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 
70  public function stream(
71  $headers = [], $sendErrors = true, $optHeaders = [], $flags = 0
72  ) {
73  // Don't stream it out as text/html if there was a PHP error
74  if ( ( ( $flags & self::STREAM_HEADLESS ) == 0 || $headers ) && headers_sent() ) {
75  echo "Headers already sent, terminating.\n";
76  return false;
77  }
78 
79  $headerFunc = ( $flags & self::STREAM_HEADLESS )
80  ? function ( $header ) {
81  // no-op
82  }
83  : function ( $header ) {
84  is_int( $header ) ? HttpStatus::header( $header ) : header( $header );
85  };
86 
87  MediaWiki\suppressWarnings();
88  $info = stat( $this->path );
89  MediaWiki\restoreWarnings();
90 
91  if ( !is_array( $info ) ) {
92  if ( $sendErrors ) {
93  self::send404Message( $this->path, $flags );
94  }
95  return false;
96  }
97 
98  // Send Last-Modified HTTP header for client-side caching
99  $mtimeCT = new ConvertibleTimestamp( $info['mtime'] );
100  $headerFunc( 'Last-Modified: ' . $mtimeCT->getTimestamp( TS_RFC2822 ) );
101 
102  if ( ( $flags & self::STREAM_ALLOW_OB ) == 0 ) {
103  call_user_func( $this->obResetFunc );
104  }
105 
106  $type = call_user_func( $this->streamMimeFunc, $this->path );
107  if ( $type && $type != 'unknown/unknown' ) {
108  $headerFunc( "Content-type: $type" );
109  } else {
110  // Send a content type which is not known to Internet Explorer, to
111  // avoid triggering IE's content type detection. Sending a standard
112  // unknown content type here essentially gives IE license to apply
113  // whatever content type it likes.
114  $headerFunc( 'Content-type: application/x-wiki' );
115  }
116 
117  // Don't send if client has up to date cache
118  if ( isset( $optHeaders['if-modified-since'] ) ) {
119  $modsince = preg_replace( '/;.*$/', '', $optHeaders['if-modified-since'] );
120  if ( $mtimeCT->getTimestamp( TS_UNIX ) <= strtotime( $modsince ) ) {
121  ini_set( 'zlib.output_compression', 0 );
122  $headerFunc( 304 );
123  return true; // ok
124  }
125  }
126 
127  // Send additional headers
128  foreach ( $headers as $header ) {
129  header( $header ); // always use header(); specifically requested
130  }
131 
132  if ( isset( $optHeaders['range'] ) ) {
133  $range = self::parseRange( $optHeaders['range'], $info['size'] );
134  if ( is_array( $range ) ) {
135  $headerFunc( 206 );
136  $headerFunc( 'Content-Length: ' . $range[2] );
137  $headerFunc( "Content-Range: bytes {$range[0]}-{$range[1]}/{$info['size']}" );
138  } elseif ( $range === 'invalid' ) {
139  if ( $sendErrors ) {
140  $headerFunc( 416 );
141  $headerFunc( 'Cache-Control: no-cache' );
142  $headerFunc( 'Content-Type: text/html; charset=utf-8' );
143  $headerFunc( 'Content-Range: bytes */' . $info['size'] );
144  }
145  return false;
146  } else { // unsupported Range request (e.g. multiple ranges)
147  $range = null;
148  $headerFunc( 'Content-Length: ' . $info['size'] );
149  }
150  } else {
151  $range = null;
152  $headerFunc( 'Content-Length: ' . $info['size'] );
153  }
154 
155  if ( is_array( $range ) ) {
156  $handle = fopen( $this->path, 'rb' );
157  if ( $handle ) {
158  $ok = true;
159  fseek( $handle, $range[0] );
160  $remaining = $range[2];
161  while ( $remaining > 0 && $ok ) {
162  $bytes = min( $remaining, 8 * 1024 );
163  $data = fread( $handle, $bytes );
164  $remaining -= $bytes;
165  $ok = ( $data !== false );
166  print $data;
167  }
168  } else {
169  return false;
170  }
171  } else {
172  return readfile( $this->path ) !== false; // faster
173  }
174 
175  return true;
176  }
177 
185  public static function send404Message( $fname, $flags = 0 ) {
186  if ( ( $flags & self::STREAM_HEADLESS ) == 0 ) {
187  HttpStatus::header( 404 );
188  header( 'Cache-Control: no-cache' );
189  header( 'Content-Type: text/html; charset=utf-8' );
190  }
191  $encFile = htmlspecialchars( $fname );
192  $encScript = htmlspecialchars( $_SERVER['SCRIPT_NAME'] );
193  echo "<!DOCTYPE html><html><body>
194  <h1>File not found</h1>
195  <p>Although this PHP script ($encScript) exists, the file requested for output
196  ($encFile) does not.</p>
197  </body></html>
198  ";
199  }
200 
209  public static function parseRange( $range, $size ) {
210  $m = [];
211  if ( preg_match( '#^bytes=(\d*)-(\d*)$#', $range, $m ) ) {
212  list( , $start, $end ) = $m;
213  if ( $start === '' && $end === '' ) {
214  $absRange = [ 0, $size - 1 ];
215  } elseif ( $start === '' ) {
216  $absRange = [ $size - $end, $size - 1 ];
217  } elseif ( $end === '' ) {
218  $absRange = [ $start, $size - 1 ];
219  } else {
220  $absRange = [ $start, $end ];
221  }
222  if ( $absRange[0] >= 0 && $absRange[1] >= $absRange[0] ) {
223  if ( $absRange[0] < $size ) {
224  $absRange[1] = min( $absRange[1], $size - 1 ); // stop at EOF
225  $absRange[2] = $absRange[1] - $absRange[0] + 1;
226  return $absRange;
227  } elseif ( $absRange[0] == 0 && $size == 0 ) {
228  return 'unrecognized'; // the whole file should just be sent
229  }
230  }
231  return 'invalid';
232  }
233  return 'unrecognized';
234  }
235 
236  protected static function resetOutputBuffers() {
237  while ( ob_get_status() ) {
238  if ( !ob_end_clean() ) {
239  // Could not remove output buffer handler; abort now
240  // to avoid getting in some kind of infinite loop.
241  break;
242  }
243  }
244  }
245 
252  protected static function contentTypeFromPath( $filename ) {
253  $ext = strrchr( $filename, '.' );
254  $ext = $ext === false ? '' : strtolower( substr( $ext, 1 ) );
255 
256  switch ( $ext ) {
257  case 'gif':
258  return 'image/gif';
259  case 'png':
260  return 'image/png';
261  case 'jpg':
262  return 'image/jpeg';
263  case 'jpeg':
264  return 'image/jpeg';
265  }
266 
267  return 'unknown/unknown';
268  }
269 }
__construct($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
it s the revision text itself In either if gzip is the revision text is gzipped $flags
Definition: hooks.txt:2805
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')) $fname
Customization point after all loading (constants, functions, classes, DefaultSettings, LocalSettings).
Definition: Setup.php:112
stream($headers=[], $sendErrors=true, $optHeaders=[], $flags=0)
Stream a file to the browser, adding all the headings and fun stuff.