How do I alias a name in nginx w/o aliasing the domain name?

Question

I have this line in my config file

server_name site.com m.site.com

My code checks if the url is m.site.com and serves the mobile version. However when I do this going to m.site.com/abc will show my code site.com/abc which is wrong. If I copy/paste the entire block and change site.com to m.site.com it works fine. But I'd rather not have duplicate config (or code).

Is there a way around this?

Answer 1

You have two choices here:

1) Have "duplicate" config blocks for nginx

2) Have your site detect the server name (in PHP, $_SERVER['SERVER_NAME'] or $_SERVER['HTTP_HOST']) and serve up a different site depending on what it is.

Answer 2

It is an ineffective way even if you check $http_host in config. So, the best way is put all common bits in a file and include it in separate server block:

server {
    listen       80;
    server_name  site.com;
    root         /var/www/localhost/htdocs/site.com;
    include      asp.conf
}

server {
    listen       80;
    server_name  m.site.com;
    root         /var/www/localhost/htdocs/m.site.com;
    include      asp.conf
    ...
}

Answer 3

If you're using nginx as a reverse proxy, try adding the proxy_set_header directive near your proxy_pass directive, like this:

proxy_pass   http://my.asp.net.hostname:8000;
proxy_set_header Host $http_host;

This ensures that nginx is passing the Host header verbatim, instead of taking the main server_name.