Sometimes you may need to implement controlled downloads when all downloads requests being sent to your script and then this script decides what to do: to send some file to the user or to show some access denied page or, maybe, do something else. In lighttpd server it can be done by returning X-Sendfile header from script. Nginx have its own implementation of such idea using X-Accel-Redirect header. In this short post I will try to describe how to use this feature from PHP and Rails applications.
Lets assume, that you have some site and using Apache with PHP or Rails for dynamic content on this site. If you will use nginx as reverse-proxy in front of your Apache server, you will reach two goals:
1. You would be able free some resources on server while nginx will handle all slow requests to dynamic content (details are here).
2. You would be able to implement controlled downloads of static files from site.In this article I will assume, that site is located in /var/www directory and there are some static files (like movies or song or something else) in /var/www/files directory. Apache is listening on
http://127.0.0.1:8080.
First of all, lets take a look at our nginx configuration:
http {
....
server {
listen 80;
server_name your-domain.com;
location / {
rewrite ^/download/(.*) /down.php?path=$1 last;
proxy_pass http://127.0.0.1:8080/;
proxy_redirect off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
client_max_body_size 10m;
client_body_buffer_size 128k;
proxy_connect_timeout 90;
proxy_send_timeout 90;
proxy_read_timeout 90;
proxy_buffer_size 4k;
proxy_buffers 4 32k;
proxy_busy_buffers_size 64k;
proxy_temp_file_write_size 64k;
}
location /files {
root /var/www;
internal;
}
}
}Code: [Select]<?php
// Get requested file name
$path = $_GET["path"];
//...
// Perform any required security checks, validation
// and/or stats accounting
//...
// And redirect user to internal location
header("X-Accel-Redirect: /files/" . $path);
?>
In Rails applications you can use following code in your controller:
// Get requested file name
path = @params["path"]
# ...
# Perform any required security checks, validation
# and/or stats accounting
# ...
# And redirect user to internal location
@response.headers['X-Accel-Redirect'] = "/files/" + path
