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                         header( "HTTP/1.1 500 MediaWiki exception" );
 250                         header( "Status: 500 MediaWiki exception", true );
 251
 252                         $this->reportHTML();
 253                 }
 254         }
 255
 256         /**
 257          * @static
 258          * @return bool
 259          */
 260         static function isCommandLine() {
 261                 return !empty( $GLOBALS['wgCommandLineMode'] );
 262         }
 263 }
 264
 265 /**
 266  * Exception class which takes an HTML error message, and does not
 267  * produce a backtrace. Replacement for OutputPage::fatalError().
 268  * @ingroup Exception
 269  */
 270 class FatalError extends MWException {
 271
 272         /**
 273          * @return string
 274          */
 275         function getHTML() {
 276                 return $this->getMessage();
 277         }
 278
 279         /**
 280          * @return string
 281          */
 282         function getText() {
 283                 return $this->getMessage();
 284         }
 285 }
 286
 287 /**
 288  * An error page which can definitely be safely rendered using the OutputPage
 289  * @ingroup Exception
 290  */
 291 class ErrorPageError extends MWException {
 292         public $title, $msg, $params;
 293
 294         /**
 295          * @todo document
 296          *
 297          * Note: these arguments are keys into wfMsg(), not text!
 298          *
 299          * @param $title A title
 300          * @param $msg String|Message . In string form, should be a message key
 301          * @param $params Array Array to wfMsg()
 302          */
 303         function __construct( $title, $msg, $params = null ) {
 304                 $this->title = $title;
 305                 $this->msg = $msg;
 306                 $this->params = $params;
 307
 308                 if( $msg instanceof Message ){
 309                         parent::__construct( $msg );
 310                 } else {
 311                         parent::__construct( wfMsg( $msg ) );
 312                 }
 313         }
 314
 315         function report() {
 316                 global $wgOut;
 317
 318                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 319                 $wgOut->output();
 320         }
 321 }
 322
 323 /**
 324  * Show an error page on a badtitle.
 325  * Similar to ErrorPage, but emit a 400 HTTP error code to let mobile
 326  * browser it is not really a valid content.
 327  */
 328 class BadTitleError extends ErrorPageError {
 329
 330         /**
 331          * @param $msg string A message key (default: 'badtitletext')
 332          * @param $params Array parameter to wfMsg()
 333          */
 334         function __construct( $msg = 'badtitletext', $params = null ) {
 335                 parent::__construct( 'badtitle', $msg, $params );
 336         }
 337
 338         /**
 339          * Just like ErrorPageError::report() but additionally set
 340          * a 400 HTTP status code (bug 33646).
 341          */
 342         function report() {
 343                 global $wgOut;
 344
 345                 // bug 33646: a badtitle error page need to return an error code
 346                 // to let mobile browser now that it is not a normal page.
 347                 $wgOut->setStatusCode( 400 );
 348                 parent::report();
 349         }
 350
 351 }
 352
 353 /**
 354  * Show an error when a user tries to do something they do not have the necessary
 355  * permissions for.
 356  * @ingroup Exception
 357  */
 358 class PermissionsError extends ErrorPageError {
 359         public $permission, $errors;
 360
 361         function __construct( $permission, $errors = array() ) {
 362                 global $wgLang;
 363
 364                 $this->permission = $permission;
 365
 366                 if ( !count( $errors ) ) {
 367                         $groups = array_map(
 368                                 array( 'User', 'makeGroupLinkWiki' ),
 369                                 User::getGroupsWithPermission( $this->permission )
 370                         );
 371
 372                         if ( $groups ) {
 373                                 $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
 374                         } else {
 375                                 $errors[] = array( 'badaccess-group0' );
 376                         }
 377                 }
 378
 379                 $this->errors = $errors;
 380         }
 381
 382         function report() {
 383                 global $wgOut;
 384
 385                 $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
 386                 $wgOut->output();
 387         }
 388 }
 389
 390 /**
 391  * Show an error when the wiki is locked/read-only and the user tries to do
 392  * something that requires write access
 393  * @ingroup Exception
 394  */
 395 class ReadOnlyError extends ErrorPageError {
 396         public function __construct(){
 397                 parent::__construct(
 398                         'readonly',
 399                         'readonlytext',
 400                         wfReadOnlyReason()
 401                 );
 402         }
 403 }
 404
 405 /**
 406  * Show an error when the user hits a rate limit
 407  * @ingroup Exception
 408  */
 409 class ThrottledError extends ErrorPageError {
 410         public function __construct(){
 411                 parent::__construct(
 412                         'actionthrottled',
 413                         'actionthrottledtext'
 414                 );
 415         }
 416
 417         public function report(){
 418                 global $wgOut;
 419                 $wgOut->setStatusCode( 503 );
 420                 parent::report();
 421         }
 422 }
 423
 424 /**
 425  * Show an error when the user tries to do something whilst blocked
 426  * @ingroup Exception
 427  */
 428 class UserBlockedError extends ErrorPageError {
 429         public function __construct( Block $block ){
 430                 global $wgLang, $wgRequest;
 431
 432                 $blocker = $block->getBlocker();
 433                 if ( $blocker instanceof User ) { // local user
 434                         $blockerUserpage = $block->getBlocker()->getUserPage();
 435                         $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 436                 } else { // foreign user
 437                         $link = $blocker;
 438                 }
 439
 440                 $reason = $block->mReason;
 441                 if( $reason == '' ) {
 442                         $reason = wfMsg( 'blockednoreason' );
 443                 }
 444
 445                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 446                  * This could be a username, an IP range, or a single IP. */
 447                 $intended = $block->getTarget();
 448
 449                 parent::__construct(
 450                         'blockedtitle',
 451                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 452                         array(
 453                                 $link,
 454                                 $reason,
 455                                 $wgRequest->getIP(),
 456                                 $block->getByName(),
 457                                 $block->getId(),
 458                                 $wgLang->formatExpiry( $block->mExpiry ),
 459                                 $intended,
 460                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 461                         )
 462                 );
 463         }
 464 }
 465
 466 /**
 467  * Shows a generic "user is not logged in" error page.
 468  *
 469  * This is essentially an ErrorPageError exception which by default use the
 470  * 'exception-nologin' as a title and 'exception-nologin-text' for the message.
 471  * @see bug 37627
 472  *
 473  * @par Example:
 474  * @code
 475  * if( $user->isAnon ) {
 476  *      throw new UserNotLoggedIn();
 477  * }
 478  * @endcode
 479  *
 480  * Please note the parameters are mixed up compared to ErrorPageError, this
 481  * is done to be able to simply specify a reason whitout overriding the default
 482  * title.
 483  *
 484  * @par Example:
 485  * @code
 486  * if( $user->isAnon ) {
 487  *      throw new UserNotLoggedIn( 'action-require-loggedin' );
 488  * }
 489  * @endcode
 490  *
 491  * @param $reasonMsg A message key containing the reason for the error.
 492  *        Optional, default: 'exception-nologin-text'
 493  * @param $titleMsg A message key to set the page title.
 494  *        Optional, default: 'exception-nologin'
 495  * @param $params Parameters to wfMsg().
 496  *        Optiona, default: null
 497  */
 498 class UserNotLoggedIn extends ErrorPageError {
 499
 500         public function __construct(
 501                 $reasonMsg = 'exception-nologin-text',
 502                 $titleMsg  = 'exception-nologin',
 503                 $params = null
 504         ) {
 505                 parent::__construct( $titleMsg, $reasonMsg, $params );
 506         }
 507 }
 508
 509 /**
 510  * Show an error that looks like an HTTP server error.
 511  * Replacement for wfHttpError().
 512  *
 513  * @ingroup Exception
 514  */
 515 class HttpError extends MWException {
 516         private $httpCode, $header, $content;
 517
 518         /**
 519          * Constructor
 520          *
 521          * @param $httpCode Integer: HTTP status code to send to the client
 522          * @param $content String|Message: content of the message
 523          * @param $header String|Message: content of the header (\<title\> and \<h1\>)
 524          */
 525         public function __construct( $httpCode, $content, $header = null ){
 526                 parent::__construct( $content );
 527                 $this->httpCode = (int)$httpCode;
 528                 $this->header = $header;
 529                 $this->content = $content;
 530         }
 531
 532         public function report() {
 533                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 534
 535                 header( "Status: {$this->httpCode} {$httpMessage}" );
 536                 header( 'Content-type: text/html; charset=utf-8' );
 537
 538                 if ( $this->header === null ) {
 539                         $header = $httpMessage;
 540                 } elseif ( $this->header instanceof Message ) {
 541                         $header = $this->header->escaped();
 542                 } else {
 543                         $header = htmlspecialchars( $this->header );
 544                 }
 545
 546                 if ( $this->content instanceof Message ) {
 547                         $content = $this->content->escaped();
 548                 } else {
 549                         $content = htmlspecialchars( $this->content );
 550                 }
 551
 552                 print "<!DOCTYPE html>\n".
 553                         "<html><head><title>$header</title></head>\n" .
 554                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 555         }
 556 }
 557
 558 /**
 559  * Handler class for MWExceptions
 560  * @ingroup Exception
 561  */
 562 class MWExceptionHandler {
 563         /**
 564          * Install an exception handler for MediaWiki exception types.
 565          */
 566         public static function installHandler() {
 567                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 568         }
 569
 570         /**
 571          * Report an exception to the user
 572          */
 573         protected static function report( Exception $e ) {
 574                 global $wgShowExceptionDetails;
 575
 576                 $cmdLine = MWException::isCommandLine();
 577
 578                 if ( $e instanceof MWException ) {
 579                         try {
 580                                 // Try and show the exception prettily, with the normal skin infrastructure
 581                                 $e->report();
 582                         } catch ( Exception $e2 ) {
 583                                 // Exception occurred from within exception handler
 584                                 // Show a simpler error message for the original exception,
 585                                 // don't try to invoke report()
 586                                 $message = "MediaWiki internal error.\n\n";
 587
 588                                 if ( $wgShowExceptionDetails ) {
 589                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 590                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 591                                 } else {
 592                                         $message .= "Exception caught inside exception handler.\n\n" .
 593                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 594                                                 "to show detailed debugging information.";
 595                                 }
 596
 597                                 $message .= "\n";
 598
 599                                 if ( $cmdLine ) {
 600                                         self::printError( $message );
 601                                 } else {
 602                                         self::escapeEchoAndDie( $message );
 603                                 }
 604                         }
 605                 } else {
 606                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 607                                 $e->__toString() . "\n";
 608
 609                         if ( $wgShowExceptionDetails ) {
 610                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 611                         }
 612
 613                         if ( $cmdLine ) {
 614                                 self::printError( $message );
 615                         } else {
 616                                 self::escapeEchoAndDie( $message );
 617                         }
 618                 }
 619         }
 620
 621         /**
 622          * Print a message, if possible to STDERR.
 623          * Use this in command line mode only (see isCommandLine)
 624          * @param $message String Failure text
 625          */
 626         public static function printError( $message ) {
 627                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 628                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 629                 if ( defined( 'STDERR' ) ) {
 630                         fwrite( STDERR, $message );
 631                 } else {
 632                         echo( $message );
 633                 }
 634         }
 635
 636         /**
 637          * Print a message after escaping it and converting newlines to <br>
 638          * Use this for non-command line failures
 639          * @param $message String Failure text
 640          */
 641         private static function escapeEchoAndDie( $message ) {
 642                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 643                 die(1);
 644         }
 645
 646         /**
 647          * Exception handler which simulates the appropriate catch() handling:
 648          *
 649          *   try {
 650          *       ...
 651          *   } catch ( MWException $e ) {
 652          *       $e->report();
 653          *   } catch ( Exception $e ) {
 654          *       echo $e->__toString();
 655          *   }
 656          */
 657         public static function handle( $e ) {
 658                 global $wgFullyInitialised;
 659
 660                 self::report( $e );
 661
 662                 // Final cleanup
 663                 if ( $wgFullyInitialised ) {
 664                         try {
 665                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 666                         } catch ( Exception $e ) {}
 667                 }
 668
 669                 // Exit value should be nonzero for the benefit of shell jobs
 670                 exit( 1 );
 671         }
 672 }