WooCommerce product add-ons are custom input fields that show on the single product page. They’re called “add-ons” as you can add a product personalization or an upsell (at a cost of course).
For example, you can display a text input to print something on the product. Or radio buttons to select different kinds of product upgrades. Or a checkbox to upsell gift wrapping.
Either way, and of course, there are plugins for that. But first, I want to give you a tutorial to code this by yourself (case study: global custom input text field and no surcharge), so that you can learn something new. Enjoy!
Add a custom input field to each product @ WooCommerce Single Product page
PHP Snippet: Show Custom Input Field @ WooCommerce Single Product Page
/**
* @snippet Add input field to products - WooCommerce
* @how-to Get tutoraspire.com FREE
* @author Tutor Aspire
* @compatible WooCommerce 3.9
* @donate $9 https://tutoraspire.com
*/
// -----------------------------------------
// 1. Show custom input field above Add to Cart
add_action( 'woocommerce_before_add_to_cart_button', 'tutoraspire_product_add_on', 9 );
function tutoraspire_product_add_on() {
$value = isset( $_POST['custom_text_add_on'] ) ? sanitize_text_field( $_POST['custom_text_add_on'] ) : '';
echo '
';
}
// -----------------------------------------
// 2. Throw error if custom input field empty
add_filter( 'woocommerce_add_to_cart_validation', 'tutoraspire_product_add_on_validation', 10, 3 );
function tutoraspire_product_add_on_validation( $passed, $product_id, $qty ){
if( isset( $_POST['custom_text_add_on'] ) && sanitize_text_field( $_POST['custom_text_add_on'] ) == '' ) {
wc_add_notice( 'Custom Text Add-On is a required field', 'error' );
$passed = false;
}
return $passed;
}
// -----------------------------------------
// 3. Save custom input field value into cart item data
add_filter( 'woocommerce_add_cart_item_data', 'tutoraspire_product_add_on_cart_item_data', 10, 2 );
function tutoraspire_product_add_on_cart_item_data( $cart_item, $product_id ){
if( isset( $_POST['custom_text_add_on'] ) ) {
$cart_item['custom_text_add_on'] = sanitize_text_field( $_POST['custom_text_add_on'] );
}
return $cart_item;
}
// -----------------------------------------
// 4. Display custom input field value @ Cart
add_filter( 'woocommerce_get_item_data', 'tutoraspire_product_add_on_display_cart', 10, 2 );
function tutoraspire_product_add_on_display_cart( $data, $cart_item ) {
if ( isset( $cart_item['custom_text_add_on'] ) ){
$data[] = array(
'name' => 'Custom Text Add-On',
'value' => sanitize_text_field( $cart_item['custom_text_add_on'] )
);
}
return $data;
}
// -----------------------------------------
// 5. Save custom input field value into order item meta
add_action( 'woocommerce_add_order_item_meta', 'tutoraspire_product_add_on_order_item_meta', 10, 2 );
function tutoraspire_product_add_on_order_item_meta( $item_id, $values ) {
if ( ! empty( $values['custom_text_add_on'] ) ) {
wc_add_order_item_meta( $item_id, 'Custom Text Add-On', $values['custom_text_add_on'], true );
}
}
// -----------------------------------------
// 6. Display custom input field value into order table
add_filter( 'woocommerce_order_item_product', 'tutoraspire_product_add_on_display_order', 10, 2 );
function tutoraspire_product_add_on_display_order( $cart_item, $order_item ){
if( isset( $order_item['custom_text_add_on'] ) ){
$cart_item['custom_text_add_on'] = $order_item['custom_text_add_on'];
}
return $cart_item;
}
// -----------------------------------------
// 7. Display custom input field value into order emails
add_filter( 'woocommerce_email_order_meta_fields', 'tutoraspire_product_add_on_display_emails' );
function tutoraspire_product_add_on_display_emails( $fields ) {
$fields['custom_text_add_on'] = 'Custom Text Add-On';
return $fields;
}
