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                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 217                         if ( $hookResult ) {
 218                                 die( $hookResult );
 219                         }
 220
 221                         echo $this->getHTML();
 222                         die(1);
 223                 }
 224         }
 225
 226         /**
 227          * Output a report about the exception and takes care of formatting.
 228          * It will be either HTML or plain text based on isCommandLine().
 229          */
 230         function report() {
 231                 global $wgLogExceptionBacktrace;
 232                 $log = $this->getLogMessage();
 233
 234                 if ( $log ) {
 235                         if ( $wgLogExceptionBacktrace ) {
 236                                 wfDebugLog( 'exception', $log . "\n" . $this->getTraceAsString() . "\n" );
 237                         } else {
 238                                 wfDebugLog( 'exception', $log );
 239                         }
 240                 }
 241
 242                 if ( defined( 'MW_API' ) ) {
 243                         // Unhandled API exception, we can't be sure that format printer is alive
 244                         header( 'MediaWiki-API-Error: internal_api_error_' . get_class( $this ) );
 245                         wfHttpError(500, 'Internal Server Error', $this->getText() );
 246                 } elseif ( self::isCommandLine() ) {
 247                         MWExceptionHandler::printError( $this->getText() );
 248                 } else {
 249                         $this->reportHTML();
 250                 }
 251         }
 252
 253         /**
 254          * @static
 255          * @return bool
 256          */
 257         static function isCommandLine() {
 258                 return !empty( $GLOBALS['wgCommandLineMode'] );
 259         }
 260 }
 261
 262 /**
 263  * Exception class which takes an HTML error message, and does not
 264  * produce a backtrace. Replacement for OutputPage::fatalError().
 265  * @ingroup Exception
 266  */
 267 class FatalError extends MWException {
 268
 269         /**
 270          * @return string
 271          */
 272         function getHTML() {
 273                 return $this->getMessage();
 274         }
 275
 276         /**
 277          * @return string
 278          */
 279         function getText() {
 280                 return $this->getMessage();
 281         }
 282 }
 283
 284 /**
 285  * An error page which can definitely be safely rendered using the OutputPage
 286  * @ingroup Exception
 287  */
 288 class ErrorPageError extends MWException {
 289         public $title, $msg, $params;
 290
 291         /**
 292          * Note: these arguments are keys into wfMsg(), not text!
 293          */
 294         function __construct( $title, $msg, $params = null ) {
 295                 $this->title = $title;
 296                 $this->msg = $msg;
 297                 $this->params = $params;
 298
 299                 if( $msg instanceof Message ){
 300                         parent::__construct( $msg );
 301                 } else {
 302                         parent::__construct( wfMsg( $msg ) );
 303                 }
 304         }
 305
 306         function report() {
 307                 global $wgOut;
 308
 309                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 310                 $wgOut->output();
 311         }
 312 }
 313
 314 /**
 315  * Show an error page on a badtitle.
 316  * Similar to ErrorPage, but emit a 400 HTTP error code to let mobile
 317  * browser it is not really a valid content.
 318  */
 319 class BadTitleError extends ErrorPageError {
 320
 321         /**
 322          * @param $msg string A message key (default: 'badtitletext')
 323          * @param $params Array parameter to wfMsg()
 324          */
 325         function __construct( $msg = 'badtitletext', $params = null ) {
 326                 parent::__construct( 'badtitle', $msg, $params );
 327         }
 328
 329         /**
 330          * Just like ErrorPageError::report() but additionally set
 331          * a 400 HTTP status code (bug 33646).
 332          */
 333         function report() {
 334                 global $wgOut;
 335
 336                 // bug 33646: a badtitle error page need to return an error code
 337                 // to let mobile browser now that it is not a normal page.
 338                 $wgOut->setStatusCode( 400 );
 339                 parent::report();
 340         }
 341
 342 }
 343
 344 /**
 345  * Show an error when a user tries to do something they do not have the necessary
 346  * permissions for.
 347  * @ingroup Exception
 348  */
 349 class PermissionsError extends ErrorPageError {
 350         public $permission, $errors;
 351
 352         function __construct( $permission, $errors = array() ) {
 353                 global $wgLang;
 354
 355                 $this->permission = $permission;
 356
 357                 if ( !count( $errors ) ) {
 358                         $groups = array_map(
 359                                 array( 'User', 'makeGroupLinkWiki' ),
 360                                 User::getGroupsWithPermission( $this->permission )
 361                         );
 362
 363                         if ( $groups ) {
 364                                 $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
 365                         } else {
 366                                 $errors[] = array( 'badaccess-group0' );
 367                         }
 368                 }
 369
 370                 $this->errors = $errors;
 371         }
 372
 373         function report() {
 374                 global $wgOut;
 375
 376                 $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
 377                 $wgOut->output();
 378         }
 379 }
 380
 381 /**
 382  * Show an error when the wiki is locked/read-only and the user tries to do
 383  * something that requires write access
 384  * @ingroup Exception
 385  */
 386 class ReadOnlyError extends ErrorPageError {
 387         public function __construct(){
 388                 parent::__construct(
 389                         'readonly',
 390                         'readonlytext',
 391                         wfReadOnlyReason()
 392                 );
 393         }
 394 }
 395
 396 /**
 397  * Show an error when the user hits a rate limit
 398  * @ingroup Exception
 399  */
 400 class ThrottledError extends ErrorPageError {
 401         public function __construct(){
 402                 parent::__construct(
 403                         'actionthrottled',
 404                         'actionthrottledtext'
 405                 );
 406         }
 407
 408         public function report(){
 409                 global $wgOut;
 410                 $wgOut->setStatusCode( 503 );
 411                 parent::report();
 412         }
 413 }
 414
 415 /**
 416  * Show an error when the user tries to do something whilst blocked
 417  * @ingroup Exception
 418  */
 419 class UserBlockedError extends ErrorPageError {
 420         public function __construct( Block $block ){
 421                 global $wgLang, $wgRequest;
 422
 423                 $blocker = $block->getBlocker();
 424                 if ( $blocker instanceof User ) { // local user
 425                         $blockerUserpage = $block->getBlocker()->getUserPage();
 426                         $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 427                 } else { // foreign user
 428                         $link = $blocker;
 429                 }
 430
 431                 $reason = $block->mReason;
 432                 if( $reason == '' ) {
 433                         $reason = wfMsg( 'blockednoreason' );
 434                 }
 435
 436                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 437                  * This could be a username, an IP range, or a single IP. */
 438                 $intended = $block->getTarget();
 439
 440                 parent::__construct(
 441                         'blockedtitle',
 442                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 443                         array(
 444                                 $link,
 445                                 $reason,
 446                                 $wgRequest->getIP(),
 447                                 $block->getByName(),
 448                                 $block->getId(),
 449                                 $wgLang->formatExpiry( $block->mExpiry ),
 450                                 $intended,
 451                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 452                         )
 453                 );
 454         }
 455 }
 456
 457 /**
 458  * Show an error that looks like an HTTP server error.
 459  * Replacement for wfHttpError().
 460  *
 461  * @ingroup Exception
 462  */
 463 class HttpError extends MWException {
 464         private $httpCode, $header, $content;
 465
 466         /**
 467          * Constructor
 468          *
 469          * @param $httpCode Integer: HTTP status code to send to the client
 470          * @param $content String|Message: content of the message
 471          * @param $header String|Message: content of the header (\<title\> and \<h1\>)
 472          */
 473         public function __construct( $httpCode, $content, $header = null ){
 474                 parent::__construct( $content );
 475                 $this->httpCode = (int)$httpCode;
 476                 $this->header = $header;
 477                 $this->content = $content;
 478         }
 479
 480         public function report() {
 481                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 482
 483                 header( "Status: {$this->httpCode} {$httpMessage}" );
 484                 header( 'Content-type: text/html; charset=utf-8' );
 485
 486                 if ( $this->header === null ) {
 487                         $header = $httpMessage;
 488                 } elseif ( $this->header instanceof Message ) {
 489                         $header = $this->header->escaped();
 490                 } else {
 491                         $header = htmlspecialchars( $this->header );
 492                 }
 493
 494                 if ( $this->content instanceof Message ) {
 495                         $content = $this->content->escaped();
 496                 } else {
 497                         $content = htmlspecialchars( $this->content );
 498                 }
 499
 500                 print "<!DOCTYPE html>\n".
 501                         "<html><head><title>$header</title></head>\n" .
 502                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 503         }
 504 }
 505
 506 /**
 507  * Handler class for MWExceptions
 508  * @ingroup Exception
 509  */
 510 class MWExceptionHandler {
 511         /**
 512          * Install an exception handler for MediaWiki exception types.
 513          */
 514         public static function installHandler() {
 515                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 516         }
 517
 518         /**
 519          * Report an exception to the user
 520          */
 521         protected static function report( Exception $e ) {
 522                 global $wgShowExceptionDetails;
 523
 524                 $cmdLine = MWException::isCommandLine();
 525
 526                 if ( $e instanceof MWException ) {
 527                         try {
 528                                 // Try and show the exception prettily, with the normal skin infrastructure
 529                                 $e->report();
 530                         } catch ( Exception $e2 ) {
 531                                 // Exception occurred from within exception handler
 532                                 // Show a simpler error message for the original exception,
 533                                 // don't try to invoke report()
 534                                 $message = "MediaWiki internal error.\n\n";
 535
 536                                 if ( $wgShowExceptionDetails ) {
 537                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 538                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 539                                 } else {
 540                                         $message .= "Exception caught inside exception handler.\n\n" .
 541                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 542                                                 "to show detailed debugging information.";
 543                                 }
 544
 545                                 $message .= "\n";
 546
 547                                 if ( $cmdLine ) {
 548                                         self::printError( $message );
 549                                 } else {
 550                                         self::escapeEchoAndDie( $message );
 551                                 }
 552                         }
 553                 } else {
 554                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 555                                 $e->__toString() . "\n";
 556
 557                         if ( $wgShowExceptionDetails ) {
 558                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 559                         }
 560
 561                         if ( $cmdLine ) {
 562                                 self::printError( $message );
 563                         } else {
 564                                 self::escapeEchoAndDie( $message );
 565                         }
 566                 }
 567         }
 568
 569         /**
 570          * Print a message, if possible to STDERR.
 571          * Use this in command line mode only (see isCommandLine)
 572          * @param $message String Failure text
 573          */
 574         public static function printError( $message ) {
 575                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 576                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 577                 if ( defined( 'STDERR' ) ) {
 578                         fwrite( STDERR, $message );
 579                 } else {
 580                         echo( $message );
 581                 }
 582         }
 583
 584         /**
 585          * Print a message after escaping it and converting newlines to <br>
 586          * Use this for non-command line failures
 587          * @param $message String Failure text
 588          */
 589         private static function escapeEchoAndDie( $message ) {
 590                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 591                 die(1);
 592         }
 593
 594         /**
 595          * Exception handler which simulates the appropriate catch() handling:
 596          *
 597          *   try {
 598          *       ...
 599          *   } catch ( MWException $e ) {
 600          *       $e->report();
 601          *   } catch ( Exception $e ) {
 602          *       echo $e->__toString();
 603          *   }
 604          */
 605         public static function handle( $e ) {
 606                 global $wgFullyInitialised;
 607
 608                 self::report( $e );
 609
 610                 // Final cleanup
 611                 if ( $wgFullyInitialised ) {
 612                         try {
 613                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 614                         } catch ( Exception $e ) {}
 615                 }
 616
 617                 // Exit value should be nonzero for the benefit of shell jobs
 618                 exit( 1 );
 619         }
 620 }