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 the Message class/wfMessage to get i18n-ed 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 string $name class name of the exception
  68          * @param array $args 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 string $key message name
 103          * @param string $fallback 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 wfMessage( $key, $args )->plain();
 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 "<div class=\"errorbox\">" .
 134                                 '[' . $this->getLogId() . '] ' .
 135                                 gmdate( 'Y-m-d H:i:s' ) .
 136                                 ": Fatal exception of type " . get_class( $this ) . "</div>\n" .
 137                                 "<!-- Set \$wgShowExceptionDetails = true; " .
 138                                 "at the bottom of LocalSettings.php to show detailed " .
 139                                 "debugging information. -->";
 140                 }
 141         }
 142
 143         /**
 144          * Get the text to display when reporting the error on the command line.
 145          * If $wgShowExceptionDetails is true, return a text message with a
 146          * backtrace to the error.
 147          *
 148          * @return string
 149          */
 150         function getText() {
 151                 global $wgShowExceptionDetails;
 152
 153                 if ( $wgShowExceptionDetails ) {
 154                         return $this->getMessage() .
 155                                 "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
 156                 } else {
 157                         return "Set \$wgShowExceptionDetails = true; " .
 158                                 "in LocalSettings.php to show detailed debugging information.\n";
 159                 }
 160         }
 161
 162         /**
 163          * Return the title of the page when reporting this error in a HTTP response.
 164          *
 165          * @return string
 166          */
 167         function getPageTitle() {
 168                 return $this->msg( 'internalerror', "Internal error" );
 169         }
 170
 171         /**
 172          * Get a random ID for this error.
 173          * This allows to link the exception to its corresponding log entry when
 174          * $wgShowExceptionDetails is set to false.
 175          *
 176          * @return string
 177          */
 178         function getLogId() {
 179                 if ( $this->logId === null ) {
 180                         $this->logId = wfRandomString( 8 );
 181                 }
 182                 return $this->logId;
 183         }
 184
 185         /**
 186          * Return the requested URL and point to file and line number from which the
 187          * exception occurred
 188          *
 189          * @return string
 190          */
 191         function getLogMessage() {
 192                 global $wgRequest;
 193
 194                 $id = $this->getLogId();
 195                 $file = $this->getFile();
 196                 $line = $this->getLine();
 197                 $message = $this->getMessage();
 198
 199                 if ( isset( $wgRequest ) && !$wgRequest instanceof FauxRequest ) {
 200                         $url = $wgRequest->getRequestURL();
 201                         if ( !$url ) {
 202                                 $url = '[no URL]';
 203                         }
 204                 } else {
 205                         $url = '[no req]';
 206                 }
 207
 208                 return "[$id] $url   Exception from line $line of $file: $message";
 209         }
 210
 211         /**
 212          * Output the exception report using HTML.
 213          */
 214         function reportHTML() {
 215                 global $wgOut;
 216                 if ( $this->useOutputPage() ) {
 217                         $wgOut->prepareErrorPage( $this->getPageTitle() );
 218
 219                         $hookResult = $this->runHooks( get_class( $this ) );
 220                         if ( $hookResult ) {
 221                                 $wgOut->addHTML( $hookResult );
 222                         } else {
 223                                 $wgOut->addHTML( $this->getHTML() );
 224                         }
 225
 226                         $wgOut->output();
 227                 } else {
 228                         header( "Content-Type: text/html; charset=utf-8" );
 229                         echo "<!doctype html>\n" .
 230                                 '<html><head>' .
 231                                 '<title>' . htmlspecialchars( $this->getPageTitle() ) . '</title>' .
 232                                 "</head><body>\n";
 233
 234                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 235                         if ( $hookResult ) {
 236                                 echo $hookResult;
 237                         } else {
 238                                 echo $this->getHTML();
 239                         }
 240
 241                         echo "</body></html>\n";
 242                 }
 243         }
 244
 245         /**
 246          * Output a report about the exception and takes care of formatting.
 247          * It will be either HTML or plain text based on isCommandLine().
 248          */
 249         function report() {
 250                 global $wgLogExceptionBacktrace, $wgMimeType;
 251                 $log = $this->getLogMessage();
 252
 253                 if ( $log ) {
 254                         if ( $wgLogExceptionBacktrace ) {
 255                                 wfDebugLog( 'exception', $log . "\n" . $this->getTraceAsString() . "\n" );
 256                         } else {
 257                                 wfDebugLog( 'exception', $log );
 258                         }
 259                 }
 260
 261                 if ( defined( 'MW_API' ) ) {
 262                         // Unhandled API exception, we can't be sure that format printer is alive
 263                         header( 'MediaWiki-API-Error: internal_api_error_' . get_class( $this ) );
 264                         wfHttpError( 500, 'Internal Server Error', $this->getText() );
 265                 } elseif ( self::isCommandLine() ) {
 266                         MWExceptionHandler::printError( $this->getText() );
 267                 } else {
 268                         header( "HTTP/1.1 500 MediaWiki exception" );
 269                         header( "Status: 500 MediaWiki exception", true );
 270                         header( "Content-Type: $wgMimeType; charset=utf-8", true );
 271
 272                         $this->reportHTML();
 273                 }
 274         }
 275
 276         /**
 277          * Check whether we are in command line mode or not to report the exception
 278          * in the correct format.
 279          *
 280          * @return bool
 281          */
 282         static function isCommandLine() {
 283                 return !empty( $GLOBALS['wgCommandLineMode'] );
 284         }
 285 }
 286
 287 /**
 288  * Exception class which takes an HTML error message, and does not
 289  * produce a backtrace. Replacement for OutputPage::fatalError().
 290  *
 291  * @since 1.7
 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  * @since 1.7
 315  * @ingroup Exception
 316  */
 317 class ErrorPageError extends MWException {
 318         public $title, $msg, $params;
 319
 320         /**
 321          * Note: these arguments are keys into wfMessage(), not text!
 322          *
 323          * @param string|Message $title Message key (string) for page title, or a Message object
 324          * @param string|Message $msg Message key (string) for error text, or a Message object
 325          * @param array $params with parameters to wfMessage()
 326          */
 327         function __construct( $title, $msg, $params = null ) {
 328                 $this->title = $title;
 329                 $this->msg = $msg;
 330                 $this->params = $params;
 331
 332                 // Bug 44111: Messages in the log files should be in English and not
 333                 // customized by the local wiki. So get the default English version for
 334                 // passing to the parent constructor. Our overridden report() below
 335                 // makes sure that the page shown to the user is not forced to English.
 336                 if( $msg instanceof Message ) {
 337                         $enMsg = clone( $msg );
 338                 } else {
 339                         $enMsg = wfMessage( $msg, $params );
 340                 }
 341                 $enMsg->inLanguage( 'en' )->useDatabase( false );
 342                 parent::__construct( $enMsg->text() );
 343         }
 344
 345         function report() {
 346                 global $wgOut;
 347
 348                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 349                 $wgOut->output();
 350         }
 351 }
 352
 353 /**
 354  * Show an error page on a badtitle.
 355  * Similar to ErrorPage, but emit a 400 HTTP error code to let mobile
 356  * browser it is not really a valid content.
 357  *
 358  * @since 1.19
 359  * @ingroup Exception
 360  */
 361 class BadTitleError extends ErrorPageError {
 362         /**
 363          * @param string|Message $msg A message key (default: 'badtitletext')
 364          * @param array $params parameter to wfMessage()
 365          */
 366         function __construct( $msg = 'badtitletext', $params = null ) {
 367                 parent::__construct( 'badtitle', $msg, $params );
 368         }
 369
 370         /**
 371          * Just like ErrorPageError::report() but additionally set
 372          * a 400 HTTP status code (bug 33646).
 373          */
 374         function report() {
 375                 global $wgOut;
 376
 377                 // bug 33646: a badtitle error page need to return an error code
 378                 // to let mobile browser now that it is not a normal page.
 379                 $wgOut->setStatusCode( 400 );
 380                 parent::report();
 381         }
 382
 383 }
 384
 385 /**
 386  * Show an error when a user tries to do something they do not have the necessary
 387  * permissions for.
 388  *
 389  * @since 1.18
 390  * @ingroup Exception
 391  */
 392 class PermissionsError extends ErrorPageError {
 393         public $permission, $errors;
 394
 395         function __construct( $permission, $errors = array() ) {
 396                 global $wgLang;
 397
 398                 $this->permission = $permission;
 399
 400                 if ( !count( $errors ) ) {
 401                         $groups = array_map(
 402                                 array( 'User', 'makeGroupLinkWiki' ),
 403                                 User::getGroupsWithPermission( $this->permission )
 404                         );
 405
 406                         if ( $groups ) {
 407                                 $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
 408                         } else {
 409                                 $errors[] = array( 'badaccess-group0' );
 410                         }
 411                 }
 412
 413                 $this->errors = $errors;
 414         }
 415
 416         function report() {
 417                 global $wgOut;
 418
 419                 $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
 420                 $wgOut->output();
 421         }
 422 }
 423
 424 /**
 425  * Show an error when the wiki is locked/read-only and the user tries to do
 426  * something that requires write access.
 427  *
 428  * @since 1.18
 429  * @ingroup Exception
 430  */
 431 class ReadOnlyError extends ErrorPageError {
 432         public function __construct() {
 433                 parent::__construct(
 434                         'readonly',
 435                         'readonlytext',
 436                         wfReadOnlyReason()
 437                 );
 438         }
 439 }
 440
 441 /**
 442  * Show an error when the user hits a rate limit.
 443  *
 444  * @since 1.18
 445  * @ingroup Exception
 446  */
 447 class ThrottledError extends ErrorPageError {
 448         public function __construct() {
 449                 parent::__construct(
 450                         'actionthrottled',
 451                         'actionthrottledtext'
 452                 );
 453         }
 454
 455         public function report() {
 456                 global $wgOut;
 457                 $wgOut->setStatusCode( 503 );
 458                 parent::report();
 459         }
 460 }
 461
 462 /**
 463  * Show an error when the user tries to do something whilst blocked.
 464  *
 465  * @since 1.18
 466  * @ingroup Exception
 467  */
 468 class UserBlockedError extends ErrorPageError {
 469         public function __construct( Block $block ) {
 470                 global $wgLang, $wgRequest;
 471
 472                 $blocker = $block->getBlocker();
 473                 if ( $blocker instanceof User ) { // local user
 474                         $blockerUserpage = $block->getBlocker()->getUserPage();
 475                         $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 476                 } else { // foreign user
 477                         $link = $blocker;
 478                 }
 479
 480                 $reason = $block->mReason;
 481                 if( $reason == '' ) {
 482                         $reason = wfMessage( 'blockednoreason' )->text();
 483                 }
 484
 485                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 486                  * This could be a username, an IP range, or a single IP. */
 487                 $intended = $block->getTarget();
 488
 489                 parent::__construct(
 490                         'blockedtitle',
 491                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 492                         array(
 493                                 $link,
 494                                 $reason,
 495                                 $wgRequest->getIP(),
 496                                 $block->getByName(),
 497                                 $block->getId(),
 498                                 $wgLang->formatExpiry( $block->mExpiry ),
 499                                 $intended,
 500                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 501                         )
 502                 );
 503         }
 504 }
 505
 506 /**
 507  * Shows a generic "user is not logged in" error page.
 508  *
 509  * This is essentially an ErrorPageError exception which by default uses the
 510  * 'exception-nologin' as a title and 'exception-nologin-text' for the message.
 511  * @see bug 37627
 512  * @since 1.20
 513  *
 514  * @par Example:
 515  * @code
 516  * if( $user->isAnon() ) {
 517  *      throw new UserNotLoggedIn();
 518  * }
 519  * @endcode
 520  *
 521  * Note the parameter order differs from ErrorPageError, this allows you to
 522  * simply specify a reason without overriding the default title.
 523  *
 524  * @par Example:
 525  * @code
 526  * if( $user->isAnon() ) {
 527  *      throw new UserNotLoggedIn( 'action-require-loggedin' );
 528  * }
 529  * @endcode
 530  *
 531  * @ingroup Exception
 532  */
 533 class UserNotLoggedIn extends ErrorPageError {
 534
 535         /**
 536          * @param $reasonMsg A message key containing the reason for the error.
 537          *        Optional, default: 'exception-nologin-text'
 538          * @param $titleMsg A message key to set the page title.
 539          *        Optional, default: 'exception-nologin'
 540          * @param $params Parameters to wfMessage().
 541          *        Optional, default: null
 542          */
 543         public function __construct(
 544                 $reasonMsg = 'exception-nologin-text',
 545                 $titleMsg = 'exception-nologin',
 546                 $params = null
 547         ) {
 548                 parent::__construct( $titleMsg, $reasonMsg, $params );
 549         }
 550 }
 551
 552 /**
 553  * Show an error that looks like an HTTP server error.
 554  * Replacement for wfHttpError().
 555  *
 556  * @since 1.19
 557  * @ingroup Exception
 558  */
 559 class HttpError extends MWException {
 560         private $httpCode, $header, $content;
 561
 562         /**
 563          * Constructor
 564          *
 565          * @param $httpCode Integer: HTTP status code to send to the client
 566          * @param string|Message $content content of the message
 567          * @param string|Message $header content of the header (\<title\> and \<h1\>)
 568          */
 569         public function __construct( $httpCode, $content, $header = null ) {
 570                 parent::__construct( $content );
 571                 $this->httpCode = (int)$httpCode;
 572                 $this->header = $header;
 573                 $this->content = $content;
 574         }
 575
 576         /**
 577          * Returns the HTTP status code supplied to the constructor.
 578          *
 579          * @return int
 580          */
 581         public function getStatusCode() {
 582                 return $this->httpCode;
 583         }
 584
 585         /**
 586          * Report the HTTP error.
 587          * Sends the appropriate HTTP status code and outputs an
 588          * HTML page with an error message.
 589          */
 590         public function report() {
 591                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 592
 593                 header( "Status: {$this->httpCode} {$httpMessage}", true, $this->httpCode );
 594                 header( 'Content-type: text/html; charset=utf-8' );
 595
 596                 print $this->getHTML();
 597         }
 598
 599         /**
 600          * Returns HTML for reporting the HTTP error.
 601          * This will be a minimal but complete HTML document.
 602          *
 603          * @return string HTML
 604          */
 605         public function getHTML() {
 606                 if ( $this->header === null ) {
 607                         $header = HttpStatus::getMessage( $this->httpCode );
 608                 } elseif ( $this->header instanceof Message ) {
 609                         $header = $this->header->escaped();
 610                 } else {
 611                         $header = htmlspecialchars( $this->header );
 612                 }
 613
 614                 if ( $this->content instanceof Message ) {
 615                         $content = $this->content->escaped();
 616                 } else {
 617                         $content = htmlspecialchars( $this->content );
 618                 }
 619
 620                 return "<!DOCTYPE html>\n".
 621                         "<html><head><title>$header</title></head>\n" .
 622                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 623         }
 624 }
 625
 626 /**
 627  * Handler class for MWExceptions
 628  * @ingroup Exception
 629  */
 630 class MWExceptionHandler {
 631         /**
 632          * Install an exception handler for MediaWiki exception types.
 633          */
 634         public static function installHandler() {
 635                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 636         }
 637
 638         /**
 639          * Report an exception to the user
 640          */
 641         protected static function report( Exception $e ) {
 642                 global $wgShowExceptionDetails;
 643
 644                 $cmdLine = MWException::isCommandLine();
 645
 646                 if ( $e instanceof MWException ) {
 647                         try {
 648                                 // Try and show the exception prettily, with the normal skin infrastructure
 649                                 $e->report();
 650                         } catch ( Exception $e2 ) {
 651                                 // Exception occurred from within exception handler
 652                                 // Show a simpler error message for the original exception,
 653                                 // don't try to invoke report()
 654                                 $message = "MediaWiki internal error.\n\n";
 655
 656                                 if ( $wgShowExceptionDetails ) {
 657                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 658                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 659                                 } else {
 660                                         $message .= "Exception caught inside exception handler.\n\n" .
 661                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 662                                                 "to show detailed debugging information.";
 663                                 }
 664
 665                                 $message .= "\n";
 666
 667                                 if ( $cmdLine ) {
 668                                         self::printError( $message );
 669                                 } else {
 670                                         echo nl2br( htmlspecialchars( $message ) ) . "\n";
 671                                 }
 672                         }
 673                 } else {
 674                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 675                                 $e->__toString() . "\n";
 676
 677                         if ( $wgShowExceptionDetails ) {
 678                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 679                         }
 680
 681                         if ( $cmdLine ) {
 682                                 self::printError( $message );
 683                         } else {
 684                                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 685                         }
 686                 }
 687         }
 688
 689         /**
 690          * Print a message, if possible to STDERR.
 691          * Use this in command line mode only (see isCommandLine)
 692          *
 693          * @param string $message Failure text
 694          */
 695         public static function printError( $message ) {
 696                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 697                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 698                 if ( defined( 'STDERR' ) ) {
 699                         fwrite( STDERR, $message );
 700                 } else {
 701                         echo( $message );
 702                 }
 703         }
 704
 705         /**
 706          * Exception handler which simulates the appropriate catch() handling:
 707          *
 708          *   try {
 709          *       ...
 710          *   } catch ( MWException $e ) {
 711          *       $e->report();
 712          *   } catch ( Exception $e ) {
 713          *       echo $e->__toString();
 714          *   }
 715          */
 716         public static function handle( $e ) {
 717                 global $wgFullyInitialised;
 718
 719                 self::report( $e );
 720
 721                 // Final cleanup
 722                 if ( $wgFullyInitialised ) {
 723                         try {
 724                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 725                         } catch ( Exception $e ) {}
 726                 }
 727
 728                 // Exit value should be nonzero for the benefit of shell jobs
 729                 exit( 1 );
 730         }
 731 }