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         /**
  80          * Get a message from i18n
  81          *
  82          * @param $key String: message name
  83          * @param $fallback String: default message if the message cache can't be
  84          *                  called by the exception
  85          * The function also has other parameters that are arguments for the message
  86          * @return String message with arguments replaced
  87          */
  88         function msg( $key, $fallback /*[, params...] */ ) {
  89                 $args = array_slice( func_get_args(), 2 );
  90
  91                 if ( $this->useMessageCache() ) {
  92                         return wfMsgNoTrans( $key, $args );
  93                 } else {
  94                         return wfMsgReplaceArgs( $fallback, $args );
  95                 }
  96         }
  97
  98         /**
  99          * If $wgShowExceptionDetails is true, return a HTML message with a
 100          * backtrace to the error, otherwise show a message to ask to set it to true
 101          * to show that information.
 102          *
 103          * @return String html to output
 104          */
 105         function getHTML() {
 106                 global $wgShowExceptionDetails;
 107
 108                 if ( $wgShowExceptionDetails ) {
 109                         return '<p>' . nl2br( htmlspecialchars( $this->getMessage() ) ) .
 110                                 '</p><p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
 111                                 "</p>\n";
 112                 } else {
 113                         return "<p>Set <b><tt>\$wgShowExceptionDetails = true;</tt></b> " .
 114                                 "at the bottom of LocalSettings.php to show detailed " .
 115                                 "debugging information.</p>";
 116                 }
 117         }
 118
 119         /**
 120          * If $wgShowExceptionDetails is true, return a text message with a
 121          * backtrace to the error.
 122          */
 123         function getText() {
 124                 global $wgShowExceptionDetails;
 125
 126                 if ( $wgShowExceptionDetails ) {
 127                         return $this->getMessage() .
 128                                 "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
 129                 } else {
 130                         return "Set \$wgShowExceptionDetails = true; " .
 131                                 "in LocalSettings.php to show detailed debugging information.\n";
 132                 }
 133         }
 134
 135         /**
 136          * Return titles of this error page
 137          * @return String
 138          */
 139         function getPageTitle() {
 140                 global $wgSitename;
 141                 return $this->msg( 'internalerror', "$wgSitename error" );
 142         }
 143
 144         /**
 145          * Return the requested URL and point to file and line number from which the
 146          * exception occured
 147          *
 148          * @return String
 149          */
 150         function getLogMessage() {
 151                 global $wgRequest;
 152
 153                 $file = $this->getFile();
 154                 $line = $this->getLine();
 155                 $message = $this->getMessage();
 156
 157                 if ( isset( $wgRequest ) && !$wgRequest instanceof FauxRequest ) {
 158                         $url = $wgRequest->getRequestURL();
 159                         if ( !$url ) {
 160                                 $url = '[no URL]';
 161                         }
 162                 } else {
 163                         $url = '[no req]';
 164                 }
 165
 166                 return "$url   Exception from line $line of $file: $message";
 167         }
 168
 169         /** Output the exception report using HTML */
 170         function reportHTML() {
 171                 global $wgOut;
 172                 if ( $this->useOutputPage() ) {
 173                         $wgOut->setPageTitle( $this->getPageTitle() );
 174                         $wgOut->setRobotPolicy( "noindex,nofollow" );
 175                         $wgOut->setArticleRelated( false );
 176                         $wgOut->enableClientCache( false );
 177                         $wgOut->redirect( '' );
 178                         $wgOut->clearHTML();
 179
 180                         $hookResult = $this->runHooks( get_class( $this ) );
 181                         if ( $hookResult ) {
 182                                 $wgOut->addHTML( $hookResult );
 183                         } else {
 184                                 $wgOut->addHTML( $this->getHTML() );
 185                         }
 186
 187                         $wgOut->output();
 188                 } else {
 189                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 190                         if ( $hookResult ) {
 191                                 die( $hookResult );
 192                         }
 193
 194                         echo $this->getHTML();
 195                         die(1);
 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'] );
 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                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 263                 $wgOut->output();
 264         }
 265 }
 266
 267 /**
 268  * Show an error when a user tries to do something they do not have the necessary
 269  * permissions for.
 270  * @ingroup Exception
 271  */
 272 class PermissionsError extends ErrorPageError {
 273         public $permission;
 274
 275         function __construct( $permission ) {
 276                 global $wgLang;
 277
 278                 $this->permission = $permission;
 279
 280                 $groups = array_map(
 281                         array( 'User', 'makeGroupLinkWiki' ),
 282                         User::getGroupsWithPermission( $this->permission )
 283                 );
 284
 285                 if( $groups ) {
 286                         parent::__construct(
 287                                 'badaccess',
 288                                 'badaccess-groups',
 289                                 array(
 290                                         $wgLang->commaList( $groups ),
 291                                         count( $groups )
 292                                 )
 293                         );
 294                 } else {
 295                         parent::__construct(
 296                                 'badaccess',
 297                                 'badaccess-group0'
 298                         );
 299                 }
 300         }
 301 }
 302
 303 /**
 304  * Show an error when the wiki is locked/read-only and the user tries to do
 305  * something that requires write access
 306  * @ingroup Exception
 307  */
 308 class ReadOnlyError extends ErrorPageError {
 309         public function __construct(){
 310                 parent::__construct(
 311                         'readonly',
 312                         'readonlytext',
 313                         wfReadOnlyReason()
 314                 );
 315         }
 316 }
 317
 318 /**
 319  * Show an error when the user hits a rate limit
 320  * @ingroup Exception
 321  */
 322 class ThrottledError extends ErrorPageError {
 323         public function __construct(){
 324                 parent::__construct(
 325                         'actionthrottled',
 326                         'actionthrottledtext'
 327                 );
 328         }
 329         public function report(){
 330                 global $wgOut;
 331                 $wgOut->setStatusCode( 503 );
 332                 return parent::report();
 333         }
 334 }
 335
 336 /**
 337  * Show an error when the user tries to do something whilst blocked
 338  * @ingroup Exception
 339  */
 340 class UserBlockedError extends ErrorPageError {
 341         public function __construct( Block $block ){
 342                 global $wgLang, $wgRequest;
 343
 344                 $blockerUserpage = $block->getBlocker()->getUserPage();
 345                 $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 346
 347                 $reason = $block->mReason;
 348                 if( $reason == '' ) {
 349                         $reason = wfMsg( 'blockednoreason' );
 350                 }
 351
 352                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 353                  * This could be a username, an IP range, or a single IP. */
 354                 $intended = $block->getTarget();
 355
 356                 parent::__construct(
 357                         'blockedtitle',
 358                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 359                         array(
 360                                 $link,
 361                                 $reason,
 362                                 $wgRequest->getIP(),
 363                                 $block->getBlocker()->getName(),
 364                                 $block->getId(),
 365                                 $wgLang->formatExpiry( $block->mExpiry ),
 366                                 $intended,
 367                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 368                         )
 369                 );
 370         }
 371 }
 372
 373 /**
 374  * Show an error that looks like an HTTP server error.
 375  * Replacement for wfHttpError().
 376  *
 377  * @ingroup Exception
 378  */
 379 class HttpError extends MWException {
 380         private $httpCode, $header, $content;
 381
 382         /**
 383          * Constructor
 384          *
 385          * @param $httpCode Integer: HTTP status code to send to the client
 386          * @param $content String|Message: content of the message
 387          * @param $header String|Message: content of the header (\<title\> and \<h1\>)
 388          */
 389         public function __construct( $httpCode, $content, $header = null ){
 390                 parent::__construct( $content );
 391                 $this->httpCode = (int)$httpCode;
 392                 $this->header = $header;
 393                 $this->content = $content;
 394         }
 395
 396         public function reportHTML() {
 397                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 398
 399                 header( "Status: {$this->httpCode} {$httpMessage}" );
 400                 header( 'Content-type: text/html; charset=utf-8' );
 401
 402                 if ( $this->header === null ) {
 403                         $header = $httpMessage;
 404                 } elseif ( $this->header instanceof Message ) {
 405                         $header = $this->header->escaped();
 406                 } else {
 407                         $header = htmlspecialchars( $this->header );
 408                 }
 409
 410                 if ( $this->content instanceof Message ) {
 411                         $content = $this->content->escaped();
 412                 } else {
 413                         $content = htmlspecialchars( $this->content );
 414                 }
 415
 416                 print "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n".
 417                         "<html><head><title>$header</title></head>\n" .
 418                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 419         }
 420 }
 421
 422 /**
 423  * Handler class for MWExceptions
 424  * @ingroup Exception
 425  */
 426 class MWExceptionHandler {
 427         /**
 428          * Install an exception handler for MediaWiki exception types.
 429          */
 430         public static function installHandler() {
 431                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 432         }
 433
 434         /**
 435          * Report an exception to the user
 436          */
 437         protected static function report( Exception $e ) {
 438                 global $wgShowExceptionDetails;
 439
 440                 $cmdLine = MWException::isCommandLine();
 441
 442                 if ( $e instanceof MWException ) {
 443                         try {
 444                                 // Try and show the exception prettily, with the normal skin infrastructure
 445                                 $e->report();
 446                         } catch ( Exception $e2 ) {
 447                                 // Exception occurred from within exception handler
 448                                 // Show a simpler error message for the original exception,
 449                                 // don't try to invoke report()
 450                                 $message = "MediaWiki internal error.\n\n";
 451
 452                                 if ( $wgShowExceptionDetails ) {
 453                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 454                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 455                                 } else {
 456                                         $message .= "Exception caught inside exception handler.\n\n" .
 457                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 458                                                 "to show detailed debugging information.";
 459                                 }
 460
 461                                 $message .= "\n";
 462
 463                                 if ( $cmdLine ) {
 464                                         self::printError( $message );
 465                                 } else {
 466                                         self::escapeEchoAndDie( $message );
 467                                 }
 468                         }
 469                 } else {
 470                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 471                                 $e->__toString() . "\n";
 472
 473                         if ( $wgShowExceptionDetails ) {
 474                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 475                         }
 476
 477                         if ( $cmdLine ) {
 478                                 self::printError( $message );
 479                         } else {
 480                                 self::escapeEchoAndDie( $message );
 481                         }
 482                 }
 483         }
 484
 485         /**
 486          * Print a message, if possible to STDERR.
 487          * Use this in command line mode only (see isCommandLine)
 488          * @param $message String Failure text
 489          */
 490         public static function printError( $message ) {
 491                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 492                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 493                 if ( defined( 'STDERR' ) ) {
 494                         fwrite( STDERR, $message );
 495                 } else {
 496                         echo( $message );
 497                 }
 498         }
 499
 500         /**
 501          * Print a message after escaping it and converting newlines to <br>
 502          * Use this for non-command line failures
 503          * @param $message String Failure text
 504          */
 505         private static function escapeEchoAndDie( $message ) {
 506                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 507                 die(1);
 508         }
 509
 510         /**
 511          * Exception handler which simulates the appropriate catch() handling:
 512          *
 513          *   try {
 514          *       ...
 515          *   } catch ( MWException $e ) {
 516          *       $e->report();
 517          *   } catch ( Exception $e ) {
 518          *       echo $e->__toString();
 519          *   }
 520          */
 521         public static function handle( $e ) {
 522                 global $wgFullyInitialised;
 523
 524                 self::report( $e );
 525
 526                 // Final cleanup
 527                 if ( $wgFullyInitialised ) {
 528                         try {
 529                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 530                         } catch ( Exception $e ) {}
 531                 }
 532
 533                 // Exit value should be nonzero for the benefit of shell jobs
 534                 exit( 1 );
 535         }
 536 }