Shipping Class Restrictions

Restrict WooCommerce shipping methods by the shipping classes in the cart, per method instance and zone. Works with any third-party method. Adds two fields to every shipping method's settings (in the zone editor): Availability: a single rule choosing when the method shows, based on the classes in the cart Shipping classes: which classes the rule applies to (including "No shipping class") Availability options: Show only if cart contains only these classes Show if cart contains any of these classes Hide if cart contains any of these classes Hide if cart contains only these classes For example, a letterbox-only method can be set to "Show only if cart contains only [letterbox]", while the default parcel method is set to "Hide if cart contains only [letterbox]" — so the parcel method disappears for an all-letterbox cart but returns as soon as a parcel item is added. Because configuration is per method instance, it is inherently scoped to the shipping zone the instance belongs to. Initial release.