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[mediawiki.git] / includes / OutputHandler.php
blobb0bbcddbd33418f98b3f7bc793df1dafcbb26265
1 <?php
2 /**
3 * Functions to be used with PHP's output buffer.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
20 * @file
23 /**
24 * Standard output handler for use with ob_start
26 * @param string $s
28 * @return string
30 function wfOutputHandler( $s ) {
31 global $wgDisableOutputCompression, $wgValidateAllHtml, $wgMangleFlashPolicy;
32 if ( $wgMangleFlashPolicy ) {
33 $s = wfMangleFlashPolicy( $s );
35 if ( $wgValidateAllHtml ) {
36 $headers = headers_list();
37 $isHTML = false;
38 foreach ( $headers as $header ) {
39 $parts = explode( ':', $header, 2 );
40 if ( count( $parts ) !== 2 ) {
41 continue;
43 $name = strtolower( trim( $parts[0] ) );
44 $value = trim( $parts[1] );
45 if ( $name == 'content-type' && ( strpos( $value, 'text/html' ) === 0
46 || strpos( $value, 'application/xhtml+xml' ) === 0 )
47 ) {
48 $isHTML = true;
49 break;
52 if ( $isHTML ) {
53 $s = wfHtmlValidationHandler( $s );
56 if ( !$wgDisableOutputCompression && !ini_get( 'zlib.output_compression' ) ) {
57 if ( !defined( 'MW_NO_OUTPUT_COMPRESSION' ) ) {
58 $s = wfGzipHandler( $s );
60 if ( !ini_get( 'output_handler' ) ) {
61 wfDoContentLength( strlen( $s ) );
64 return $s;
67 /**
68 * Get the "file extension" that some client apps will estimate from
69 * the currently-requested URL.
70 * This isn't on WebRequest because we need it when things aren't initialized
71 * @private
73 * @return string
75 function wfRequestExtension() {
76 /// @todo FIXME: this sort of dupes some code in WebRequest::getRequestUrl()
77 if ( isset( $_SERVER['REQUEST_URI'] ) ) {
78 // Strip the query string...
79 list( $path ) = explode( '?', $_SERVER['REQUEST_URI'], 2 );
80 } elseif ( isset( $_SERVER['SCRIPT_NAME'] ) ) {
81 // Probably IIS. QUERY_STRING appears separately.
82 $path = $_SERVER['SCRIPT_NAME'];
83 } else {
84 // Can't get the path from the server? :(
85 return '';
88 $period = strrpos( $path, '.' );
89 if ( $period !== false ) {
90 return strtolower( substr( $path, $period ) );
92 return '';
95 /**
96 * Handler that compresses data with gzip if allowed by the Accept header.
97 * Unlike ob_gzhandler, it works for HEAD requests too.
99 * @param string $s
101 * @return string
103 function wfGzipHandler( $s ) {
104 if ( !function_exists( 'gzencode' ) ) {
105 wfDebug( __FUNCTION__ . "() skipping compression (gzencode unavailable)\n" );
106 return $s;
108 if ( headers_sent() ) {
109 wfDebug( __FUNCTION__ . "() skipping compression (headers already sent)\n" );
110 return $s;
113 $ext = wfRequestExtension();
114 if ( $ext == '.gz' || $ext == '.tgz' ) {
115 // Don't do gzip compression if the URL path ends in .gz or .tgz
116 // This confuses Safari and triggers a download of the page,
117 // even though it's pretty clearly labeled as viewable HTML.
118 // Bad Safari! Bad!
119 return $s;
122 if ( wfClientAcceptsGzip() ) {
123 wfDebug( __FUNCTION__ . "() is compressing output\n" );
124 header( 'Content-Encoding: gzip' );
125 $s = gzencode( $s, 6 );
128 // Set vary header if it hasn't been set already
129 $headers = headers_list();
130 $foundVary = false;
131 foreach ( $headers as $header ) {
132 if ( substr( $header, 0, 5 ) == 'Vary:' ) {
133 $foundVary = true;
134 break;
137 if ( !$foundVary ) {
138 header( 'Vary: Accept-Encoding' );
139 global $wgUseXVO;
140 if ( $wgUseXVO ) {
141 header( 'X-Vary-Options: Accept-Encoding;list-contains=gzip' );
144 return $s;
148 * Mangle flash policy tags which open up the site to XSS attacks.
150 * @param string $s
152 * @return string
154 function wfMangleFlashPolicy( $s ) {
155 # Avoid weird excessive memory usage in PCRE on big articles
156 if ( preg_match( '/\<\s*cross-domain-policy\s*\>/i', $s ) ) {
157 return preg_replace( '/\<\s*cross-domain-policy\s*\>/i', '<NOT-cross-domain-policy>', $s );
158 } else {
159 return $s;
164 * Add a Content-Length header if possible. This makes it cooperate with squid better.
166 * @param int $length
168 function wfDoContentLength( $length ) {
169 if ( !headers_sent()
170 && isset( $_SERVER['SERVER_PROTOCOL'] )
171 && $_SERVER['SERVER_PROTOCOL'] == 'HTTP/1.0'
173 header( "Content-Length: $length" );
178 * Replace the output with an error if the HTML is not valid
180 * @param string $s
182 * @return string
184 function wfHtmlValidationHandler( $s ) {
186 $errors = '';
187 if ( MWTidy::checkErrors( $s, $errors ) ) {
188 return $s;
191 header( 'Cache-Control: no-cache' );
193 $out = Html::element( 'h1', null, 'HTML validation error' );
194 $out .= Html::openElement( 'ul' );
196 $error = strtok( $errors, "\n" );
197 $badLines = array();
198 while ( $error !== false ) {
199 if ( preg_match( '/^line (\d+)/', $error, $m ) ) {
200 $lineNum = intval( $m[1] );
201 $badLines[$lineNum] = true;
202 $out .= Html::rawElement( 'li', null,
203 Html::element( 'a', array( 'href' => "#line-{$lineNum}" ), $error ) ) . "\n";
205 $error = strtok( "\n" );
208 $out .= Html::closeElement( 'ul' );
209 $out .= Html::element( 'pre', null, $errors );
210 $out .= Html::openElement( 'ol' ) . "\n";
211 $line = strtok( $s, "\n" );
212 $i = 1;
213 while ( $line !== false ) {
214 $attrs = array();
215 if ( isset( $badLines[$i] ) ) {
216 $attrs['class'] = 'highlight';
217 $attrs['id'] = "line-$i";
219 $out .= Html::element( 'li', $attrs, $line ) . "\n";
220 $line = strtok( "\n" );
221 $i++;
223 $out .= Html::closeElement( 'ol' );
225 $style = <<<CSS
226 .highlight { background-color: #ffc }
227 li { white-space: pre }
228 CSS;
230 $out = Html::htmlHeader( array( 'lang' => 'en', 'dir' => 'ltr' ) ) .
231 Html::rawElement( 'head', null,
232 Html::element( 'title', null, 'HTML validation error' ) .
233 Html::inlineStyle( $style ) ) .
234 Html::rawElement( 'body', null, $out ) .
235 Html::closeElement( 'html' );
237 return $out;