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
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