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          * @return string
 123          */
 124         function getText() {
 125                 global $wgShowExceptionDetails;
 126
 127                 if ( $wgShowExceptionDetails ) {
 128                         return $this->getMessage() .
 129                                 "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
 130                 } else {
 131                         return "Set \$wgShowExceptionDetails = true; " .
 132                                 "in LocalSettings.php to show detailed debugging information.\n";
 133                 }
 134         }
 135
 136         /**
 137          * Return titles of this error page
 138          * @return String
 139          */
 140         function getPageTitle() {
 141                 return $this->msg( 'internalerror', "Internal 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->prepareErrorPage( $this->getPageTitle() );
 174
 175                         $hookResult = $this->runHooks( get_class( $this ) );
 176                         if ( $hookResult ) {
 177                                 $wgOut->addHTML( $hookResult );
 178                         } else {
 179                                 $wgOut->addHTML( $this->getHTML() );
 180                         }
 181
 182                         $wgOut->output();
 183                 } else {
 184                         header( "Content-Type: text/html; charset=utf-8" );
 185                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 186                         if ( $hookResult ) {
 187                                 die( $hookResult );
 188                         }
 189
 190                         echo $this->getHTML();
 191                         die(1);
 192                 }
 193         }
 194
 195         /**
 196          * Output a report about the exception and takes care of formatting.
 197          * It will be either HTML or plain text based on isCommandLine().
 198          */
 199         function report() {
 200                 $log = $this->getLogMessage();
 201
 202                 if ( $log ) {
 203                         wfDebugLog( 'exception', $log );
 204                 }
 205
 206                 if ( self::isCommandLine() ) {
 207                         MWExceptionHandler::printError( $this->getText() );
 208                 } else {
 209                         $this->reportHTML();
 210                 }
 211         }
 212
 213         /**
 214          * @static
 215          * @return bool
 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
 229         /**
 230          * @return string
 231          */
 232         function getHTML() {
 233                 return $this->getMessage();
 234         }
 235
 236         /**
 237          * @return string
 238          */
 239         function getText() {
 240                 return $this->getMessage();
 241         }
 242 }
 243
 244 /**
 245  * An error page which can definitely be safely rendered using the OutputPage
 246  * @ingroup Exception
 247  */
 248 class ErrorPageError extends MWException {
 249         public $title, $msg, $params;
 250
 251         /**
 252          * Note: these arguments are keys into wfMsg(), not text!
 253          */
 254         function __construct( $title, $msg, $params = null ) {
 255                 $this->title = $title;
 256                 $this->msg = $msg;
 257                 $this->params = $params;
 258
 259                 if( $msg instanceof Message ){
 260                         parent::__construct( $msg );
 261                 } else {
 262                         parent::__construct( wfMsg( $msg ) );
 263                 }
 264         }
 265
 266         function report() {
 267                 global $wgOut;
 268
 269                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 270                 $wgOut->output();
 271         }
 272 }
 273
 274 /**
 275  * Show an error when a user tries to do something they do not have the necessary
 276  * permissions for.
 277  * @ingroup Exception
 278  */
 279 class PermissionsError extends ErrorPageError {
 280         public $permission, $errors;
 281
 282         function __construct( $permission, $errors = array() ) {
 283                 global $wgLang;
 284
 285                 $this->permission = $permission;
 286
 287                 if ( !count( $errors ) ) {
 288                         $groups = array_map(
 289                                 array( 'User', 'makeGroupLinkWiki' ),
 290                                 User::getGroupsWithPermission( $this->permission )
 291                         );
 292
 293                         if ( $groups ) {
 294                                 $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
 295                         } else {
 296                                 $errors[] = array( 'badaccess-group0' );
 297                         }
 298                 }
 299
 300                 $this->errors = $errors;
 301         }
 302
 303         function report() {
 304                 global $wgOut;
 305
 306                 $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
 307                 $wgOut->output();
 308         }
 309 }
 310
 311 /**
 312  * Show an error when the wiki is locked/read-only and the user tries to do
 313  * something that requires write access
 314  * @ingroup Exception
 315  */
 316 class ReadOnlyError extends ErrorPageError {
 317         public function __construct(){
 318                 parent::__construct(
 319                         'readonly',
 320                         'readonlytext',
 321                         wfReadOnlyReason()
 322                 );
 323         }
 324 }
 325
 326 /**
 327  * Show an error when the user hits a rate limit
 328  * @ingroup Exception
 329  */
 330 class ThrottledError extends ErrorPageError {
 331         public function __construct(){
 332                 parent::__construct(
 333                         'actionthrottled',
 334                         'actionthrottledtext'
 335                 );
 336         }
 337
 338         public function report(){
 339                 global $wgOut;
 340                 $wgOut->setStatusCode( 503 );
 341                 return parent::report();
 342         }
 343 }
 344
 345 /**
 346  * Show an error when the user tries to do something whilst blocked
 347  * @ingroup Exception
 348  */
 349 class UserBlockedError extends ErrorPageError {
 350         public function __construct( Block $block ){
 351                 global $wgLang, $wgRequest;
 352
 353                 $blocker = $block->getBlocker();
 354                 if ( $blocker instanceof User ) { // local user
 355                         $blockerUserpage = $block->getBlocker()->getUserPage();
 356                         $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 357                 } else { // foreign user
 358                         $link = $blocker;
 359                 }
 360
 361                 $reason = $block->mReason;
 362                 if( $reason == '' ) {
 363                         $reason = wfMsg( 'blockednoreason' );
 364                 }
 365
 366                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 367                  * This could be a username, an IP range, or a single IP. */
 368                 $intended = $block->getTarget();
 369
 370                 parent::__construct(
 371                         'blockedtitle',
 372                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 373                         array(
 374                                 $link,
 375                                 $reason,
 376                                 $wgRequest->getIP(),
 377                                 $block->getByName(),
 378                                 $block->getId(),
 379                                 $wgLang->formatExpiry( $block->mExpiry ),
 380                                 $intended,
 381                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 382                         )
 383                 );
 384         }
 385 }
 386
 387 /**
 388  * Show an error that looks like an HTTP server error.
 389  * Replacement for wfHttpError().
 390  *
 391  * @ingroup Exception
 392  */
 393 class HttpError extends MWException {
 394         private $httpCode, $header, $content;
 395
 396         /**
 397          * Constructor
 398          *
 399          * @param $httpCode Integer: HTTP status code to send to the client
 400          * @param $content String|Message: content of the message
 401          * @param $header String|Message: content of the header (\<title\> and \<h1\>)
 402          */
 403         public function __construct( $httpCode, $content, $header = null ){
 404                 parent::__construct( $content );
 405                 $this->httpCode = (int)$httpCode;
 406                 $this->header = $header;
 407                 $this->content = $content;
 408         }
 409
 410         public function reportHTML() {
 411                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 412
 413                 header( "Status: {$this->httpCode} {$httpMessage}" );
 414                 header( 'Content-type: text/html; charset=utf-8' );
 415
 416                 if ( $this->header === null ) {
 417                         $header = $httpMessage;
 418                 } elseif ( $this->header instanceof Message ) {
 419                         $header = $this->header->escaped();
 420                 } else {
 421                         $header = htmlspecialchars( $this->header );
 422                 }
 423
 424                 if ( $this->content instanceof Message ) {
 425                         $content = $this->content->escaped();
 426                 } else {
 427                         $content = htmlspecialchars( $this->content );
 428                 }
 429
 430                 print "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n".
 431                         "<html><head><title>$header</title></head>\n" .
 432                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 433         }
 434 }
 435
 436 /**
 437  * Handler class for MWExceptions
 438  * @ingroup Exception
 439  */
 440 class MWExceptionHandler {
 441         /**
 442          * Install an exception handler for MediaWiki exception types.
 443          */
 444         public static function installHandler() {
 445                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 446         }
 447
 448         /**
 449          * Report an exception to the user
 450          */
 451         protected static function report( Exception $e ) {
 452                 global $wgShowExceptionDetails;
 453
 454                 $cmdLine = MWException::isCommandLine();
 455
 456                 if ( $e instanceof MWException ) {
 457                         try {
 458                                 // Try and show the exception prettily, with the normal skin infrastructure
 459                                 $e->report();
 460                         } catch ( Exception $e2 ) {
 461                                 // Exception occurred from within exception handler
 462                                 // Show a simpler error message for the original exception,
 463                                 // don't try to invoke report()
 464                                 $message = "MediaWiki internal error.\n\n";
 465
 466                                 if ( $wgShowExceptionDetails ) {
 467                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 468                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 469                                 } else {
 470                                         $message .= "Exception caught inside exception handler.\n\n" .
 471                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 472                                                 "to show detailed debugging information.";
 473                                 }
 474
 475                                 $message .= "\n";
 476
 477                                 if ( $cmdLine ) {
 478                                         self::printError( $message );
 479                                 } else {
 480                                         self::escapeEchoAndDie( $message );
 481                                 }
 482                         }
 483                 } else {
 484                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 485                                 $e->__toString() . "\n";
 486
 487                         if ( $wgShowExceptionDetails ) {
 488                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 489                         }
 490
 491                         if ( $cmdLine ) {
 492                                 self::printError( $message );
 493                         } else {
 494                                 self::escapeEchoAndDie( $message );
 495                         }
 496                 }
 497         }
 498
 499         /**
 500          * Print a message, if possible to STDERR.
 501          * Use this in command line mode only (see isCommandLine)
 502          * @param $message String Failure text
 503          */
 504         public static function printError( $message ) {
 505                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 506                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 507                 if ( defined( 'STDERR' ) ) {
 508                         fwrite( STDERR, $message );
 509                 } else {
 510                         echo( $message );
 511                 }
 512         }
 513
 514         /**
 515          * Print a message after escaping it and converting newlines to <br>
 516          * Use this for non-command line failures
 517          * @param $message String Failure text
 518          */
 519         private static function escapeEchoAndDie( $message ) {
 520                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 521                 die(1);
 522         }
 523
 524         /**
 525          * Exception handler which simulates the appropriate catch() handling:
 526          *
 527          *   try {
 528          *       ...
 529          *   } catch ( MWException $e ) {
 530          *       $e->report();
 531          *   } catch ( Exception $e ) {
 532          *       echo $e->__toString();
 533          *   }
 534          */
 535         public static function handle( $e ) {
 536                 global $wgFullyInitialised;
 537
 538                 self::report( $e );
 539
 540                 // Final cleanup
 541                 if ( $wgFullyInitialised ) {
 542                         try {
 543                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 544                         } catch ( Exception $e ) {}
 545                 }
 546
 547                 // Exit value should be nonzero for the benefit of shell jobs
 548                 exit( 1 );
 549         }
 550 }