In general, we can direct the user to download files by directly having the URL point to a file located under document root.
However, in doing so, there is no way to do some statistics, permission checks, etc. work. So, a lot of times, we use to make PHP to do forwarding, to provide users with file downloads.
Copy Code code as follows:
<?php
$file = "/tmp/dummy.tar.gz";
Header ("Content-type:application/octet-stream");
Header (' Content-disposition:attachment filename= '. basename ($file). '"');
Header ("Content-length:"). FileSize ($file));
ReadFile ($file);
But this has a problem, that is, if the file is Chinese name, some users may download the file name is garbled.
So, let's make a change:
Copy Code code as follows:
<?php
$file = "/tmp/Chinese name. tar.gz";
$filename = basename ($file);
Header ("Content-type:application/octet-stream");
Working with Chinese file names
$ua = $_server["Http_user_agent"];
$encoded _filename = Rawurlencode ($filename);
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= "'. $filename. '"');
}
Header ("Content-length:"). FileSize ($file));
ReadFile ($file);
Well, it looks a lot better now, but there is another problem, that is ReadFile, although PHP's ReadFile try to achieve as efficiently as possible without consuming PHP's own memory, but in fact it still needs to use MMAP (if supported), Or a fixed buffer to iterate through the file, directly output.
When the output, if it is Apache + PHP mod, then also need to send to Apache output buffer. Last sent to the user. For Nginx + FPM, if they were deployed separately, it would also bring in additional network IO.
So, can not go through the PHP layer, directly to the webserver directly to send the file to the user?
Today, I saw an interesting article: how I php:x-sendfile.
We can use the Apache module Mod_xsendfile to have Apache send this file directly to the user:
Copy Code code as follows:
<?php
$file = "/tmp/Chinese name. tar.gz";
$filename = basename ($file);
Header ("Content-type:application/octet-stream");
Working with Chinese file names
$ua = $_server["Http_user_agent"];
$encoded _filename = Rawurlencode ($filename);
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. '"');
}
Let Xsendfile send a file
Header ("X-sendfile: $file");
The X-sendfile header will be processed by Apache and send the response file directly to the client.
LIGHTTPD and Nginx also have similar modules, we are interested can go look for
