Add and save custom meta data to fees in WooCommerce

Question

I'm adding a custom fees to WC with WC()->cart->add_fee() method.

My problem is that I'd like to add metadata to that fee item too. Preferably same time I'm adding the actual fee.

Apparently the WC_Order_Item_Fee Object is generated in the order creation only, so there seems to be no way to add FeeItem-specific metadata to custom fees.

Of course I could save this meta to session, but because add_fee doesn't return any identifier I have no idea which custom fee is actually which.

Any ideas how to solve this issue?

This is the code I use to add Fees:

add_filter('woocommerce_cart_calculate_fees', function (){
    foreach( FeeChecker::getFees() as $fee )
    {
        $cart->add_fee("Added fee: ". $fee, 10 , true, $tax_class);
    }
}

Answer 1

Note: In your code the $cart argument is missing from the hooked function and it's an action hook, but not a filter hook.

The WC_Cart method add_fee() doesn't allow to add custom meta data, so you will need to add it before on add_to_cart event or in WC_Session.

You can add custom meta data to WC_Order_Item_Fee when order is submitted using the following code example (using WC_Session to set and get the custom meta data in here):

// Add a custom cart fee
add_action( 'woocommerce_cart_calculate_fees', 'adding_cart_fees', 10, 1 );
function adding_cart_fees( $cart ){
    $cart->add_fee(__("Added fee"), 10, true, '');
}

// Set Fee custom meta data in WC_Session
add_action( 'woocommerce_calculate_totals', 'calculate_totals_for_fees_meta_data', 10, 1 );
function calculate_totals_for_fees_meta_data( $cart ){
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    $fees_meta = WC()->session->get('fees_meta');
    $update    = false;

    // Loop through applied fees
    foreach( $cart->get_fees() as $fee_key => $fee ) {
        // Set the fee in the fee custom meta data array
        if( ! isset($fees_meta[$fee_key]) ){
            $fees_meta[$fee_key] = 'some value';
            $update = true;
        }
    }
    // If any fee meta data doesn't exist yet, we update the WC_Session custom meta data array
    if ( $update ) {
        WC()->session->set('fees_meta', $fees_meta);
    }
}

// Save fee custom meta data to WC_Order_Item_Fee.
add_action( 'woocommerce_checkout_create_order_fee_item', 'save_custom_met_data_to_fee_order_items', 10, 4 );
function save_custom_met_data_to_fee_order_items( $item, $fee_key, $fee, $order ) {
    // Get fee meta data from WC_Session
    $fees_meta = WC()->session->get('fees_meta');
    // If fee custom meta data exist, save it to fee order item
    if ( isset($fees_meta[$fee_key]) ) {
        $item->update_meta_data( 'custom_key', $fees_meta[$fee_key] );
    }
}

// Remove Fee meta data from WC_Session.
add_action( 'woocommerce_checkout_create_order', 'remove_fee_custom_met_data_from_wc_session', 10, 2 );
function remove_fee_custom_met_data_from_wc_session( $order, $data ) {
    $fees_meta = WC()->session->__unset('fees_meta');
}

Code goes in function.php file of your active child theme (or active theme). Tested and works.

The custom meta data is saved to WC_Order_Item_Fee and you can get it using something like:

// Get an instance of the WC_Order Object (if needed)
$order = wc_get_order( $order_id );

// loop through fee order items
foreach ( $order->get_items('fee') as $fee_key => $item ) {
    // Get the fee custom meta data
    $fee_custom_meta = $item->get_meta('custom_key');

    if ( $fee_custom_meta ) {
        // Display the custom meta data value
        echo '<p>' . $fee_custom_meta . '</p>';
    }
}

Answer 2

A somewhat hacky way is to use the ID field of the fee item to link to data stored somewhere else.

$args = array(
    'id'        => $data_id,
    'name'      => $name,
    'amount'    => (float) $amount,
    'taxable'   => false,
    'tax_class' => '',
);
$cart->fees_api()->add_fee( $args );

Later you can use the hook woocommerce_checkout_create_order_fee_item to fetch the data and populate the order item fee. In my case:

add_action( 'woocommerce_checkout_create_order_fee_item', array( $this, 'create_order_fee_item' ), 20, 4 );
public function create_order_fee_item( $item, $fee_key, $fee, $order ) {
    $item->add_meta_data( 'product_id', $fee_key, true );
}

Answer 3

It seems I overlooked WC_Cart->fees_api

In there I have method that actually returns the created Fee so I know the exact Fee in woocommerce_checkout_create_order_fee_item action

Edit: This code was originally mostly done by LoicTheAztec. I edited it to fit my particular use case and posted it as solution. Unfortunatelly he deleted his post which could have been beneficial to others.

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

    //Make sure it's the right payment method
    if( WC()->session->chosen_payment_method == "cod"){

        $tax_class = '';
        $amount = 5;

        $session_data = [];
        foreach(  $cart->get_shipping_packages() as $package)
        {
            $fee = $cart->fees_api()->add_fee(

                array(
                    'name'      => "Additional cost: ".$package['custom_data'],
                    'amount'    => (float) $amount,
                    'taxable'   => true,
                    'tax_class' => $tax_class,
                )
            );

            $session_data [ $fee->id ] = $package['custom_data'];
        }

        WC()->session->set('COD_fee_meta', $session_data);

    }

}, 10, 2);

// Save fee custom meta data to WC_Order_Item_Fee.
add_action( 'woocommerce_checkout_create_order_fee_item', function ( $item, $fee_key, $fee, $order ) {
    // Get fee meta data from WC_Session
    $fees_meta = WC()->session->get('COD_fee_meta');

    // If fee custom meta data exist, save it to fee order item
    if ( isset($fees_meta[$fee_key]) ) {
        $item->update_meta_data( '_custom_data', $fees_meta[$fee_key] );
    }

}, 10, 4 );

// Remove Fee meta data from WC_Session.
add_action( 'woocommerce_checkout_create_order', function ( $order, $data ) {
    WC()->session->__unset('COD_fee_meta');
}, 10, 2 );