Sprd:getCheckoutUrl

getCheckoutUrl.php

<?php
/**
     * Retrieve Basket Checkout URL
     * Returns the checkout URL for the current basket that will used in the iFrame on shop checkout.
     * @param $basketUrl
     * @param $namespaces
     * @return string
     */
    private function getCheckoutUrl($basketUrl, $namespaces)
    {

        $basketXml =  simplexml_load_file($basketUrl);
        foreach($basketXml->links->link as $link){
            if((string)$link['type'] == 'shopCheckout')
            $checkoutUrl = (string)$link->attributes($namespaces['xlink']);
        }

        return $checkoutUrl;
    }