includes/Exception.php

   1 <?php
   2
   3 /**
   4  * MediaWiki exception
   5  * @addtogroup Exception
   6  */
   7 class MWException extends Exception {
   8
   9         /**
  10          * Should the exception use $wgOut to output the error ?
  11          * @return bool
  12          */
  13         function useOutputPage() {
  14                 return !empty( $GLOBALS['wgFullyInitialised'] ) &&
  15                         !empty( $GLOBALS['wgArticle'] ) && !empty( $GLOBALS['wgTitle'] );
  16         }
  17
  18         /**
  19          * Can the extension use wfMsg() to get i18n messages ?
  20          * @return bool
  21          */
  22         function useMessageCache() {
  23                 global $wgLang;
  24                 return is_object( $wgLang );
  25         }
  26
  27         /**
  28          * Run hook to allow extensions to modify the text of the exception
  29          *
  30          * @param String $name class name of the exception
  31          * @param Array $args arguments to pass to the callback functions
  32          * @return mixed string to output or null if any hook has been called
  33          */
  34         function runHooks( $name, $args = array() ) {
  35                 global $wgExceptionHooks;
  36                 if( !isset( $wgExceptionHooks ) || !is_array( $wgExceptionHooks ) )
  37                         return; // Just silently ignore
  38                 if( !array_key_exists( $name, $wgExceptionHooks ) || !is_array( $wgExceptionHooks[ $name ] ) )
  39                         return;
  40                 $hooks = $wgExceptionHooks[ $name ];
  41                 $callargs = array_merge( array( $this ), $args );
  42
  43                 foreach( $hooks as $hook ) {
  44                         if( is_string( $hook ) || ( is_array( $hook ) && count( $hook ) >= 2 && is_string( $hook[0] ) ) ) {     //'function' or array( 'class', hook' )
  45                                 $result = call_user_func_array( $hook, $callargs );
  46                         } else {
  47                                 $result = null;
  48                         }
  49                         if( is_string( $result ) )
  50                                 return $result;
  51                 }
  52         }
  53
  54         /**
  55          * Get a message from i18n
  56          *
  57          * @param String $key message name
  58          * @param String $fallback default message if the message cache can't be
  59          *                         called by the exception
  60          * The function also has other parameters that are arguments for the message
  61          * @return String message with arguments replaced
  62          */
  63         function msg( $key, $fallback /*[, params...] */ ) {
  64                 $args = array_slice( func_get_args(), 2 );
  65                 if ( $this->useMessageCache() ) {
  66                         return wfMsgReal( $key, $args );
  67                 } else {
  68                         return wfMsgReplaceArgs( $fallback, $args );
  69                 }
  70         }
  71
  72         /**
  73          * If $wgShowExceptionDetails is true, return a HTML message with a
  74          * backtrace to the error, otherwise show a message to ask to set it to true
  75          * to show that information.
  76          *
  77          * @return String html to output
  78          */
  79         function getHTML() {
  80                 global $wgShowExceptionDetails;
  81                 if( $wgShowExceptionDetails ) {
  82                         return '<p>' . htmlspecialchars( $this->getMessage() ) .
  83                                 '</p><p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
  84                                 "</p>\n";
  85                 } else {
  86                         return "<p>Set <b><tt>\$wgShowExceptionDetails = true;</tt></b> " .
  87                                 "at the bottom of LocalSettings.php to show detailed " .
  88                                 "debugging information.</p>";
  89                 }
  90         }
  91
  92         /**
  93          * If $wgShowExceptionDetails is true, return a text message with a
  94          * backtrace to the error.
  95          */
  96         function getText() {
  97                 global $wgShowExceptionDetails;
  98                 if( $wgShowExceptionDetails ) {
  99                         return $this->getMessage() .
 100                                 "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
 101                 } else {
 102                         return "<p>Set <tt>\$wgShowExceptionDetails = true;</tt> " .
 103                                 "in LocalSettings.php to show detailed debugging information.</p>";
 104                 }
 105         }
 106
 107         /* Return titles of this error page */
 108         function getPageTitle() {
 109                 if ( $this->useMessageCache() ) {
 110                         return wfMsg( 'internalerror' );
 111                 } else {
 112                         global $wgSitename;
 113                         return "$wgSitename error";
 114                 }
 115         }
 116
 117         /**
 118          * Return the requested URL and point to file and line number from which the
 119          * exception occured
 120          *
 121          * @return string
 122          */
 123         function getLogMessage() {
 124                 global $wgRequest;
 125                 $file = $this->getFile();
 126                 $line = $this->getLine();
 127                 $message = $this->getMessage();
 128                 return $wgRequest->getRequestURL() . " Exception from line $line of $file: $message";
 129         }
 130
 131         /** Output the exception report using HTML */
 132         function reportHTML() {
 133                 global $wgOut;
 134                 if ( $this->useOutputPage() ) {
 135                         $wgOut->setPageTitle( $this->getPageTitle() );
 136                         $wgOut->setRobotpolicy( "noindex,nofollow" );
 137                         $wgOut->setArticleRelated( false );
 138                         $wgOut->enableClientCache( false );
 139                         $wgOut->redirect( '' );
 140                         $wgOut->clearHTML();
 141                         if( $hookResult = $this->runHooks( get_class( $this ) ) ) {
 142                                 $wgOut->addHTML( $hookResult );
 143                         } else {
 144                                 $wgOut->addHTML( $this->getHTML() );
 145                         }
 146                         $wgOut->output();
 147                 } else {
 148                         if( $hookResult = $this->runHooks( get_class( $this ) . "Raw" ) ) {
 149                                 die( $hookResult );
 150                         }
 151                         echo $this->htmlHeader();
 152                         echo $this->getHTML();
 153                         echo $this->htmlFooter();
 154                 }
 155         }
 156
 157         /**
 158          * Output a report about the exception and takes care of formatting.
 159          * It will be either HTML or plain text based on $wgCommandLineMode.
 160          */
 161         function report() {
 162                 global $wgCommandLineMode;
 163                 if ( $wgCommandLineMode ) {
 164                         fwrite( STDERR, $this->getText() );
 165                 } else {
 166                         $log = $this->getLogMessage();
 167                         if ( $log ) {
 168                                 wfDebugLog( 'exception', $log );
 169                         }
 170                         $this->reportHTML();
 171                 }
 172         }
 173
 174         /**
 175          * Send headers and output the beginning of the html page if not using
 176          * $wgOut to output the exception.
 177          */
 178         function htmlHeader() {
 179                 global $wgLogo, $wgSitename, $wgOutputEncoding;
 180
 181                 if ( !headers_sent() ) {
 182                         header( 'HTTP/1.0 500 Internal Server Error' );
 183                         header( 'Content-type: text/html; charset='.$wgOutputEncoding );
 184                         /* Don't cache error pages!  They cause no end of trouble... */
 185                         header( 'Cache-control: none' );
 186                         header( 'Pragma: nocache' );
 187                 }
 188                 $title = $this->getPageTitle();
 189                 echo "<html>
 190                 <head>
 191                 <title>$title</title>
 192                 </head>
 193                 <body>
 194                 <h1><img src='$wgLogo' style='float:left;margin-right:1em' alt=''>$title</h1>
 195                 ";
 196         }
 197
 198         /**
 199          * print the end of the html page if not using $wgOut.
 200          */
 201         function htmlFooter() {
 202                 echo "</body></html>";
 203         }
 204 }
 205
 206 /**
 207  * Exception class which takes an HTML error message, and does not
 208  * produce a backtrace. Replacement for OutputPage::fatalError().
 209  * @addtogroup Exception
 210  */
 211 class FatalError extends MWException {
 212         function getHTML() {
 213                 return $this->getMessage();
 214         }
 215
 216         function getText() {
 217                 return $this->getMessage();
 218         }
 219 }
 220
 221 /**
 222  * @addtogroup Exception
 223  */
 224 class ErrorPageError extends MWException {
 225         public $title, $msg;
 226
 227         /**
 228          * Note: these arguments are keys into wfMsg(), not text!
 229          */
 230         function __construct( $title, $msg ) {
 231                 $this->title = $title;
 232                 $this->msg = $msg;
 233                 parent::__construct( wfMsg( $msg ) );
 234         }
 235
 236         function report() {
 237                 global $wgOut;
 238                 $wgOut->showErrorPage( $this->title, $this->msg );
 239                 $wgOut->output();
 240         }
 241 }
 242
 243 /**
 244  * Install an exception handler for MediaWiki exception types.
 245  */
 246 function wfInstallExceptionHandler() {
 247         set_exception_handler( 'wfExceptionHandler' );
 248 }
 249
 250 /**
 251  * Report an exception to the user
 252  */
 253 function wfReportException( Exception $e ) {
 254          if ( $e instanceof MWException ) {
 255                  try {
 256                          $e->report();
 257                  } catch ( Exception $e2 ) {
 258                          // Exception occurred from within exception handler
 259                          // Show a simpler error message for the original exception,
 260                          // don't try to invoke report()
 261                          $message = "MediaWiki internal error.\n\n" .
 262                          "Original exception: " . $e->__toString() .
 263                          "\n\nException caught inside exception handler: " .
 264                          $e2->__toString() . "\n";
 265
 266                          if ( !empty( $GLOBALS['wgCommandLineMode'] ) ) {
 267                                  fwrite( STDERR, $message );
 268                          } else {
 269                                  echo nl2br( htmlspecialchars( $message ) ). "\n";
 270                          }
 271                  }
 272          } else {
 273                  echo $e->__toString();
 274          }
 275 }
 276
 277 /**
 278  * Exception handler which simulates the appropriate catch() handling:
 279  *
 280  *   try {
 281  *       ...
 282  *   } catch ( MWException $e ) {
 283  *       $e->report();
 284  *   } catch ( Exception $e ) {
 285  *       echo $e->__toString();
 286  *   }
 287  */
 288 function wfExceptionHandler( $e ) {
 289         global $wgFullyInitialised;
 290         wfReportException( $e );
 291
 292         // Final cleanup, similar to wfErrorExit()
 293         if ( $wgFullyInitialised ) {
 294                 try {
 295                         wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 296                 } catch ( Exception $e ) {}
 297         }
 298
 299         // Exit value should be nonzero for the benefit of shell jobs
 300         exit( 1 );
 301 }
 302
 303