3 * Functions related to the output of file content.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
23 use Wikimedia\AtEase\AtEase
;
24 use Wikimedia\Timestamp\ConvertibleTimestamp
;
27 * Functions related to the output of file content
31 class HTTPFileStreamer
{
35 protected $obResetFunc;
37 protected $streamMimeFunc;
39 // Do not send any HTTP headers unless requested by caller (e.g. body only)
40 const STREAM_HEADLESS
= 1;
41 // Do not try to tear down any PHP output buffers
42 const STREAM_ALLOW_OB
= 2;
45 * Takes HTTP headers in a name => value format and converts them to the weird format
46 * expected by stream().
47 * @param string[] $headers
48 * @return array[] [ $headers, $optHeaders ]
51 public static function preprocessHeaders( $headers ) {
54 foreach ( $headers as $name => $header ) {
55 $nameLower = strtolower( $name );
56 if ( in_array( $nameLower, [ 'range', 'if-modified-since' ], true ) ) {
57 $optHeaders[$nameLower] = $header;
59 $rawHeaders[] = "$name: $header";
62 return [ $rawHeaders, $optHeaders ];
66 * @param string $path Local filesystem path to a file
67 * @param array $params Options map, which includes:
68 * - obResetFunc : alternative callback to clear the output buffer
69 * - streamMimeFunc : alternative method to determine the content type from the path
71 public function __construct( $path, array $params = [] ) {
73 $this->obResetFunc
= $params['obResetFunc'] ??
[ __CLASS__
, 'resetOutputBuffers' ];
74 $this->streamMimeFunc
= $params['streamMimeFunc'] ??
[ __CLASS__
, 'contentTypeFromPath' ];
78 * Stream a file to the browser, adding all the headings and fun stuff.
79 * Headers sent include: Content-type, Content-Length, Last-Modified,
80 * and Content-Disposition.
82 * @param array $headers Any additional headers to send if the file exists
83 * @param bool $sendErrors Send error messages if errors occur (like 404)
84 * @param array $optHeaders HTTP request header map (e.g. "range") (use lowercase keys)
85 * @param int $flags Bitfield of STREAM_* constants
86 * @return bool Success
88 public function stream(
89 $headers = [], $sendErrors = true, $optHeaders = [], $flags = 0
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";
97 $headerFunc = ( $flags & self
::STREAM_HEADLESS
)
98 ?
function ( $header ) {
101 : function ( $header ) {
102 is_int( $header ) ? HttpStatus
::header( $header ) : header( $header );
105 AtEase
::suppressWarnings();
106 $info = stat( $this->path
);
107 AtEase
::restoreWarnings();
109 if ( !is_array( $info ) ) {
111 self
::send404Message( $this->path
, $flags );
116 // Send Last-Modified HTTP header for client-side caching
117 $mtimeCT = new ConvertibleTimestamp( $info['mtime'] );
118 $headerFunc( 'Last-Modified: ' . $mtimeCT->getTimestamp( TS_RFC2822
) );
120 if ( ( $flags & self
::STREAM_ALLOW_OB
) == 0 ) {
121 call_user_func( $this->obResetFunc
);
124 $type = call_user_func( $this->streamMimeFunc
, $this->path
);
125 if ( $type && $type != 'unknown/unknown' ) {
126 $headerFunc( "Content-type: $type" );
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' );
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 );
145 // Send additional headers
146 foreach ( $headers as $header ) {
147 header( $header ); // always use header(); specifically requested
150 if ( isset( $optHeaders['range'] ) ) {
151 $range = self
::parseRange( $optHeaders['range'], $info['size'] );
152 if ( is_array( $range ) ) {
154 $headerFunc( 'Content-Length: ' . $range[2] );
155 $headerFunc( "Content-Range: bytes {$range[0]}-{$range[1]}/{$info['size']}" );
156 } elseif ( $range === 'invalid' ) {
159 $headerFunc( 'Cache-Control: no-cache' );
160 $headerFunc( 'Content-Type: text/html; charset=utf-8' );
161 $headerFunc( 'Content-Range: bytes */' . $info['size'] );
164 } else { // unsupported Range request (e.g. multiple ranges)
166 $headerFunc( 'Content-Length: ' . $info['size'] );
170 $headerFunc( 'Content-Length: ' . $info['size'] );
173 if ( is_array( $range ) ) {
174 $handle = fopen( $this->path
, 'rb' );
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 );
190 return readfile( $this->path
) !== false; // faster
197 * Send out a standard 404 message for a file
199 * @param string $fname Full name and path of the file to stream
200 * @param int $flags Bitfield of STREAM_* constants
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' );
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>
220 * Convert a Range header value to an absolute (start, end) range tuple
222 * @param string $range Range header value
223 * @param int $size File size
224 * @return array|string Returns error string on failure (start, end, length)
227 public static function parseRange( $range, $size ) {
229 if ( preg_match( '#^bytes=(\d*)-(\d*)$#', $range, $m ) ) {
230 list( , $start, $end ) = $m;
231 if ( $start === '' && $end === '' ) {
232 $absRange = [ 0, $size - 1 ];
233 } elseif ( $start === '' ) {
234 $absRange = [ $size - $end, $size - 1 ];
235 } elseif ( $end === '' ) {
236 $absRange = [ $start, $size - 1 ];
238 $absRange = [ $start, $end ];
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;
245 } elseif ( $absRange[0] == 0 && $size == 0 ) {
246 return 'unrecognized'; // the whole file should just be sent
251 return 'unrecognized';
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.
265 * Determine the file type of a file based on the path
267 * @param string $filename Storage path or file system path
268 * @return null|string
270 protected static function contentTypeFromPath( $filename ) {
271 $ext = strrchr( $filename, '.' );
272 $ext = $ext === false ?
'' : strtolower( substr( $ext, 1 ) );
285 return 'unknown/unknown';