How to VAR_DUMP a $variable during checkout process (Is my product meta callable?)

Question

Sorry guys, had to post this again as site wouldn't let me respond to comments (new account).

I have been working on some code to decrease quantity of a variable product based on the numeric values of a custom field.

This is working fine, however I have implemented a checkbox that will essentially TURN ON/OFF the feature on each product. This custom checkbox also works fine, appears in 'Product General Settings' and is storing the data fine - I have confirmed this with a VAR_DUMP() on the product page that is accurately dumping yes - (length = 3).

Although the data is storing, I can't seem to use it as a condition and when that condition is in place if ( 'yes' == $stock_weight_checkbox ) the correct decrease in quantity does not work.

I can't seem to get a VAR_DUMP() to work during this process either as it takes place during the checkout confirmation, so I can't see if any values are being displayed there at that point.

My assumptions are as follows: I am improperly calling the post_meta in this area (checkout). Perhaps this call works on the product page but I am missing something or the way I am approaching the call is incorrect.

This is a variable product that is looking for a custom field in the General Settings area during checkout, at which point it is unavailable? (Guess)

Below is the code:

// reduce stock based on 'custom_field'

add_filter( 'woocommerce_order_item_quantity', 'filter_order_item_quantity', 10, 3 ); 
function filter_order_item_quantity( $quantity, $order, $item )  
{
    $product   = $item->get_product();
    $term_name = $product->get_meta( 'custom_field', true );
    $stock_weight_checkbox = $product->get_meta( '_stock_weight_checkbox', true );

    // 'pa_weight' attribute value is "15 grams" - keep only the numbers
    $quantity_grams = preg_replace('/[^0-9.]+/', '', $term_name);

    // new quantity
    if( 'yes' == $stock_weight_checkbox && is_numeric ( $quantity_grams ) && $quantity_grams != 0 )
        $quantity *= $quantity_grams;

    return $quantity;
}

function validate_attribute_weight( $passed, $product_id, $quantity, $variation_id = null, $variations = null ) {
    // Get custom field
    $weight = get_post_meta( $variation_id, 'custom_field', true );
    $stock_weight_checkbox = get_post_meta( get_the_id(),'_stock_weight_checkbox', true );

    if ( 'yes' == $stock_weight_checkbox && ! empty( $weight ) ) {
        // Get product object
        $product = wc_get_product( $product_id );

        // Get current product stock
        $product_stock = $product->get_stock_quantity();

        // ( Weight * quantity ) > product stock
        if( ( ( $weight * $quantity ) > $product_stock ) ) {
            wc_add_notice( sprintf( 'Sorry, you cannot add <strong>' . $weight .'</strong> of <strong>%1$s</strong> to the cart because there are only <strong>%2$sg</strong> left in our inventory. Please choose a lesser amount. We hope to have more in stock shortly.', $product->get_name(), $product_stock ), 'error' );
            $passed = false;
        }
    }

    return $passed;
}
add_filter( 'woocommerce_add_to_cart_validation', 'validate_attribute_weight', 10, 5 );

Can anyone notice something wrong? Or at the very least, let me know how I can view the VAR_DUMP() during the checkout process? (I'm used to just spitting it out on some part of my page ie: product page)

Answer 1

There are some points in your code might need to review practically.

Here is something you might be interested to update and a method for you to var_dump the process.

function validate_attribute_weight( $passed, $product_id, $quantity, $variation_id = null, $variations = null ) {

    // Get custom field

    // 1. I am not sure if you directly get the post meta using WP builtin return expected result or not since I can see you use $product->get_meta() before
    // $weight = get_post_meta( $variation_id, 'custom_field', true );
    // $stock_weight_checkbox = get_post_meta( get_the_id(),'_stock_weight_checkbox', true );

    // you may try to change to
    // current product from the filter, it is better than get_the_id() because if filter provides to you, more directly and bullet-proof
    $product           = wc_get_product( $product_id );

    // with $product fetched, you may use the same code previously which ensure consistency 
    $stock_weight_checkbox = $product->get_meta( '_stock_weight_checkbox', true );

    if ( 'yes' == $stock_weight_checkbox && ! empty( $weight ) ) {
        // Get product object
        // $product = wc_get_product( $product_id ); // since already get, no need to do so

        // Get current product stock
        $product_stock = $product->get_stock_quantity();

        // ( Weight * quantity ) > product stock
        if( ( ( $weight * $quantity ) > $product_stock ) ) {
            wc_add_notice( sprintf( 'Sorry, you cannot add <strong>' . $weight .'</strong> of <strong>%1$s</strong> to the cart because there are only <strong>%2$sg</strong> left in our inventory. Please choose a lesser amount. We hope to have more in stock shortly.', $product->get_name(), $product_stock ), 'error' );
            $passed = false;
        }
    }

    // what you concern is the testing logic, if you want to intercept, you may add exit()
    // var_dump() here
    exit();

    return $passed;
}
add_filter( 'woocommerce_add_to_cart_validation', 'validate_attribute_weight', 10, 5 );

Because the WordPress ajax process is like:

• you click the add to cart
• it pass the data by JS ajax with URL and then return with something, it will fire the action to the php to process <== this is the point that you can intercept, when the php exit here, anything during the process is in the middle and thus you could see the var_dump();
• after process completed, the php return result (false/true) and return something to the page

Additional notes on intercepting the process: When you var_dump to track, it is better var_dump($_REQUEST) also. If you have options then need to confirm it is passed from the form to php. This could help to trace and confirm. If the parameter does not exist in $_REQUEST, most likely it is not in the form that is being submitted.