File download class implemented in PHP that supports breakpoint resume transfer, _PHP tutorial

File download class implemented by PHP that supports breakpoint resume transfer,

The example in this article describes the file download class implemented by PHP that supports breakpoint resume download and its usage. It is a very practical technique. Share it with everyone for your reference. The specific method is as follows:

Generally speaking, PHP supports breakpoint resumption, mainly relying on the header HTTP_RANGE in the HTTP protocol.

HTTP breakpoint resumption principle:

Http header Range, Content-Range()
Range and Content-Range entity headers are generally used in HTTP headers for breakpoint downloads,
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

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 class file code is as follows:

<&#63;php 
/** php下载类,支持断点续传 
*  Date:  2013-06-30 
*  Author: test 
*  Ver:  1.0 
* 
*  Func: 
*  download: 下载文件 
*  setSpeed: 设置下载速度 
*  getRange: 获取header中Range 
*/ 
 
class FileDownload{ // class start 
 
  private $_speed = 512;  // 下载速度 
 
  /** 下载 
  * @param String $file  要下载的文件路径 
  * @param String $name  文件名称,为空则与下载的文件名称一样 
  * @param boolean $reload 是否开启断点续传 
  */ 
  public function download($file, $name='', $reload=false){ 
    if(file_exists($file)){ 
      if($name==''){ 
        $name = basename($file); 
      } 
 
      $fp = fopen($file, 'rb'); 
      $file_size = filesize($file); 
      $ranges = $this->getRange($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 
 
&#63;> 

The demo sample code is as follows:

<&#63;php 
require('FileDownload.class.php'); 
$file = 'book.zip'; 
$name = time().'.zip'; 
$obj = new FileDownload(); 
$flag = $obj->download($file, $name); 
//$flag = $obj->download($file, $name, true); // 断点续传 
 
if(!$flag){ 
  echo 'file not exists'; 
} 
&#63;>

Test method for resuming download at breakpoint:

Use linux wget command to test the download, wget -c -O file http://xxx

1. Turn off breakpoint resuming first

$flag = $obj->download($file, $name);

test@ubuntu:~/Downloads$ wget -O test.rar http://demo.test.com/demo.php 
--2013-06-30 16:52:44-- http://demo.test.com/demo.php 
正在解析主机 demo.test.com... 127.0.0.1 
正在连接 demo.test.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 
test@ubuntu:~/Downloads$ wget -c -O test.rar http://demo.test.com/demo.php 
--2013-06-30 16:52:57-- http://demo.test.com/demo.php 
正在解析主机 demo.test.com... 127.0.0.1 
正在连接 demo.test.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 

As you can see, wget -c cannot resume the upload

2. Enable breakpoint resume download

$flag = $obj->download($file, $name, true);

test@ubuntu:~/Downloads$ wget -O test.rar http://demo.test.com/demo.php 
--2013-06-30 16:53:19-- http://demo.test.com/demo.php 
正在解析主机 demo.test.com... 127.0.0.1 
正在连接 demo.test.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 
test@ubuntu:~/Downloads$ wget -c -O test.rar http://demo.test.com/demo.php 
--2013-06-30 16:53:31-- http://demo.test.com/demo.php 
正在解析主机 demo.test.com... 127.0.0.1 
正在连接 demo.test.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]) 

You can see that the download will start from the breakpoint position (%20).

The complete source code of the examples in this article can be downloaded from this website by clicking here.

I believe that what is described in this article has certain reference value for everyone’s PHP program design.

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