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HTTPFileStreamer.php
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HTTPFileStreamer.php
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<?php
/**
* Functions related to the output of file content.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
namespace Wikimedia\FileBackend;
use HttpStatus;
use Wikimedia\AtEase\AtEase;
use Wikimedia\Timestamp\ConvertibleTimestamp;
/**
* Functions related to the output of file content
*
* @since 1.28
*/
class HTTPFileStreamer {
/** @var string */
protected $path;
/** @var callable */
protected $obResetFunc;
/** @var callable */
protected $streamMimeFunc;
/** @var callable */
protected $headerFunc;
// Do not send any HTTP headers (i.e. body only)
public const STREAM_HEADLESS = 1;
// Do not try to tear down any PHP output buffers
public const STREAM_ALLOW_OB = 2;
/**
* Takes HTTP headers in a name => value format and converts them to the weird format
* expected by stream().
* @param string[] $headers
* @return array[] [ $headers, $optHeaders ]
* @since 1.34
*/
public static function preprocessHeaders( $headers ) {
$rawHeaders = [];
$optHeaders = [];
foreach ( $headers as $name => $header ) {
$nameLower = strtolower( $name );
if ( in_array( $nameLower, [ 'range', 'if-modified-since' ], true ) ) {
$optHeaders[$nameLower] = $header;
} else {
$rawHeaders[] = "$name: $header";
}
}
return [ $rawHeaders, $optHeaders ];
}
/**
* @param string $path Local filesystem path to a file
* @param array $params Options map, which includes:
* - obResetFunc : alternative callback to clear the output buffer
* - streamMimeFunc : alternative method to determine the content type from the path
* - headerFunc : alternative method for sending response headers
*/
public function __construct( $path, array $params = [] ) {
$this->path = $path;
$this->obResetFunc = $params['obResetFunc'] ??
[ __CLASS__, 'resetOutputBuffers' ];
$this->streamMimeFunc = $params['streamMimeFunc'] ??
[ __CLASS__, 'contentTypeFromPath' ];
$this->headerFunc = $params['headerFunc'] ?? 'header';
}
/**
* Stream a file to the browser, adding all the headings and fun stuff.
* Headers sent include: Content-type, Content-Length, Last-Modified,
* and Content-Disposition.
*
* @param array $headers Any additional headers to send if the file exists
* @param bool $sendErrors Send error messages if errors occur (like 404)
* @param array $optHeaders HTTP request header map (e.g. "range") (use lowercase keys)
* @param int $flags Bitfield of STREAM_* constants
* @return bool Success
*/
public function stream(
$headers = [], $sendErrors = true, $optHeaders = [], $flags = 0
) {
$headless = ( $flags & self::STREAM_HEADLESS );
// Don't stream it out as text/html if there was a PHP error
if ( $headers && headers_sent() ) {
echo "Headers already sent, terminating.\n";
return false;
}
$headerFunc = $headless
? static function ( $header ) {
// no-op
}
: [ $this, 'header' ];
AtEase::suppressWarnings();
$info = stat( $this->path );
AtEase::restoreWarnings();
if ( !is_array( $info ) ) {
if ( $sendErrors ) {
self::send404Message( $this->path, $flags );
}
return false;
}
// Send Last-Modified HTTP header for client-side caching
$mtimeCT = new ConvertibleTimestamp( $info['mtime'] );
$headerFunc( 'Last-Modified: ' . $mtimeCT->getTimestamp( TS_RFC2822 ) );
if ( ( $flags & self::STREAM_ALLOW_OB ) == 0 ) {
call_user_func( $this->obResetFunc );
}
$type = call_user_func( $this->streamMimeFunc, $this->path );
if ( $type && $type != 'unknown/unknown' ) {
$headerFunc( "Content-type: $type" );
} else {
// Send a content type which is not known to Internet Explorer, to
// avoid triggering IE's content type detection. Sending a standard
// unknown content type here essentially gives IE license to apply
// whatever content type it likes.
$headerFunc( 'Content-type: application/x-wiki' );
}
// Don't send if client has up to date cache
if ( isset( $optHeaders['if-modified-since'] ) ) {
$modsince = preg_replace( '/;.*$/', '', $optHeaders['if-modified-since'] );
if ( $mtimeCT->getTimestamp( TS_UNIX ) <= strtotime( $modsince ) ) {
ini_set( 'zlib.output_compression', 0 );
$headerFunc( 304 );
return true; // ok
}
}
// Send additional headers
foreach ( $headers as $header ) {
$headerFunc( $header );
}
if ( isset( $optHeaders['range'] ) ) {
$range = self::parseRange( $optHeaders['range'], $info['size'] );
if ( is_array( $range ) ) {
$headerFunc( 206 );
$headerFunc( 'Content-Length: ' . $range[2] );
$headerFunc( "Content-Range: bytes {$range[0]}-{$range[1]}/{$info['size']}" );
} elseif ( $range === 'invalid' ) {
if ( $sendErrors ) {
$headerFunc( 416 );
$headerFunc( 'Cache-Control: no-cache' );
$headerFunc( 'Content-Type: text/html; charset=utf-8' );
$headerFunc( 'Content-Range: bytes */' . $info['size'] );
}
return false;
} else { // unsupported Range request (e.g. multiple ranges)
$range = null;
$headerFunc( 'Content-Length: ' . $info['size'] );
}
} else {
$range = null;
$headerFunc( 'Content-Length: ' . $info['size'] );
}
if ( is_array( $range ) ) {
$handle = fopen( $this->path, 'rb' );
if ( $handle ) {
$ok = true;
fseek( $handle, $range[0] );
$remaining = $range[2];
while ( $remaining > 0 && $ok ) {
$bytes = min( $remaining, 8 * 1024 );
$data = fread( $handle, $bytes );
$remaining -= $bytes;
$ok = ( $data !== false );
print $data;
}
} else {
return false;
}
} else {
return readfile( $this->path ) !== false; // faster
}
return true;
}
/**
* Send out a standard 404 message for a file
*
* @param string $fname Full name and path of the file to stream
* @param int $flags Bitfield of STREAM_* constants
* @since 1.24
*/
public static function send404Message( $fname, $flags = 0 ) {
if ( ( $flags & self::STREAM_HEADLESS ) == 0 ) {
HttpStatus::header( 404 );
header( 'Cache-Control: no-cache' );
header( 'Content-Type: text/html; charset=utf-8' );
}
$encFile = htmlspecialchars( $fname );
$encScript = htmlspecialchars( $_SERVER['SCRIPT_NAME'] );
echo "<!DOCTYPE html><html><body>
<h1>File not found</h1>
<p>Although this PHP script ($encScript) exists, the file requested for output
($encFile) does not.</p>
</body></html>
";
}
/**
* Convert a Range header value to an absolute (start, end) range tuple
*
* @param string $range Range header value
* @param int $size File size
* @return array|string Returns error string on failure (start, end, length)
* @since 1.24
*/
public static function parseRange( $range, $size ) {
$m = [];
if ( preg_match( '#^bytes=(\d*)-(\d*)$#', $range, $m ) ) {
[ , $start, $end ] = $m;
if ( $start === '' && $end === '' ) {
$absRange = [ 0, $size - 1 ];
} elseif ( $start === '' ) {
$absRange = [ $size - (int)$end, $size - 1 ];
} elseif ( $end === '' ) {
$absRange = [ (int)$start, $size - 1 ];
} else {
$absRange = [ (int)$start, (int)$end ];
}
if ( $absRange[0] >= 0 && $absRange[1] >= $absRange[0] ) {
if ( $absRange[0] < $size ) {
$absRange[1] = min( $absRange[1], $size - 1 ); // stop at EOF
$absRange[2] = $absRange[1] - $absRange[0] + 1;
return $absRange;
} elseif ( $absRange[0] == 0 && $size == 0 ) {
return 'unrecognized'; // the whole file should just be sent
}
}
return 'invalid';
}
return 'unrecognized';
}
protected static function resetOutputBuffers() {
while ( ob_get_status() ) {
if ( !ob_end_clean() ) {
// Could not remove output buffer handler; abort now
// to avoid getting in some kind of infinite loop.
break;
}
}
}
/**
* Determine the file type of a file based on the path
*
* @param string $filename Storage path or file system path
* @return null|string
*/
protected static function contentTypeFromPath( $filename ) {
$ext = strrchr( $filename, '.' );
$ext = $ext ? strtolower( substr( $ext, 1 ) ) : '';
switch ( $ext ) {
case 'gif':
return 'image/gif';
case 'png':
return 'image/png';
case 'jpg':
case 'jpeg':
return 'image/jpeg';
// T366422: Support webp here as well for consistency
case 'webp':
return 'image/webp';
}
return 'unknown/unknown';
}
private function header( $header ) {
if ( is_int( $header ) ) {
$header = HttpStatus::getHeader( $header );
}
( $this->headerFunc )( $header );
}
}
/** @deprecated class alias since 1.43 */
class_alias( HTTPFileStreamer::class, 'HTTPFileStreamer' );

File Metadata

Mime Type
text/x-php
Expires
Tue, Aug 18, 14:18 (3 w, 6 d ago)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
c9/89/0830914819b504bdb902ebb71803
Default Alt Text
HTTPFileStreamer.php (9 KB)

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