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          * Run hook to allow extensions to modify the text of the exception
  68          *
  69          * @param string $name Class name of the exception
  70          * @param array $args Arguments to pass to the callback functions
  71          * @return string|null String to output or null if any hook has been called
  72          */
  73         public function runHooks( $name, $args = array() ) {
  74                 global $wgExceptionHooks;
  75
  76                 if ( !isset( $wgExceptionHooks ) || !is_array( $wgExceptionHooks ) ) {
  77                         return null; // Just silently ignore
  78                 }
  79
  80                 if ( !array_key_exists( $name, $wgExceptionHooks ) ||
  81                         !is_array( $wgExceptionHooks[$name] )
  82                 ) {
  83                         return null;
  84                 }
  85
  86                 $hooks = $wgExceptionHooks[$name];
  87                 $callargs = array_merge( array( $this ), $args );
  88
  89                 foreach ( $hooks as $hook ) {
  90                         if (
  91                                 is_string( $hook ) ||
  92                                 ( is_array( $hook ) && count( $hook ) >= 2 && is_string( $hook[0] ) )
  93                         ) {
  94                                 // 'function' or array( 'class', hook' )
  95                                 $result = call_user_func_array( $hook, $callargs );
  96                         } else {
  97                                 $result = null;
  98                         }
  99
 100                         if ( is_string( $result ) ) {
 101                                 return $result;
 102                         }
 103                 }
 104                 return null;
 105         }
 106
 107         /**
 108          * Get a message from i18n
 109          *
 110          * @param string $key Message name
 111          * @param string $fallback Default message if the message cache can't be
 112          *                  called by the exception
 113          * The function also has other parameters that are arguments for the message
 114          * @return string Message with arguments replaced
 115          */
 116         public function msg( $key, $fallback /*[, params...] */ ) {
 117                 $args = array_slice( func_get_args(), 2 );
 118
 119                 if ( $this->useMessageCache() ) {
 120                         try {
 121                                 return wfMessage( $key, $args )->text();
 122                         } catch ( Exception $e ) {}
 123                 }
 124                 return wfMsgReplaceArgs( $fallback, $args );
 125         }
 126
 127         /**
 128          * If $wgShowExceptionDetails is true, return a HTML message with a
 129          * backtrace to the error, otherwise show a message to ask to set it to true
 130          * to show that information.
 131          *
 132          * @return string Html to output
 133          */
 134         public function getHTML() {
 135                 global $wgShowExceptionDetails;
 136
 137                 if ( $wgShowExceptionDetails ) {
 138                         return '<p>' . nl2br( htmlspecialchars( MWExceptionHandler::getLogMessage( $this ) ) ) .
 139                         '</p><p>Backtrace:</p><p>' .
 140                         nl2br( htmlspecialchars( MWExceptionHandler::getRedactedTraceAsString( $this ) ) ) .
 141                         "</p>\n";
 142                 } else {
 143                         $logId = MWExceptionHandler::getLogId( $this );
 144                         $type = get_class( $this );
 145                         return "<div class=\"errorbox\">" .
 146                         '[' . $logId . '] ' .
 147                         gmdate( 'Y-m-d H:i:s' ) . ": " .
 148                         $this->msg( "internalerror-fatal-exception",
 149                                 "Fatal exception of type $1",
 150                                 $type,
 151                                 $logId,
 152                                 MWExceptionHandler::getURL( $this )
 153                         ) . "</div>\n" .
 154                         "<!-- Set \$wgShowExceptionDetails = true; " .
 155                         "at the bottom of LocalSettings.php to show detailed " .
 156                         "debugging information. -->";
 157                 }
 158         }
 159
 160         /**
 161          * Get the text to display when reporting the error on the command line.
 162          * If $wgShowExceptionDetails is true, return a text message with a
 163          * backtrace to the error.
 164          *
 165          * @return string
 166          */
 167         public function getText() {
 168                 global $wgShowExceptionDetails;
 169
 170                 if ( $wgShowExceptionDetails ) {
 171                         return MWExceptionHandler::getLogMessage( $this ) .
 172                         "\nBacktrace:\n" . MWExceptionHandler::getRedactedTraceAsString( $this ) . "\n";
 173                 } else {
 174                         return "Set \$wgShowExceptionDetails = true; " .
 175                         "in LocalSettings.php to show detailed debugging information.\n";
 176                 }
 177         }
 178
 179         /**
 180          * Return the title of the page when reporting this error in a HTTP response.
 181          *
 182          * @return string
 183          */
 184         public function getPageTitle() {
 185                 return $this->msg( 'internalerror', 'Internal error' );
 186         }
 187
 188         /**
 189          * Output the exception report using HTML.
 190          */
 191         public function reportHTML() {
 192                 global $wgOut, $wgSitename;
 193                 if ( $this->useOutputPage() ) {
 194                         $wgOut->prepareErrorPage( $this->getPageTitle() );
 195
 196                         $hookResult = $this->runHooks( get_class( $this ) );
 197                         if ( $hookResult ) {
 198                                 $wgOut->addHTML( $hookResult );
 199                         } else {
 200                                 $wgOut->addHTML( $this->getHTML() );
 201                         }
 202
 203                         $wgOut->output();
 204                 } else {
 205                         self::header( 'Content-Type: text/html; charset=utf-8' );
 206                         echo "<!DOCTYPE html>\n" .
 207                                 '<html><head>' .
 208                                 // Mimick OutputPage::setPageTitle behaviour
 209                                 '<title>' .
 210                                 htmlspecialchars( $this->msg( 'pagetitle', "$1 - $wgSitename", $this->getPageTitle() ) ) .
 211                                 '</title>' .
 212                                 '<style>body { font-family: sans-serif; margin: 0; padding: 0.5em 2em; }</style>' .
 213                                 "</head><body>\n";
 214
 215                         $hookResult = $this->runHooks( get_class( $this ) . 'Raw' );
 216                         if ( $hookResult ) {
 217                                 echo $hookResult;
 218                         } else {
 219                                 echo $this->getHTML();
 220                         }
 221
 222                         echo "</body></html>\n";
 223                 }
 224         }
 225
 226         /**
 227          * Output a report about the exception and takes care of formatting.
 228          * It will be either HTML or plain text based on isCommandLine().
 229          */
 230         public function report() {
 231                 global $wgMimeType;
 232
 233                 if ( defined( 'MW_API' ) ) {
 234                         // Unhandled API exception, we can't be sure that format printer is alive
 235                         self::header( 'MediaWiki-API-Error: internal_api_error_' . get_class( $this ) );
 236                         wfHttpError( 500, 'Internal Server Error', $this->getText() );
 237                 } elseif ( self::isCommandLine() ) {
 238                         MWExceptionHandler::printError( $this->getText() );
 239                 } else {
 240                         self::header( 'HTTP/1.1 500 MediaWiki exception' );
 241                         self::header( 'Status: 500 MediaWiki exception' );
 242                         self::header( "Content-Type: $wgMimeType; charset=utf-8" );
 243
 244                         $this->reportHTML();
 245                 }
 246         }
 247
 248         /**
 249          * Check whether we are in command line mode or not to report the exception
 250          * in the correct format.
 251          *
 252          * @return bool
 253          */
 254         public static function isCommandLine() {
 255                 return !empty( $GLOBALS['wgCommandLineMode'] );
 256         }
 257
 258         /**
 259          * Send a header, if we haven't already sent them. We shouldn't,
 260          * but sometimes we might in a weird case like Export
 261          * @param string $header
 262          */
 263         private static function header( $header ) {
 264                 if ( !headers_sent() ) {
 265                         header( $header );
 266                 }
 267         }
 268 }