Empty cart upon page load allowing add to cart in WooCommerce - php

Question

In WooCommerce, I'm trying to create a one-page landing page with a product and checkout.
When the page is loaded I want the cart to empty.
But I want to be able to add to cart, and checkout on the same page.
I want to achieve this only on pages with a specific page-template.
I'm working from Clear Woocommerce Cart on Page Load Even for logged in users answer code.
This is what I have:
?>
<?php
//epmty cart
if (! WC()->cart->is_empty() ) {
WC()->cart->empty_cart( true );
}
<?php
// show add to cart button
echo do_shortcode( '[add_to_cart id='22']');
?>
// allow checkout Even though Cart Is Empty
add_filter( 'woocommerce_checkout_redirect_empty_cart', '__return_false' );
add_filter( 'woocommerce_checkout_update_order_review_expired', '__return_false' );
?>
<?php
echo do_shortcode( '[woocommerce_checkout' );
?>
The problem I think is that the page refreshes upon add to cart and therefor empties the cart again. How do I make it run only once? or is there a better way to clear the cart?

Answer 1

Update 2
You could try the following code in your template:
$current_product_id = 22; // The product ID
$cart = WC()->cart; // The WC_Cart Object
// When cart is not empty
if ( ! $cart->is_empty() ) {
// Loop through cart items
foreach( $cart->get_cart() as $cart_item_key => $cart_item ) {
// If the cart item is not the current defined product ID
if( $current_product_id != $cart_item['product_id'] ) {
$cart->remove_cart_item( $cart_item_key ); // remove it from cart
}
}
}
// When cart is empty
else {
// allow checkout Event
add_filter( 'woocommerce_checkout_redirect_empty_cart', '__return_false' );
add_filter( 'woocommerce_checkout_update_order_review_expired', '__return_false' );
}
// show add to cart button
echo do_shortcode( "[add_to_cart id='22']");
// show Checkout
echo do_shortcode( "[woocommerce_checkout]" );