按属性值扣减WooCommerce商品库存的技术实现问询

Hey there! I’ve got you covered on this. To make your WooCommerce store deduct stock based on the "size" variant value (like subtracting 15 instead of 1 when someone buys the 15g option), we’ll use the woocommerce_order_item_quantity filter you mentioned from the wc-stock-functions file. Here’s a step-by-step solution:

Step 1: Add the Custom Filter Code #

You’ll want to add this code to your theme’s functions.php file or a custom plugin (never edit core WooCommerce files directly—they’ll get overwritten on updates):

add_filter( 'woocommerce_order_item_quantity', 'adjust_stock_deduction_by_variant_weight', 10, 3 );
function adjust_stock_deduction_by_variant_weight( $quantity, $order_item, $order ) {
    // Only target variable product variations
    $product = $order_item->get_product();
    if ( ! $product || ! $product->is_type( 'variation' ) ) {
        return $quantity;
    }

    // Get the "size" attribute value (e.g., "15克", "100克")
    $size_attribute = $product->get_attribute( 'size' );
    
    // Extract the numeric value from the attribute string
    preg_match( '/\d+/', $size_attribute, $weight_matches );
    if ( empty( $weight_matches ) ) {
        return $quantity; // Fallback if no number is found
    }
    $weight_number = (int) $weight_matches[0];

    // Calculate adjusted stock quantity: purchase quantity × weight value
    $adjusted_quantity = $quantity * $weight_number;

    return $adjusted_quantity;
}

Step 2: Customize if Needed #

• Double-check your attribute slug: If your size attribute has a different slug (like pa_weight instead of size), update $product->get_attribute( 'size' ) to match the correct slug. You can find this in WooCommerce > Products > Attributes.
• Test thoroughly: Place a test order for each variant to confirm stock is deducted correctly. For example, buying 1x 15g variant should reduce your total stock by 15, not 1.

How This Works #

• The filter hooks into the stock calculation process right before WooCommerce deducts inventory.
• It checks if the order item is a product variation, then pulls the size attribute value.
• We use a regular expression to grab the numeric part of the attribute (ignoring the "克" text), then multiply that number by the quantity the customer bought.
• The adjusted number is returned, telling WooCommerce to deduct that amount from stock instead of the default quantity.

内容的提问来源于stack exchange，提问作者Steve Goerger