SpreePromotionActionCreateLineItems

spree_promotion_action_create_line_items locks the items that Spree's Create line items promotion action adds to the cart.

Spree's action can add a free gift (a 0-priced product) to every cart that meets the promotion's rules. Out of the box, though, customers can treat that gift like any other product: put it in the cart on its own from the product page, change its quantity or remove it. This extension leaves the gift entirely under the promotion's control.

A variant set on a Create line items action is a campaign item, whether or not the promotion is currently active. For campaign items:

• The product page shows no add-to-cart button and no quantity selector (the product itself stays visible in search results and listings, so customers can see what they were given)
• The cart shows the quantity as plain text, with no remove button and no low-stock notice
• Requests sent directly are refused too: the storefront POST /line_items, PATCH /line_items/:id and DELETE /line_items/:id, and the Storefront API's cart/add_item, cart/set_quantity and cart/remove_line_item (422)

The promotion itself still adds and removes the item as usual — only customer actions are blocked. Admins can still edit campaign items on orders in the Spree admin.

Add this line to your application's Gemfile:

gem 'spree_promotion_action_create_line_items'

Then run:

bundle install

No migration is needed — campaign items are read from Spree's own spree_promotion_action_line_items table.

Create a promotion in the Spree admin with the Create line items action and pick the variant to add. That variant becomes a campaign item.

When the campaign ends, set the campaign product to draft or archived (or discontinue it). Spree then removes it from any cart that still holds it the next time the customer opens the cart or checkout. Customers cannot remove it themselves.

Other promotion actions can mark their own variants as campaign items by prepending a module to Spree::Variant:

module MyPromotionAction
  module VariantDecorator
    def campaign_variant?
      super || MyPromotionActionLineItem.exists?(variant_id: id)
    end
  end
end

Spree::Variant.prepend(MyPromotionAction::VariantDecorator)

Require this gem before your own engine so that super is defined.

• Spree 5.3.6 (spree_storefront for the storefront screens)

AGPL-3.0-or-later. See LICENSE.