Checklist For Perfect WordPress-Nginx Setup

Today’s article details an internal checklist we will follow when testing if a WordPress-Nginx setup is working perfectly.

Following tests are most common & important:

• Testing WordPress content cache for PHP/MySQL crash
• Testing Browser cache for static files
• Testing Gzip Compression
• Testing Nginx Map{} for Multisite Files

Testing WordPress content cache for PHP/MySQL crash

An ideal WordPress-Nginx setup will utilize caching at multiple levels. Most common way of caching is done by WordPress plugins like W3 Total Cache & WP Super Cache.

Test if WP Super Cache or W3 Total Cache is working:

Please run following command for at least 2 posts minimum and 2-3 times on each post. If you are testing a Multisite setup, you must repeat everything for at least 2 different sites in network.

Command to run:

curl http://example.com/wordpress-post-url/ | tail -n 4 && echo -e

You should get the following output:

</html>
<!-- Dynamic page generated in 0.050 seconds. -->
<!-- Cached page generated by WP-Super-Cache on 2012-09-14 04:52:06 -->
<!-- super cache -->

Please note the timestamp (highlighted in bold above).

If it remains the same after running command many times, your cache is working.

Test if Content Cache works after PHP crashes

You should run above test again after stopping PHP.

If your WP Super Cache or W3 Total Cache was taking help from PHP to serve cache files, you will get “bad gateway error” after PHP stops.

Testing Browser cache for static files

Browser caching must be done on Nginx’s end.

Take any file on your server and run command like below:

Command to run:

curl -I http://example.com/wp-content/uploads/2012/09/wow.png

HTTP/1.1 200 OK
Server: nginx/1.2.3
Date: Wed, 19 Sep 2012 19:32:14 GMT
Content-Type: image/png
Content-Length: 3035
Last-Modified: Thu, 06 Sep 2012 15:14:25 GMT
Connection: keep-alive
Expires: Thu, 31 Dec 2037 23:55:55 GMT Cache-Control: max-age=315360000
Accept-Ranges: bytes

If you see lines in bold with future date, then it means browser cache is working. This will reduce load on server for repeat visitors!

Testing Gzip Compression:

Gzip support is by default enabled/handled by Nginx so we need not add config lines for it again. For this reason, none of my Nginx configuration have gzip block.

In case you are not sure, you can test if your site is using gzip here - http://www.whatsmyip.org/http-compression-test/

Testing Nginx Map{} for Multisite Files

If you are following our WordPress-Nginx series, then you must be using Nginx Maps{} directive on your WordPress Multisite setup.

In that case, you must check if static file uploads on Multisite can be accessed when PHP crashed.

Just stop PHP, and run following command.

curl -I http://example.com/wp-content/uploads/2012/09/wow.png

HTTP/1.1 200 OK

That means, you can access files without PHP.

For added safety, clear browser cache and open file URL in browser.