PHP download file, Chinese garbled problem

By setting the Content-Type to application/octet-stream, you can download dynamically generated content as a file. I believe everyone knows this. Then use Content-Disposition to set the downloaded file name. Many people know this. Basically, the download program is written like this:

<?php
$filename = "document.txt";
header('Content-Type: application/octet-stream');
header('Content-Disposition : attachment; filename=' . $filename);
print "Hello!";
?>
[/cdoe]
After opening it with a browser, you can download document.txt.

However, if $filename is UTF-8 encoded, some browsers cannot handle it properly. For example, slightly change the above program:
[code]
<?php
$filename = "Chinese file name.txt";
header('Content-Type: application/octet-stream');
header(' Content-Disposition: attachment; filename=' . $filename);
print "Hello!";
?>
[/cdoe]
Save the program in UTF-8 encoding and access it again. The file name downloaded by IE6 will be garbled. . The file name downloaded under FF3 only has the word "Chinese". Everything works fine under Opera 9.

The output header actually looks like this:

Content-Disposition: attachment; filename=Chinese file name.txt In fact, according to the definition of RFC2231, the multi-language encoding Content-Disposition should be defined like this:

Content-Disposition: attachment ; filename*="utf8''%E4%B8%AD%E6%96%87%20%E6%96%87%E4%BB%B6%E5%90%8D.txt" that is:

after filename Add * before the equal sign
The value of filename is divided into three segments with single quotes, which are character set (utf8), language (empty) and urlencoded file name.
It is best to add double quotes, otherwise the part after the space in the file name will not be displayed in Firefox
Note that the result of urlencode is not the same as the result of php's urlencode function. PHP's urlencode will replace the space with +, which is required here Replace with %20
After testing, it was found that the support of several mainstream browsers is as follows:

IE6 attachment; filename="<UTF-8 file name after URL encoding>"
FF3 attachment; filename="UTF- 8 file name"
attachment; filename*="utf8''<UTF-8 file name after URL encoding>"
O9 attachment; filename="UTF-8 file name"
Safari3(Win) Doesn’t seem to support it? None of the above methods work

It seems that the program must be written like this to support all mainstream browsers:
[code]
<?php
$ua = $_SERVER["HTTP_USER_AGENT"];
$filename = "Chinese file name.txt";
$encoded_filename = urlencode($filename);
$encoded_filename = str_replace("+", "%20", $encoded_filename);
header('Content-Type: application/octet-stream');
if (preg_match("/MSIE/", $ua)) {
header('Content-Disposition: attachment; filename="' . $encoded_filename . '"');
} else if (preg_match("/Firefox/ ", $ua)) {
header('Content-Disposition: attachment; filename*="utf8''' . $filename . '"');
} else {
header('Content-Disposition: attachment; filename= "' . $filename . '"');
}
print 'ABC';
?>