WooCommerce Development

E-commerce development with WooCommerce for WordPress.

Essential Hooks

Product Hooks

// Modify product price display add_filter( 'woocommerce_get_price_html', function( $price_html, $product ) { if ( $product->is_on_sale() ) { $price_html .= '<span class="sale-badge">Sale!</span>'; } return $price_html; }, 10, 2 );

// Add custom field to product add_action( 'woocommerce_product_options_general_product_data', function() { woocommerce_wp_text_input( array( 'id' => '_custom_field', 'label' => __( 'Custom Field', 'textdomain' ), 'description' => __( 'Enter custom value', 'textdomain' ), 'desc_tip' => true, ) ); } );

// Save custom field add_action( 'woocommerce_process_product_meta', function( $post_id ) { $value = isset( $_POST['_custom_field'] ) ? sanitize_text_field( $_POST['_custom_field'] ) : ''; update_post_meta( $post_id, '_custom_field', $value ); } );

Cart Hooks

// Add fee to cart add_action( 'woocommerce_cart_calculate_fees', function( $cart ) { if ( is_admin() && ! defined( 'DOING_AJAX' ) ) { return; }

$subtotal = $cart->get_subtotal();

// Add handling fee for orders under $50
if ( $subtotal < 50 ) {
    $cart->add_fee( __( 'Handling Fee', 'textdomain' ), 5.00 );
}

} );

// Validate cart items add_action( 'woocommerce_check_cart_items', function() { $cart = WC()->cart;

foreach ( $cart->get_cart() as $cart_item_key => $cart_item ) {
    $product = $cart_item['data'];

    // Check stock or custom validation
    if ( ! $product->is_in_stock() ) {
        wc_add_notice(
            sprintf( __( '%s is out of stock.', 'textdomain' ), $product->get_name() ),
            'error'
        );
    }
}

} );

// Modify cart item data add_filter( 'woocommerce_add_cart_item_data', function( $cart_item_data, $product_id, $variation_id ) { if ( isset( $_POST['custom_option'] ) ) { $cart_item_data['custom_option'] = sanitize_text_field( $_POST['custom_option'] ); } return $cart_item_data; }, 10, 3 );

Checkout Hooks

// Add custom checkout field add_action( 'woocommerce_after_order_notes', function( $checkout ) { woocommerce_form_field( 'delivery_date', array( 'type' => 'date', 'class' => array( 'form-row-wide' ), 'label' => __( 'Preferred Delivery Date', 'textdomain' ), 'required' => true, ), $checkout->get_value( 'delivery_date' ) ); } );

// Validate custom field add_action( 'woocommerce_checkout_process', function() { if ( empty( $_POST['delivery_date'] ) ) { wc_add_notice( __( 'Please select a delivery date.', 'textdomain' ), 'error' ); } } );

// Save custom field to order add_action( 'woocommerce_checkout_update_order_meta', function( $order_id ) { if ( ! empty( $_POST['delivery_date'] ) ) { update_post_meta( $order_id, '_delivery_date', sanitize_text_field( $_POST['delivery_date'] ) ); } } );

Order Hooks

// After order is completed add_action( 'woocommerce_order_status_completed', function( $order_id ) { $order = wc_get_order( $order_id );

// Send to external system
$data = array(
    'order_id'    => $order_id,
    'customer'    => $order->get_billing_email(),
    'total'       => $order->get_total(),
    'items'       => array(),
);

foreach ( $order->get_items() as $item ) {
    $data['items'][] = array(
        'product_id' => $item->get_product_id(),
        'quantity'   => $item->get_quantity(),
        'total'      => $item->get_total(),
    );
}

// Send to webhook
wp_remote_post( 'https://api.example.com/orders', array(
    'body'    => wp_json_encode( $data ),
    'headers' => array( 'Content-Type' => 'application/json' ),
) );

} );

// Order status change add_action( 'woocommerce_order_status_changed', function( $order_id, $old_status, $new_status, $order ) { // Custom notification logic }, 10, 4 );

Custom Product Types

// Register custom product type add_action( 'init', function() { class WC_Product_Subscription extends WC_Product { public function __construct( $product = 0 ) { $this->product_type = 'subscription'; parent::__construct( $product ); }

    public function get_type() {
        return 'subscription';
    }

    // Custom methods
    public function get_subscription_period() {
        return $this->get_meta( '_subscription_period' );
    }
}

} );

// Add to product type selector add_filter( 'product_type_selector', function( $types ) { $types['subscription'] = __( 'Subscription', 'textdomain' ); return $types; } );

// Show price fields add_action( 'woocommerce_product_options_general_product_data', function() { global $product_object;

if ( 'subscription' === $product_object->get_type() ) {
    woocommerce_wp_select( array(
        'id'      => '_subscription_period',
        'label'   => __( 'Billing Period', 'textdomain' ),
        'options' => array(
            'month' => __( 'Monthly', 'textdomain' ),
            'year'  => __( 'Yearly', 'textdomain' ),
        ),
    ) );
}

} );

Payment Gateways

class WC_Gateway_Custom extends WC_Payment_Gateway { public function __construct() { $this->id = 'custom_gateway'; $this->icon = ''; $this->has_fields = true; $this->method_title = __( 'Custom Gateway', 'textdomain' ); $this->method_description = __( 'Custom payment gateway.', 'textdomain' );

    $this->supports = array(
        'products',
        'refunds',
    );

    $this->init_form_fields();
    $this->init_settings();

    $this->title       = $this->get_option( 'title' );
    $this->description = $this->get_option( 'description' );
    $this->enabled     = $this->get_option( 'enabled' );
    $this->api_key     = $this->get_option( 'api_key' );

    add_action( 'woocommerce_update_options_payment_gateways_' . $this->id, array( $this, 'process_admin_options' ) );
}

public function init_form_fields() {
    $this->form_fields = array(
        'enabled' => array(
            'title'   => __( 'Enable/Disable', 'textdomain' ),
            'type'    => 'checkbox',
            'label'   => __( 'Enable Custom Gateway', 'textdomain' ),
            'default' => 'no',
        ),
        'api_key' => array(
            'title'       => __( 'API Key', 'textdomain' ),
            'type'        => 'password',
            'description' => __( 'Enter your API key', 'textdomain' ),
        ),
    );
}

public function process_payment( $order_id ) {
    $order = wc_get_order( $order_id );

    // Process payment with external API
    $response = wp_remote_post( 'https://api.payment.com/charge', array(
        'body' => array(
            'amount'   => $order->get_total(),
            'currency' => $order->get_currency(),
            'token'    => sanitize_text_field( $_POST['payment_token'] ),
        ),
        'headers' => array(
            'Authorization' => 'Bearer ' . $this->api_key,
        ),
    ) );

    $body = json_decode( wp_remote_retrieve_body( $response ), true );

    if ( isset( $body['success'] ) && $body['success'] ) {
        $order->payment_complete( $body['transaction_id'] );
        WC()->cart->empty_cart();

        return array(
            'result'   => 'success',
            'redirect' => $this->get_return_url( $order ),
        );
    } else {
        wc_add_notice( $body['error'] ?? __( 'Payment failed', 'textdomain' ), 'error' );
        return array( 'result' => 'fail' );
    }
}

public function process_refund( $order_id, $amount = null, $reason = '' ) {
    $order = wc_get_order( $order_id );

    $response = wp_remote_post( 'https://api.payment.com/refund', array(
        'body' => array(
            'transaction_id' => $order->get_transaction_id(),
            'amount'         => $amount,
        ),
    ) );

    $body = json_decode( wp_remote_retrieve_body( $response ), true );

    if ( isset( $body['success'] ) && $body['success'] ) {
        return true;
    }

    return new WP_Error( 'refund_failed', $body['error'] ?? 'Refund failed' );
}

}

// Register gateway add_filter( 'woocommerce_payment_gateways', function( $gateways ) { $gateways[] = 'WC_Gateway_Custom'; return $gateways; } );

REST API

Custom Endpoints

add_action( 'rest_api_init', function() { register_rest_route( 'custom/v1', '/products/featured', array( 'methods' => 'GET', 'callback' => 'get_featured_products', 'permission_callback' => '__return_true', ) ); } );

function get_featured_products( WP_REST_Request $request ) { $args = array( 'post_type' => 'product', 'posts_per_page' => $request->get_param( 'per_page' ) ?: 10, 'tax_query' => array( array( 'taxonomy' => 'product_visibility', 'field' => 'name', 'terms' => 'featured', ), ), );

$products = wc_get_products( $args );

return array_map( function( $product ) {
    return array(
        'id'         => $product->get_id(),
        'name'       => $product->get_name(),
        'price'      => $product->get_price(),
        'image'      => wp_get_attachment_url( $product->get_image_id() ),
        'permalink'  => $product->get_permalink(),
    );
}, $products );

}

Extend Existing Endpoints

// Add custom field to product API response add_filter( 'woocommerce_rest_prepare_product_object', function( $response, $product, $request ) { $response->data['custom_field'] = $product->get_meta( '_custom_field' ); $response->data['stock_status_label'] = $product->is_in_stock() ? 'Available' : 'Out of Stock'; return $response; }, 10, 3 );

// Allow updating custom field via API add_action( 'woocommerce_rest_insert_product_object', function( $product, $request, $creating ) { if ( isset( $request['custom_field'] ) ) { $product->update_meta_data( '_custom_field', sanitize_text_field( $request['custom_field'] ) ); $product->save(); } }, 10, 3 );

Performance

Query Optimization

// Disable unnecessary features add_filter( 'woocommerce_background_image_regeneration', '__return_false' ); add_filter( 'woocommerce_enable_nocache_headers', '__return_false' );

// Limit product queries add_filter( 'loop_shop_per_page', function() { return 24; // Products per page } );

// Cache expensive queries function get_best_sellers( $limit = 5 ) { $cache_key = 'wc_best_sellers_' . $limit; $products = get_transient( $cache_key );

if ( false === $products ) {
    global $wpdb;

    $products = $wpdb->get_results( $wpdb->prepare( "
        SELECT p.ID, p.post_title, SUM(oim.meta_value) as total_sales
        FROM {$wpdb->posts} p
        INNER JOIN {$wpdb->prefix}woocommerce_order_items oi ON p.ID = oi.order_item_name
        INNER JOIN {$wpdb->prefix}woocommerce_order_itemmeta oim ON oi.order_item_id = oim.order_item_id
        WHERE oim.meta_key = '_qty'
        AND p.post_type = 'product'
        AND p.post_status = 'publish'
        GROUP BY p.ID
        ORDER BY total_sales DESC
        LIMIT %d
    ", $limit ) );

    set_transient( $cache_key, $products, HOUR_IN_SECONDS );
}

return $products;

}

// Clear cache on order add_action( 'woocommerce_order_status_completed', function() { delete_transient( 'wc_best_sellers_5' ); } );

AJAX Cart

// Update cart via AJAX add_action( 'wp_ajax_update_cart_item', 'ajax_update_cart_item' ); add_action( 'wp_ajax_nopriv_update_cart_item', 'ajax_update_cart_item' );

function ajax_update_cart_item() { check_ajax_referer( 'wc_cart_nonce', 'nonce' );

$cart_item_key = sanitize_text_field( $_POST['cart_item_key'] );
$quantity      = absint( $_POST['quantity'] );

if ( $quantity > 0 ) {
    WC()->cart->set_quantity( $cart_item_key, $quantity );
} else {
    WC()->cart->remove_cart_item( $cart_item_key );
}

WC_AJAX::get_refreshed_fragments();

}

Email Customization

// Add content to order emails add_action( 'woocommerce_email_order_details', function( $order, $sent_to_admin, $plain_text, $email ) { if ( 'customer_completed_order' === $email->id ) { echo '<h2>Thank you for your order!</h2>'; echo '<p>Your order will be shipped within 2-3 business days.</p>'; } }, 5, 4 );

// Custom email class WC_Email_Custom extends WC_Email { public function __construct() { $this->id = 'custom_email'; $this->title = __( 'Custom Email', 'textdomain' ); $this->description = __( 'Custom email notification', 'textdomain' ); $this->template_html = 'emails/custom-email.php'; $this->template_plain = 'emails/plain/custom-email.php';

    parent::__construct();
}

public function trigger( $order_id ) {
    if ( ! $order_id ) return;

    $this->object = wc_get_order( $order_id );
    $this->recipient = $this->object->get_billing_email();

    if ( ! $this->is_enabled() || ! $this->get_recipient() ) return;

    $this->send(
        $this->get_recipient(),
        $this->get_subject(),
        $this->get_content(),
        $this->get_headers(),
        $this->get_attachments()
    );
}

}

add_filter( 'woocommerce_email_classes', function( $emails ) { $emails['WC_Email_Custom'] = new WC_Email_Custom(); return $emails; } );