Nginx Configuration - Cache headers on certain paths

I think of the following for your nginx configuration :

• since it is just the expires header that differs for your two different locations, although both matching the proxy to the same server.
• try putting both the locations in the single block
• based on the query string, (or location match string) set a different expires header

tag.

server {
  listen  80;
  server_name salessystem.acmecorp.com;

  location ~* (/extjs/|/) {
    ## proxy_buffers 128 256k;
    proxy_pass http://localhost:5400/;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    add_header 'X-UA-Compatible' 'IE=Edge;chrome=1';
    expires max;
      if ($query_string ~ \/extjs\/) {
      expires epoch;
      }
    gzip  on;
    gzip_http_version 1.1;
    gzip_vary on;
    gzip_comp_level 7;
    gzip_proxied any;
    gzip_types text/html text/css text/pdf application/json application/x-javascript text/javascript;
    access_log off;
    break;
  }

}

Please however test according to your needs, especially near the regex matches at location and query_string value matching.

However it is not clear, why would you want to extjs to be served out of a proxied server (seems like a dynamic app server), since they are just plain text files if my assumption is right. The requests pertaining to extjs need not go through the proxy or app logic system just incase while they can be served independently through the filesystem. I think of keeping it in its seperate location itself, and have the unique gzip/expires directives unique to it in its own location block while the other common directives can be held in the server block itself.

For example:

server {
   ...
   common gzip directives
   common header setters
   common expires setters
   ...
   location / {
     proxy to backend app server
     settings unique to / location
     ..
   }
   location /extjs {
     settings unique to /extjs location
     expires header reset
     ...
   }
}