(bug 33321. Sort of) Adding a line to MediaWiki:Sidebar that contains a pipe, but...

[mediawiki.git] / includes / Exception.php

<?php
/**
 * Exception class and handler
 *
 * @file
 */

/**
 * @defgroup Exception Exception
 */

/**
 * MediaWiki exception
 *
 * @ingroup Exception
 */
class MWException extends Exception {
        /**
         * Should the exception use $wgOut to output the error ?
         * @return bool
         */
        function useOutputPage() {
                return $this->useMessageCache() &&
                        !empty( $GLOBALS['wgFullyInitialised'] ) &&
                        !empty( $GLOBALS['wgOut'] ) &&
                        !empty( $GLOBALS['wgTitle'] );
        }

        /**
         * Can the extension use wfMsg() to get i18n messages ?
         * @return bool
         */
        function useMessageCache() {
                global $wgLang;

                foreach ( $this->getTrace() as $frame ) {
                        if ( isset( $frame['class'] ) && $frame['class'] === 'LocalisationCache' ) {
                                return false;
                        }
                }

                return $wgLang instanceof Language;
        }

        /**
         * Run hook to allow extensions to modify the text of the exception
         *
         * @param $name String: class name of the exception
         * @param $args Array: arguments to pass to the callback functions
         * @return Mixed: string to output or null if any hook has been called
         */
        function runHooks( $name, $args = array() ) {
                global $wgExceptionHooks;

                if ( !isset( $wgExceptionHooks ) || !is_array( $wgExceptionHooks ) ) {
                        return; // Just silently ignore
                }

                if ( !array_key_exists( $name, $wgExceptionHooks ) || !is_array( $wgExceptionHooks[ $name ] ) ) {
                        return;
                }

                $hooks = $wgExceptionHooks[ $name ];
                $callargs = array_merge( array( $this ), $args );

                foreach ( $hooks as $hook ) {
                        if ( is_string( $hook ) || ( is_array( $hook ) && count( $hook ) >= 2 && is_string( $hook[0] ) ) ) {    // 'function' or array( 'class', hook' )
                                $result = call_user_func_array( $hook, $callargs );
                        } else {
                                $result = null;
                        }

                        if ( is_string( $result ) ) {
                                return $result;
                        }
                }
        }

        /**
         * Get a message from i18n
         *
         * @param $key String: message name
         * @param $fallback String: default message if the message cache can't be
         *                  called by the exception
         * The function also has other parameters that are arguments for the message
         * @return String message with arguments replaced
         */
        function msg( $key, $fallback /*[, params...] */ ) {
                $args = array_slice( func_get_args(), 2 );

                if ( $this->useMessageCache() ) {
                        return wfMsgNoTrans( $key, $args );
                } else {
                        return wfMsgReplaceArgs( $fallback, $args );
                }
        }

        /**
         * If $wgShowExceptionDetails is true, return a HTML message with a
         * backtrace to the error, otherwise show a message to ask to set it to true
         * to show that information.
         *
         * @return String html to output
         */
        function getHTML() {
                global $wgShowExceptionDetails;

                if ( $wgShowExceptionDetails ) {
                        return '<p>' . nl2br( htmlspecialchars( $this->getMessage() ) ) .
                                '</p><p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
                                "</p>\n";
                } else {
                        return "<p>Set <b><tt>\$wgShowExceptionDetails = true;</tt></b> " .
                                "at the bottom of LocalSettings.php to show detailed " .
                                "debugging information.</p>";
                }
        }

        /**
         * If $wgShowExceptionDetails is true, return a text message with a
         * backtrace to the error.
         * @return string
         */
        function getText() {
                global $wgShowExceptionDetails;

                if ( $wgShowExceptionDetails ) {
                        return $this->getMessage() .
                                "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
                } else {
                        return "Set \$wgShowExceptionDetails = true; " .
                                "in LocalSettings.php to show detailed debugging information.\n";
                }
        }

        /**
         * Return titles of this error page
         * @return String
         */
        function getPageTitle() {
                return $this->msg( 'internalerror', "Internal error" );
        }

        /**
         * Return the requested URL and point to file and line number from which the
         * exception occured
         *
         * @return String
         */
        function getLogMessage() {
                global $wgRequest;

                $file = $this->getFile();
                $line = $this->getLine();
                $message = $this->getMessage();

                if ( isset( $wgRequest ) && !$wgRequest instanceof FauxRequest ) {
                        $url = $wgRequest->getRequestURL();
                        if ( !$url ) {
                                $url = '[no URL]';
                        }
                } else {
                        $url = '[no req]';
                }

                return "$url   Exception from line $line of $file: $message";
        }

        /** Output the exception report using HTML */
        function reportHTML() {
                global $wgOut;
                if ( $this->useOutputPage() ) {
                        $wgOut->prepareErrorPage( $this->getPageTitle() );

                        $hookResult = $this->runHooks( get_class( $this ) );
                        if ( $hookResult ) {
                                $wgOut->addHTML( $hookResult );
                        } else {
                                $wgOut->addHTML( $this->getHTML() );
                        }

                        $wgOut->output();
                } else {
                        header( "Content-Type: text/html; charset=utf-8" );
                        $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
                        if ( $hookResult ) {
                                die( $hookResult );
                        }

                        echo $this->getHTML();
                        die(1);
                }
        }

        /**
         * Output a report about the exception and takes care of formatting.
         * It will be either HTML or plain text based on isCommandLine().
         */
        function report() {
                $log = $this->getLogMessage();

                if ( $log ) {
                        wfDebugLog( 'exception', $log );
                }

                if ( self::isCommandLine() ) {
                        MWExceptionHandler::printError( $this->getText() );
                } else {
                        $this->reportHTML();
                }
        }

        /**
         * @static
         * @return bool
         */
        static function isCommandLine() {
                return !empty( $GLOBALS['wgCommandLineMode'] );
        }
}

/**
 * Exception class which takes an HTML error message, and does not
 * produce a backtrace. Replacement for OutputPage::fatalError().
 * @ingroup Exception
 */
class FatalError extends MWException {

        /**
         * @return string
         */
        function getHTML() {
                return $this->getMessage();
        }

        /**
         * @return string
         */
        function getText() {
                return $this->getMessage();
        }
}

/**
 * An error page which can definitely be safely rendered using the OutputPage
 * @ingroup Exception
 */
class ErrorPageError extends MWException {
        public $title, $msg, $params;

        /**
         * Note: these arguments are keys into wfMsg(), not text!
         */
        function __construct( $title, $msg, $params = null ) {
                $this->title = $title;
                $this->msg = $msg;
                $this->params = $params;

                if( $msg instanceof Message ){
                        parent::__construct( $msg );
                } else {
                        parent::__construct( wfMsg( $msg ) );
                }
        }

        function report() {
                global $wgOut;

                $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
                $wgOut->output();
        }
}

/**
 * Show an error when a user tries to do something they do not have the necessary
 * permissions for.
 * @ingroup Exception
 */
class PermissionsError extends ErrorPageError {
        public $permission, $errors;

        function __construct( $permission, $errors = array() ) {
                global $wgLang;

                $this->permission = $permission;

                if ( !count( $errors ) ) {
                        $groups = array_map(
                                array( 'User', 'makeGroupLinkWiki' ),
                                User::getGroupsWithPermission( $this->permission )
                        );

                        if ( $groups ) {
                                $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
                        } else {
                                $errors[] = array( 'badaccess-group0' );
                        }
                }

                $this->errors = $errors;
        }

        function report() {
                global $wgOut;

                $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
                $wgOut->output();
        }
}

/**
 * Show an error when the wiki is locked/read-only and the user tries to do
 * something that requires write access
 * @ingroup Exception
 */
class ReadOnlyError extends ErrorPageError {
        public function __construct(){
                parent::__construct(
                        'readonly',
                        'readonlytext',
                        wfReadOnlyReason()
                );
        }
}

/**
 * Show an error when the user hits a rate limit
 * @ingroup Exception
 */
class ThrottledError extends ErrorPageError {
        public function __construct(){
                parent::__construct(
                        'actionthrottled',
                        'actionthrottledtext'
                );
        }

        public function report(){
                global $wgOut;
                $wgOut->setStatusCode( 503 );
                return parent::report();
        }
}

/**
 * Show an error when the user tries to do something whilst blocked
 * @ingroup Exception
 */
class UserBlockedError extends ErrorPageError {
        public function __construct( Block $block ){
                global $wgLang, $wgRequest;

                $blocker = $block->getBlocker();
                if ( $blocker instanceof User ) { // local user
                        $blockerUserpage = $block->getBlocker()->getUserPage();
                        $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
                } else { // foreign user
                        $link = $blocker;
                }

                $reason = $block->mReason;
                if( $reason == '' ) {
                        $reason = wfMsg( 'blockednoreason' );
                }

                /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
                 * This could be a username, an IP range, or a single IP. */
                $intended = $block->getTarget();

                parent::__construct(
                        'blockedtitle',
                        $block->mAuto ? 'autoblockedtext' : 'blockedtext',
                        array(
                                $link,
                                $reason,
                                $wgRequest->getIP(),
                                $block->getByName(),
                                $block->getId(),
                                $wgLang->formatExpiry( $block->mExpiry ),
                                $intended,
                                $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
                        )
                );
        }
}

/**
 * Show an error that looks like an HTTP server error.
 * Replacement for wfHttpError().
 *
 * @ingroup Exception
 */
class HttpError extends MWException {
        private $httpCode, $header, $content;

        /**
         * Constructor
         *
         * @param $httpCode Integer: HTTP status code to send to the client
         * @param $content String|Message: content of the message
         * @param $header String|Message: content of the header (\<title\> and \<h1\>)
         */
        public function __construct( $httpCode, $content, $header = null ){
                parent::__construct( $content );
                $this->httpCode = (int)$httpCode;
                $this->header = $header;
                $this->content = $content;
        }

        public function reportHTML() {
                $httpMessage = HttpStatus::getMessage( $this->httpCode );

                header( "Status: {$this->httpCode} {$httpMessage}" );
                header( 'Content-type: text/html; charset=utf-8' );

                if ( $this->header === null ) {
                        $header = $httpMessage;
                } elseif ( $this->header instanceof Message ) {
                        $header = $this->header->escaped();
                } else {
                        $header = htmlspecialchars( $this->header );
                }

                if ( $this->content instanceof Message ) {
                        $content = $this->content->escaped();
                } else {
                        $content = htmlspecialchars( $this->content );
                }

                print "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n".
                        "<html><head><title>$header</title></head>\n" .
                        "<body><h1>$header</h1><p>$content</p></body></html>\n";
        }
}

/**
 * Handler class for MWExceptions
 * @ingroup Exception
 */
class MWExceptionHandler {
        /**
         * Install an exception handler for MediaWiki exception types.
         */
        public static function installHandler() {
                set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
        }

        /**
         * Report an exception to the user
         */
        protected static function report( Exception $e ) {
                global $wgShowExceptionDetails;

                $cmdLine = MWException::isCommandLine();

                if ( $e instanceof MWException ) {
                        try {
                                // Try and show the exception prettily, with the normal skin infrastructure
                                $e->report();
                        } catch ( Exception $e2 ) {
                                // Exception occurred from within exception handler
                                // Show a simpler error message for the original exception,
                                // don't try to invoke report()
                                $message = "MediaWiki internal error.\n\n";

                                if ( $wgShowExceptionDetails ) {
                                        $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
                                                'Exception caught inside exception handler: ' . $e2->__toString();
                                } else {
                                        $message .= "Exception caught inside exception handler.\n\n" .
                                                "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
                                                "to show detailed debugging information.";
                                }

                                $message .= "\n";

                                if ( $cmdLine ) {
                                        self::printError( $message );
                                } else {
                                        self::escapeEchoAndDie( $message );
                                }
                        }
                } else {
                        $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
                                $e->__toString() . "\n";

                        if ( $wgShowExceptionDetails ) {
                                $message .= "\n" . $e->getTraceAsString() . "\n";
                        }

                        if ( $cmdLine ) {
                                self::printError( $message );
                        } else {
                                self::escapeEchoAndDie( $message );
                        }
                }
        }

        /**
         * Print a message, if possible to STDERR.
         * Use this in command line mode only (see isCommandLine)
         * @param $message String Failure text
         */
        public static function printError( $message ) {
                # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
                #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
                if ( defined( 'STDERR' ) ) {
                        fwrite( STDERR, $message );
                } else {
                        echo( $message );
                }
        }

        /**
         * Print a message after escaping it and converting newlines to <br>
         * Use this for non-command line failures
         * @param $message String Failure text
         */
        private static function escapeEchoAndDie( $message ) {
                echo nl2br( htmlspecialchars( $message ) ) . "\n";
                die(1);
        }

        /**
         * Exception handler which simulates the appropriate catch() handling:
         *
         *   try {
         *       ...
         *   } catch ( MWException $e ) {
         *       $e->report();
         *   } catch ( Exception $e ) {
         *       echo $e->__toString();
         *   }
         */
        public static function handle( $e ) {
                global $wgFullyInitialised;

                self::report( $e );

                // Final cleanup
                if ( $wgFullyInitialised ) {
                        try {
                                wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
                        } catch ( Exception $e ) {}
                }

                // Exit value should be nonzero for the benefit of shell jobs
                exit( 1 );
        }
}