我之前遇到过这个问题,使用下面的脚本下载文件,将大文件分成块来下载,而不是一次性尝试获取整个文件。该脚本还考虑了浏览器的使用情况,因为某些浏览器(主要是IE)可能会稍微不同地处理头部信息。
private function outputFile($file, $name, $mime_type='') {
$fileChunkSize = 1024*30;
if(!is_readable($file)) die('File not found or inaccessible!');
$size = filesize($file);
$name = rawurldecode($name);
$known_mime_types=array(
"pdf" => "application/pdf",
"txt" => "text/plain",
"html" => "text/html",
"htm" => "text/html",
"exe" => "application/octet-stream",
"zip" => "application/zip",
"doc" => "application/msword",
"xls" => "application/vnd.ms-excel",
"ppt" => "application/vnd.ms-powerpoint",
"gif" => "image/gif",
"png" => "image/png",
"jpeg"=> "image/jpg",
"jpg" => "image/jpg",
"php" => "text/plain"
);
if($mime_type=='')
{
$file_extension = strtolower(substr(strrchr($file,"."),1));
if(array_key_exists($file_extension, $known_mime_types))
$mime_type=$known_mime_types[$file_extension];
else
$mime_type="application/force-download";
}
@ob_end_clean();
if(ini_get('zlib.output_compression'))
ini_set('zlib.output_compression', 'Off');
header('Content-Type: ' . $mime_type);
header('Content-Disposition: attachment; filename="'.$name.'"');
header("Content-Transfer-Encoding: binary");
header('Accept-Ranges: bytes');
header("Cache-control: private");
header('Pragma: private');
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
if(isset($_SERVER['HTTP_RANGE']))
{
list($a, $range) = explode("=",$_SERVER['HTTP_RANGE'],2);
list($range) = explode(",",$range,2);
list($range, $range_end) = explode("-", $range);
$range=intval($range);
if(!$range_end)
$range_end=$size-1;
else
$range_end=intval($range_end);
$new_length = $range_end-$range+1;
header("HTTP/1.1 206 Partial Content");
header("Content-Length: $new_length");
header("Content-Range: bytes $range-$range_end/$size");
}
else
{
$new_length=$size;
header("Content-Length: ".$size);
}
$chunksize = 1*($fileChunkSize);
$bytes_send = 0;
if ($file = fopen($file, 'r'))
{
if(isset($_SERVER['HTTP_RANGE']))
fseek($file, $range);
while(!feof($file) &&
(!connection_aborted()) &&
($bytes_send<$new_length)
)
{
$buffer = fread($file, $chunksize);
print($buffer);
flush();
$bytes_send += strlen($buffer);
}
fclose($file);
}
else die('Error - can not open file.');
die();
}
fread
(和带有b
标志的fopen
)还可以让您控制下载的最大速度。 - Daniel W.