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<?php
/**
* Functions to be used with PHP's output buffer.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
/**
* Standard output handler for use with ob_start
*
* @param $s string
*
* @return string
*/
function wfOutputHandler( $s ) {
global $wgDisableOutputCompression, $wgValidateAllHtml;
$s = wfMangleFlashPolicy( $s );
if ( $wgValidateAllHtml ) {
$headers = apache_response_headers();
$isHTML = true;
foreach ( $headers as $name => $value ) {
if ( strtolower( $name ) == 'content-type' && strpos( $value, 'text/html' ) === false && strpos( $value, 'application/xhtml+xml' ) === false ) {
$isHTML = false;
break;
}
}
if ( $isHTML ) {
$s = wfHtmlValidationHandler( $s );
}
}
if ( !$wgDisableOutputCompression && !ini_get( 'zlib.output_compression' ) ) {
if ( !defined( 'MW_NO_OUTPUT_COMPRESSION' ) ) {
$s = wfGzipHandler( $s );
}
if ( !ini_get( 'output_handler' ) ) {
wfDoContentLength( strlen( $s ) );
}
}
return $s;
}
/**
* Get the "file extension" that some client apps will estimate from
* the currently-requested URL.
* This isn't on WebRequest because we need it when things aren't initialized
* @private
*
* @return string
*/
function wfRequestExtension() {
/// @todo FIXME: this sort of dupes some code in WebRequest::getRequestUrl()
if( isset( $_SERVER['REQUEST_URI'] ) ) {
// Strip the query string...
list( $path ) = explode( '?', $_SERVER['REQUEST_URI'], 2 );
} elseif( isset( $_SERVER['SCRIPT_NAME'] ) ) {
// Probably IIS. QUERY_STRING appears separately.
$path = $_SERVER['SCRIPT_NAME'];
} else {
// Can't get the path from the server? :(
return '';
}
$period = strrpos( $path, '.' );
if( $period !== false ) {
return strtolower( substr( $path, $period ) );
}
return '';
}
/**
* Handler that compresses data with gzip if allowed by the Accept header.
* Unlike ob_gzhandler, it works for HEAD requests too.
*
* @param $s string
*
* @return string
*/
function wfGzipHandler( $s ) {
if( !function_exists( 'gzencode' ) ) {
wfDebug( __FUNCTION__ . "() skipping compression (gzencode unavailable)\n" );
return $s;
}
if( headers_sent() ) {
wfDebug( __FUNCTION__ . "() skipping compression (headers already sent)\n" );
return $s;
}
$ext = wfRequestExtension();
if( $ext == '.gz' || $ext == '.tgz' ) {
// Don't do gzip compression if the URL path ends in .gz or .tgz
// This confuses Safari and triggers a download of the page,
// even though it's pretty clearly labeled as viewable HTML.
// Bad Safari! Bad!
return $s;
}
if( wfClientAcceptsGzip() ) {
wfDebug( __FUNCTION__ . "() is compressing output\n" );
header( 'Content-Encoding: gzip' );
$s = gzencode( $s, 6 );
}
// Set vary header if it hasn't been set already
$headers = headers_list();
$foundVary = false;
foreach ( $headers as $header ) {
if ( substr( $header, 0, 5 ) == 'Vary:' ) {
$foundVary = true;
break;
}
}
if ( !$foundVary ) {
header( 'Vary: Accept-Encoding' );
global $wgUseXVO;
if ( $wgUseXVO ) {
header( 'X-Vary-Options: Accept-Encoding;list-contains=gzip' );
}
}
return $s;
}
/**
* Mangle flash policy tags which open up the site to XSS attacks.
*
* @param $s string
*
* @return string
*/
function wfMangleFlashPolicy( $s ) {
# Avoid weird excessive memory usage in PCRE on big articles
if ( preg_match( '/\<\s*cross-domain-policy\s*\>/i', $s ) ) {
return preg_replace( '/\<\s*cross-domain-policy\s*\>/i', '<NOT-cross-domain-policy>', $s );
} else {
return $s;
}
}
/**
* Add a Content-Length header if possible. This makes it cooperate with squid better.
*
* @param $length int
*/
function wfDoContentLength( $length ) {
if ( !headers_sent() && isset( $_SERVER['SERVER_PROTOCOL'] ) && $_SERVER['SERVER_PROTOCOL'] == 'HTTP/1.0' ) {
header( "Content-Length: $length" );
}
}
/**
* Replace the output with an error if the HTML is not valid
*
* @param $s string
*
* @return string
*/
function wfHtmlValidationHandler( $s ) {
$errors = '';
if ( MWTidy::checkErrors( $s, $errors ) ) {
return $s;
}
header( 'Cache-Control: no-cache' );
$out = <<<EOT
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" dir="ltr">
<head>
<title>HTML validation error</title>
<style>
.highlight { background-color: #ffc }
li { white-space: pre }
</style>
</head>
<body>
<h1>HTML validation error</h1>
<ul>
EOT;
$error = strtok( $errors, "\n" );
$badLines = array();
while ( $error !== false ) {
if ( preg_match( '/^line (\d+)/', $error, $m ) ) {
$lineNum = intval( $m[1] );
$badLines[$lineNum] = true;
$out .= "<li><a href=\"#line-{$lineNum}\">" . htmlspecialchars( $error ) . "</a></li>\n";
}
$error = strtok( "\n" );
}
$out .= '</ul>';
$out .= '<pre>' . htmlspecialchars( $errors ) . '</pre>';
$out .= "<ol>\n";
$line = strtok( $s, "\n" );
$i = 1;
while ( $line !== false ) {
if ( isset( $badLines[$i] ) ) {
$out .= "<li class=\"highlight\" id=\"line-$i\">";
} else {
$out .= '<li>';
}
$out .= htmlspecialchars( $line ) . "</li>\n";
$line = strtok( "\n" );
$i++;
}
$out .= '</ol></body></html>';
return $out;
}
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