range协议用途:一般是用在断点续传的时候,但是实际的用户很大,例如你的web server需要输出一个大文件,那么用range可以分段输出,缓解压力。同时在提供音乐视频等服务时可以缓冲下载,如果用户中途关闭,可以节约网络带宽。
<?php// 文件名$filename = $_GET ["filename"];// 文件路径$location = "media/" . $filename;// 后缀$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"], $matches )) {// 读取文件,起始节点$begin = intval ( $matches [1] );// 读取文件,结束节点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;// 定位指针fseek ( $fm, $begin, 0 );while ( ! feof ( $fm ) && $cur <= $end && (connection_status () == 0) ) {print fread ( $fm, min ( 1024 * 16, ($end - $cur) + 1 ) );$cur += 1024 * 16;}range协议官方文档:http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html