includes/exception/MWException.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20
  21 /**
  22  * MediaWiki exception
  23  *
  24  * @ingroup Exception
  25  */
  26 class MWException extends Exception {
  27         /**
  28          * Should the exception use $wgOut to output the error?
  29          *
  30          * @return bool
  31          */
  32         public function useOutputPage() {
  33                 return $this->useMessageCache() &&
  34                 !empty( $GLOBALS['wgFullyInitialised'] ) &&
  35                 !empty( $GLOBALS['wgOut'] ) &&
  36                 !defined( 'MEDIAWIKI_INSTALL' );
  37         }
  38
  39         /**
  40          * Whether to log this exception in the exception debug log.
  41          *
  42          * @since 1.23
  43          * @return bool
  44          */
  45         public function isLoggable() {
  46                 return true;
  47         }
  48
  49         /**
  50          * Can the extension use the Message class/wfMessage to get i18n-ed messages?
  51          *
  52          * @return bool
  53          */
  54         public function useMessageCache() {
  55                 global $wgLang;
  56
  57                 foreach ( $this->getTrace() as $frame ) {
  58                         if ( isset( $frame['class'] ) && $frame['class'] === 'LocalisationCache' ) {
  59                                 return false;
  60                         }
  61                 }
  62
  63                 return $wgLang instanceof Language;
  64         }
  65
  66         /**
  67          * Get a message from i18n
  68          *
  69          * @param string $key Message name
  70          * @param string $fallback Default message if the message cache can't be
  71          *                  called by the exception
  72          * The function also has other parameters that are arguments for the message
  73          * @return string Message with arguments replaced
  74          */
  75         public function msg( $key, $fallback /*[, params...] */ ) {
  76                 $args = array_slice( func_get_args(), 2 );
  77
  78                 if ( $this->useMessageCache() ) {
  79                         try {
  80                                 return wfMessage( $key, $args )->text();
  81                         } catch ( Exception $e ) {
  82                         }
  83                 }
  84                 return wfMsgReplaceArgs( $fallback, $args );
  85         }
  86
  87         /**
  88          * If $wgShowExceptionDetails is true, return a HTML message with a
  89          * backtrace to the error, otherwise show a message to ask to set it to true
  90          * to show that information.
  91          *
  92          * @return string Html to output
  93          */
  94         public function getHTML() {
  95                 global $wgShowExceptionDetails;
  96
  97                 if ( $wgShowExceptionDetails ) {
  98                         return '<p>' . nl2br( htmlspecialchars( MWExceptionHandler::getLogMessage( $this ) ) ) .
  99                         '</p><p>Backtrace:</p><p>' .
 100                         nl2br( htmlspecialchars( MWExceptionHandler::getRedactedTraceAsString( $this ) ) ) .
 101                         "</p>\n";
 102                 } else {
 103                         $logId = WebRequest::getRequestId();
 104                         $type = static::class;
 105                         return "<div class=\"errorbox\">" .
 106                         '[' . $logId . '] ' .
 107                         gmdate( 'Y-m-d H:i:s' ) . ": " .
 108                         $this->msg( "internalerror-fatal-exception",
 109                                 "Fatal exception of type $1",
 110                                 $type,
 111                                 $logId,
 112                                 MWExceptionHandler::getURL( $this )
 113                         ) . "</div>\n" .
 114                         "<!-- Set \$wgShowExceptionDetails = true; " .
 115                         "at the bottom of LocalSettings.php to show detailed " .
 116                         "debugging information. -->";
 117                 }
 118         }
 119
 120         /**
 121          * Get the text to display when reporting the error on the command line.
 122          * If $wgShowExceptionDetails is true, return a text message with a
 123          * backtrace to the error.
 124          *
 125          * @return string
 126          */
 127         public function getText() {
 128                 global $wgShowExceptionDetails;
 129
 130                 if ( $wgShowExceptionDetails ) {
 131                         return MWExceptionHandler::getLogMessage( $this ) .
 132                         "\nBacktrace:\n" . MWExceptionHandler::getRedactedTraceAsString( $this ) . "\n";
 133                 } else {
 134                         return "Set \$wgShowExceptionDetails = true; " .
 135                         "in LocalSettings.php to show detailed debugging information.\n";
 136                 }
 137         }
 138
 139         /**
 140          * Return the title of the page when reporting this error in a HTTP response.
 141          *
 142          * @return string
 143          */
 144         public function getPageTitle() {
 145                 return $this->msg( 'internalerror', 'Internal error' );
 146         }
 147
 148         /**
 149          * Output the exception report using HTML.
 150          */
 151         public function reportHTML() {
 152                 global $wgOut, $wgSitename;
 153                 if ( $this->useOutputPage() ) {
 154                         $wgOut->prepareErrorPage( $this->getPageTitle() );
 155
 156                         $wgOut->addHTML( $this->getHTML() );
 157
 158                         $wgOut->output();
 159                 } else {
 160                         self::header( 'Content-Type: text/html; charset=utf-8' );
 161                         echo "<!DOCTYPE html>\n" .
 162                                 '<html><head>' .
 163                                 // Mimick OutputPage::setPageTitle behaviour
 164                                 '<title>' .
 165                                 htmlspecialchars( $this->msg( 'pagetitle', "$1 - $wgSitename", $this->getPageTitle() ) ) .
 166                                 '</title>' .
 167                                 '<style>body { font-family: sans-serif; margin: 0; padding: 0.5em 2em; }</style>' .
 168                                 "</head><body>\n";
 169
 170                         echo $this->getHTML();
 171
 172                         echo "</body></html>\n";
 173                 }
 174         }
 175
 176         /**
 177          * Output a report about the exception and takes care of formatting.
 178          * It will be either HTML or plain text based on isCommandLine().
 179          */
 180         public function report() {
 181                 global $wgMimeType;
 182
 183                 if ( defined( 'MW_API' ) ) {
 184                         // Unhandled API exception, we can't be sure that format printer is alive
 185                         self::header( 'MediaWiki-API-Error: internal_api_error_' . static::class );
 186                         wfHttpError( 500, 'Internal Server Error', $this->getText() );
 187                 } elseif ( self::isCommandLine() ) {
 188                         $message = $this->getText();
 189                         // T17602: STDERR may not be available
 190                         if ( defined( 'STDERR' ) ) {
 191                                 fwrite( STDERR, $message );
 192                         } else {
 193                                 echo $message;
 194                         }
 195                 } else {
 196                         self::statusHeader( 500 );
 197                         self::header( "Content-Type: $wgMimeType; charset=utf-8" );
 198
 199                         $this->reportHTML();
 200                 }
 201         }
 202
 203         /**
 204          * Check whether we are in command line mode or not to report the exception
 205          * in the correct format.
 206          *
 207          * @return bool
 208          */
 209         public static function isCommandLine() {
 210                 return !empty( $GLOBALS['wgCommandLineMode'] );
 211         }
 212
 213         /**
 214          * Send a header, if we haven't already sent them. We shouldn't,
 215          * but sometimes we might in a weird case like Export
 216          * @param string $header
 217          */
 218         private static function header( $header ) {
 219                 if ( !headers_sent() ) {
 220                         header( $header );
 221                 }
 222         }
 223         private static function statusHeader( $code ) {
 224                 if ( !headers_sent() ) {
 225                         HttpStatus::header( $code );
 226                 }
 227         }
 228 }