Shared catalog: can multiple vendors sell the same product?
I evaluated GrandNode2 for a marketplace project and read through the catalog domain model. One question I couldn't settle from the code, so I'd rather ask than assume.
Observation
Product carries the seller, price and stock on a single document — VendorId (line 82), Sku (147), StockQuantity (335), Price (431) — and IPricingService takes Product as the price-bearing entity throughout. One catalog record therefore belongs to one vendor.
That supports a marketplace where each vendor owns their own listings. It doesn't support a shared catalog, where several vendors compete on the same record and the storefront selects a winning offer — Amazon's buy box, Google Shopping. Under the current model, two vendors selling the same title produce two products, two URLs and two sets of reviews.
What already exists
Several pieces are in place. ProductAttributeCombination already models SKU, price and stock as a unit hanging off a product; it simply doesn't carry a VendorId. OrderItem already has VendorId and Commission. Vendor already has the rating aggregates a ranking would need. InventoryJournal is already polymorphic over ObjectType.
The gap appears to be one entity — an Offer holding vendor, product, price, stock and status — plus a selection service, and an OfferId on ShoppingCartItem so the cart remembers which vendor the customer chose.
On compatibility
This could be additive. If an offer service synthesises an implicit offer from the product when no explicit ones exist, an installation with zero offer rows behaves exactly as it does today: no migration, no setting change, no rewrite.
Question
Is a shared-catalog marketplace in scope for GrandNode2, or is one-product-one-vendor a deliberate boundary? Either answer is useful — if it's out of scope, I'll close this.
Happy to expand on any of the above. I can't commit to implementing it, so please treat this as a design question rather than a proposal of work.
Shared catalog: can multiple vendors sell the same product?
I evaluated GrandNode2 for a marketplace project and read through the catalog domain model. One question I couldn't settle from the code, so I'd rather ask than assume.
Observation
Productcarries the seller, price and stock on a single document —VendorId(line 82),Sku(147),StockQuantity(335),Price(431) — andIPricingServicetakesProductas the price-bearing entity throughout. One catalog record therefore belongs to one vendor.That supports a marketplace where each vendor owns their own listings. It doesn't support a shared catalog, where several vendors compete on the same record and the storefront selects a winning offer — Amazon's buy box, Google Shopping. Under the current model, two vendors selling the same title produce two products, two URLs and two sets of reviews.
What already exists
Several pieces are in place.
ProductAttributeCombinationalready models SKU, price and stock as a unit hanging off a product; it simply doesn't carry aVendorId.OrderItemalready hasVendorIdandCommission.Vendoralready has the rating aggregates a ranking would need.InventoryJournalis already polymorphic overObjectType.The gap appears to be one entity — an
Offerholding vendor, product, price, stock and status — plus a selection service, and anOfferIdonShoppingCartItemso the cart remembers which vendor the customer chose.On compatibility
This could be additive. If an offer service synthesises an implicit offer from the product when no explicit ones exist, an installation with zero offer rows behaves exactly as it does today: no migration, no setting change, no rewrite.
Question
Is a shared-catalog marketplace in scope for GrandNode2, or is one-product-one-vendor a deliberate boundary? Either answer is useful — if it's out of scope, I'll close this.
Happy to expand on any of the above. I can't commit to implementing it, so please treat this as a design question rather than a proposal of work.