woocommerce custom checkout field to add fee to order ajax - php

Question

I'm trying to ad a custom fee to the order total upon checkout.
I've added a checkbox within woocommerce
add_action( 'woocommerce_after_checkout_billing_form', 'add_box_option_to_checkout' );
function add_box_option_to_checkout( $checkout ) {
echo '<div id="message_fields">';
woocommerce_form_field( 'add_gift_box', array(
'type' => 'checkbox',
'class' => array('add_gift_box form-row-wide'),
'label' => __('Ilość pudełek ozdobnych - 25 PLN/szt'),
'placeholder' => __(''),
), $checkout->get_value( 'add_gift_box' ));
}
Included a custom js file which schould handle the event
jQuery( document ).ready(function( $ ) {
$('#add_gift_box').click(function(){
var data = {
action: 'woocommerce_add_gift_box',
state: '200',
};
jQuery.ajax({
type: 'POST',
url: wc_checkout_params.ajax_url,
data: data,
success: function (code) {
console.log(code);
jQuery('body').trigger('update_checkout');
},
dataType: 'html'
});
});
});
And a php fee handling function
function woo_add_cart_fee( $data ){
if ( is_admin() && ! defined( 'DOING_AJAX' ) || ! $_POST ) return;
$extracost = 0;
if (isset($_POST['state'])) {
$extracost = intval($_POST['state']);
}
WC()->cart->add_fee( 'Ozdobne pudełka:', $extracost );
}
add_action( 'woocommerce_cart_calculate_fees', 'woo_add_cart_fee' );
add_action('wp_ajax_woocommerce_add_gift_box', 'woo_add_cart_fee', 10);
add_action('wp_ajax_nopriv_woocommerce_add_gift_box', 'woo_add_cart_fee', 10);
For some reasons the value of $_POST['state'] isn't added, the function works when I give a hard coded value, I've tried many option but cant get this to work.
I've seen similar posts but none of them had the answer.

Answer 1

The post data is sent by the AJAX functions in 'post_data', serialized. So to get the value of your checkbox, you only need to parse_str() this!
parse_str( $_POST['post_data'], $post_data );
then you can get your 'add_gift_box' option from $post_data['add_gift_box']. Note that upon order completion, this 'post_data' element is not available anymore and everything is in $_POST.
Complete example, based on your code:
1) adding the checkbox to the checkout
add_action( 'woocommerce_after_checkout_billing_form', 'add_box_option_to_checkout' );
function add_box_option_to_checkout( $checkout ) {
echo '<div id="message_fields">';
woocommerce_form_field( 'add_gift_box', array(
'type' => 'checkbox',
'class' => array('add_gift_box form-row-wide'),
'label' => __('Ilość pudełek ozdobnych - 25 PLN/szt'),
'placeholder' => __(''),
), $checkout->get_value( 'add_gift_box' ));
echo '</div>';
}
2) script to update cart when checkbox clicked (no need for extra AJAX requests!)
add_action( 'wp_footer', 'woocommerce_add_gift_box' );
function woocommerce_add_gift_box() {
if (is_checkout()) {
?>
<script type="text/javascript">
jQuery( document ).ready(function( $ ) {
$('#add_gift_box').click(function(){
jQuery('body').trigger('update_checkout');
});
});
</script>
<?php
}
}
3) action to add the fee
add_action( 'woocommerce_cart_calculate_fees', 'woo_add_cart_fee' );
function woo_add_cart_fee( $cart ){
if ( ! $_POST || ( is_admin() && ! is_ajax() ) ) {
return;
}
if ( isset( $_POST['post_data'] ) ) {
parse_str( $_POST['post_data'], $post_data );
} else {
$post_data = $_POST; // fallback for final checkout (non-ajax)
}
if (isset($post_data['add_gift_box'])) {
$extracost = 25; // not sure why you used intval($_POST['state']) ?
WC()->cart->add_fee( 'Ozdobne pudełka:', $extracost );
}
}

Answer 2

This is awesome!! Thanks a lot. I've changed it a little bit to add a percentage instead. I know this is not a better answer but I have no reputation to push your answer up. For whoever was stuck like me..
add_action( 'woocommerce_cart_calculate_fees', 'woo_add_cart_fee' ); function woo_add_cart_fee( $cart ){
global $woocommerce;
if ( ! $_POST || ( is_admin() && ! is_ajax() ) ) {
return;
}
if ( isset( $_POST['post_data'] ) ) {
parse_str( $_POST['post_data'], $post_data );
} else {
$post_data = $_POST; // fallback for final checkout (non-ajax)
}
if (isset($post_data['add_gift_box'])) {
$percentage = 0.01;
$surcharge = ( $woocommerce->cart->cart_contents_total + $woocommerce->cart->shipping_total ) * $percentage;
$woocommerce->cart->add_fee( 'Surcharge', $surcharge, true, '' );
}
}