<?php
/**
* 文件传输，支持断点续传。
* 2g以上超大文件也有效
*/
class Transfer {
/**
* 缓冲单元
*/
const BUFF_SIZE = 5120; // 1024 * 5
/**
* 文件地址
* @var <String>
*/
private $filePath;
/**
* 文件大小
* @var <String> Php超大数字 字符串形式描述
*/
private $fileSize;
/**
* 文件类型
* @var <String>
*/
private $mimeType;
/**
* 请求区域（范围）
* @var <String>
*/
private $range;
/**
* 是否写入日志
* @var <Boolean>
*/
private $isLog = false;
/**
*
* @param <String> $filePath 文件路径
* @param <String> $mimeType 文件类型
* @param <String> $range 请求区域（范围）
*/
function __construct($filePath, $mimeType = null, $range = null) {
$this->filePath = $filePath;
$this->fileSize = sprintf('%u', filesize($filePath));
$this->mimeType = ($mimeType != null) ? $mimeType : "application/octet-stream"; // bin
$this->range = trim($range);
}
/**
* 获取文件区域
* @return <Map> {'start':long,'end':long} or null
*/
private function getRange() {
/**
* Range: bytes=-128
* Range: bytes=-128
* Range: bytes=28-175,382-399,510-541,644-744,977-980
* Range: bytes=28-175\n380
* type 1
* RANGE: bytes=1000-9999
* RANGE: bytes=2000-9999
* type 2
* RANGE: bytes=1000-1999
* RANGE: bytes=2000-2999
* RANGE: bytes=3000-3999
*/
if (!empty($this->range)) {
$range = preg_replace('/[\s|,].*/', '', $this->range);
$range = explode('-', substr($range, 6));
if (count($range) < 2) {
$range[1] = $this->fileSize; // Range: bytes=-100
}
$range = array_combine(array('start', 'end'), $range);
if (empty($range['start'])) {
$range['start'] = 0;
}
if (!isset($range['end']) || empty($range['end'])) {
$range['end'] = $this->fileSize;
}
return $range;
}
return null;
}
/**
* 向客户端发送文件
*/
public function send() {
$fileHande = fopen($this->filePath, 'rb');
if ($fileHande) {
// setting
ob_end_clean(); // clean cache
ob_start();
ini_set('output_buffering', 'Off');
ini_set('zlib.output_compression', 'Off');
$magicQuotes = get_magic_quotes_gpc();
// set_magic_quotes_runtime(0);
// init
$lastModified = gmdate('D, d M Y H:i:s', filemtime($this->filePath)) . ' GMT';
$etag = sprintf('w/"%s:%s"', md5($lastModified), $this->fileSize);
$ranges = $this->getRange();
// headers
header(sprintf('Last-Modified: %s', $lastModified));
header(sprintf('ETag: %s', $etag));
header(sprintf('Content-Type: %s', $this->mimeType));
$disposition = 'attachment';
if (strpos($this->mimeType, 'image/') !== FALSE) {
$disposition = 'inline';
}
header(sprintf('Content-Disposition: %s; filename="%s"', $disposition, basename($this->filePath)));
if ($ranges != null) {
if ($this->isLog) {
$this->log(json_encode($ranges) . ' ' . $_SERVER['HTTP_RANGE']);
}
header('HTTP/1.1 206 Partial Content');
header('Accept-Ranges: bytes');
header(sprintf('Content-Length: %u', $ranges['end'] - $ranges['start']));
header(sprintf('Content-Range: bytes %s-%s/%s', $ranges['start'], $ranges['end'], $this->fileSize));
//
fseek($fileHande, sprintf('%u', $ranges['start']));
} else {
header("HTTP/1.1 200 OK");
header(sprintf('Content-Length: %s', $this->fileSize));
}
// read file
$lastSize = 0;
while (!feof($fileHande) && !connection_aborted()) {
$lastSize = sprintf("%u", bcsub($this->fileSize, sprintf("%u", ftell($fileHande))));
if (bccomp($lastSize, self::BUFF_SIZE) > 0) {
$lastSize = self::BUFF_SIZE;
}
echo fread($fileHande, $lastSize);
ob_flush();
flush();
}
set_magic_quotes_runtime($magicQuotes);
ob_end_flush();
}
if ($fileHande != null) {
fclose($fileHande);
}
}
/**
* 设置记录
* @param <Boolean> $isLog 是否记录
*/
public function setIsLog($isLog = true) {
$this->isLog = $isLog;
}
/**
* 记录
* @param <String> $msg 记录信息
*/
private function log($msg) {
try {
$handle = fopen('transfer_log.txt', 'a');
fwrite($handle, sprintf('%s : %s' . PHP_EOL, date('Y-m-d H:i:s'), $msg));
fclose($handle);
} catch (Exception $e) {
// null;
}
}
}
?>
