nginx rewrite rules with Passenger

Question

Hi,

I'm trying to migrate to nginx from Apache using Passenger in both instances to host a Rails app. The app takes a request, which is for an image- if the image exists at /system/logos/$requestedimage then it should get served, or it should be allowed to hit the Rails app to generate it if needed (where it is then cached to /system/logos).

In Apache I used the following:

RewriteCond %{DOCUMENT_ROOT}/system/logos/%{REQUEST_FILENAME} -f
RewriteRule ^/(.*)$ http://assets.clg.eve-metrics.com/system/logos/$1

This worked fine. The assets. subdomain is another subdomain but with the same root, just Passenger disabled, specifically set up for hosting static files (expires-wise).

In nginx I am using the following:

server {
  listen 80;
  passenger_enabled on;
  server_name  clg.eve-metrics.com www.clg.eve-metrics.com;
  root /opt/www/clg/current/public;
  gzip             on;
  gzip_min_length  1000;
  gzip_proxied     expired no-cache no-store private auth;
  gzip_types       text/plain application/xml text/css application/javascript;
  gzip_disable     msie6;
  error_page   500 502 503 504  /50x.html;
  location = /50x.html {
  }
  if (-f $document_root/system/logos$request_filename) { 
    rewrite ^/(.*)$ http://assets.clg.eve-metrics.com/system/logos/$1 break;
  }
}

This doesn't work so well. At all, in fact. It never redirects to the cached path and it never hits the Rails app. It's like nginx is assuming it's a static asset so not passing it on to Passenger. Is there a way to stop this behaviour so it hits the app?

Answer 1

My rails application is running on nginx and passenger. I have moved my rails cache directory from the default /public to /public/system/cache/. To make it work, I had to insert this into my vhost config file:

if (-f $document_root/system/cache/$uri/index.html) {
  rewrite (.*) /system/cache/$1/index.html break;
}

if (-f $document_root/system/cache/$uri.html) {
  rewrite (.*) /system/cache/$1.html break;
}

I remember that I too tried to make it work with $request_filename, but didn't get it to work. Try with $uri instead and see if it works :-)