Create/update relationships with attributes

1

Hello,

after reading specification, I’m a bit confused about creating/updating resources with relationships that contains attributes. Let’s say I need to create new resource with relationship that has attributes, I’d do it like this:

{
    "data": {
        "type": "carts",
        "attributes": {
            note: "Some note about cart",
         },
         "relationships": {
             "products": [
                  {
                      "data": {  
                          "type": "products",
                          "id": "10",
                          "attributes": {
                              "quantity": 5
                          }
                      }
                  }
              ]
         }
    }    
}

Althouth I could not find this stated explicitly (maybe I’ve missed it), but for me it seems they way to do this. Am I correct about it?

Thanks in advance for your replies! :slight_smile:

1 Like
2

I get what you are trying to do but unfortunately that’s not supported by spec.

The data value of a relationship object must only be a resource identifier objects (has-one) or an array of resource identifier objects (has-many). Using a resource object is not supported. These ones may only be linked by the resource identifier objects. Therefore this feature is called resource linkage.

I get from your example that you are trying to put additional information on the relationship itself. You could model that as meta information using a meta object but I would not recommend this. This goes against the intend of the specification and updating a meta information is not covered by spec.

I would recommend to add an intermediate model, e.g. cart-items which has a relationship to carts and products and a quantity attribute.

Unfortunately JSON:API spec does not support creation of multiple resources with one request yet. So you would need to create the cart and it’s cart-items with separate requests. This limitation should be solved by a new feature called operations, which is proposed for v1.2.

2 Likes
3

@jelhan thanks a lot for your reply! :slightly_smiling_face:

1 Like
4

I believe there’s nothing forbidding the client to use the included top-level member. Would you agree the following is valid?

{
    "data": {
        "type": "carts",
        "attributes": {
            "note": "Some note about cart",
        },
        "relationships": {
            "products": [
                "data": {
                    "type": "products",
                    "lid": "some-uuid"
                }
            ]
        }
    },
    "included": [
        {
            "type": "products",
            "lid": "some-uuid",
            "attributes": {
                "quantity": 5
            }
        }
    ]
}
1 Like
5

Compound documents are only valid for responses. Creating, modifing, or deleting multiple resources in a single request is not supported by the base specification. However it can be achieved using an extension. The Atomic Operations and Bulk Create extensions are two examples how that could be done.