WooCommerce REST API Performance Optimization

Introduction

Optimizing WooCommerce REST API performance is crucial for headless implementations and custom integrations. Here’s how to make your API endpoints faster and more efficient.

Key Optimization Strategies

1. Custom Endpoint Optimization

function register_optimized_endpoints() {
    register_rest_route('wc/v3', '/optimized-products', [
        'methods' => 'GET',
        'callback' => 'get_optimized_products',
        'permission_callback' => function() {
            return current_user_can('manage_woocommerce');
        }
    ]);
}

function get_optimized_products() {
    global $wpdb;
    
    // Direct SQL for better performance
    $results = $wpdb->get_results("
        SELECT p.ID, p.post_title, pm.meta_value as price 
        FROM {$wpdb->posts} p 
        LEFT JOIN {$wpdb->postmeta} pm ON p.ID = pm.post_id 
        WHERE p.post_type = 'product' 
        AND p.post_status = 'publish' 
        AND pm.meta_key = '_price'
    ");
    
    return new WP_REST_Response($results, 200);
}

2. Response Optimization

function optimize_api_response($response, $handler, $request) {
    // Remove unnecessary data
    if (isset($response->data)) {
        unset($response->data['_links']);
        unset($response->data['_embedded']);
    }
    
    // Add cache headers
    $response->header('Cache-Control', 'public, max-age=3600');
    
    return $response;
}

add_filter('rest_post_dispatch', 'optimize_api_response', 10, 3);

3. Query Optimization

function optimize_product_queries($args, $request) {
    // Optimize query arguments
    $args['update_post_meta_cache'] = false;
    $args['update_post_term_cache'] = false;
    
    if (!empty($request['fields'])) {
        $args['fields'] = explode(',', $request['fields']);
    }
    
    return $args;
}

add_filter('woocommerce_rest_product_query', 'optimize_product_queries', 10, 2);

Best Practices

1. Pagination

   function implement_cursor_pagination($args, $request) {
       if (isset($request['after'])) {
           $args['post__in'] = get_posts_after_cursor($request['after']);
       }
       return $args;
   }
   
   function get_posts_after_cursor($cursor) {
       global $wpdb;
       return $wpdb->get_col($wpdb->prepare("
           SELECT ID FROM {$wpdb->posts} 
           WHERE post_type = 'product' 
           AND ID > %d 
           ORDER BY ID ASC 
           LIMIT 100
       ", $cursor));
   }

2. Caching

   function cache_api_response($response, $handler, $request) {
       $cache_key = 'wc_api_' . md5($request->get_route() . serialize($request->get_params()));
       
       $cached = wp_cache_get($cache_key);
       if (false !== $cached) {
           return $cached;
       }
       
       wp_cache_set($cache_key, $response, '', 3600);
       return $response;
   }

3. Field Selection

   function filter_response_fields($response, $post, $request) {
       if (empty($request['fields'])) {
           return $response;
       }
       
       $fields = explode(',', $request['fields']);
       $data = array_intersect_key($response->data, array_flip($fields));
       
       return new WP_REST_Response($data, 200);
   }

Implementation Example

add_action('rest_api_init', function() {
    register_optimized_endpoints();
    
    // Add filters
    add_filter('woocommerce_rest_product_query', 'optimize_product_queries', 10, 2);
    add_filter('woocommerce_rest_prepare_product', 'filter_response_fields', 10, 3);
    
    // Add caching
    add_filter('rest_post_dispatch', 'cache_api_response', 10, 3);
});

Monitoring and Testing

1. Performance Metrics

   function log_api_performance($response, $handler, $request) {
       $start_time = defined('REST_REQUEST_START_TIME') ? REST_REQUEST_START_TIME : 0;
       $execution_time = microtime(true) - $start_time;
       
       error_log(sprintf(
           'API Request: %s, Time: %f seconds',
           $request->get_route(),
           $execution_time
       ));
       
       return $response;
   }

Conclusion

Optimizing your WooCommerce REST API is crucial for maintaining performance as your store grows. These strategies will help you build faster, more efficient API endpoints that can handle high traffic loads while maintaining responsiveness.