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PHP - resumable download
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<?php | |
class ResumeDownload { | |
private $file; | |
private $name; | |
private $boundary; | |
private $delay = 0; | |
private $size = 0; | |
function __construct($file, $delay = 0) { | |
if (! is_file($file)) { | |
header("HTTP/1.1 400 Invalid Request"); | |
die("<h3>File Not Found</h3>"); | |
} | |
$this->size = filesize($file); | |
$this->file = fopen($file, "r"); | |
$this->boundary = md5($file); | |
$this->delay = $delay; | |
$this->name = basename($file); | |
} | |
public function process() { | |
$ranges = NULL; | |
$t = 0; | |
if ($_SERVER['REQUEST_METHOD'] == 'GET' && isset($_SERVER['HTTP_RANGE']) && $range = stristr(trim($_SERVER['HTTP_RANGE']), 'bytes=')) { | |
$range = substr($range, 6); | |
$ranges = explode(',', $range); | |
$t = count($ranges); | |
} | |
header("Accept-Ranges: bytes"); | |
header("Content-Type: application/octet-stream"); | |
header("Content-Transfer-Encoding: binary"); | |
header(sprintf('Content-Disposition: attachment; filename="%s"', $this->name)); | |
if ($t > 0) { | |
header("HTTP/1.1 206 Partial content"); | |
$t === 1 ? $this->pushSingle($range) : $this->pushMulti($ranges); | |
} else { | |
header("Content-Length: " . $this->size); | |
$this->readFile(); | |
} | |
flush(); | |
} | |
private function pushSingle($range) { | |
$start = $end = 0; | |
$this->getRange($range, $start, $end); | |
header("Content-Length: " . ($end - $start + 1)); | |
header(sprintf("Content-Range: bytes %d-%d/%d", $start, $end, $this->size)); | |
fseek($this->file, $start); | |
$this->readBuffer($end - $start + 1); | |
$this->readFile(); | |
} | |
private function pushMulti($ranges) { | |
$length = $start = $end = 0; | |
$output = ""; | |
$tl = "Content-type: application/octet-stream\r\n"; | |
$formatRange = "Content-range: bytes %d-%d/%d\r\n\r\n"; | |
foreach ( $ranges as $range ) { | |
$this->getRange($range, $start, $end); | |
$length += strlen("\r\n--$this->boundary\r\n"); | |
$length += strlen($tl); | |
$length += strlen(sprintf($formatRange, $start, $end, $this->size)); | |
$length += $end - $start + 1; | |
} | |
$length += strlen("\r\n--$this->boundary--\r\n"); | |
header("Content-Length: $length"); | |
header("Content-Type: multipart/x-byteranges; boundary=$this->boundary"); | |
foreach ( $ranges as $range ) { | |
$this->getRange($range, $start, $end); | |
echo "\r\n--$this->boundary\r\n"; | |
echo $tl; | |
echo sprintf($formatRange, $start, $end, $this->size); | |
fseek($this->file, $start); | |
$this->readBuffer($end - $start + 1); | |
} | |
echo "\r\n--$this->boundary--\r\n"; | |
} | |
private function getRange($range, &$start, &$end) { | |
list($start, $end) = explode('-', $range); | |
$fileSize = $this->size; | |
if ($start == '') { | |
$tmp = $end; | |
$end = $fileSize - 1; | |
$start = $fileSize - $tmp; | |
if ($start < 0) | |
$start = 0; | |
} else { | |
if ($end == '' || $end > $fileSize - 1) | |
$end = $fileSize - 1; | |
} | |
if ($start > $end) { | |
header("Status: 416 Requested range not satisfiable"); | |
header("Content-Range: */" . $fileSize); | |
exit(); | |
} | |
return array( | |
$start, | |
$end | |
); | |
} | |
private function readFile() { | |
while ( ! feof($this->file) ) { | |
echo fgets($this->file); | |
flush(); | |
usleep($this->delay); | |
} | |
} | |
private function readBuffer($bytes, $size = 1024) { | |
$bytesLeft = $bytes; | |
while ( $bytesLeft > 0 && ! feof($this->file) ) { | |
$bytesLeft > $size ? $bytesRead = $size : $bytesRead = $bytesLeft; | |
$bytesLeft -= $bytesRead; | |
echo fread($this->file, $bytesRead); | |
flush(); | |
usleep($this->delay); | |
} | |
} | |
} | |
$file = '/home/file.zip'; | |
set_time_limit(0); | |
$download = new ResumeDownload($file, 50000); //delay about in microsecs | |
$download->process(); |
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