使用 PHP 下载脚本发送正确的文件大小
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Sending correct file size with PHP download script
提问by Rocket Hazmat
I created a file download script in PHP, it works, but web browsers report the file as "Unknown Length". My code is as follows:
我在 PHP 中创建了一个文件下载脚本，它可以工作，但是网络浏览器将该文件报告为“未知长度”。我的代码如下：
function downloadFile($file){
// Set up the download system...
header('Content-Description: File Transfer');
header('Content-Type: '.mime_content_type($file));
header('Content-Disposition: attachment; filename="'.basename($file).'"');
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: '.filesize($file));
// Flush the cache
ob_clean();
flush();
// Send file to browser
readfile($file);
// DO NOT DO ANYTHING AFTER FILE DOWNLOAD
exit;
}
回答by Honso
Originally from http://paul.luminos.nl/update/471:
最初来自http://paul.luminos.nl/update/471：
The CrimsonBase websiteverifies downloads by passing them through a robust PHP script similar to the one published by Andrew Johnson in his article about PHP-controlled file downloads.
Andrew makes a very important comment at the end of the article:
"If you compress files with Zlib, mod_deflate and so on the Content-Length header won't be accurate so you'll end up seeing "Unknown size" and "Unknown time remaining" when downloading files."
I would like to stress this: if your browser doesn't appear to be obeying the headers generated by your PHP script—especially
Content-Length—it is fairly likely that Apache'smod_deflateextension is enabled.You can easily disable it for a single script using the following line in an applicable
.htaccessfile:SetEnvIfNoCase Request_URI ^/download\.php no-gzip dont-varywhere download.php is here assumed to be in the download script located in the server's root directory path (e.g.
www.crimsonbase.com/download.php). (That's because the regular expression is^/download\.php.)
该CrimsonBase网站验证下载使它们通过类似于安德鲁·约翰逊在发布的一个强大的PHP脚本他对PHP控制文件下载的文章。
安德鲁在文章的最后做了一个非常重要的评论：
“如果您使用 Zlib、mod_deflate 等压缩文件，则 Content-Length 标头将不准确，因此您最终会在下载文件时看到“未知大小”和“剩余时间未知”。”
我想强调这一点：如果您的浏览器似乎没有遵守由您的 PHP 脚本生成的标头——尤其是
Content-Length——很可能mod_deflate启用了 Apache 的扩展。您可以使用适用
.htaccess文件中的以下行轻松为单个脚本禁用它：SetEnvIfNoCase Request_URI ^/download\.php no-gzip dont-vary这里假定 download.php 位于位于服务器根目录路径（例如
www.crimsonbase.com/download.php）中的下载脚本中。（那是因为正则表达式是^/download\.php.）
回答by Skylar Ittner
I had this same problem, and I fixed it by sending the Content-Lengthheader before the Content-Disposition.
我遇到了同样的问题，我通过Content-Length在Content-Disposition.
header('Content-Type: video/mp4');
header("Content-Transfer-Encoding: Binary");
header("Content-Length: ".filesize($file_url));
header("Content-disposition: attachment; filename=\"" . basename($file_url) . "\"");
readfile($file_url);
回答by Rocket Hazmat
Try not flushing the cache before readfile() function. My code is almost identical to yours otherwise, and works fine.
尽量不要在 readfile() 函数之前刷新缓存。我的代码与您的代码几乎相同，并且工作正常。
