Change cart items price dynamically from a custom field value in WooCommerce

Question

I am currently working on a WordPress website, with WooCommerce functionality.

Each Product Page, has a Custom Field which allows site visitors to enter text that they would like to apply to the Product. Charges are applied on a 'per letter entered' basis.

To work out the overall cost of the product (Product Price + Custom Letters Entered), I have inserted the following code, into the functions.php file:

<?php 
    function calculate_engrave_text_fee( $cart_object ) {  
        foreach ( $cart_object->cart_contents as $key => $value ) {
            if( isset( $value["engrave_text"] ) ) {
                // Quantity of characters entered into Custom Text Field:
                $chars = strlen( $value["engrave_text"] );
                // Characters Entered Multiplied by Cost of Each Letter:
                $engrave_text_fee = $chars * 3; //Need to dynamically call this.
                $orgPrice = floatval( $value['data']->price );
                $value['data']->set_price( $orgPrice + $engrave_text_fee );
            }
        }
    }
    add_action( 'woocommerce_before_calculate_totals', 'calculate_engrave_text_fee', 99 );
?>

The above code works absolutely fine; with one exception.

Since the cost of each Letter will be different, depending on the product, having a static entry such as $engrave_text_fee = $chars * 3; is not ideal. Alternatively, I have created a Custom Field in the WooCommerce Product Dashboard whereby a Site Admin is able to enter the price for each Product's individual Custom Lettering.

The Problem

To dynamically call the Custom Field entry, from the WooCommerce Product Dashboard and place this into the Maths above, I tried replacing: $engrave_text_fee = $chars * 3; with:

$engrave_text_fee = $chars * <?php global $post; echo get_post_meta($post->ID,'_pricing_engrave_text_option',true)?>;

Unfortunately, this only sends the website offline. I can only assume there is an issue with the coding syntax!? Is anyone able to point out where I may be going wrong here?

LoicTheAztec LoicTheAztec · Accepted Answer · 2017-11-24T23:44:35

Updated (October 2018)

Your correct dynamic code should be (as you have some errors and outdated code):

add_action( 'woocommerce_before_calculate_totals', 'calculate_engrave_text_fee', 99, 1 );
function calculate_engrave_text_fee( $cart ) {  
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    if ( did_action( 'woocommerce_before_calculate_totals' ) >= 2 )
        return;

    // Loop through cart items
    foreach ( $cart->get_cart() as $cart_item ) {
        // Checking that we got the engrave text in cart object
        if( isset( $cart_item["engrave_text"] ) && ! empty( $cart_item["engrave_text"] ) ) {

            // Quantity of characters entered into Custom Text Field:
            $lenght = strlen( $cart_item["engrave_text"] );

            // Get the engrave pricing for this product
            $pricing_engrave = get_post_meta( $cart_item['data']->get_id(), '_pricing_engrave_text_option', true );

            // Characters Entered Multiplied by Cost of Each Letter:
            $engrave_text_fee = $lenght * $pricing_engrave; 

            // get product price
            $price = floatval( $cart_item['data']->get_price() );

            // set new price
            $cart_item['data']->set_price( $price + $engrave_text_fee );
        }
    }
}

Code goes in function.php file of your active child theme (or theme) or also in any plugin file.

This code should work

Change cart items price dynamically from a custom field value in WooCommerce

2 Answers