Implemented file download php class that supports breakpoint resume transfer

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 only for breakpoint downloads.
In the Range user request header, specify the position of the first byte and the last byte. The position like (Range: 200-300)
Content-Range is used for the response header

Request to download the entire file:

GET /test.rar HTTP/1.1
Connection: close
Host: 116.1.219.219
Range: bytes=0-801 //General request to download the entire file is 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:

  /**
 * Download class, supports resumed downloads
 * @time: 2015 06 30 09:36
 * @author:guoyu@xzdkiosk.com
 * PHP download class, supports resumed downloads
 * Func:
 * download: Download file
 * setSpeed: Set the download speed
 * getRange: Get the Range in the header
*/

 class FileDownload{ // class start

 private $_speed = 512; // Download speed

 /**Download
 * @param String $file The path of the file to be downloaded
 * @param String $name The file name, if it is empty, it will be the same as the downloaded file name
 * @param boolean $reload Whether to enable breakpoint resumption
*/
 public function download($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){ // Use resume
 header('HTTP/1.1 206 Partial Content');
 header('Accept-Ranges:bytes');

 // Remaining length
 header(sprintf('content-length:%u',$ranges['end']-$ranges['start']));

 // range information
 header(sprintf('content-range:bytes % s-%s/%s', $ranges['start'], $ranges['end'], $file_size));

 // The fp pointer jumps to the breakpoint position
 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); // For testing, minus Slow download speed
 }

 ($fp!=null) && fclose($fp);

 }else{
 return '';
 }
 }

 /**Set download speed
 * @param int $speed
*/
 public function setSpeed( $speed){
 if(is_numeric($speed) && $speed>16 && $speed<4096){
 $this->_speed = $speed;
 }
 }

 /**Get header range information
 * @param int $file_size file size
 * @return Array
*/
 private function getRange($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

 ?>

The demo code is as follows:

  require('FileDownload.class.php');
 $file = 'book.zip';
 $name = time().'.zip';
 $obj = new FileDownload();
 $flag = $obj->download($file, $name);
 //$flag = $obj->download($file, $name, true); // Resume upload from breakpoint

 if(!$flag){
 echo 'file not exists';
 }
 ?>

Test method for resumable download:

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

1. Turn off breakpoint resumption 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
 Resolving host demo.test.com... 127.0.0.1
 Connecting demo.test.com|127.0.0.1|:80... Connected.
 HTTP request sent, waiting for response... 200 OK
 Length: 10445120 (10.0M) [application/octet-stream]
 Saving to: “test.rar”

 30% [====== ======================> ] 3,146,580 513K/s Estimated time 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
 Resolving host demo.test .com... 127.0.0.1
 Connecting demo.test.com|127.0.0.1|:80... Connected.
 HTTP request sent, waiting for response... 200 OK
 Length: 10445120 (10.0M) [application/octet-stream]
 Saving to: “test.rar”
 30% [======== =====================> ] 3,146,580 515K/s Estimated time 14s
 ^C

You can see that wget -c cannot resume the upload

2. Enable breakpoint resumption

 $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
 Resolving host demo.test.com... 127.0.0.1
 Connecting demo.test.com|127.0.0.1|:80... Connected.
 HTTP request sent, waiting for response... 200 OK
 Length: 10445120 (10.0M) [application/octet-stream]
 Saving to: “test.rar”

 20% [====== ============> ] 2,097,720 516K/s Estimated time 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
 Resolving host demo.test.com... 127.0.0.1
 Resolving Connect demo.test.com|127.0.0.1|:80... Connected.
 HTTP request sent, waiting for response... 206 Partial Content
 Length: 10445121 (10.0M), 7822971 (7.5M) Bytes remaining [application/octet-stream]
 Saving to: “test.rar”

 100%[++++++++++++++++++++++++====================== ================================================== ]
 You can see that the download will start from the breakpoint position (%20).

Resume upload from breakpoint, php