includes/OutputHandler.php

   1 <?php
   2
   3 /**
   4  * Standard output handler for use with ob_start
   5  */
   6 function wfOutputHandler( $s ) {
   7         global $wgDisableOutputCompression;
   8         $s = wfMangleFlashPolicy( $s );
   9         if ( !$wgDisableOutputCompression && !ini_get( 'zlib.output_compression' ) ) {
  10                 if ( !defined( 'MW_NO_OUTPUT_COMPRESSION' ) ) {
  11                         $s = wfGzipHandler( $s );
  12                 }
  13                 if ( !ini_get( 'output_handler' ) ) {
  14                         wfDoContentLength( strlen( $s ) );
  15                 }
  16         }
  17         return $s;
  18 }
  19
  20 /**
  21  * Handler that compresses data with gzip if allowed by the Accept header.
  22  * Unlike ob_gzhandler, it works for HEAD requests too.
  23  */
  24 function wfGzipHandler( $s ) {
  25         if ( function_exists( 'gzencode' ) && !headers_sent() ) {
  26                 $tokens = preg_split( '/[,; ]/', $_SERVER['HTTP_ACCEPT_ENCODING'] );
  27                 if ( in_array( 'gzip', $tokens ) ) {
  28                         header( 'Content-Encoding: gzip' );
  29                         $s = gzencode( $s, 3 );
  30
  31                         # Set vary header if it hasn't been set already
  32                         $headers = headers_list();
  33                         $foundVary = false;
  34                         foreach ( $headers as $header ) {
  35                                 if ( substr( $header, 0, 5 ) == 'Vary:' ) {
  36                                         $foundVary = true;
  37                                         break;
  38                                 }
  39                         }
  40                         if ( !$foundVary ) {
  41                                 header( 'Vary: Accept-Encoding' );
  42                         }
  43                 }
  44         }
  45         return $s;
  46 }
  47
  48 /**
  49  * Mangle flash policy tags which open up the site to XSS attacks.
  50  */
  51 function wfMangleFlashPolicy( $s ) {
  52         return preg_replace( '/\<\s*cross-domain-policy\s*\>/i', '<NOT-cross-domain-policy>', $s );
  53 }
  54
  55 /**
  56  * Add a Content-Length header if possible. This makes it cooperate with squid better.
  57  */
  58 function wfDoContentLength( $length ) {
  59         if ( !headers_sent() && $_SERVER['SERVER_PROTOCOL'] == 'HTTP/1.0' ) {
  60                 header( "Content-Length: $length" );
  61         }
  62 }
  63
  64 ?>