Explain the related content of PHP file download class that supports breakpoint resume transfer-PHP Tutorial-php.cn

php supports breakpoint resumption, mainly relying on the header HTTP_RANGE in the HTTP protocol.
HTTP breakpoint resume download principle
Http header Range, Content-Range()
Range and Content are generally used in HTTP headers only for breakpoint downloads -Range entity header,
In the Range user request header, specify the position of the first byte and the position of the last byte, such as (Range: 200-300)
Content-Range is used for response headers
Request to download the entire file:
GET /test.rar HTTP/1.1
Connection: close
Host: 116.1.219.219
Range: bytes=0-801 //General requests to download the entire file are bytes =0- or do not use this header
Generally normal response
HTTP/1.1 200 OK
Content-Length: 801
Content-Type: application/octet-stream
Content-Range: bytes 0 -800/801 //801: Total file size
FileDownload.class.php

getRange($file_size); header('cache-control:public'); header('content-type:application/octet-stream'); header('content-disposition:attachment; filename='.$name); if($reload && $ranges!=null){ // 使用续传 header('HTTP/1.1 206 Partial Content'); header('Accept-Ranges:bytes'); // 剩余长度 header(sprintf('content-length:%u',$ranges['end']-$ranges['start'])); // range信息 header(sprintf('content-range:bytes %s-%s/%s', $ranges['start'], $ranges['end'], $file_size)); // fp指针跳到断点位置 fseek($fp, sprintf('%u', $ranges['start'])); }else{ header('HTTP/1.1 200 OK'); header('content-length:'.$file_size); } while(!feof($fp)){ echo fread($fp, round($this->_speed*1024,0)); ob_flush(); //sleep(1); // 用于测试,减慢下载速度 } ($fp!=null) && fclose($fp); }else{ return ''; } } /** 设置下载速度 * @param int $speed */ public function setSpeed($speed){ if(is_numeric($speed) && $speed>16 && $speed<4096){ $this->_speed = $speed; } } /** 获取header range信息 * @param int $file_size 文件大小 * @return Array */ private function getRange($file_size){ if(isset($_SERVER['HTTP_RANGE']) && !empty($_SERVER['HTTP_RANGE'])){ $range = $_SERVER['HTTP_RANGE']; $range = preg_replace('/[\s|,].*/', '', $range); $range = explode('-', substr($range, 6)); if(count($range)<2){ $range[1] = $file_size; } $range = array_combine(array('start','end'), $range); if(empty($range['start'])){ $range['start'] = 0; } if(empty($range['end'])){ $range['end'] = $file_size; } return $range; } return null; } } // class end ?>

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demo

download($file, $name); //$flag = $obj->download($file, $name, true); // 断点续传 if(!$flag){ echo 'file not exists'; } ?>

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Breakpoint resume test method:
Use the linuxwgetcommand to test the download, wget -c -O file http://xxx
1. Turn off breakpoint resumption first
$flag = $obj->download($file, $name);

fdipzone@ubuntu:~/Downloads$ wget -O test.rar http://demo.fdipzone.com/demo.php --2013-06-30 16:52:44-- http://demo.fdipzone.com/demo.php 正在解析主机 demo.fdipzone.com... 127.0.0.1 正在连接 demo.fdipzone.com|127.0.0.1|:80... 已连接。 已发出 HTTP 请求，正在等待回应... 200 OK 长度： 10445120 (10.0M) [application/octet-stream] 正在保存至: “test.rar” 30% [============================> ] 3,146,580 513K/s 估时 14s ^C fdipzone@ubuntu:~/Downloads$ wget -c -O test.rar http://demo.fdipzone.com/demo.php --2013-06-30 16:52:57-- http://demo.fdipzone.com/demo.php 正在解析主机 demo.fdipzone.com... 127.0.0.1 正在连接 demo.fdipzone.com|127.0.0.1|:80... 已连接。 已发出 HTTP 请求，正在等待回应... 200 OK 长度： 10445120 (10.0M) [application/octet-stream] 正在保存至: “test.rar” 30% [============================> ] 3,146,580 515K/s 估时 14s ^C 可以看到,wget -c不能断点续传

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2. Enable breakpoint resume download
$flag = $obj->download($file, $name,true);

fdipzone@ubuntu:~/Downloads$ wget -O test.rar http://demo.fdipzone.com/demo.php --2013-06-30 16:53:19-- http://demo.fdipzone.com/demo.php 正在解析主机 demo.fdipzone.com... 127.0.0.1 正在连接 demo.fdipzone.com|127.0.0.1|:80... 已连接。 已发出 HTTP 请求，正在等待回应... 200 OK 长度： 10445120 (10.0M) [application/octet-stream] 正在保存至: “test.rar” 20% [==================> ] 2,097,720 516K/s 估时 16s ^C fdipzone@ubuntu:~/Downloads$ wget -c -O test.rar http://demo.fdipzone.com/demo.php --2013-06-30 16:53:31-- http://demo.fdipzone.com/demo.php 正在解析主机 demo.fdipzone.com... 127.0.0.1 正在连接 demo.fdipzone.com|127.0.0.1|:80... 已连接。 已发出 HTTP 请求，正在等待回应... 206 Partial Content 长度： 10445121 (10.0M)，7822971 (7.5M) 字节剩余 [application/octet-stream] 正在保存至: “test.rar” 100%[++++++++++++++++++++++++=========================================================================>] 10,445,121 543K/s 花时 14s 2013-06-30 16:53:45 (543 KB/s) - 已保存 “test.rar” [10445121/10445121]) 可以看到会从断点的位置(%20)开始下载。

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