A file download class that supports breakpoint renewal in PHP

PHP support breakpoint Continuation, mainly rely on the HTTP protocol header Http_range implementation.

The principle of HTTP breakpoint continuous transmission

HTTP header Range, Content-range ()

Range and Content-range entity headers are used when a general breakpoint in the HTTP header is downloaded.

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 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 request download entire file is bytes=0-or not this head

General Normal response

http/1.1 OK

content-length:801

Content-type:application/octet-stream

Content-range:bytes 0-800/801//801: Total File size

FileDownload.class.php

<?php/** PHP Download class, support breakpoint continuation * date:2013-06-30 * author:fdipzone * ver:1.0 * Func: * Download: Download file * setspeed: Set download speed * GetRange: Get header in range */class filedownload{//Class start Privat   e $_speed = 512;  
    Download speed/** Download * @param string $file The file path to download * @param String $name file name, blank, same as the downloaded file name * @param boolean $reload whether to open a breakpoint continuation/public function download ($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 the continued 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  
                      
                '], $file _size));  
            FP pointer jumps to the breakpoint position fseek ($fp, sprintf ('%u ', $ranges [' Start ']));  
                }else{header (' http/1.1 OK ');  
            Header (' Content-length: '. $file _size);  
                while (!feof ($fp)) {echo fread ($fp, round ($this->_speed*1024,0));  
                Ob_flush (); Sleep (1);  
      
        For testing, slowing download speed} ($fp!=null) && fclose ($FP);  
        }else{return "; }  
    /** Set Download speed * @param int $speed */Public Function setspeed ($speed) {i  
        F (Is_numeric ($speed) && $speed >16 && $speed <4096) {$this->_speed = $speed; /** Get Header Range Info * View this column more highlights: Http://www.bianceng.cnhttp://www.bianceng.cn/webkf/P  
        hp/* @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?>