WooCommerce : Add custom Metabox to admin order page

Question

I am currently successfully adding a field to my WooCommerce product pages which is showing the value:

• in the cart (front end),
• on checkout page (fron

Answer 1

UPDATE 2017/11/02 (Works perfectly in Woocommerce 3+)

First I have get everything working has expected, except getting the value for my_field_name in back end "Custom fields" Metabox within Order pages.

Then after a real nightmare, I have found a pretty nice working solution, better than before. In back end you have now a Custom metabox with the custom field my_field_name displaying the right value, like in this screenshot:

---

My code is divided In 2 parts.

1) The backend Metabox in Order pages, with an editable field showing the correct value coming from a custom field on the product pages (in front end):

// Adding Meta container admin shop_order pages
add_action( 'add_meta_boxes', 'mv_add_meta_boxes' );
if ( ! function_exists( 'mv_add_meta_boxes' ) )
{
    function mv_add_meta_boxes()
    {
        add_meta_box( 'mv_other_fields', __('My Field','woocommerce'), 'mv_add_other_fields_for_packaging', 'shop_order', 'side', 'core' );
    }
}

// Adding Meta field in the meta container admin shop_order pages
if ( ! function_exists( 'mv_add_other_fields_for_packaging' ) )
{
    function mv_add_other_fields_for_packaging()
    {
        global $post;

        $meta_field_data = get_post_meta( $post->ID, '_my_field_slug', true ) ? get_post_meta( $post->ID, '_my_field_slug', true ) : '';

        echo '
        

            
';

    }
}

// Save the data of the Meta field
add_action( 'save_post', 'mv_save_wc_order_other_fields', 10, 1 );
if ( ! function_exists( 'mv_save_wc_order_other_fields' ) )
{

    function mv_save_wc_order_other_fields( $post_id ) {

        // We need to verify this with the proper authorization (security stuff).

        // Check if our nonce is set.
        if ( ! isset( $_POST[ 'mv_other_meta_field_nonce' ] ) ) {
            return $post_id;
        }
        $nonce = $_REQUEST[ 'mv_other_meta_field_nonce' ];

        //Verify that the nonce is valid.
        if ( ! wp_verify_nonce( $nonce ) ) {
            return $post_id;
        }

        // If this is an autosave, our form has not been submitted, so we don't want to do anything.
        if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
            return $post_id;
        }

        // Check the user's permissions.
        if ( 'page' == $_POST[ 'post_type' ] ) {

            if ( ! current_user_can( 'edit_page', $post_id ) ) {
                return $post_id;
            }
        } else {

            if ( ! current_user_can( 'edit_post', $post_id ) ) {
                return $post_id;
            }
        }
        // --- Its safe for us to save the data ! --- //

        // Sanitize user input  and update the meta field in the database.
        update_post_meta( $post_id, '_my_field_slug', $_POST[ 'my_field_name' ] );
    }
}

---

2) Front end / Back end:

• The product page custom field (front end).
• Displaying this data on cart, checkout pages and thank you order (front end).
• Displaying data on order page (back end)

// Add the field to the product
add_action('woocommerce_before_add_to_cart_button', 'my_custom_product_field');
function my_custom_product_field() {
    echo '

        ' . __( 'My Field') . ' 
        
    

';
}

// Store custom field
add_filter( 'woocommerce_add_cart_item_data', 'save_my_custom_product_field', 10, 2 );
function save_my_custom_product_field( $cart_item_data, $product_id ) {
    if( isset( $_REQUEST['my_field_name'] ) ) {
        $cart_item_data[ 'my_field_name' ] = $_REQUEST['my_field_name'];
        // below statement make sure every add to cart action as unique line item
        $cart_item_data['unique_key'] = md5( microtime().rand() );
        WC()->session->set( 'my_order_data', $_REQUEST['my_field_name'] );
    }
    return $cart_item_data;
}

// Add a hidden field with the correct value to the checkout
add_action( 'woocommerce_after_order_notes', 'my_custom_checkout_field' );
function my_custom_checkout_field( $checkout ) {
    $value = WC()->session->get( 'my_order_data' );
    echo '

            
    
';
}

// Save the order meta with hidden field value
add_action( 'woocommerce_checkout_update_order_meta', 'my_custom_checkout_field_update_order_meta' );
function my_custom_checkout_field_update_order_meta( $order_id ) {
    if ( ! empty( $_POST['my_field_name'] ) ) {
        update_post_meta( $order_id, '_my_field_slug', $_POST['my_field_name'] );
    }
}

// Display field value on the order edit page (not in custom fields metabox)
add_action( 'woocommerce_admin_order_data_after_billing_address', 'my_custom_checkout_field_display_admin_order_meta', 10, 1 );
function my_custom_checkout_field_display_admin_order_meta($order){
    $my_custom_field = get_post_meta( $order->id, '_my_field_slug', true );
    if ( ! empty( $my_custom_field ) ) {
        echo '
'. __("My Field", "woocommerce").': ' . get_post_meta( $order->id, '_my_field_slug', true ) . '
';
    }
}

// Render meta on cart and checkout
add_filter( 'woocommerce_get_item_data', 'render_meta_on_cart_and_checkout', 10, 2 );
function render_meta_on_cart_and_checkout( $cart_data, $cart_item = null ) {
    $custom_items = array();
    if( !empty( $cart_data ) ) $custom_items = $cart_data;

    if( isset( $cart_item['my_field_name'] ) )
        $custom_items[] = array( "name" => 'My Field', "value" => $cart_item['my_field_name'] );

    return $custom_items;
}

// Add the information as meta data so that it can be seen as part of the order
add_action('woocommerce_add_order_item_meta','add_values_to_order_item_meta', 10, 3 );
function add_values_to_order_item_meta( $item_id, $cart_item, $cart_item_key ) {
    // lets add the meta data to the order (with a label as key slug)
    if( ! empty( $cart_item['my_field_name'] ) )
        wc_add_order_item_meta($item_id, __('My field label name'), $cart_item['my_field_name'], true);
}

Everything is working as expected now.