Filtering out shipping method in WooCommerce [duplicate]

Question

I'd like to force a specific shipping method when a condition is met in the cart (in my case the presence of some specific items), i.e to disable all methods except the specific one.

Thank you

Answer 1

add_filter('woocommerce_package_rates', 'force_shipping_for_specific_item', 100, 2);

function force_shipping_for_specific_item($rates, $package) {

    $product_id = 1631819031; // specific item id
    $shipping_method_id = 'free_shipping'; // specific shipping method
    foreach ($package['contents'] as $cart_item) {
        if (isset($cart_item['data']) && $product_id == $cart_item['data']->get_id()) {
            $found = true;
            break; // Stop the loop
        }
    }

    if (!( isset($found) && $found ))
        return $rates; // Exit

    $allowed_shipping_method = array();
    foreach ($rates as $rate_id => $rate) {
        if ($shipping_method_id === $rate->method_id) {
            $allowed_shipping_method[$rate_id] = $rate;
            break;
        }
    }
    return !empty($allowed_shipping_method) ? $allowed_shipping_method : $rates;
}