WooCommerce Caching Strategies That Work with Dynamic Cart Data (woocustomdev.com)

01-nginx-page-cache-cart-exclusions.conf

## nginx.conf — Page cache with WooCommerce cart/session exclusions
## Place inside your server {} block (or FastCGI Cache config)

fastcgi_cache_path /tmp/nginx-cache levels=1:2 keys_zone=WORDPRESS:100m inactive=60m;
fastcgi_cache_key "$scheme$request_method$host$request_uri";

server {
    # ... your existing server config ...

    set $skip_cache 0;

    # Skip cache for POST requests
    if ($request_method = POST) {
        set $skip_cache 1;
    }

    # Skip cache when query string is present
    if ($query_string != "") {
        set $skip_cache 1;
    }

    # Skip cache for WooCommerce dynamic pages
    if ($request_uri ~* "(/cart|/checkout|/my-account|/wc-api|/addons|/store|/shop.*add-to-cart=)") {
        set $skip_cache 1;
    }

    # Skip cache when WooCommerce session cookies are present
    if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|woocommerce_items_in_cart|woocommerce_cart_hash|wp_woocommerce_session") {
        set $skip_cache 1;
    }

    location ~ \.php$ {
        fastcgi_cache            WORDPRESS;
        fastcgi_cache_valid       200 60m;
        fastcgi_cache_bypass     $skip_cache;
        fastcgi_no_cache         $skip_cache;
        add_header X-FastCGI-Cache $upstream_cache_status;

        fastcgi_pass unix:/run/php/php8.2-fpm.sock;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }
}

02-redis-object-cache-config.php

<?php
/**
 * wp-config.php additions — Redis object cache configuration
 * Requires: Redis server + redis PHP extension (or predis) + wp-redis drop-in
 *
 * Install the drop-in:
 *   wp plugin install wp-redis --activate
 *   wp redis enable
 */

// Redis connection settings
define( 'WP_REDIS_HOST', '127.0.0.1' );
define( 'WP_REDIS_PORT', 6379 );
define( 'WP_REDIS_DATABASE', 0 );
define( 'WP_REDIS_TIMEOUT', 1 );
define( 'WP_REDIS_READ_TIMEOUT', 1 );

// Prefix all keys with the site name to support multi-site Redis instances
define( 'WP_REDIS_PREFIX', 'woocustomdev_' );

// Groups that should NEVER be cached in Redis (volatile WooCommerce data)
define( 'WP_REDIS_IGNORED_GROUPS', [
    'counts',
    'plugins',
    'wc_session_id',
    'wc_cart_',
] );

// Selective group flushing: flush only wc_* keys on cart updates
// (requires object-cache.php that supports group-level flushing, e.g., wp-redis 1.7+)
define( 'WP_REDIS_SELECTIVE_FLUSH', true );

03-fragment-cache-transient.php

<?php
/**
 * Fragment caching for WooCommerce — cache expensive partial outputs as transients.
 *
 * Use case: cache a "Featured Products" section that runs 4-5 DB queries,
 * while leaving the mini-cart (dynamic) outside the cached fragment.
 */

/**
 * Output a cached product loop fragment.
 *
 * @param string   $fragment_key  Unique identifier for this fragment.
 * @param callable $callback      The expensive rendering callback.
 * @param int      $expiry        Cache duration in seconds (default 1 hour).
 */
function wcd_fragment_cache( string $fragment_key, callable $callback, int $expiry = HOUR_IN_SECONDS ): void {
    $transient_key = 'wcd_frag_' . md5( $fragment_key );
    $cached        = get_transient( $transient_key );

    if ( false !== $cached ) {
        echo $cached; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
        return;
    }

    ob_start();
    $callback();
    $output = ob_get_clean();

    set_transient( $transient_key, $output, $expiry );
    echo $output; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
}

/**
 * Invalidate a fragment when a product is saved.
 * Hooked to save_post_product so stale fragments are purged immediately.
 */
add_action( 'save_post_product', function ( int $post_id ): void {
    // Bust the featured products fragment whenever any product is updated.
    delete_transient( 'wcd_frag_' . md5( 'featured_products' ) );
} );

// --- Usage example in a theme template ---

wcd_fragment_cache(
    'featured_products',
    function (): void {
        $products = wc_get_products( [
            'featured' => true,
            'limit'    => 8,
            'status'   => 'publish',
        ] );

        foreach ( $products as $product ) {
            echo '<div class="product-card">';
            echo '<a href="' . esc_url( $product->get_permalink() ) . '">';
            echo esc_html( $product->get_name() );
            echo '</a>';
            echo '</div>';
        }
    }
);

04-cart-ajax-no-cache.php

<?php
/**
 * WooCommerce AJAX cart handler — always bypasses page/fragment cache.
 *
 * Pattern: Register an AJAX endpoint that returns fresh cart HTML,
 * then update the DOM via JS. This keeps the rest of the page cached
 * while the cart stays accurate on every request.
 */

/**
 * Register the AJAX action for both logged-in and guest users.
 */
add_action( 'wp_ajax_wcd_get_cart_fragment',        'wcd_get_cart_fragment_handler' );
add_action( 'wp_ajax_nopriv_wcd_get_cart_fragment', 'wcd_get_cart_fragment_handler' );

/**
 * Return JSON with fresh cart HTML and item count.
 * Sets no-cache headers so proxies / CDNs never cache this response.
 */
function wcd_get_cart_fragment_handler(): void {
    // Hard no-cache headers — CDN / Varnish must NOT cache this endpoint.
    nocache_headers();
    header( 'Surrogate-Control: no-store' );

    WC()->cart->calculate_totals();

    ob_start();
    woocommerce_mini_cart();
    $mini_cart_html = ob_get_clean();

    wp_send_json_success( [
        'cart_html'  => $mini_cart_html,
        'cart_count' => WC()->cart->get_cart_contents_count(),
        'cart_total' => WC()->cart->get_cart_total(),
    ] );
}

/**
 * Enqueue the JS that polls for fresh cart data.
 * Uses wp_localize_script to pass nonce + ajaxurl safely.
 */
add_action( 'wp_enqueue_scripts', function (): void {
    wp_enqueue_script(
        'wcd-cart-refresh',
        get_template_directory_uri() . '/assets/js/cart-refresh.js',
        [ 'jquery', 'wc-cart-fragments' ],
        '1.0.0',
        true
    );

    wp_localize_script( 'wcd-cart-refresh', 'wcdCart', [
        'ajaxurl' => admin_url( 'admin-ajax.php' ),
        'action'  => 'wcd_get_cart_fragment',
        'nonce'   => wp_create_nonce( 'wcd_cart_nonce' ),
    ] );
} );

05-cache-invalidation-hooks.php

<?php
/**
 * Targeted cache invalidation for WooCommerce.
 *
 * Instead of flushing everything on every action, these hooks
 * purge only the URLs and object-cache groups that actually changed.
 */

/**
 * Purge the product page cache when stock changes.
 * Works with Nginx FastCGI cache and WP Rocket / LiteSpeed / W3TC.
 */
add_action( 'woocommerce_product_set_stock', function ( WC_Product $product ): void {
    $url = get_permalink( $product->get_id() );

    // WP Rocket
    if ( function_exists( 'rocket_clean_post' ) ) {
        rocket_clean_post( $product->get_id() );
    }

    // LiteSpeed Cache
    if ( class_exists( 'LiteSpeed_Cache_API' ) ) {
        LiteSpeed_Cache_API::purge_post( $product->get_id() );
    }

    // W3 Total Cache
    if ( function_exists( 'w3tc_pgcache_flush_post' ) ) {
        w3tc_pgcache_flush_post( $product->get_id() );
    }

    // Object cache: clear product transients
    wc_delete_product_transients( $product->get_id() );

    // Optional: hit a custom Nginx purge endpoint
    if ( defined( 'WCD_NGINX_PURGE_URL' ) ) {
        wp_remote_get( WCD_NGINX_PURGE_URL . str_replace( home_url(), '', $url ) );
    }
} );

/**
 * Flush shop/category pages when a product status changes
 * (e.g., published → draft drops it from archive listings).
 */
add_action( 'transition_post_status', function ( string $new, string $old, WP_Post $post ): void {
    if ( 'product' !== $post->post_type || $new === $old ) {
        return;
    }

    // WP Rocket: flush the shop archive and all category pages
    if ( function_exists( 'rocket_clean_term' ) ) {
        $terms = get_the_terms( $post->ID, 'product_cat' );
        if ( is_array( $terms ) ) {
            foreach ( $terms as $term ) {
                rocket_clean_term( $term, 'product_cat' );
            }
        }
    }

    // Bust shop page object cache
    wp_cache_delete( 'woocommerce_product_ids', 'woocommerce' );
}, 10, 3 );

/**
 * Clear session-scoped object cache groups after checkout.
 * Prevents stale order totals showing up in My Account for a brief window.
 */
add_action( 'woocommerce_checkout_order_processed', function ( int $order_id ): void {
    wp_cache_delete( 'customer_get_last_order', 'woocommerce' );
    wp_cache_flush_group( 'wc_orders' ); // WordPress 6.1+ / Redis 1.8+
    wc_delete_shop_order_transients( $order_id );
} );