Detailed explanation of how to enable PHP to implement breakpoint resume downloading

How to make PHP realize breakpoint resume download? In fact, to put it simply, it is to obtain the range of the file requested by the user through this variable $_SERVER['HTTP_RANGE'], and then the program controls the output of the file. For example, the first request for a file ranges from 0 to 999 bytes, the second request is for 1000 to 1999 bytes, and so on. Each time it requests 1000 bytes of content, the program then uses the fseek function to obtain the corresponding file location. Then output. I hope to be helpful.

$fname = './05e58c19552bb26b158f6621a6650899'; 
$fp = fopen($fname,'rb'); 
$fsize = filesize($fname); 
if (isset($_SERVER['HTTP_RANGE']) && ($_SERVER['HTTP_RANGE'] != "") && preg_match("/^bytes=([0-9]+)-$/i", $_SERVER['HTTP_RANGE'], $match) && ($match[1] < $fsize)) { 
$start = $match[1]; 
} else { 
$start = 0; 
} 
@header("Cache-control: public"); 
@header("Pragma: public"); 
if ($start > 0) { 
fseek($fp, $start); 
Header("HTTP/1.1 206 Partial Content"); 
Header("Content-Length: " . ($fsize - $start)); 
Header("Content-Ranges: bytes" . $start . "-" . ($fsize - 1) . "/" . $fsize); 
} else { 
header("Content-Length: $fsize"); 
Header("Accept-Ranges: bytes"); 
} 
@header("Content-Type: application/octet-stream"); 
@header("Content-Disposition: attachment;filename=1.rm"); 
fpassthru($fp);

You can also take a look at how Discuz!’s attachment.php file implements breakpoint resumption. Please look at the code:

also obtains the range of the file requested by the user through $_SERVER['HTTP_RANGE']. For details, you can view its source code analysis. Here I'm just going to start a discussion.

$range = 0; 
if($readmod == 4) { 
dheader('Accept-Ranges: bytes'); 
if(!emptyempty($_SERVER['HTTP_RANGE'])) { 
list($range) = explode('-',(str_replace('bytes=', '', $_SERVER['HTTP_RANGE']))); 
$rangesize = ($filesize - $range) > 0 ? ($filesize - $range) : 0; 
dheader('Content-Length: '.$rangesize); 
dheader('HTTP/1.1 206 Partial Content'); 
dheader('Content-Range: bytes='.$range.'-'.($filesize-1).'/'.($filesize)); 
} 
}

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