includes/Exception.php

   1 <?php
   2 /**
   3  * Exception class and handler
   4  *
   5  * @file
   6  */
   7
   8 /**
   9  * @defgroup Exception Exception
  10  */
  11
  12 /**
  13  * MediaWiki exception
  14  *
  15  * @ingroup Exception
  16  */
  17 class MWException extends Exception {
  18         /**
  19          * Should the exception use $wgOut to output the error ?
  20          * @return bool
  21          */
  22         function useOutputPage() {
  23                 return $this->useMessageCache() &&
  24                         !empty( $GLOBALS['wgFullyInitialised'] ) &&
  25                         ( !empty( $GLOBALS['wgArticle'] ) || ( !empty( $GLOBALS['wgOut'] ) && !$GLOBALS['wgOut']->isArticleRelated() ) ) &&
  26                         !empty( $GLOBALS['wgTitle'] );
  27         }
  28
  29         /**
  30          * Can the extension use wfMsg() to get i18n messages ?
  31          * @return bool
  32          */
  33         function useMessageCache() {
  34                 global $wgLang;
  35
  36                 foreach ( $this->getTrace() as $frame ) {
  37                         if ( isset( $frame['class'] ) && $frame['class'] === 'LocalisationCache' ) {
  38                                 return false;
  39                         }
  40                 }
  41
  42                 return $wgLang instanceof Language;
  43         }
  44
  45         /**
  46          * Run hook to allow extensions to modify the text of the exception
  47          *
  48          * @param $name String: class name of the exception
  49          * @param $args Array: arguments to pass to the callback functions
  50          * @return Mixed: string to output or null if any hook has been called
  51          */
  52         function runHooks( $name, $args = array() ) {
  53                 global $wgExceptionHooks;
  54
  55                 if ( !isset( $wgExceptionHooks ) || !is_array( $wgExceptionHooks ) ) {
  56                         return; // Just silently ignore
  57                 }
  58
  59                 if ( !array_key_exists( $name, $wgExceptionHooks ) || !is_array( $wgExceptionHooks[ $name ] ) ) {
  60                         return;
  61                 }
  62
  63                 $hooks = $wgExceptionHooks[ $name ];
  64                 $callargs = array_merge( array( $this ), $args );
  65
  66                 foreach ( $hooks as $hook ) {
  67                         if ( is_string( $hook ) || ( is_array( $hook ) && count( $hook ) >= 2 && is_string( $hook[0] ) ) ) {    // 'function' or array( 'class', hook' )
  68                                 $result = call_user_func_array( $hook, $callargs );
  69                         } else {
  70                                 $result = null;
  71                         }
  72
  73                         if ( is_string( $result ) )
  74                                 return $result;
  75                 }
  76         }
  77
  78         /**
  79          * Get a message from i18n
  80          *
  81          * @param $key String: message name
  82          * @param $fallback String: default message if the message cache can't be
  83          *                  called by the exception
  84          * The function also has other parameters that are arguments for the message
  85          * @return String message with arguments replaced
  86          */
  87         function msg( $key, $fallback /*[, params...] */ ) {
  88                 $args = array_slice( func_get_args(), 2 );
  89
  90                 if ( $this->useMessageCache() ) {
  91                         return wfMsgNoTrans( $key, $args );
  92                 } else {
  93                         return wfMsgReplaceArgs( $fallback, $args );
  94                 }
  95         }
  96
  97         /**
  98          * If $wgShowExceptionDetails is true, return a HTML message with a
  99          * backtrace to the error, otherwise show a message to ask to set it to true
 100          * to show that information.
 101          *
 102          * @return String html to output
 103          */
 104         function getHTML() {
 105                 global $wgShowExceptionDetails;
 106
 107                 if ( $wgShowExceptionDetails ) {
 108                         return '<p>' . nl2br( htmlspecialchars( $this->getMessage() ) ) .
 109                                 '</p><p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
 110                                 "</p>\n";
 111                 } else {
 112                         return "<p>Set <b><tt>\$wgShowExceptionDetails = true;</tt></b> " .
 113                                 "at the bottom of LocalSettings.php to show detailed " .
 114                                 "debugging information.</p>";
 115                 }
 116         }
 117
 118         /**
 119          * If $wgShowExceptionDetails is true, return a text message with a
 120          * backtrace to the error.
 121          */
 122         function getText() {
 123                 global $wgShowExceptionDetails;
 124
 125                 if ( $wgShowExceptionDetails ) {
 126                         return $this->getMessage() .
 127                                 "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
 128                 } else {
 129                         return "Set \$wgShowExceptionDetails = true; " .
 130                                 "in LocalSettings.php to show detailed debugging information.\n";
 131                 }
 132         }
 133
 134         /* Return titles of this error page */
 135         function getPageTitle() {
 136                 global $wgSitename;
 137                 return $this->msg( 'internalerror', "$wgSitename error" );
 138         }
 139
 140         /**
 141          * Return the requested URL and point to file and line number from which the
 142          * exception occured
 143          *
 144          * @return String
 145          */
 146         function getLogMessage() {
 147                 global $wgRequest;
 148
 149                 $file = $this->getFile();
 150                 $line = $this->getLine();
 151                 $message = $this->getMessage();
 152
 153                 if ( isset( $wgRequest ) ) {
 154                         $url = $wgRequest->getRequestURL();
 155                         if ( !$url ) {
 156                                 $url = '[no URL]';
 157                         }
 158                 } else {
 159                         $url = '[no req]';
 160                 }
 161
 162                 return "$url   Exception from line $line of $file: $message";
 163         }
 164
 165         /** Output the exception report using HTML */
 166         function reportHTML() {
 167                 global $wgOut;
 168
 169                 if ( $this->useOutputPage() ) {
 170                         $wgOut->setPageTitle( $this->getPageTitle() );
 171                         $wgOut->setRobotPolicy( "noindex,nofollow" );
 172                         $wgOut->setArticleRelated( false );
 173                         $wgOut->enableClientCache( false );
 174                         $wgOut->redirect( '' );
 175                         $wgOut->clearHTML();
 176
 177                         $hookResult = $this->runHooks( get_class( $this ) );
 178                         if ( $hookResult ) {
 179                                 $wgOut->addHTML( $hookResult );
 180                         } else {
 181                                 $wgOut->addHTML( $this->getHTML() );
 182                         }
 183
 184                         $wgOut->output();
 185                 } else {
 186                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 187                         if ( $hookResult ) {
 188                                 die( $hookResult );
 189                         }
 190
 191                         if ( defined( 'MEDIAWIKI_INSTALL' ) || $this->htmlBodyOnly() ) {
 192                                 echo $this->getHTML();
 193                         } else {
 194                                 echo $this->htmlHeader();
 195                                 echo $this->getHTML();
 196                                 echo $this->htmlFooter();
 197                         }
 198                 }
 199         }
 200
 201         /**
 202          * Output a report about the exception and takes care of formatting.
 203          * It will be either HTML or plain text based on isCommandLine().
 204          */
 205         function report() {
 206                 $log = $this->getLogMessage();
 207
 208                 if ( $log ) {
 209                         wfDebugLog( 'exception', $log );
 210                 }
 211
 212                 if ( self::isCommandLine() ) {
 213                         wfPrintError( $this->getText() );
 214                 } else {
 215                         $this->reportHTML();
 216                 }
 217         }
 218
 219         /**
 220          * Send headers and output the beginning of the html page if not using
 221          * $wgOut to output the exception.
 222          */
 223         function htmlHeader() {
 224                 global $wgLogo, $wgOutputEncoding, $wgLang;
 225
 226                 if ( !headers_sent() ) {
 227                         header( 'HTTP/1.0 500 Internal Server Error' );
 228                         header( 'Content-type: text/html; charset=' . $wgOutputEncoding );
 229                         /* Don't cache error pages!  They cause no end of trouble... */
 230                         header( 'Cache-control: none' );
 231                         header( 'Pragma: nocache' );
 232                 }
 233
 234                 $head = Html::element( 'title', null, $this->getPageTitle() ) . "\n";
 235                 $head .= Html::inlineStyle( <<<ENDL
 236         body {
 237                 color: #000;
 238                 background-color: #fff;
 239                 font-family: sans-serif;
 240                 padding: 2em;
 241                 text-align: center;
 242         }
 243         p, img, h1 {
 244                 text-align: left;
 245                 margin: 0.5em 0;
 246         }
 247         h1 {
 248                 font-size: 120%;
 249         }
 250 ENDL
 251                 );
 252
 253                 $dir = 'ltr';
 254                 $code = 'en';
 255
 256                 if ( $wgLang instanceof Language ) {
 257                         $dir = $wgLang->getDir();
 258                         $code = $wgLang->getCode();
 259                 }
 260
 261                 $header = Html::element( 'img', array(
 262                         'src' => $wgLogo,
 263                         'alt' => '' ) );
 264
 265                 $attribs = array( 'dir' => $dir, 'lang' => $code );
 266
 267                 return
 268                         Html::htmlHeader( $attribs ) .
 269                         Html::rawElement( 'head', null, $head ) . "\n".
 270                         Html::openElement( 'body' ) . "\n" .
 271                         $header . "\n";
 272         }
 273
 274         /**
 275          * print the end of the html page if not using $wgOut.
 276          */
 277         function htmlFooter() {
 278                 return Html::closeElement( 'body' ) . Html::closeElement( 'html' );
 279         }
 280
 281         /**
 282          * headers handled by subclass?
 283          */
 284         function htmlBodyOnly() {
 285                 return false;
 286         }
 287
 288         static function isCommandLine() {
 289                 return !empty( $GLOBALS['wgCommandLineMode'] ) && !defined( 'MEDIAWIKI_INSTALL' );
 290         }
 291 }
 292
 293 /**
 294  * Exception class which takes an HTML error message, and does not
 295  * produce a backtrace. Replacement for OutputPage::fatalError().
 296  * @ingroup Exception
 297  */
 298 class FatalError extends MWException {
 299         function getHTML() {
 300                 return $this->getMessage();
 301         }
 302
 303         function getText() {
 304                 return $this->getMessage();
 305         }
 306 }
 307
 308 /**
 309  * An error page which can definitely be safely rendered using the OutputPage
 310  * @ingroup Exception
 311  */
 312 class ErrorPageError extends MWException {
 313         public $title, $msg, $params;
 314
 315         /**
 316          * Note: these arguments are keys into wfMsg(), not text!
 317          */
 318         function __construct( $title, $msg, $params = null ) {
 319                 $this->title = $title;
 320                 $this->msg = $msg;
 321                 $this->params = $params;
 322
 323                 if( $msg instanceof Message ){
 324                         parent::__construct( $msg );
 325                 } else {
 326                         parent::__construct( wfMsg( $msg ) );
 327                 }
 328         }
 329
 330         function report() {
 331                 global $wgOut;
 332
 333                 if ( $wgOut->getTitle() ) {
 334                         $wgOut->debug( 'Original title: ' . $wgOut->getTitle()->getPrefixedText() . "\n" );
 335                 }
 336                 $wgOut->setPageTitle( wfMsg( $this->title ) );
 337                 $wgOut->setHTMLTitle( wfMsg( 'errorpagetitle' ) );
 338                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 339                 $wgOut->setArticleRelated( false );
 340                 $wgOut->enableClientCache( false );
 341                 $wgOut->mRedirect = '';
 342                 $wgOut->clearHTML();
 343
 344                 if( $this->msg instanceof Message ){
 345                         $wgOut->addHTML( $this->msg->parse() );
 346                 } else {
 347                         $wgOut->addWikiMsgArray( $this->msg, $this->params );
 348                 }
 349
 350                 $wgOut->returnToMain();
 351                 $wgOut->output();
 352         }
 353 }
 354
 355 /**
 356  * Show an error when a user tries to do something they do not have the necessary
 357  * permissions for.
 358  */
 359 class PermissionsError extends ErrorPageError {
 360         public $permission;
 361
 362         function __construct( $permission ) {
 363                 global $wgLang;
 364
 365                 $this->permission = $permission;
 366
 367                 $groups = array_map(
 368                         array( 'User', 'makeGroupLinkWiki' ),
 369                         User::getGroupsWithPermission( $this->permission )
 370                 );
 371
 372                 if( $groups ) {
 373                         parent::__construct(
 374                                 'badaccess',
 375                                 'badaccess-groups',
 376                                 array(
 377                                         $wgLang->commaList( $groups ),
 378                                         count( $groups )
 379                                 )
 380                         );
 381                 } else {
 382                         parent::__construct(
 383                                 'badaccess',
 384                                 'badaccess-group0'
 385                         );
 386                 }
 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  */
 394 class ReadOnlyError extends ErrorPageError {
 395         public function __construct(){
 396                 parent::__construct(
 397                         'readonly',
 398                         'readonlytext',
 399                         wfReadOnlyReason()
 400                 );
 401         }
 402 }
 403
 404 /**
 405  * Show an error when the user hits a rate limit
 406  */
 407 class ThrottledError extends ErrorPageError {
 408         public function __construct(){
 409                 parent::__construct(
 410                         'actionthrottled',
 411                         'actionthrottledtext'
 412                 );
 413         }
 414         public function report(){
 415                 global $wgOut;
 416                 $wgOut->setStatusCode( 503 );
 417                 return parent::report();
 418         }
 419 }
 420
 421 /**
 422  * Show an error when the user tries to do something whilst blocked
 423  */
 424 class UserBlockedError extends ErrorPageError {
 425         public function __construct( Block $block ){
 426                 global $wgLang;
 427
 428                 $blockerUserpage = $block->getBlocker()->getUserPage();
 429                 $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 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 ? 'autoblocketext' : 'blockedtext',
 443                         array(
 444                                 $link,
 445                                 $reason,
 446                                 wfGetIP(),
 447                                 $block->getBlocker()->getName(),
 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  * Install an exception handler for MediaWiki exception types.
 459  */
 460 function wfInstallExceptionHandler() {
 461         set_exception_handler( 'wfExceptionHandler' );
 462 }
 463
 464 /**
 465  * Report an exception to the user
 466  */
 467 function wfReportException( Exception $e ) {
 468         global $wgShowExceptionDetails;
 469
 470         $cmdLine = MWException::isCommandLine();
 471
 472         if ( $e instanceof MWException ) {
 473                 try {
 474                         // Try and show the exception prettily, with the normal skin infrastructure
 475                         $e->report();
 476                 } catch ( Exception $e2 ) {
 477                         // Exception occurred from within exception handler
 478                         // Show a simpler error message for the original exception,
 479                         // don't try to invoke report()
 480                         $message = "MediaWiki internal error.\n\n";
 481
 482                         if ( $wgShowExceptionDetails ) {
 483                                 $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 484                                         'Exception caught inside exception handler: ' . $e2->__toString();
 485                         } else {
 486                                 $message .= "Exception caught inside exception handler.\n\n" .
 487                                         "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 488                                         "to show detailed debugging information.";
 489                         }
 490
 491                         $message .= "\n";
 492
 493                         if ( $cmdLine ) {
 494                                 wfPrintError( $message );
 495                         } else {
 496                                 wfDie( htmlspecialchars( $message ) ) . "\n";
 497                         }
 498                 }
 499         } else {
 500                 $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 501                         $e->__toString() . "\n";
 502
 503                 if ( $wgShowExceptionDetails ) {
 504                         $message .= "\n" . $e->getTraceAsString() . "\n";
 505                 }
 506
 507                 if ( $cmdLine ) {
 508                         wfPrintError( $message );
 509                 } else {
 510                         wfDie( htmlspecialchars( $message ) ) . "\n";
 511                 }
 512         }
 513 }
 514
 515 /**
 516  * Print a message, if possible to STDERR.
 517  * Use this in command line mode only (see isCommandLine)
 518  */
 519 function wfPrintError( $message ) {
 520         # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 521         #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 522         if ( defined( 'STDERR' ) ) {
 523                 fwrite( STDERR, $message );
 524         } else {
 525                 echo( $message );
 526         }
 527 }
 528
 529 /**
 530  * Exception handler which simulates the appropriate catch() handling:
 531  *
 532  *   try {
 533  *       ...
 534  *   } catch ( MWException $e ) {
 535  *       $e->report();
 536  *   } catch ( Exception $e ) {
 537  *       echo $e->__toString();
 538  *   }
 539  */
 540 function wfExceptionHandler( $e ) {
 541         global $wgFullyInitialised;
 542
 543         wfReportException( $e );
 544
 545         // Final cleanup
 546         if ( $wgFullyInitialised ) {
 547                 try {
 548                         wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 549                 } catch ( Exception $e ) {}
 550         }
 551
 552         // Exit value should be nonzero for the benefit of shell jobs
 553         exit( 1 );
 554 }