MediaWiki master
HTTPFileStreamer.php
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1<?php
23use Wikimedia\AtEase\AtEase;
24use Wikimedia\Timestamp\ConvertibleTimestamp;
25
33 protected $path;
35 protected $obResetFunc;
37 protected $streamMimeFunc;
38
39 // Do not send any HTTP headers unless requested by caller (e.g. body only)
40 public const STREAM_HEADLESS = 1;
41 // Do not try to tear down any PHP output buffers
42 public const STREAM_ALLOW_OB = 2;
43
51 public static function preprocessHeaders( $headers ) {
52 $rawHeaders = [];
53 $optHeaders = [];
54 foreach ( $headers as $name => $header ) {
55 $nameLower = strtolower( $name );
56 if ( in_array( $nameLower, [ 'range', 'if-modified-since' ], true ) ) {
57 $optHeaders[$nameLower] = $header;
58 } else {
59 $rawHeaders[] = "$name: $header";
60 }
61 }
62 return [ $rawHeaders, $optHeaders ];
63 }
64
71 public function __construct( $path, array $params = [] ) {
72 $this->path = $path;
73 $this->obResetFunc = $params['obResetFunc'] ?? [ __CLASS__, 'resetOutputBuffers' ];
74 $this->streamMimeFunc = $params['streamMimeFunc'] ?? [ __CLASS__, 'contentTypeFromPath' ];
75 }
76
88 public function stream(
89 $headers = [], $sendErrors = true, $optHeaders = [], $flags = 0
90 ) {
91 // Don't stream it out as text/html if there was a PHP error
92 if ( ( ( $flags & self::STREAM_HEADLESS ) == 0 || $headers ) && headers_sent() ) {
93 echo "Headers already sent, terminating.\n";
94 return false;
95 }
96
97 $headerFunc = ( $flags & self::STREAM_HEADLESS )
98 ? static function ( $header ) {
99 // no-op
100 }
101 : static function ( $header ) {
102 is_int( $header ) ? HttpStatus::header( $header ) : header( $header );
103 };
104
105 AtEase::suppressWarnings();
106 $info = stat( $this->path );
107 AtEase::restoreWarnings();
108
109 if ( !is_array( $info ) ) {
110 if ( $sendErrors ) {
111 self::send404Message( $this->path, $flags );
112 }
113 return false;
114 }
115
116 // Send Last-Modified HTTP header for client-side caching
117 $mtimeCT = new ConvertibleTimestamp( $info['mtime'] );
118 $headerFunc( 'Last-Modified: ' . $mtimeCT->getTimestamp( TS_RFC2822 ) );
119
120 if ( ( $flags & self::STREAM_ALLOW_OB ) == 0 ) {
121 call_user_func( $this->obResetFunc );
122 }
123
124 $type = call_user_func( $this->streamMimeFunc, $this->path );
125 if ( $type && $type != 'unknown/unknown' ) {
126 $headerFunc( "Content-type: $type" );
127 } else {
128 // Send a content type which is not known to Internet Explorer, to
129 // avoid triggering IE's content type detection. Sending a standard
130 // unknown content type here essentially gives IE license to apply
131 // whatever content type it likes.
132 $headerFunc( 'Content-type: application/x-wiki' );
133 }
134
135 // Don't send if client has up to date cache
136 if ( isset( $optHeaders['if-modified-since'] ) ) {
137 $modsince = preg_replace( '/;.*$/', '', $optHeaders['if-modified-since'] );
138 if ( $mtimeCT->getTimestamp( TS_UNIX ) <= strtotime( $modsince ) ) {
139 ini_set( 'zlib.output_compression', 0 );
140 $headerFunc( 304 );
141 return true; // ok
142 }
143 }
144
145 // Send additional headers
146 foreach ( $headers as $header ) {
147 header( $header ); // always use header(); specifically requested
148 }
149
150 if ( isset( $optHeaders['range'] ) ) {
151 $range = self::parseRange( $optHeaders['range'], $info['size'] );
152 if ( is_array( $range ) ) {
153 $headerFunc( 206 );
154 $headerFunc( 'Content-Length: ' . $range[2] );
155 $headerFunc( "Content-Range: bytes {$range[0]}-{$range[1]}/{$info['size']}" );
156 } elseif ( $range === 'invalid' ) {
157 if ( $sendErrors ) {
158 $headerFunc( 416 );
159 $headerFunc( 'Cache-Control: no-cache' );
160 $headerFunc( 'Content-Type: text/html; charset=utf-8' );
161 $headerFunc( 'Content-Range: bytes */' . $info['size'] );
162 }
163 return false;
164 } else { // unsupported Range request (e.g. multiple ranges)
165 $range = null;
166 $headerFunc( 'Content-Length: ' . $info['size'] );
167 }
168 } else {
169 $range = null;
170 $headerFunc( 'Content-Length: ' . $info['size'] );
171 }
172
173 if ( is_array( $range ) ) {
174 $handle = fopen( $this->path, 'rb' );
175 if ( $handle ) {
176 $ok = true;
177 fseek( $handle, $range[0] );
178 $remaining = $range[2];
179 while ( $remaining > 0 && $ok ) {
180 $bytes = min( $remaining, 8 * 1024 );
181 $data = fread( $handle, $bytes );
182 $remaining -= $bytes;
183 $ok = ( $data !== false );
184 print $data;
185 }
186 } else {
187 return false;
188 }
189 } else {
190 return readfile( $this->path ) !== false; // faster
191 }
192
193 return true;
194 }
195
203 public static function send404Message( $fname, $flags = 0 ) {
204 if ( ( $flags & self::STREAM_HEADLESS ) == 0 ) {
205 HttpStatus::header( 404 );
206 header( 'Cache-Control: no-cache' );
207 header( 'Content-Type: text/html; charset=utf-8' );
208 }
209 $encFile = htmlspecialchars( $fname );
210 $encScript = htmlspecialchars( $_SERVER['SCRIPT_NAME'] );
211 echo "<!DOCTYPE html><html><body>
212 <h1>File not found</h1>
213 <p>Although this PHP script ($encScript) exists, the file requested for output
214 ($encFile) does not.</p>
215 </body></html>
216 ";
217 }
218
227 public static function parseRange( $range, $size ) {
228 $m = [];
229 if ( preg_match( '#^bytes=(\d*)-(\d*)$#', $range, $m ) ) {
230 [ , $start, $end ] = $m;
231 if ( $start === '' && $end === '' ) {
232 $absRange = [ 0, $size - 1 ];
233 } elseif ( $start === '' ) {
234 $absRange = [ $size - (int)$end, $size - 1 ];
235 } elseif ( $end === '' ) {
236 $absRange = [ (int)$start, $size - 1 ];
237 } else {
238 $absRange = [ (int)$start, (int)$end ];
239 }
240 if ( $absRange[0] >= 0 && $absRange[1] >= $absRange[0] ) {
241 if ( $absRange[0] < $size ) {
242 $absRange[1] = min( $absRange[1], $size - 1 ); // stop at EOF
243 $absRange[2] = $absRange[1] - $absRange[0] + 1;
244 return $absRange;
245 } elseif ( $absRange[0] == 0 && $size == 0 ) {
246 return 'unrecognized'; // the whole file should just be sent
247 }
248 }
249 return 'invalid';
250 }
251 return 'unrecognized';
252 }
253
254 protected static function resetOutputBuffers() {
255 while ( ob_get_status() ) {
256 if ( !ob_end_clean() ) {
257 // Could not remove output buffer handler; abort now
258 // to avoid getting in some kind of infinite loop.
259 break;
260 }
261 }
262 }
263
270 protected static function contentTypeFromPath( $filename ) {
271 $ext = strrchr( $filename, '.' );
272 $ext = $ext ? strtolower( substr( $ext, 1 ) ) : '';
273
274 switch ( $ext ) {
275 case 'gif':
276 return 'image/gif';
277 case 'png':
278 return 'image/png';
279 case 'jpg':
280 return 'image/jpeg';
281 case 'jpeg':
282 return 'image/jpeg';
283 }
284
285 return 'unknown/unknown';
286 }
287}
Functions related to the output of file content.
static preprocessHeaders( $headers)
Takes HTTP headers in a name => value format and converts them to the weird format expected by stream...
static send404Message( $fname, $flags=0)
Send out a standard 404 message for a file.
static contentTypeFromPath( $filename)
Determine the file type of a file based on the path.
static parseRange( $range, $size)
Convert a Range header value to an absolute (start, end) range tuple.
__construct( $path, array $params=[])
stream( $headers=[], $sendErrors=true, $optHeaders=[], $flags=0)
Stream a file to the browser, adding all the headings and fun stuff.
$header