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 wfMsgReal( $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                 if ( $this->useMessageCache() ) {
 137                         return wfMsg( 'internalerror' );
 138                 } else {
 139                         global $wgSitename;
 140
 141                         return "$wgSitename error";
 142                 }
 143         }
 144
 145         /**
 146          * Return the requested URL and point to file and line number from which the
 147          * exception occured
 148          *
 149          * @return String
 150          */
 151         function getLogMessage() {
 152                 global $wgRequest;
 153
 154                 $file = $this->getFile();
 155                 $line = $this->getLine();
 156                 $message = $this->getMessage();
 157
 158                 if ( isset( $wgRequest ) ) {
 159                         $url = $wgRequest->getRequestURL();
 160                         if ( !$url ) {
 161                                 $url = '[no URL]';
 162                         }
 163                 } else {
 164                         $url = '[no req]';
 165                 }
 166
 167                 return "$url   Exception from line $line of $file: $message";
 168         }
 169
 170         /** Output the exception report using HTML */
 171         function reportHTML() {
 172                 global $wgOut;
 173
 174                 if ( $this->useOutputPage() ) {
 175                         $wgOut->setPageTitle( $this->getPageTitle() );
 176                         $wgOut->setRobotPolicy( "noindex,nofollow" );
 177                         $wgOut->setArticleRelated( false );
 178                         $wgOut->enableClientCache( false );
 179                         $wgOut->redirect( '' );
 180                         $wgOut->clearHTML();
 181
 182                         $hookResult = $this->runHooks( get_class( $this ) );
 183                         if ( $hookResult ) {
 184                                 $wgOut->addHTML( $hookResult );
 185                         } else {
 186                                 $wgOut->addHTML( $this->getHTML() );
 187                         }
 188
 189                         $wgOut->output();
 190                 } else {
 191                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 192                         if ( $hookResult ) {
 193                                 die( $hookResult );
 194                         }
 195
 196                         if ( defined( 'MEDIAWIKI_INSTALL' ) || $this->htmlBodyOnly() ) {
 197                                 echo $this->getHTML();
 198                         } else {
 199                                 echo $this->htmlHeader();
 200                                 echo $this->getHTML();
 201                                 echo $this->htmlFooter();
 202                         }
 203                 }
 204         }
 205
 206         /**
 207          * Output a report about the exception and takes care of formatting.
 208          * It will be either HTML or plain text based on isCommandLine().
 209          */
 210         function report() {
 211                 $log = $this->getLogMessage();
 212
 213                 if ( $log ) {
 214                         wfDebugLog( 'exception', $log );
 215                 }
 216
 217                 if ( self::isCommandLine() ) {
 218                         wfPrintError( $this->getText() );
 219                 } else {
 220                         $this->reportHTML();
 221                 }
 222         }
 223
 224         /**
 225          * Send headers and output the beginning of the html page if not using
 226          * $wgOut to output the exception.
 227          */
 228         function htmlHeader() {
 229                 global $wgLogo, $wgOutputEncoding, $wgLang;
 230
 231                 if ( !headers_sent() ) {
 232                         header( 'HTTP/1.0 500 Internal Server Error' );
 233                         header( 'Content-type: text/html; charset=' . $wgOutputEncoding );
 234                         /* Don't cache error pages!  They cause no end of trouble... */
 235                         header( 'Cache-control: none' );
 236                         header( 'Pragma: nocache' );
 237                 }
 238
 239                 $head = Html::element( 'title', null, $this->getPageTitle() ) . "\n";
 240                 $head .= Html::inlineStyle( <<<ENDL
 241         body {
 242                 color: #000;
 243                 background-color: #fff;
 244                 font-family: sans-serif;
 245                 padding: 2em;
 246                 text-align: center;
 247         }
 248         p, img, h1 {
 249                 text-align: left;
 250                 margin: 0.5em 0;
 251         }
 252         h1 {
 253                 font-size: 120%;
 254         }
 255 ENDL
 256                 );
 257
 258                 $dir = 'ltr';
 259                 $code = 'en';
 260
 261                 if ( $wgLang instanceof Language ) {
 262                         $dir = $wgLang->getDir();
 263                         $code = $wgLang->getCode();
 264                 }
 265
 266                 $header = Html::element( 'img', array(
 267                         'src' => $wgLogo,
 268                         'alt' => '' ), $this->getPageTitle() );
 269
 270                 $attribs = array( 'dir' => $dir, 'lang' => $code );
 271
 272                 return
 273                         Html::htmlHeader( $attribs ) .
 274                         Html::rawElement( 'head', null, $head ) . "\n".
 275                         Html::openElement( 'body' ) . "\n" .
 276                         $header . "\n";
 277         }
 278
 279         /**
 280          * print the end of the html page if not using $wgOut.
 281          */
 282         function htmlFooter() {
 283                 return Html::closeElement( 'body' ) . Html::closeElement( 'html' );
 284         }
 285
 286         /**
 287          * headers handled by subclass?
 288          */
 289         function htmlBodyOnly() {
 290                 return false;
 291         }
 292
 293         static function isCommandLine() {
 294                 return !empty( $GLOBALS['wgCommandLineMode'] ) && !defined( 'MEDIAWIKI_INSTALL' );
 295         }
 296 }
 297
 298 /**
 299  * Exception class which takes an HTML error message, and does not
 300  * produce a backtrace. Replacement for OutputPage::fatalError().
 301  * @ingroup Exception
 302  */
 303 class FatalError extends MWException {
 304         function getHTML() {
 305                 return $this->getMessage();
 306         }
 307
 308         function getText() {
 309                 return $this->getMessage();
 310         }
 311 }
 312
 313 /**
 314  * An error page which can definitely be safely rendered using the OutputPage
 315  * @ingroup Exception
 316  */
 317 class ErrorPageError extends MWException {
 318         public $title, $msg, $params;
 319
 320         /**
 321          * Note: these arguments are keys into wfMsg(), not text!
 322          */
 323         function __construct( $title, $msg, $params = null ) {
 324                 $this->title = $title;
 325                 $this->msg = $msg;
 326                 $this->params = $params;
 327
 328                 if( $msg instanceof Message ){
 329                         parent::__construct( $msg );
 330                 } else {
 331                         parent::__construct( wfMsg( $msg ) );
 332                 }
 333         }
 334
 335         function report() {
 336                 global $wgOut;
 337
 338                 if ( $wgOut->getTitle() ) {
 339                         $wgOut->debug( 'Original title: ' . $wgOut->getTitle()->getPrefixedText() . "\n" );
 340                 }
 341                 $wgOut->setPageTitle( wfMsg( $this->title ) );
 342                 $wgOut->setHTMLTitle( wfMsg( 'errorpagetitle' ) );
 343                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 344                 $wgOut->setArticleRelated( false );
 345                 $wgOut->enableClientCache( false );
 346                 $wgOut->mRedirect = '';
 347                 $wgOut->clearHTML();
 348
 349                 if( $this->msg instanceof Message ){
 350                         $wgOut->addHTML( $this->msg->parse() );
 351                 } else {
 352                         $wgOut->addWikiMsgArray( $this->msg, $this->params );
 353                 }
 354
 355                 $wgOut->returnToMain();
 356                 $wgOut->output();
 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  */
 364 class PermissionsError extends ErrorPageError {
 365         public $permission;
 366
 367         function __construct( $permission ) {
 368                 global $wgLang;
 369
 370                 $this->permission = $permission;
 371
 372                 $groups = array_map(
 373                         array( 'User', 'makeGroupLinkWiki' ),
 374                         User::getGroupsWithPermission( $this->permission )
 375                 );
 376
 377                 if( $groups ) {
 378                         parent::__construct(
 379                                 'badaccess',
 380                                 'badaccess-groups',
 381                                 array(
 382                                         $wgLang->commaList( $groups ),
 383                                         count( $groups )
 384                                 )
 385                         );
 386                 } else {
 387                         parent::__construct(
 388                                 'badaccess',
 389                                 'badaccess-group0'
 390                         );
 391                 }
 392         }
 393 }
 394
 395 /**
 396  * Show an error when the wiki is locked/read-only and the user tries to do
 397  * something that requires write access
 398  */
 399 class ReadOnlyError extends ErrorPageError {
 400         public function __construct(){
 401                 parent::__construct(
 402                         'readonly',
 403                         'readonlytext',
 404                         wfReadOnlyReason()
 405                 );
 406         }
 407 }
 408
 409 /**
 410  * Show an error when the user hits a rate limit
 411  */
 412 class ThrottledError extends ErrorPageError {
 413         public function __construct(){
 414                 parent::__construct(
 415                         'actionthrottled',
 416                         'actionthrottledtext'
 417                 );
 418         }
 419         public function report(){
 420                 global $wgOut;
 421                 $wgOut->setStatusCode( 503 );
 422                 return parent::report();
 423         }
 424 }
 425
 426 /**
 427  * Show an error when the user tries to do something whilst blocked
 428  */
 429 class UserBlockedError extends ErrorPageError {
 430         public function __construct( Block $block ){
 431                 global $wgLang;
 432
 433                 $blockerUserpage = $block->getBlocker()->getUserPage();
 434                 $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 435
 436                 $reason = $block->mReason;
 437                 if( $reason == '' ) {
 438                         $reason = wfMsg( 'blockednoreason' );
 439                 }
 440
 441                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 442                  * This could be a username, an IP range, or a single IP. */
 443                 $intended = $block->getTarget();
 444
 445                 parent::__construct(
 446                         'blockedtitle',
 447                         $block->mAuto ? 'autoblocketext' : 'blockedtext',
 448                         array(
 449                                 $link,
 450                                 $reason,
 451                                 wfGetIP(),
 452                                 $block->getBlocker()->getName(),
 453                                 $block->getId(),
 454                                 $wgLang->formatExpiry( $block->mExpiry ),
 455                                 $intended,
 456                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 457                         )
 458                 );
 459         }
 460 }
 461
 462 /**
 463  * Install an exception handler for MediaWiki exception types.
 464  */
 465 function wfInstallExceptionHandler() {
 466         set_exception_handler( 'wfExceptionHandler' );
 467 }
 468
 469 /**
 470  * Report an exception to the user
 471  */
 472 function wfReportException( Exception $e ) {
 473         global $wgShowExceptionDetails;
 474
 475         $cmdLine = MWException::isCommandLine();
 476
 477         if ( $e instanceof MWException ) {
 478                 try {
 479                         // Try and show the exception prettily, with the normal skin infrastructure
 480                         $e->report();
 481                 } catch ( Exception $e2 ) {
 482                         // Exception occurred from within exception handler
 483                         // Show a simpler error message for the original exception,
 484                         // don't try to invoke report()
 485                         $message = "MediaWiki internal error.\n\n";
 486
 487                         if ( $wgShowExceptionDetails ) {
 488                                 $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 489                                         'Exception caught inside exception handler: ' . $e2->__toString();
 490                         } else {
 491                                 $message .= "Exception caught inside exception handler.\n\n" .
 492                                         "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 493                                         "to show detailed debugging information.";
 494                         }
 495
 496                         $message .= "\n";
 497
 498                         if ( $cmdLine ) {
 499                                 wfPrintError( $message );
 500                         } else {
 501                                 wfDie( htmlspecialchars( $message ) ) . "\n";
 502                         }
 503                 }
 504         } else {
 505                 $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 506                         $e->__toString() . "\n";
 507
 508                 if ( $wgShowExceptionDetails ) {
 509                         $message .= "\n" . $e->getTraceAsString() . "\n";
 510                 }
 511
 512                 if ( $cmdLine ) {
 513                         wfPrintError( $message );
 514                 } else {
 515                         wfDie( htmlspecialchars( $message ) ) . "\n";
 516                 }
 517         }
 518 }
 519
 520 /**
 521  * Print a message, if possible to STDERR.
 522  * Use this in command line mode only (see isCommandLine)
 523  */
 524 function wfPrintError( $message ) {
 525         # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 526         #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 527         if ( defined( 'STDERR' ) ) {
 528                 fwrite( STDERR, $message );
 529         } else {
 530                 echo( $message );
 531         }
 532 }
 533
 534 /**
 535  * Exception handler which simulates the appropriate catch() handling:
 536  *
 537  *   try {
 538  *       ...
 539  *   } catch ( MWException $e ) {
 540  *       $e->report();
 541  *   } catch ( Exception $e ) {
 542  *       echo $e->__toString();
 543  *   }
 544  */
 545 function wfExceptionHandler( $e ) {
 546         global $wgFullyInitialised;
 547
 548         wfReportException( $e );
 549
 550         // Final cleanup
 551         if ( $wgFullyInitialised ) {
 552                 try {
 553                         wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 554                 } catch ( Exception $e ) {}
 555         }
 556
 557         // Exit value should be nonzero for the benefit of shell jobs
 558         exit( 1 );
 559 }