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::class ) {
  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                 global $wgSitename;
  77                 $args = array_slice( func_get_args(), 2 );
  78
  79                 // FIXME: Keep logic in sync with MWExceptionRenderer::msg.
  80                 $res = false;
  81                 if ( $this->useMessageCache() ) {
  82                         try {
  83                                 $res = wfMessage( $key, $args )->text();
  84                         } catch ( Exception $e ) {
  85                         }
  86                 }
  87                 if ( $res === false ) {
  88                         $res = wfMsgReplaceArgs( $fallback, $args );
  89                         // If an exception happens inside message rendering,
  90                         // {{SITENAME}} sometimes won't be replaced.
  91                         $res = strtr( $res, [
  92                                 '{{SITENAME}}' => $wgSitename,
  93                         ] );
  94                 }
  95                 return $res;
  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         public function getHTML() {
 106                 global $wgShowExceptionDetails;
 107
 108                 if ( $wgShowExceptionDetails ) {
 109                         return '<p>' . nl2br( htmlspecialchars( MWExceptionHandler::getLogMessage( $this ) ) ) .
 110                         '</p><p>Backtrace:</p><p>' .
 111                         nl2br( htmlspecialchars( MWExceptionHandler::getRedactedTraceAsString( $this ) ) ) .
 112                         "</p>\n";
 113                 } else {
 114                         $logId = WebRequest::getRequestId();
 115                         $type = static::class;
 116                         return Html::errorBox(
 117                         htmlspecialchars(
 118                                 '[' . $logId . '] ' .
 119                                 gmdate( 'Y-m-d H:i:s' ) . ": " .
 120                                 $this->msg( "internalerror-fatal-exception",
 121                                         "Fatal exception of type $1",
 122                                         $type,
 123                                         $logId,
 124                                         MWExceptionHandler::getURL()
 125                                 )
 126                         ) ) .
 127                         "<!-- Set \$wgShowExceptionDetails = true; " .
 128                         "at the bottom of LocalSettings.php to show detailed " .
 129                         "debugging information. -->";
 130                 }
 131         }
 132
 133         /**
 134          * Get the text to display when reporting the error on the command line.
 135          * If $wgShowExceptionDetails is true, return a text message with a
 136          * backtrace to the error.
 137          *
 138          * @return string
 139          */
 140         public function getText() {
 141                 global $wgShowExceptionDetails;
 142
 143                 if ( $wgShowExceptionDetails ) {
 144                         return MWExceptionHandler::getLogMessage( $this ) .
 145                         "\nBacktrace:\n" . MWExceptionHandler::getRedactedTraceAsString( $this ) . "\n";
 146                 } else {
 147                         return "Set \$wgShowExceptionDetails = true; " .
 148                         "in LocalSettings.php to show detailed debugging information.\n";
 149                 }
 150         }
 151
 152         /**
 153          * Return the title of the page when reporting this error in a HTTP response.
 154          *
 155          * @return string
 156          */
 157         public function getPageTitle() {
 158                 return $this->msg( 'internalerror', 'Internal error' );
 159         }
 160
 161         /**
 162          * Output the exception report using HTML.
 163          */
 164         public function reportHTML() {
 165                 global $wgOut, $wgSitename;
 166                 if ( $this->useOutputPage() ) {
 167                         $wgOut->prepareErrorPage( $this->getPageTitle() );
 168                         // Manually set the html title, since sometimes
 169                         // {{SITENAME}} does not get replaced for exceptions
 170                         // happening inside message rendering.
 171                         $wgOut->setHTMLTitle(
 172                                 $this->msg(
 173                                         'pagetitle',
 174                                         "$1 - $wgSitename",
 175                                         $this->getPageTitle()
 176                                 )
 177                         );
 178
 179                         $wgOut->addHTML( $this->getHTML() );
 180
 181                         $wgOut->output();
 182                 } else {
 183                         self::header( 'Content-Type: text/html; charset=utf-8' );
 184                         echo "<!DOCTYPE html>\n" .
 185                                 '<html><head>' .
 186                                 // Mimick OutputPage::setPageTitle behaviour
 187                                 '<title>' .
 188                                 htmlspecialchars( $this->msg( 'pagetitle', "$1 - $wgSitename", $this->getPageTitle() ) ) .
 189                                 '</title>' .
 190                                 '<style>body { font-family: sans-serif; margin: 0; padding: 0.5em 2em; }</style>' .
 191                                 "</head><body>\n";
 192
 193                         echo $this->getHTML();
 194
 195                         echo "</body></html>\n";
 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         public function report() {
 204                 global $wgMimeType;
 205
 206                 if ( defined( 'MW_API' ) ) {
 207                         // Unhandled API exception, we can't be sure that format printer is alive
 208                         self::header( 'MediaWiki-API-Error: internal_api_error_' . static::class );
 209                         wfHttpError( 500, 'Internal Server Error', $this->getText() );
 210                 } elseif ( self::isCommandLine() ) {
 211                         $message = $this->getText();
 212                         // T17602: STDERR may not be available
 213                         if ( !defined( 'MW_PHPUNIT_TEST' ) && defined( 'STDERR' ) ) {
 214                                 fwrite( STDERR, $message );
 215                         } else {
 216                                 echo $message;
 217                         }
 218                 } else {
 219                         self::statusHeader( 500 );
 220                         self::header( "Content-Type: $wgMimeType; charset=utf-8" );
 221
 222                         $this->reportHTML();
 223                 }
 224         }
 225
 226         /**
 227          * Check whether we are in command line mode or not to report the exception
 228          * in the correct format.
 229          *
 230          * @return bool
 231          */
 232         public static function isCommandLine() {
 233                 return !empty( $GLOBALS['wgCommandLineMode'] );
 234         }
 235
 236         /**
 237          * Send a header, if we haven't already sent them. We shouldn't,
 238          * but sometimes we might in a weird case like Export
 239          * @param string $header
 240          */
 241         private static function header( $header ) {
 242                 if ( !headers_sent() ) {
 243                         header( $header );
 244                 }
 245         }
 246         private static function statusHeader( $code ) {
 247                 if ( !headers_sent() ) {
 248                         HttpStatus::header( $code );
 249                 }
 250         }
 251 }