Setup FastCGI Caching With Nginx To Improve WordPress Performance

If you’re running a WordPress blog on a Nginx webserver, you should also enable FastCGI caching module. Nginx webserver is fast. When you combine Nginx and FastCGI caching module, you’ll greatly improve the performance of your web application, including a WordPress site.

FastCGI module has a Nginx directive for caching dynamic content that are served through PHP backend. When a web page is cached, repeated requests for the same page by web clients is quickly returned by the webserver because the page is coming from a cached location.

Instead of the webserver compiling all the dynamic data the makes up the page before returning it to the web clients on each request, a page is cached as a whole (all the data the makes up the page are stored together) and that the webserver doesn’t have to fetch dynamic data before returning that page to web clients.

This is an advantage of caching web pages.

This blog assumes that you already have working Nginx, PHP-FPM and WordPress setup. Check out our blog on setting up Nginx and WordPress.

Setup Nginx FastCGI Directive In Nginx.Conf file.

Most Linux distributions got Nginx main config file in /etc/nginx directory. In there you should see nginx.conf. This is the main configuration file for Nginx.

Open the file and add these FastCGI directives in the http block {  …..}. The http block begins with  http {  and ends with   }.

fastcgi_cache_path /var/cache/nginx/fastcgi_temp levels=1:2 keys_zone=CZONE:15m inactive=60m;

fastcgi_cache_key "$scheme$request_method$host$request_uri";

fastcgi_cache_use_stale error timeout invalid_header http_500;
 
Save the file. The highlighted location is where the cached content will be stored. The keys_zone is a unique name to identify the cache location.
 
Setup PHP Directives In Default.conf file.

 
When you’re done with nginx.conf file, go to the site definition file. This file is usually at /etc/nginx/conf.d/default.conf.  Edit it and add these PHP location directives.
    location ~ \.php$ {

        fastcgi_split_path_info ^(.+\.php)(/.+)$;

        fastcgi_pass unix:/var/run/php-fpm/php-fpm.sock;

        fastcgi_index index.php;

        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

        include fastcgi_params;

        fastcgi_intercept_errors on;

        fastcgi_ignore_client_abort off;

        fastcgi_connect_timeout 60;

        fastcgi_send_timeout 90;

        fastcgi_read_timeout 90;

        fastcgi_buffer_size 128k;

        fastcgi_buffers 4 256k;

        fastcgi_busy_buffers_size 256k;

        fastcgi_temp_file_write_size 256k;

        fastcgi_cache_bypass $no_cache;

        fastcgi_no_cache $no_cache;

        fastcgi_cache   CZONE;

        fastcgi_cache_valid   200 302  1h;

        fastcgi_cache_valid   301 1h;

        fastcgi_cache_valid   any 1h;

        fastcgi_cache_min_uses  2;

    }
 
Save the file.
The highlighted lines machines the 
 
Do Not Cache Files For Logged In Users

 
These lines below prevent caching for logged-in users. Those who signed in to WordPress will always see live data and no cached content.
Add these lines in the default site configuration file in the Server block  {  ……. }.  The server block is the one the begins with Server { and ends with   }.
 
set $no_cache 0;


    if ($request_method = POST) {

        set $no_cache 1;

    }


    if ($query_string != "") {

        set $no_cache 1;

    }


    if ($request_uri ~* "(/wp-admin/|/xmlrpc.php|/wp-(app|cron|login|register|mail).php|wp-.*.php|/feed/|index.php|wp-comments-popup.php|wp-links-opml.php|wp-locations.php|sitemap(_index)?.xml|[a-z0-9_-]+-sitemap([0-9]+)?.xml)") {

        set $no_cache 1;

   }


   if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_no_cache|wordpress_logged_in") {

        set $no_cache 1;

   }
 
Save the file and you’re almost done.
 
Setup PHP-FPM To Complete The Setup

 
Finally, open PHP-FPM config file and set the listen socket to what was added in Nginx config. 
;listen = 127.0.0.1:9000

listen = /var/run/php-fpm/php-fpm.sock
 
Change the listen directives to match what is above and save the file. 
That’s it. 
Reload Nginx and PHP-FPM the load the settings.
service nginx reload
 
Enjoy!