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