MediaWiki  master
HTTPFileStreamer.php
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1 <?php
23 
31  protected $path;
33  protected $obResetFunc;
35  protected $streamMimeFunc;
36 
37  // Do not send any HTTP headers unless requested by caller (e.g. body only)
38  const STREAM_HEADLESS = 1;
39  // Do not try to tear down any PHP output buffers
40  const STREAM_ALLOW_OB = 2;
41 
48  public function __construct( $path, array $params = [] ) {
49  $this->path = $path;
50  $this->obResetFunc = isset( $params['obResetFunc'] )
51  ? $params['obResetFunc']
52  : [ __CLASS__, 'resetOutputBuffers' ];
53  $this->streamMimeFunc = isset( $params['streamMimeFunc'] )
54  ? $params['streamMimeFunc']
55  : [ __CLASS__, 'contentTypeFromPath' ];
56  }
57 
69  public function stream(
70  $headers = [], $sendErrors = true, $optHeaders = [], $flags = 0
71  ) {
72  // Don't stream it out as text/html if there was a PHP error
73  if ( ( ( $flags & self::STREAM_HEADLESS ) == 0 || $headers ) && headers_sent() ) {
74  echo "Headers already sent, terminating.\n";
75  return false;
76  }
77 
78  $headerFunc = ( $flags & self::STREAM_HEADLESS )
79  ? function ( $header ) {
80  // no-op
81  }
82  : function ( $header ) {
83  is_int( $header ) ? HttpStatus::header( $header ) : header( $header );
84  };
85 
86  Wikimedia\suppressWarnings();
87  $info = stat( $this->path );
88  Wikimedia\restoreWarnings();
89 
90  if ( !is_array( $info ) ) {
91  if ( $sendErrors ) {
92  self::send404Message( $this->path, $flags );
93  }
94  return false;
95  }
96 
97  // Send Last-Modified HTTP header for client-side caching
98  $mtimeCT = new ConvertibleTimestamp( $info['mtime'] );
99  $headerFunc( 'Last-Modified: ' . $mtimeCT->getTimestamp( TS_RFC2822 ) );
100 
101  if ( ( $flags & self::STREAM_ALLOW_OB ) == 0 ) {
102  call_user_func( $this->obResetFunc );
103  }
104 
105  $type = call_user_func( $this->streamMimeFunc, $this->path );
106  if ( $type && $type != 'unknown/unknown' ) {
107  $headerFunc( "Content-type: $type" );
108  } else {
109  // Send a content type which is not known to Internet Explorer, to
110  // avoid triggering IE's content type detection. Sending a standard
111  // unknown content type here essentially gives IE license to apply
112  // whatever content type it likes.
113  $headerFunc( 'Content-type: application/x-wiki' );
114  }
115 
116  // Don't send if client has up to date cache
117  if ( isset( $optHeaders['if-modified-since'] ) ) {
118  $modsince = preg_replace( '/;.*$/', '', $optHeaders['if-modified-since'] );
119  if ( $mtimeCT->getTimestamp( TS_UNIX ) <= strtotime( $modsince ) ) {
120  ini_set( 'zlib.output_compression', 0 );
121  $headerFunc( 304 );
122  return true; // ok
123  }
124  }
125 
126  // Send additional headers
127  foreach ( $headers as $header ) {
128  header( $header ); // always use header(); specifically requested
129  }
130 
131  if ( isset( $optHeaders['range'] ) ) {
132  $range = self::parseRange( $optHeaders['range'], $info['size'] );
133  if ( is_array( $range ) ) {
134  $headerFunc( 206 );
135  $headerFunc( 'Content-Length: ' . $range[2] );
136  $headerFunc( "Content-Range: bytes {$range[0]}-{$range[1]}/{$info['size']}" );
137  } elseif ( $range === 'invalid' ) {
138  if ( $sendErrors ) {
139  $headerFunc( 416 );
140  $headerFunc( 'Cache-Control: no-cache' );
141  $headerFunc( 'Content-Type: text/html; charset=utf-8' );
142  $headerFunc( 'Content-Range: bytes */' . $info['size'] );
143  }
144  return false;
145  } else { // unsupported Range request (e.g. multiple ranges)
146  $range = null;
147  $headerFunc( 'Content-Length: ' . $info['size'] );
148  }
149  } else {
150  $range = null;
151  $headerFunc( 'Content-Length: ' . $info['size'] );
152  }
153 
154  if ( is_array( $range ) ) {
155  $handle = fopen( $this->path, 'rb' );
156  if ( $handle ) {
157  $ok = true;
158  fseek( $handle, $range[0] );
159  $remaining = $range[2];
160  while ( $remaining > 0 && $ok ) {
161  $bytes = min( $remaining, 8 * 1024 );
162  $data = fread( $handle, $bytes );
163  $remaining -= $bytes;
164  $ok = ( $data !== false );
165  print $data;
166  }
167  } else {
168  return false;
169  }
170  } else {
171  return readfile( $this->path ) !== false; // faster
172  }
173 
174  return true;
175  }
176 
184  public static function send404Message( $fname, $flags = 0 ) {
185  if ( ( $flags & self::STREAM_HEADLESS ) == 0 ) {
186  HttpStatus::header( 404 );
187  header( 'Cache-Control: no-cache' );
188  header( 'Content-Type: text/html; charset=utf-8' );
189  }
190  $encFile = htmlspecialchars( $fname );
191  $encScript = htmlspecialchars( $_SERVER['SCRIPT_NAME'] );
192  echo "<!DOCTYPE html><html><body>
193  <h1>File not found</h1>
194  <p>Although this PHP script ($encScript) exists, the file requested for output
195  ($encFile) does not.</p>
196  </body></html>
197  ";
198  }
199 
208  public static function parseRange( $range, $size ) {
209  $m = [];
210  if ( preg_match( '#^bytes=(\d*)-(\d*)$#', $range, $m ) ) {
211  list( , $start, $end ) = $m;
212  if ( $start === '' && $end === '' ) {
213  $absRange = [ 0, $size - 1 ];
214  } elseif ( $start === '' ) {
215  $absRange = [ $size - $end, $size - 1 ];
216  } elseif ( $end === '' ) {
217  $absRange = [ $start, $size - 1 ];
218  } else {
219  $absRange = [ $start, $end ];
220  }
221  if ( $absRange[0] >= 0 && $absRange[1] >= $absRange[0] ) {
222  if ( $absRange[0] < $size ) {
223  $absRange[1] = min( $absRange[1], $size - 1 ); // stop at EOF
224  $absRange[2] = $absRange[1] - $absRange[0] + 1;
225  return $absRange;
226  } elseif ( $absRange[0] == 0 && $size == 0 ) {
227  return 'unrecognized'; // the whole file should just be sent
228  }
229  }
230  return 'invalid';
231  }
232  return 'unrecognized';
233  }
234 
235  protected static function resetOutputBuffers() {
236  while ( ob_get_status() ) {
237  if ( !ob_end_clean() ) {
238  // Could not remove output buffer handler; abort now
239  // to avoid getting in some kind of infinite loop.
240  break;
241  }
242  }
243  }
244 
251  protected static function contentTypeFromPath( $filename ) {
252  $ext = strrchr( $filename, '.' );
253  $ext = $ext === false ? '' : strtolower( substr( $ext, 1 ) );
254 
255  switch ( $ext ) {
256  case 'gif':
257  return 'image/gif';
258  case 'png':
259  return 'image/png';
260  case 'jpg':
261  return 'image/jpeg';
262  case 'jpeg':
263  return 'image/jpeg';
264  }
265 
266  return 'unknown/unknown';
267  }
268 }
__construct($path, array $params=[])
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global list
Definition: deferred.txt:11
the array() calling protocol came about after MediaWiki 1.4rc1.
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
static header($code)
Output an HTTP status code header.
Definition: HttpStatus.php:96
processing should stop and the error should be shown to the user * false
Definition: hooks.txt:187
Functions related to the output of file content.
$params
$header
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Definition: distributors.txt:9
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:35
static send404Message($fname, $flags=0)
Send out a standard 404 message for a file.
static parseRange($range, $size)
Convert a Range header value to an absolute (start, end) range tuple.
static contentTypeFromPath($filename)
Determine the file type of a file based on the path.
if(defined( 'MW_SETUP_CALLBACK')) $fname
Customization point after all loading (constants, functions, classes, DefaultSettings, LocalSettings).
Definition: Setup.php:118
stream($headers=[], $sendErrors=true, $optHeaders=[], $flags=0)
Stream a file to the browser, adding all the headings and fun stuff.
$ext
Definition: router.php:55