Add a cart fee from an url variable in Woocommerce

Question

With Woocommerce, this website has two types of buttons for products:

Add to shopping bag and
Contact us to order.

When clicked on "Contact us to order" button, visitors get redirected to a contact form in "Contact us to order" page. This contact form is built with Contact form 7 plugin.

For some of the products, the contact form has an exclusive checkbox field where they get to choose the lining. Based on which lining they chose, I am redirecting the visitors to the checkout page with some value passed through the URL.

For example: https://milanshopping.co.uk/checkout/?val=15

And in the functions.php file, I am using the following code:

 add_action( 'woocommerce_cart_calculate_fees','milanshopping_add_lining_fees' ); 
 function milanshopping_add_lining_fees() { 
     if ( is_admin() && ! defined( 'DOING_AJAX' ) )
         return;

    if(isset($_GET['val'])){

        if($_GET['val'] == 15){
            $leather_fee = 15;
        }else{
            $leather_fee = 20;  
        } 

    }

    if($leather_fee != 0 ){
        WC()->cart->add_fee( 'Leather fee', $leather_fee);        
    }    

}

But this fails to add the fee even though the $_GET value is present. I have checked by calling the echo $_GET['val'] and the value is printed.

But if I add the following code outside the if statement,

WC()->cart->add_fee( 'Leather fee', $leather_fee);

it works though fee added is 0 and not the fees I am trying to generate from the $_GET value. Any idea?

Redirection from contact us to order page to checkout page is done using the Contact form 7 dom event "wpcf7submit" and products are added to cart using a separate function.

LoicTheAztec LoicTheAztec · Accepted Answer · 2018-09-09T08:52:03

Updated: You need to grab the queried url variable value in sessions first, this way:

add_action( 'template_redirect', 'grab_fee_query_var' );
function grab_fee_query_var() {
    session_start();

    // Not on checkout page
    if( ! is_admin() && isset($_GET['val']) ) {
        $_SESSION['leather_fee'] = $_GET['val'];
        WC()->session->__unset('leather_fee');
    }
}

add_action( 'woocommerce_cart_calculate_fees','add_custom_cart_fee' );
function add_custom_cart_fee() {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    if(isset($_SESSION['leather_fee']) && ! WC()->session->__isset('leather_fee') ){
        $value = $_SESSION['leather_fee'] == 15 ? 15 : 20;
        WC()->session->set('leather_fee', $value );
    }

    if( WC()->session->__isset('leather_fee') ) {
       $leather_fee = WC()->session->get('leather_fee');
       WC()->cart->add_fee( 'Leather fee', $leather_fee);
    }
}

Code goes in function.php file of your active child theme (or active theme). Tested and works.

Add a cart fee from an url variable in Woocommerce

1 Answers