Optimizing WordPress and WooCommerce with NGINX FastCGI Cache

Implementing FastCGI Cache with NGINX can dramatically improve the performance of your WordPress and WooCommerce websites. This guide provides a step-by-step approach to setting up NGINX with PHP-FPM to leverage FastCGI caching effectively with help of NPP wordpress plugin.

Table of Contents

1. Introduction to FastCGI Cache
2. Prerequisites
3. Installing and Configuring NGINX and PHP-FPM
4. Configuring NGINX for FastCGI Cache
5. Configuring FastCGI Cache for WordPress
6. Optimizing FastCGI Cache for WooCommerce
7. Advanced Configuration and Optimization
8. Testing and Validation
9. Maintenance and Cache Purging
10. Conclusion

1. Introduction to FastCGI Cache

FastCGI Cache is a powerful feature in NGINX that stores dynamic content generated by PHP scripts. For WordPress and WooCommerce, this means faster page load times and reduced server load, leading to a smoother user experience and better SEO rankings.

2. Prerequisites

Before setting up FastCGI Cache, ensure you have the following. These are also the prerequisities for wordpress NPP plugin.

• A server running a Linux distribution (e.g., Ubuntu 20.04).
• Root or sudo access to the server.
• NGINX installed and running.
• PHP-FPM installed and configured.
• Properly connect NGINX and PHP-FPM (Check the basic template at the end of the article)
• WordPress and WooCommerce installed.
• If you use NPP plugin, wget needed for Preload action (required), cpulimit for CPU usage control (optional)
• If you use NPP plugin, you can use below one liner bash script giving write permission to PHP-FPM users with associated Nginx Cache paths automatically. This is required for fully functional purge and preload actions without permission issues.

bash <(curl -Ss https://psaux-it.github.io/install.sh)

This Bash script automates the management of inotify/setfacl operations, ensuring efficiency and security. It enhances the efficiency and security of cache management tasks by automating the setup and configuration processes. The install.sh script serves as a wrapper that facilitates the execution of the main fastcgi_ops_root.sh script from psaux-it.github.io. It acts as a convenient entry point for users to initiate the setup and configuration procedures seamlessly. Rest assured, this solution is entirely safe to use, providing a reliable and straightforward method for managing Nginx FastCGI cache purge operations on WordPress front-end.

• Automated Setup: Quickly sets up FastCGI cache paths and associated PHP-FPM users.
• Dynamic Configuration: Detects Nginx configuration dynamically for seamless integration.
• ACL Verification: Ensures filesystem ACL configuration for proper functionality.
• Systemd Integration: Generates and enables systemd service for continuous operation.
• Manual Configuration Support: Allows manual configuration for customized setups.
• Inotify Operations: Listens to FastCGI cache folder events for real-time updates.

3. Installing and Configuring NGINX and PHP-FPM

Step 1: Install NGINX and PHP-FPM

sudo apt update
sudo apt install nginx php-fpm

Step 2: Configure PHP-FPM

Edit the PHP-FPM configuration file /etc/php/7.4/fpm/php.ini:

cgi.fix_pathinfo=0

Restart PHP-FPM to apply the changes:

sudo systemctl restart php7.4-fpm

4. Configuring NGINX for FastCGI Cache

Step 1: Create Cache Directories

Create directories where NGINX will store cache files:

sudo mkdir -p /var/cache/nginx/fastcgi_cache
sudo chown -R www-data:www-data /var/cache/nginx

Step 2: Update NGINX Configuration

Edit your NGINX configuration file /etc/nginx/nginx.conf to include the following settings:

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;
    sendfile on;
    keepalive_timeout 65;
    server_tokens off;

    fastcgi_cache_path /var/cache/nginx/fastcgi_cache levels=1:2 keys_zone=WORDPRESS:100m inactive=60m use_temp_path=off;
    fastcgi_cache_key "$scheme$request_method$host$request_uri";
    fastcgi_cache_use_stale error timeout invalid_header updating http_500 http_502 http_503 http_504;
    fastcgi_ignore_headers Cache-Control Expires Set-Cookie;

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

Step 3: Site Configuration for WordPress

Edit your site configuration file /etc/nginx/sites-available/yourdomain.com:

server {
    listen 80;
    server_name yourdomain.com www.yourdomain.com;

    root /var/www/html;
    index index.php index.html index.htm;

    set $skip_cache 0;

    # POST requests and URLs with query parameters should not be cached
    if ($request_method = POST) {
        set $skip_cache 1;
    }
    if ($query_string != "") {
        set $skip_cache 1;
    }

    # Don't cache URIs containing specific strings
    if ($request_uri ~* "/cart.*$|/checkout.*$|/my-account.*$|/wc-api.*$|/add-to-cart.*$|/admin.*$|/login.*$|/register.*$") {
        set $skip_cache 1;
    }

    # Don't cache for logged-in users or recent commenters
    if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_logged_in|woocommerce_items_in_cart|woocommerce_cart_hash|wp_woocommerce_session") {
        set $skip_cache 1;
    }

    location / {
        try_files $uri $uri/ /index.php?$args;
    }

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/run/php/php7.4-fpm.sock;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;

        fastcgi_cache_bypass $skip_cache;
        fastcgi_no_cache $skip_cache;
        fastcgi_cache WORDPRESS;
        fastcgi_cache_valid 60m;
    }

    location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg)$ {
        expires max;
        log_not_found off;
    }

    # Additional security headers
    add_header X-Frame-Options "SAMEORIGIN";
    add_header X-XSS-Protection "1; mode=block";
    add_header X-Content-Type-Options "nosniff";
}

5. Configuring FastCGI Cache for WordPress

To further refine the caching setup, configure additional directives in your site configuration file:

Step 1: Adjust Cache Conditions

set $skip_cache 0;

# Don't cache POST requests
if ($request_method = POST) {
    set $skip_cache 1;
}

# Don't cache URLs with query parameters
if ($query_string != "") {
    set $skip_cache 1;
}

# Don't cache for logged-in users or recent commenters
if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_logged_in") {
    set $skip_cache 1;
}

# Enable cache for non-admin pages
location ~ \.php$ {
    include snippets/fastcgi-php.conf;
    fastcgi_pass unix:/run/php/php7.4-fpm.sock;
    fastcgi_cache_bypass $skip_cache;
    fastcgi_no_cache $skip_cache;
    fastcgi_cache WORDPRESS;
    fastcgi_cache_valid 60m;
}

Step 2: Setting Custom Cache Validity

You can set different cache validity periods for different types of content. For example:

fastcgi_cache_valid 200 60m;
fastcgi_cache_valid 301 302 10m;
fastcgi_cache_valid 404 1m;

6. Optimizing FastCGI Cache for WooCommerce

WooCommerce requires more specific caching rules due to its dynamic nature, especially for cart, checkout, and account pages:

Step 1: Custom Cache Conditions

Add these rules to ensure dynamic pages are not cached:

set $skip_cache 0;

if ($request_uri ~* "/cart.*$|/checkout.*$|/my-account.*$|/wc-api.*$|/add-to-cart.*$|/admin.*$|/login.*$|/register.*$") {
    set $skip_cache 1;
}

if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_logged_in|woocommerce_items_in_cart|woocommerce_cart_hash|wp_woocommerce_session") {
    set $skip_cache 1;
}

location ~ \.php$ {
    include snippets/fastcgi-php.conf;
    fastcgi_pass unix:/run/php/php7.4-fpm.sock;
    fastcgi_cache_bypass $skip_cache;
    fastcgi_no_cache $skip_cache;
    fastcgi_cache WORDPRESS;
    fastcgi_cache_valid 60m;
}

7. Advanced Configuration and Optimization

Step 1: Gzip Compression

Enable gzip compression to reduce the size of transmitted data:

gzip on;
gzip_vary on;
gzip_min_length 1024;
gzip_proxied any;
gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

Step 2: HTTP/2

Enable HTTP/2 for better performance:

server {
    listen 443 ssl http2;
    server_name yourdomain.com www.yourdomain.com;

    ssl_certificate /etc/ssl/certs/yourdomain.com.crt;
    ssl_certificate_key /etc/ssl/private/yourdomain.com.key;
    ...
}

Step 3: Rate Limiting

Implement rate limiting to protect your server from abuse:

http {
    limit_req_zone $binary_remote_addr zone=one:10m rate=1r/s;
    ...
    server {
        ...
        location / {
            limit_req zone=one burst=5 nodelay;
            ...
        }
    }
}

8. Testing and Validation

Step 1: Validate NGINX Configuration

Before restarting NGINX, validate the configuration:

sudo nginx -t

Step 2: Restart NGINX

sudo systemctl restart nginx

Step 3: Test Cache Functionality

To test if caching works, use the following command to inspect headers:

curl -I https://yourdomain.com

Look for X-FastCGI-Cache header. It should display HIT or MISS.

9. Maintenance and Cache Purging

Step 1: Manual Cache Purge

To manually purge the cache, delete the cache files:

sudo rm -rf /var/cache/nginx/fastcgi_cache/*

Step 2: Automated Cache Purge & Preload

The WordPress plugin NPP addresses the challenge of automating Nginx FastCGI cache purging and preloading (WordPress) in Nginx environments where two distinct users, WEBSERVER-USER and PHP-FPM-USER, are involved.

• WEBSERVER-USER: Responsible for creating cache folders and files with strict permissions.
• PHP-FPM-USER: Handles cache purge operations but lacks privileges

• Permission Issues: Adding PHP-FPM-USER to the WEBSERVER-GROUP doesn’t resolve permission conflicts.
• Nginx Overrides: Nginx overrides default setfacl settings, ignoring ACLs. Nginx creates cache folders and files with strict permissions.

Surprisingly, Nginx cache doesn’t adhere to DEFAULT ACLs.

setfacl -R -m d:u:php-fpm-user:rwX /var/cache/nginx/fastcgi_cache/

Solution involves combining inotifywait with setfacl under root: Here there is a well written bash script by PSAUXIT that take care of this process automatically.

• fastcgi_ops_root.sh grants PHP-FPM-USER write permissions recursively for Nginx Cache paths for multi instances.

For automate purging and preloading the cache, use plugins like NPP . NPP is a feature rich WordPress plugin that handle Nginx FastCGI Cache Purge and Preload operations automatically on WordPress admin dashboard and totally free.

Step 3: Monitoring Cache Performance

Regularly monitor your cache performance using tools like Munin, New Relic, or built-in NGINX logs to ensure optimal performance.

10. Conclusion

Implementing FastCGI Cache with NGINX can significantly enhance the performance of WordPress and WooCommerce websites by reducing load times and server load. By following this detailed guide, you ensure a properly configured caching system, leading to a smoother user experience and improved SEO rankings. Regular maintenance and proper testing ensure that your cache setup continues to perform optimally.

The PHP-FPM user should be a special user that you create for running your website, whether it is Magento, WordPress, or anything.

NGINX must run with it own unprivileged user, which is nginx (RHEL-based systems) or www-data (Debian-based systems).

We must connect things up so that WEBSERVER-USER can read files that belong to the PHP-FPM-GROUP This will allow us to control what WEBSERVER-USER can read or not, via group chmod permission bit.

Granting additional group permissions to the “nginx/www-data” user can potentially introduce security risks due to the principle of least privilege. Your PHP-FPM-USER should never have sudo privileges, even if it’s not listed in the sudoer list, as this can still pose security drawbacks.

Therefore, we will set the website content’s group permission to “g=rX” so that “nginx/www-data” can read all files and traverse all directories, but not write to them.

usermod -a -G PHP-FPM-GROUP WEBSERVER-USER

chown -R PHP-FPM-USER:PHP-FPM-GROUP /home/websiteuser/websitefiles

chmod -R u=rwX,g=rX,o= /home/websiteuser/websitefiles

1. This reads as: add WEBSERVER-USER (nginx/www-data) to PHP-FPM-GROUP (websiteuser group).
2. Here is a simple rule: all the files should be owned by the PHP-FPM-USER and the PHP-FPM-GROUP:
3. This translates to the following:

• • PHP-FPM-USER can read, write all files, and read all directories
  • PHP-FPM-GROUP (meantime WEBSERVER-USER) can read all files and traverse all directories, but not write
  • All other users cannot read or write anything

../fpm-php/fpm.d/websiteuser.conf

[websiteuser.com]
user = PHP-FPM-USER
group = PHP-FPM-GROUP
listen.owner = WEBSERVER-USER
listen.group = WEBSERVER-GROUP
listen.mode = 0660
listen = /run/php/php7.4-fpm.sock

Also you can check great more in depth tutorial from here linuxbabe