Enable/Disable PHP on Nginx for CDN - nginx

Question

I have a server with Nginx installed.
I also have 2 domains pointing to that server. (domain1.com and domain2.com). The first domain (domain1.com) is the front website. The other domain (domain2.com) is the CDN for static content like: JS, CSS, images and font files.
I setup domains config files and everything is running fine. The nginx server has PHP running on it.
My question is: How to disable PHP on the second domain (domain2.com) unless the request has "?param=something" in the GET request?!
It will be something like:
// PHP is disabled
if($_GET['param']){
// Enable PHP
}
or should I use:
location ~ /something {
deny all
}
And keep PHP running?!
Note: I need php to process the param i pass to output some JS or CSS.

Answer 1

PHP with nginx is very different than PHP with Apache, since there is no mod_php equiv for nginx (AFAIK).
PHP is handled by totally separate daemon (php-fpm, or by passing the request to an apache server, etc.) As a result, you can bypass php completely simply by letting nginx handle the request without passing it off to php-fpm or apache. There is a good chance that your nginx configuration already is setup only handoff .php files to php-fpm.
Now, if you're trying to have requests such as /some-style.css?foo=bar get handled by php, then I'd suggest simply segregating static resources from dynamic ones.
You could create a third domain, or simply use two separate directories.
/static/foo.css
vs
/dynamic/bar.css?xyz=pdq
You could then handoff to php inside the location blocks.
location ~ /static {
try_files $uri =404;
}
location ~ /dynamic {
try_files $uri =404;
include /etc/nginx/fastcgi_params;
fastcgi_pass 127.0.0.1:9000;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
}
With the above configuration, requests starting with /static will bypass php regardless of file extension (even .php) and requests starting with /dynamic will be passed on the php-fpm regardless of file extension (even .css)