171
 172         /**
 173          * Get a random ID for this error.
 174          * This allows to link the exception to its correspoding log entry when
 175          * $wgShowExceptionDetails is set to false.
 176          *
 177          * @return string
 178          */
 179         function getLogId() {
 180                 if ( $this->logId === null ) {
 181                         $this->logId = wfRandomString( 8 );
 182                 }
 183                 return $this->logId;
 184         }
 185
 186         /**
 187          * Return the requested URL and point to file and line number from which the
 188          * exception occured
 189          *
 190          * @return string
 191          */
 192         function getLogMessage() {
 193                 global $wgRequest;
 194
 195                 $id = $this->getLogId();
 196                 $file = $this->getFile();
 197                 $line = $this->getLine();
 198                 $message = $this->getMessage();
 199
 200                 if ( isset( $wgRequest ) && !$wgRequest instanceof FauxRequest ) {
 201                         $url = $wgRequest->getRequestURL();
 202                         if ( !$url ) {
 203                                 $url = '[no URL]';
 204                         }
 205                 } else {
 206                         $url = '[no req]';
 207                 }
 208
 209                 return "[$id] $url   Exception from line $line of $file: $message";
 210         }
 211
 212         /**
 213          * Output the exception report using HTML.
 214          */
 215         function reportHTML() {
 216                 global $wgOut;
 217                 if ( $this->useOutputPage() ) {
 218                         $wgOut->prepareErrorPage( $this->getPageTitle() );
 219
 220                         $hookResult = $this->runHooks( get_class( $this ) );
 221                         if ( $hookResult ) {
 222                                 $wgOut->addHTML( $hookResult );
 223                         } else {
 224                                 $wgOut->addHTML( $this->getHTML() );
 225                         }
 226
 227                         $wgOut->output();
 228                 } else {
 229                         header( "Content-Type: text/html; charset=utf-8" );
 230                         echo "<!doctype html>\n" .
 231                                 '<html><head>' .
 232                                 '<title>' . htmlspecialchars( $this->getPageTitle() ) . '</title>' .
 233                                 "</head><body>\n";
 234
 235                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 236                         if ( $hookResult ) {
 237                                 echo $hookResult;
 238                         } else {
 239                                 echo $this->getHTML();
 240                         }
 241
 242                         echo "</body></html>\n";
 243                         die( 1 );
 244                 }
 245         }
 246
 247         /**
 248          * Output a report about the exception and takes care of formatting.
 249          * It will be either HTML or plain text based on isCommandLine().
 250          */
 251         function report() {
 252                 global $wgLogExceptionBacktrace;
 253                 $log = $this->getLogMessage();
 254
 255                 if ( $log ) {
 256                         if ( $wgLogExceptionBacktrace ) {
 257                                 wfDebugLog( 'exception', $log . "\n" . $this->getTraceAsString() . "\n" );
 258                         } else {
 259                                 wfDebugLog( 'exception', $log );
 260                         }
 261                 }
 262
 263                 if ( defined( 'MW_API' ) ) {
 264                         // Unhandled API exception, we can't be sure that format printer is alive
 265                         header( 'MediaWiki-API-Error: internal_api_error_' . get_class( $this ) );
 266                         wfHttpError(500, 'Internal Server Error', $this->getText() );
 267                 } elseif ( self::isCommandLine() ) {
 268                         MWExceptionHandler::printError( $this->getText() );
 269                 } else {
 270                         header( "HTTP/1.1 500 MediaWiki exception" );
 271                         header( "Status: 500 MediaWiki exception", true );
 272
 273                         $this->reportHTML();
 274                 }
 275         }
 276
 277         /**
 278          * Check whether we are in command line mode or not to report the exception
 279          * in the correct format.
 280          *
 281          * @return bool
 282          */
 283         static function isCommandLine() {
 284                 return !empty( $GLOBALS['wgCommandLineMode'] );
 285         }
 286 }
 287
 288 /**
 289  * Exception class which takes an HTML error message, and does not
 290  * produce a backtrace. Replacement for OutputPage::fatalError().
 291  *
 292  * @ingroup Exception
 293  */
 294 class FatalError extends MWException {
 295
 296         /**
 297          * @return string
 298          */
 299         function getHTML() {
 300                 return $this->getMessage();
 301         }
 302
 303         /**
 304          * @return string
 305          */
 306         function getText() {
 307                 return $this->getMessage();
 308         }
 309 }
 310
 311 /**
 312  * An error page which can definitely be safely rendered using the OutputPage.
 313  *
 314  * @ingroup Exception
 315  */
 316 class ErrorPageError extends MWException {
 317         public $title, $msg, $params;
 318
 319         /**
 320          * @todo document
 321          *
 322          * Note: these arguments are keys into wfMsg(), not text!
 323          *
 324          * @param $title A title
 325          * @param $msg String|Message . In string form, should be a message key
 326          * @param $params Array Array to wfMsg()
 327          */
 328         function __construct( $title, $msg, $params = null ) {
 329                 $this->title = $title;
 330                 $this->msg = $msg;
 331                 $this->params = $params;
 332
 333                 if( $msg instanceof Message ){
 334                         parent::__construct( $msg );
 335                 } else {
 336                         parent::__construct( wfMsg( $msg ) );
 337                 }
 338         }
 339
 340         function report() {
 341                 global $wgOut;
 342
 343                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 344                 $wgOut->output();
 345         }
 346 }
 347
 348 /**
 349  * Show an error page on a badtitle.
 350  * Similar to ErrorPage, but emit a 400 HTTP error code to let mobile
 351  * browser it is not really a valid content.
 352  *
 353  * @ingroup Exception
 354  */
 355 class BadTitleError extends ErrorPageError {
 356
 357         /**
 358          * @param $msg string A message key (default: 'badtitletext')
 359          * @param $params Array parameter to wfMsg()
 360          */
 361         function __construct( $msg = 'badtitletext', $params = null ) {
 362                 parent::__construct( 'badtitle', $msg, $params );
 363         }
 364
 365         /**
 366          * Just like ErrorPageError::report() but additionally set
 367          * a 400 HTTP status code (bug 33646).
 368          */
 369         function report() {
 370                 global $wgOut;
 371
 372                 // bug 33646: a badtitle error page need to return an error code
 373                 // to let mobile browser now that it is not a normal page.
 374                 $wgOut->setStatusCode( 400 );
 375                 parent::report();
 376         }
 377
 378 }
 379
 380 /**
 381  * Show an error when a user tries to do something they do not have the necessary
 382  * permissions for.
 383  *
 384  * @ingroup Exception
 385  */
 386 class PermissionsError extends ErrorPageError {
 387         public $permission, $errors;
 388
 389         function __construct( $permission, $errors = array() ) {
 390                 global $wgLang;
 391
 392                 $this->permission = $permission;
 393
 394                 if ( !count( $errors ) ) {
 395                         $groups = array_map(
 396                                 array( 'User', 'makeGroupLinkWiki' ),
 397                                 User::getGroupsWithPermission( $this->permission )
 398                         );
 399
 400                         if ( $groups ) {
 401                                 $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
 402                         } else {
 403                                 $errors[] = array( 'badaccess-group0' );
 404                         }
 405                 }
 406
 407                 $this->errors = $errors;
 408         }
 409
 410         function report() {
 411                 global $wgOut;
 412
 413                 $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
 414                 $wgOut->output();
 415         }
 416 }
 417
 418 /**
 419  * Show an error when the wiki is locked/read-only and the user tries to do
 420  * something that requires write access.
 421  *
 422  * @ingroup Exception
 423  */
 424 class ReadOnlyError extends ErrorPageError {
 425         public function __construct(){
 426                 parent::__construct(
 427                         'readonly',
 428                         'readonlytext',
 429                         wfReadOnlyReason()
 430                 );
 431         }
 432 }
 433
 434 /**
 435  * Show an error when the user hits a rate limit.
 436  *
 437  * @ingroup Exception
 438  */
 439 class ThrottledError extends ErrorPageError {
 440         public function __construct(){
 441                 parent::__construct(
 442                         'actionthrottled',
 443                         'actionthrottledtext'
 444                 );
 445         }
 446
 447         public function report(){
 448                 global $wgOut;
 449                 $wgOut->setStatusCode( 503 );
 450                 parent::report();
 451         }
 452 }
 453
 454 /**
 455  * Show an error when the user tries to do something whilst blocked.
 456  *
 457  * @ingroup Exception
 458  */
 459 class UserBlockedError extends ErrorPageError {
 460         public function __construct( Block $block ){
 461                 global $wgLang, $wgRequest;
 462
 463                 $blocker = $block->getBlocker();
 464                 if ( $blocker instanceof User ) { // local user
 465                         $blockerUserpage = $block->getBlocker()->getUserPage();
 466                         $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 467                 } else { // foreign user
 468                         $link = $blocker;
 469                 }
 470
 471                 $reason = $block->mReason;
 472                 if( $reason == '' ) {
 473                         $reason = wfMsg( 'blockednoreason' );
 474                 }
 475
 476                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 477                  * This could be a username, an IP range, or a single IP. */
 478                 $intended = $block->getTarget();
 479
 480                 parent::__construct(
 481                         'blockedtitle',
 482                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 483                         array(
 484                                 $link,
 485                                 $reason,
 486                                 $wgRequest->getIP(),
 487                                 $block->getByName(),
 488                                 $block->getId(),
 489                                 $wgLang->formatExpiry( $block->mExpiry ),
 490                                 $intended,
 491                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 492                         )
 493                 );
 494         }
 495 }
 496
 497 /**
 498  * Shows a generic "user is not logged in" error page.
 499  *
 500  * This is essentially an ErrorPageError exception which by default use the
 501  * 'exception-nologin' as a title and 'exception-nologin-text' for the message.
 502  * @see bug 37627
 503  *
 504  * @par Example:
 505  * @code
 506  * if( $user->isAnon ) {
 507  *      throw new UserNotLoggedIn();
 508  * }
 509  * @endcode
 510  *
 511  * Please note the parameters are mixed up compared to ErrorPageError, this
 512  * is done to be able to simply specify a reason whitout overriding the default
 513  * title.
 514  *
 515  * @par Example:
 516  * @code
 517  * if( $user->isAnon ) {
 518  *      throw new UserNotLoggedIn( 'action-require-loggedin' );
 519  * }
 520  * @endcode
 521  *
 522  * @ingroup Exception
 523  */
 524 class UserNotLoggedIn extends ErrorPageError {
 525
 526         /**
 527          * @param $reasonMsg A message key containing the reason for the error.
 528          *        Optional, default: 'exception-nologin-text'
 529          * @param $titleMsg A message key to set the page title.
 530          *        Optional, default: 'exception-nologin'
 531          * @param $params Parameters to wfMsg().
 532          *        Optiona, default: null
 533          */
 534         public function __construct(
 535                 $reasonMsg = 'exception-nologin-text',
 536                 $titleMsg  = 'exception-nologin',
 537                 $params = null
 538         ) {
 539                 parent::__construct( $titleMsg, $reasonMsg, $params );
 540         }
 541 }
 542
 543 /**
 544  * Show an error that looks like an HTTP server error.
 545  * Replacement for wfHttpError().
 546  *
 547  * @ingroup Exception
 548  */
 549 class HttpError extends MWException {
 550         private $httpCode, $header, $content;
 551
 552         /**
 553          * Constructor
 554          *
 555          * @param $httpCode Integer: HTTP status code to send to the client
 556          * @param $content String|Message: content of the message
 557          * @param $header String|Message: content of the header (\<title\> and \<h1\>)
 558          */
 559         public function __construct( $httpCode, $content, $header = null ){
 560                 parent::__construct( $content );
 561                 $this->httpCode = (int)$httpCode;
 562                 $this->header = $header;
 563                 $this->content = $content;
 564         }
 565
 566         public function report() {
 567                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 568
 569                 header( "Status: {$this->httpCode} {$httpMessage}" );
 570                 header( 'Content-type: text/html; charset=utf-8' );
 571
 572                 if ( $this->header === null ) {
 573                         $header = $httpMessage;
 574                 } elseif ( $this->header instanceof Message ) {
 575                         $header = $this->header->escaped();
 576                 } else {
 577                         $header = htmlspecialchars( $this->header );
 578                 }
 579
 580                 if ( $this->content instanceof Message ) {
 581                         $content = $this->content->escaped();
 582                 } else {
 583                         $content = htmlspecialchars( $this->content );
 584                 }
 585
 586                 print "<!DOCTYPE html>\n".
 587                         "<html><head><title>$header</title></head>\n" .
 588                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 589         }
 590 }
 591
 592 /**
 593  * Handler class for MWExceptions
 594  * @ingroup Exception
 595  */
 596 class MWExceptionHandler {
 597         /**
 598          * Install an exception handler for MediaWiki exception types.
 599          */
 600         public static function installHandler() {
 601                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 602         }
 603
 604         /**
 605          * Report an exception to the user
 606          */
 607         protected static function report( Exception $e ) {
 608                 global $wgShowExceptionDetails;
 609
 610                 $cmdLine = MWException::isCommandLine();
 611
 612                 if ( $e instanceof MWException ) {
 613                         try {
 614                                 // Try and show the exception prettily, with the normal skin infrastructure
 615                                 $e->report();
 616                         } catch ( Exception $e2 ) {
 617                                 // Exception occurred from within exception handler
 618                                 // Show a simpler error message for the original exception,
 619                                 // don't try to invoke report()
 620                                 $message = "MediaWiki internal error.\n\n";
 621
 622                                 if ( $wgShowExceptionDetails ) {
 623                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 624                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 625                                 } else {
 626                                         $message .= "Exception caught inside exception handler.\n\n" .
 627                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 628                                                 "to show detailed debugging information.";
 629                                 }
 630
 631                                 $message .= "\n";
 632
 633                                 if ( $cmdLine ) {
 634                                         self::printError( $message );
 635                                 } else {
 636                                         self::escapeEchoAndDie( $message );
 637                                 }
 638                         }
 639                 } else {
 640                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 641                                 $e->__toString() . "\n";
 642
 643                         if ( $wgShowExceptionDetails ) {
 644                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 645                         }
 646
 647                         if ( $cmdLine ) {
 648                                 self::printError( $message );
 649                         } else {
 650                                 self::escapeEchoAndDie( $message );
 651                         }
 652                 }
 653         }
 654
 655         /**
 656          * Print a message, if possible to STDERR.
 657          * Use this in command line mode only (see isCommandLine)
 658          *
 659          * @param $message string Failure text
 660          */
 661         public static function printError( $message ) {
 662                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 663                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 664                 if ( defined( 'STDERR' ) ) {
 665                         fwrite( STDERR, $message );
 666                 } else {
 667                         echo( $message );
 668                 }
 669         }
 670
 671         /**
 672          * Print a message after escaping it and converting newlines to <br>
 673          * Use this for non-command line failures.
 674          *
 675          * @param $message string Failure text
 676          */
 677         private static function escapeEchoAndDie( $message ) {
 678                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 679                 die(1);
 680         }
 681
 682         /**
 683          * Exception handler which simulates the appropriate catch() handling:
 684          *
 685          *   try {
 686          *       ...
 687          *   } catch ( MWException $e ) {
 688          *       $e->report();
 689          *   } catch ( Exception $e ) {
 690          *       echo $e->__toString();
 691          *   }
 692          */
 693         public static function handle( $e ) {
 694                 global $wgFullyInitialised;
 695
 696                 self::report( $e );
 697
 698                 // Final cleanup
 699                 if ( $wgFullyInitialised ) {
 700                         try {
 701                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 702                         } catch ( Exception $e ) {}
 703                 }
 704
 705                 // Exit value should be nonzero for the benefit of shell jobs
 706                 exit( 1 );
 707         }
 708 }