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['wgOut'] ) &&
  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                 if ( $this->useOutputPage() ) {
 169                         $wgOut->setPageTitle( $this->getPageTitle() );
 170                         $wgOut->setRobotPolicy( "noindex,nofollow" );
 171                         $wgOut->setArticleRelated( false );
 172                         $wgOut->enableClientCache( false );
 173                         $wgOut->redirect( '' );
 174                         $wgOut->clearHTML();
 175
 176                         $hookResult = $this->runHooks( get_class( $this ) );
 177                         if ( $hookResult ) {
 178                                 $wgOut->addHTML( $hookResult );
 179                         } else {
 180                                 $wgOut->addHTML( $this->getHTML() );
 181                         }
 182
 183                         $wgOut->output();
 184                 } else {
 185                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 186                         if ( $hookResult ) {
 187                                 die( $hookResult );
 188                         }
 189
 190                         $html = $this->getHTML();
 191                         if ( defined( 'MEDIAWIKI_INSTALL' ) ) {
 192                                 echo $html;
 193                         } else {
 194                                 wfDie( $html );
 195                         }
 196                 }
 197         }
 198
 199         /**
 200          * Output a report about the exception and takes care of formatting.
 201          * It will be either HTML or plain text based on isCommandLine().
 202          */
 203         function report() {
 204                 $log = $this->getLogMessage();
 205
 206                 if ( $log ) {
 207                         wfDebugLog( 'exception', $log );
 208                 }
 209
 210                 if ( self::isCommandLine() ) {
 211                         MWExceptionHandler::printError( $this->getText() );
 212                 } else {
 213                         $this->reportHTML();
 214                 }
 215         }
 216
 217         static function isCommandLine() {
 218                 return !empty( $GLOBALS['wgCommandLineMode'] ) && !defined( 'MEDIAWIKI_INSTALL' );
 219         }
 220 }
 221
 222 /**
 223  * Exception class which takes an HTML error message, and does not
 224  * produce a backtrace. Replacement for OutputPage::fatalError().
 225  * @ingroup Exception
 226  */
 227 class FatalError extends MWException {
 228         function getHTML() {
 229                 return $this->getMessage();
 230         }
 231
 232         function getText() {
 233                 return $this->getMessage();
 234         }
 235 }
 236
 237 /**
 238  * An error page which can definitely be safely rendered using the OutputPage
 239  * @ingroup Exception
 240  */
 241 class ErrorPageError extends MWException {
 242         public $title, $msg, $params;
 243
 244         /**
 245          * Note: these arguments are keys into wfMsg(), not text!
 246          */
 247         function __construct( $title, $msg, $params = null ) {
 248                 $this->title = $title;
 249                 $this->msg = $msg;
 250                 $this->params = $params;
 251
 252                 if( $msg instanceof Message ){
 253                         parent::__construct( $msg );
 254                 } else {
 255                         parent::__construct( wfMsg( $msg ) );
 256                 }
 257         }
 258
 259         function report() {
 260                 global $wgOut;
 261
 262                 if ( $wgOut->getTitle() ) {
 263                         $wgOut->debug( 'Original title: ' . $wgOut->getTitle()->getPrefixedText() . "\n" );
 264                 }
 265                 $wgOut->setPageTitle( wfMsg( $this->title ) );
 266                 $wgOut->setHTMLTitle( wfMsg( 'errorpagetitle' ) );
 267                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 268                 $wgOut->setArticleRelated( false );
 269                 $wgOut->enableClientCache( false );
 270                 $wgOut->mRedirect = '';
 271                 $wgOut->clearHTML();
 272
 273                 if( $this->msg instanceof Message ){
 274                         $wgOut->addHTML( $this->msg->parse() );
 275                 } else {
 276                         $wgOut->addWikiMsgArray( $this->msg, $this->params );
 277                 }
 278
 279                 $wgOut->returnToMain();
 280                 $wgOut->output();
 281         }
 282 }
 283
 284 /**
 285  * Show an error when a user tries to do something they do not have the necessary
 286  * permissions for.
 287  */
 288 class PermissionsError extends ErrorPageError {
 289         public $permission;
 290
 291         function __construct( $permission ) {
 292                 global $wgLang;
 293
 294                 $this->permission = $permission;
 295
 296                 $groups = array_map(
 297                         array( 'User', 'makeGroupLinkWiki' ),
 298                         User::getGroupsWithPermission( $this->permission )
 299                 );
 300
 301                 if( $groups ) {
 302                         parent::__construct(
 303                                 'badaccess',
 304                                 'badaccess-groups',
 305                                 array(
 306                                         $wgLang->commaList( $groups ),
 307                                         count( $groups )
 308                                 )
 309                         );
 310                 } else {
 311                         parent::__construct(
 312                                 'badaccess',
 313                                 'badaccess-group0'
 314                         );
 315                 }
 316         }
 317 }
 318
 319 /**
 320  * Show an error when the wiki is locked/read-only and the user tries to do
 321  * something that requires write access
 322  */
 323 class ReadOnlyError extends ErrorPageError {
 324         public function __construct(){
 325                 parent::__construct(
 326                         'readonly',
 327                         'readonlytext',
 328                         wfReadOnlyReason()
 329                 );
 330         }
 331 }
 332
 333 /**
 334  * Show an error when the user hits a rate limit
 335  */
 336 class ThrottledError extends ErrorPageError {
 337         public function __construct(){
 338                 parent::__construct(
 339                         'actionthrottled',
 340                         'actionthrottledtext'
 341                 );
 342         }
 343         public function report(){
 344                 global $wgOut;
 345                 $wgOut->setStatusCode( 503 );
 346                 return parent::report();
 347         }
 348 }
 349
 350 /**
 351  * Show an error when the user tries to do something whilst blocked
 352  */
 353 class UserBlockedError extends ErrorPageError {
 354         public function __construct( Block $block ){
 355                 global $wgLang;
 356
 357                 $blockerUserpage = $block->getBlocker()->getUserPage();
 358                 $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 359
 360                 $reason = $block->mReason;
 361                 if( $reason == '' ) {
 362                         $reason = wfMsg( 'blockednoreason' );
 363                 }
 364
 365                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 366                  * This could be a username, an IP range, or a single IP. */
 367                 $intended = $block->getTarget();
 368
 369                 parent::__construct(
 370                         'blockedtitle',
 371                         $block->mAuto ? 'autoblocketext' : 'blockedtext',
 372                         array(
 373                                 $link,
 374                                 $reason,
 375                                 wfGetIP(),
 376                                 $block->getBlocker()->getName(),
 377                                 $block->getId(),
 378                                 $wgLang->formatExpiry( $block->mExpiry ),
 379                                 $intended,
 380                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 381                         )
 382                 );
 383         }
 384 }
 385
 386 /**
 387  * Handler class for MWExceptions
 388  */
 389 class MWExceptionHandler {
 390         /**
 391          * Install an exception handler for MediaWiki exception types.
 392          */
 393         public static function installHandler() {
 394                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 395         }
 396
 397         /**
 398          * Report an exception to the user
 399          */
 400         protected static function report( Exception $e ) {
 401                 global $wgShowExceptionDetails;
 402
 403                 $cmdLine = MWException::isCommandLine();
 404
 405                 if ( $e instanceof MWException ) {
 406                         try {
 407                                 // Try and show the exception prettily, with the normal skin infrastructure
 408                                 $e->report();
 409                         } catch ( Exception $e2 ) {
 410                                 // Exception occurred from within exception handler
 411                                 // Show a simpler error message for the original exception,
 412                                 // don't try to invoke report()
 413                                 $message = "MediaWiki internal error.\n\n";
 414
 415                                 if ( $wgShowExceptionDetails ) {
 416                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 417                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 418                                 } else {
 419                                         $message .= "Exception caught inside exception handler.\n\n" .
 420                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 421                                                 "to show detailed debugging information.";
 422                                 }
 423
 424                                 $message .= "\n";
 425
 426                                 if ( $cmdLine ) {
 427                                         self::printError( $message );
 428                                 } else {
 429                                         wfDie( nl2br( htmlspecialchars( $message ) ) ) . "\n";
 430                                 }
 431                         }
 432                 } else {
 433                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 434                                 $e->__toString() . "\n";
 435
 436                         if ( $wgShowExceptionDetails ) {
 437                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 438                         }
 439
 440                         if ( $cmdLine ) {
 441                                 self::printError( $message );
 442                         } else {
 443                                 wfDie( nl2br( htmlspecialchars( $message ) ) ) . "\n";
 444                         }
 445                 }
 446         }
 447
 448         /**
 449          * Print a message, if possible to STDERR.
 450          * Use this in command line mode only (see isCommandLine)
 451          */
 452         public static function printError( $message ) {
 453                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 454                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 455                 if ( defined( 'STDERR' ) ) {
 456                         fwrite( STDERR, $message );
 457                 } else {
 458                         echo( $message );
 459                 }
 460         }
 461
 462         /**
 463          * Exception handler which simulates the appropriate catch() handling:
 464          *
 465          *   try {
 466          *       ...
 467          *   } catch ( MWException $e ) {
 468          *       $e->report();
 469          *   } catch ( Exception $e ) {
 470          *       echo $e->__toString();
 471          *   }
 472          */
 473         public static function handle( $e ) {
 474                 global $wgFullyInitialised;
 475
 476                 self::report( $e );
 477
 478                 // Final cleanup
 479                 if ( $wgFullyInitialised ) {
 480                         try {
 481                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 482                         } catch ( Exception $e ) {}
 483                 }
 484
 485                 // Exit value should be nonzero for the benefit of shell jobs
 486                 exit( 1 );
 487         }
 488 }