An example of PHP using range protocol to realize breakpoint continuous transmission of output files

range protocol use: 1 is generally used in breakpoint transmission, but the actual user is very large, for example, your web server needs to output a large file, then range can be segmented output to relieve pressure. At the same time, when providing services such as music and video, it can buffer downloads, and if users shut down halfway, it can save network bandwidth.

<?php

//  Filename 
$filename = $_GET ['filename'];

//  File path 
$location = 'media/' . $filename;

//  Suffix 
$extension = substr ( strrchr ( $filename, '.' ), 1 );

if ($extension == "mp3") {
	$mimeType = "audio/mpeg";
} else if ($extension == "ogg") {
	$mimeType = "audio/ogg";
}

if (! file_exists ( $location )) {
	header ( "HTTP/1.1 404 Not Found" );
	return;
}

$size = filesize ( $location );
$time = date ( 'r', filemtime ( $location ) );

$fm = @fopen ( $location, 'rb' );
if (! $fm) {
	header ( "HTTP/1.1 505 Internal server error" );
	return;
}

$begin = 0;
$end = $size - 1;

if (isset ( $_SERVER ['HTTP_RANGE'] )) {
	if (preg_match ( '/bytes=\h*(\d+)-(\d*)[\D.*]?/i', $_SERVER ['HTTP_RANGE'], $matches )) {
		//  Read file, start node 
		$begin = intval ( $matches [1] );

		//  Read file, end node 
		if (! empty ( $matches [2] )) {
			$end = intval ( $matches [2] );
		}
	}
}

if (isset ( $_SERVER ['HTTP_RANGE'] )) {
	header ( 'HTTP/1.1 206 Partial Content' );
} else {
	header ( 'HTTP/1.1 200 OK' );
}

header ( "Content-Type: $mimeType" );
header ( 'Cache-Control: public, must-revalidate, max-age=0' );
header ( 'Pragma: no-cache' );
header ( 'Accept-Ranges: bytes' );
header ( 'Content-Length:' . (($end - $begin) + 1) );

if (isset ( $_SERVER ['HTTP_RANGE'] )) {
	header ( "Content-Range: bytes $begin-$end/$size" );
}

header ( "Content-Disposition: inline; filename=$filename" );
header ( "Content-Transfer-Encoding: binary" );
header ( "Last-Modified: $time" );

$cur = $begin;

//  Position pointer 
fseek ( $fm, $begin, 0 );

while ( ! feof ( $fm ) && $cur <= $end && (connection_status () == 0) ) {
	print fread ( $fm, min ( 1024 * 16, ($end - $cur) + 1 ) );
	$cur += 1024 * 16;
}

Official document of range protocol: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html