How to set Expires header for static assets in Nginx

This blog is built on Jekyll and served by Nginx. I chose Jekyll so that I could gain some performance boost from the static, pre-generated blog content rather than serving every blog request from a database. Nginx was the obvious choice because it's the efficient HTTP server out there.

However, every time I check my pages in Pagespeed, it complains that the static assets are not optimized and I should Leverage browser caching. This is because I missed to set Expires header in my Nginx configuration. Turns out it is very simple to do.

Nginx configuration to set Expires header for images and static assets

Assuming you are using a Unix flavoured operating system (Ubuntu, in my case);

1. Go to /etc/nginx/sites-available.
2. Open your site configuration in an editor. For example, vi veerasundar.com (Use sudo if necessary).
3. In the server configuration, add the code to set Expires header if an request is made to a static file. Here's my complete configuration for this server.

server {

        listen   80;
        server_name veerasundar.com;

        access_log /location/of/access.log;
        error_log /location/of/error.log;

        location / {

                        root   /location/of/www;
                        index  index.html index.htm;

                        if ($request_uri ~* ".(ico|css|js|gif|jpe?g|png)$") {
                                        expires 30d;
                                        access_log off;
                                        add_header Pragma public;
                                        add_header Cache-Control "public";
                                        break;
                                }

                        }

            }

After making the changes, save the file and restart nginx - sudo /etc/init.d/nginx restart.

Now your static files are served with Expires header and will be cached by the browser.