**What**
- add/ remove sales channels to/from PublishableApiKey in batch
- associate created cart with SC defined by PK
- filter products if PK with SC association is present
- retrieve a list of sales channels for a PK
- implement 3 new middleware
- `extendRequestParams`
- _extend req object with PK scopes (a list of sales channels) if a publishable key is present in the header of the request_
- `validateProductSalesChannelAssociation`
- _validate if the passed product id belongs to a SC from the PK's scope_
- `validateSalesChannelParam`
- _validate that passed SC ids in the req body/query are within the scope of the PK_
**How**
- The general idea was to reuse existing logic in the controller layer which expects `sales_channel_id` array to be passed. The middleware sets associated SC ids in the request context if a PK is present. These ids are then merged in the controller and passed to the service layer.
**TODO**
- filter response from the search endpoint (CORE-824)
**Testing**
- _integration tests_
- add sales channels to the publishable API key scope
- remove sales channels from the publishable API key scope
- returns products from a specific channel associated with a publishable key
- returns products from multiples sales channels associated with a publishable key
- returns all products if PK is not passed
- returns all products if passed PK doesn't have associated channels
- should assign sales channel to order on cart completion if PK is present in the header
- list sales channels from the publishable api key
- throws because sales channel in query/body is not in the scope of passed PK
---
**Discussion**
- what about the other endpoints (e.g. GET /store/product/:id - do we return 404 if the product is not in the SC associated with passed PK)
- what about products search route
- what about `/admin/products` & `/admin/orders` routes (do we add the middleware there as well)
---
RESOLVES CORE-792
RESOLVES CORE-793
RESOLVES CORE-816
322d462311