WooCommerce shipping cost calculated by weight of product - woocommerce

Question

I need to organize a system for calculating shipping on a WooCommerce project. Here's example:
If the product weighs less than 19 kilograms shipping cost: 36$
If the product weighs more than 19 kilograms shipping cost: 300$
Plus, I need to create an additional shipping class (free shipping). So that the administrator of
the store can determine which product to shipping for free.
How I tried to solve this problem:
At first in the WooCommerce -> Settings -> Shipping -> Shipping zones I created new shipping zones (Israel – Shipping by Weight) and in this zone I create three different shipping methods:
Orders Below 19kg (flat_rate:21)
Orders Above 20kg (flat_rate:22)
Free Shipping (flat_rate:24)
Then I placed in the functions.php file this chunk of code:
add_filter( 'woocommerce_package_rates', 'custom_tiered_shipping_rates', 9999, 2 );
function custom_tiered_shipping_rates( $rates, $package ) {
if ( WC()->cart->get_cart_contents_weight() < 19 ) {
if ( isset( $rates['flat_rate:21'] ) ) unset( $rates['flat_rate:22'], $rates['flat_rate:24'] );
} elseif ( WC()->cart->get_cart_contents_weight() > 20 ) {
if ( isset( $rates['flat_rate:21'] ) ) unset( $rates['flat_rate:21'], $rates['flat_rate:24'] );
} else {
if ( isset( $rates['flat_rate:21'] ) ) unset( $rates['flat_rate:21'], $rates['flat_rate:22'] );
}
return $rates;
}
The source of code with the details description I got from here: WooCommerce: Shipping by Weight (Without a Plugin!)
And everything seems to work. Only the free shipping method does not work. When I give a product the free_shipping class. The shipping cost is calculated not by the availability of this class, but by the weight of the product.Please help to fix it. I understand that I have confused something in the conditions. But the more I experiment the more I get confused now.
PS: If there is at least one item with paid shipping in the cart, then even if there is an item with free shipping, the shipping cost should be guided by paid shipping.

Answer 1

Try the following, that will check on cart items if there are only items from "Free shipping" shipping class. If it's the case and if "Free shipping" shipping method is enabled, Free shipping method will be set.
On other cases a Flat rate based on weight will be applied.
Be sure to set the correct shipping class slug, in the code below, for "Free shipping" shipping class.
add_filter( 'woocommerce_package_rates', 'custom_tiered_shipping_rates', 9999, 2 );
function custom_tiered_shipping_rates( $rates, $package ) {
// HERE below set the correct shipping class slug for "Free shipping" items.
$free_shipping_class = 'free-shipping';
$free_shipping_only = true;
$non_free_items_weight = 0;
// Check items shipping class for the current shipping package
foreach( $package['contents'] as $cart_item ) {
// For non "Free shipping items" flag them and get the calculated weight.
if( $cart_item['data']->get_shipping_class() !== $free_shipping_class ) {
$free_shipping_only = false;
$non_free_items_weight += $cart_item['data']->get_weight() * $cart_item['quantity'];
}
}
// Free shipping
if ( $free_shipping_only && isset($rates['flat_rate:24']) ) {
unset($rates['flat_rate:21'], $rates['flat_rate:22']);
}
// Other rates (Flat rates)
else {
if ( $non_free_items_weight < 20 && isset($rates['flat_rate:21']) )
unset( $rates['flat_rate:22'], $rates['flat_rate:24'] );
} elseif ( $non_free_items_weight >= 20 && isset($rates['flat_rate:22']) )
unset( $rates['flat_rate:21'], $rates['flat_rate:24'] );
}
}
return $rates;
}
Code goes in functions.php file of the active child theme (or active theme). Tested and works.
Don't forget to empty your cart to refresh shipping caches.
Now instead of using a "Flat rate" for Free shipping, you should better use WooCommerce "Free shipping" method instead (with no restrictions) and replace flat_rate:24in your code by the correct "Free shipping" method rate ID…