includes/StreamFile.php

   1 <?php
   2 /**
   3  * Functions related to the output of file content
   4  *
   5  * @file
   6  */
   7 class StreamFile {
   8         /**
   9          * Stream a file to the browser, adding all the headings and fun stuff
  10          * @param $fname string Full name and path of the file to stream
  11          * @param $headers array Any additional headers to send
  12          * @param $sendErrors bool Send error messages if errors occur (like 404)
  13          * @return bool Success
  14          */
  15         public static function stream( $fname, $headers = array(), $sendErrors = true ) {
  16                 global $wgLanguageCode;
  17
  18                 wfSuppressWarnings();
  19                 $stat = stat( $fname );
  20                 wfRestoreWarnings();
  21                 if ( !$stat ) {
  22                         if ( $sendErrors ) {
  23                                 header( 'HTTP/1.0 404 Not Found' );
  24                                 header( 'Cache-Control: no-cache' );
  25                                 header( 'Content-Type: text/html; charset=utf-8' );
  26                                 $encFile = htmlspecialchars( $fname );
  27                                 $encScript = htmlspecialchars( $_SERVER['SCRIPT_NAME'] );
  28                                 echo "<html><body>
  29                                         <h1>File not found</h1>
  30                                         <p>Although this PHP script ($encScript) exists, the file requested for output
  31                                         ($encFile) does not.</p>
  32                                         </body></html>
  33                                         ";
  34                         }
  35                         return false;
  36                 }
  37
  38                 header( 'Last-Modified: ' . gmdate( 'D, d M Y H:i:s', $stat['mtime'] ) . ' GMT' );
  39
  40                 // Cancel output buffering and gzipping if set
  41                 wfResetOutputBuffers();
  42
  43                 $type = self::getType( $fname );
  44                 if ( $type && $type != 'unknown/unknown' ) {
  45                         header( "Content-type: $type" );
  46                 } else {
  47                         header( 'Content-type: application/x-wiki' );
  48                 }
  49
  50                 // Don't stream it out as text/html if there was a PHP error
  51                 if ( headers_sent() ) {
  52                         echo "Headers already sent, terminating.\n";
  53                         return false;
  54                 }
  55
  56                 header( "Content-Disposition: inline;filename*=utf-8'$wgLanguageCode'" .
  57                         urlencode( basename( $fname ) ) );
  58
  59                 // Send additional headers
  60                 foreach ( $headers as $header ) {
  61                         header( $header );
  62                 }
  63
  64                 // Don't send if client has up to date cache
  65                 if ( !empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
  66                         $modsince = preg_replace( '/;.*$/', '', $_SERVER['HTTP_IF_MODIFIED_SINCE'] );
  67                         $sinceTime = strtotime( $modsince );
  68                         if ( $stat['mtime'] <= $sinceTime ) {
  69                                 ini_set( 'zlib.output_compression', 0 );
  70                                 header( "HTTP/1.0 304 Not Modified" );
  71                                 return true; // ok
  72                         }
  73                 }
  74
  75                 header( 'Content-Length: ' . $stat['size'] );
  76
  77                 return readfile( $fname );
  78         }
  79
  80         /**
  81          * Determine the filetype we're dealing with
  82          * @param $filename string
  83          * @param $safe bool
  84          * @return null|string
  85          */
  86         private static function getType( $filename, $safe = true ) {
  87                 global $wgTrivialMimeDetection;
  88
  89                 $ext = strrchr( $filename, '.' );
  90                 $ext = $ext === false ? '' : strtolower( substr( $ext, 1 ) );
  91
  92                 # trivial detection by file extension,
  93                 # used for thumbnails (thumb.php)
  94                 if ( $wgTrivialMimeDetection ) {
  95                         switch ( $ext ) {
  96                                 case 'gif': return 'image/gif';
  97                                 case 'png': return 'image/png';
  98                                 case 'jpg': return 'image/jpeg';
  99                                 case 'jpeg': return 'image/jpeg';
 100                         }
 101
 102                         return 'unknown/unknown';
 103                 }
 104
 105                 $magic = MimeMagic::singleton();
 106                 // Use the extension only, rather than magic numbers, to avoid opening
 107                 // up vulnerabilities due to uploads of files with allowed extensions
 108                 // but disallowed types.
 109                 $type = $magic->guessTypesForExtension( $ext );
 110
 111                 /**
 112                  * Double-check some security settings that were done on upload but might
 113                  * have changed since.
 114                  */
 115                 if ( $safe ) {
 116                         global $wgFileBlacklist, $wgCheckFileExtensions, $wgStrictFileExtensions,
 117                                 $wgFileExtensions, $wgVerifyMimeType, $wgMimeTypeBlacklist;
 118                         list( , $extList ) = UploadBase::splitExtensions( $filename );
 119                         if ( UploadBase::checkFileExtensionList( $extList, $wgFileBlacklist ) ) {
 120                                 return 'unknown/unknown';
 121                         }
 122                         if ( $wgCheckFileExtensions && $wgStrictFileExtensions
 123                                 && !UploadBase::checkFileExtensionList( $extList, $wgFileExtensions ) )
 124                         {
 125                                 return 'unknown/unknown';
 126                         }
 127                         if ( $wgVerifyMimeType && in_array( strtolower( $type ), $wgMimeTypeBlacklist ) ) {
 128                                 return 'unknown/unknown';
 129                         }
 130                 }
 131                 return $type;
 132         }
 133 }