How to upsert in JSON:API

Hi -

We’re building a REST API on top of an existing system, where there’re related “configuration” resources for a particular top-level resource. The way the team behind this is thinking is to model it something like this:

/resource/resource_id/configuration/config_name

{"data": {"attributes": {"value": "greatscott"}}}

However, what they really want is a way to “upsert” this value. We could either use the PATCH approach that’s specified, especially if the resource is simple and there aren’t other attributes or relationships anyway that need to be included for the “create” part to work… but it feels like a stretch to the JSON:API spec to do this.

We could use PUT with the full set of attributes/relationships, but that’s not defined/supported by the JSON:API spec at al.

So what’s the official way to do this?