php安全下载大文件的实现代码

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发布： 2016-07-25 08:58:51

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/**
* 一般文件安全下载
* edit bbs.it-home.org
*/
$durl = 'file/phpcms2008_o2abf32efj883c91a.iso';
$filename = 'phpcms2008_o2abf32efj883c91a.iso';
$file = @fopen($durl, 'r');
header("Content-Type: application/octet-stream");
header("Accept-Ranges: bytes");
header("Accept-Length: ".filesize($durl));
header("Content-Disposition: attachment; filename=".$filename);
echo fread($file,filesize($durl));
fclose($file);
?>

复制代码

以上的代码，在遇到大文件时，超过php.ini配置的内存最大值的文件时，服务器会非常占用CPU资源，文件不能正常下载，只能下载几十Kb的文件。可以用下面的代码来解决：

/**
* 大文件安全下载的实现代码
* edit bbs.it-home.org
*/
function download($url, $filename) {
// 获得文件大小, 防止超过2G的文件, 用sprintf来读
$filesize = sprintf ( "%u", filesize ( $url ) );
if (! $filesize) {
return;
}
header ( "Content-type:application/octet-stream\n" ); //application/octet-stream
header ( "Content-type:unknown/unknown;" );
header ( "Content-disposition: attachment; filename=\"" . $filename . "\"" );
header ( 'Content-transfer-encoding: binary' );
if ($range = getenv ( 'HTTP_RANGE' )) { // 当有偏移量的时候，采用206的断点续传头
$range = explode ( '=', $range );
$range = $range [1];
header ( "HTTP/1.1 206 Partial Content" );
header ( "Date: " . gmdate ( "D, d M Y H:i:s" ) . " GMT" );
header ( "Last-Modified: " . gmdate ( "D, d M Y H:i:s", filemtime ( $url ) ) . " GMT" );
header ( "Accept-Ranges: bytes" );
header ( "Content-Length:" . ($filesize - $range) );
header ( "Content-Range: bytes " . $range . ($filesize - 1) . "/" . $filesize );
header ( "Connection: close" . "\n\n" );
} else {
header ( "Content-Length:" . $filesize . "\n\n" );
$range = 0;
}
loadFile ( $url );
}
function loadFile($filename, $retbytes = true) {
$buffer = '';
$cnt = 0;
$handle = fopen ( $filename, 'rb' );
if ($handle === false) {
return false;
}
while ( ! feof ( $handle ) ) {
$buffer = fread ( $handle, 1024 * 1024 );
echo $buffer;
ob_flush ();
flush ();
if ($retbytes) {
$cnt += strlen ( $buffer );
}
}
$status = fclose ( $handle );
if ($retbytes && $status) {
return $cnt; // return num. bytes delivered like readfile() does.
}
return $status;
}
?>