CQRS/EventStore - Passing GUIDS to UI?

Question

I am currently using J Oliver's EventStore which as I understand uses Guids for the Stream ID and this is what is used to build my aggregate root.

From a CQRS point of view and a DDD perspective, I should be thinking about the domain and not GUIDs.

So, if I do a GET (Mvc client), am I right to say that my URL should have the identity of my domain object (aggregate root) and from that I get the GUID from the read store which is then used to build my aggregate root from the event store?

Or should I pass the GUID around to my forms and pass them back as hidden form variables? At least this way I know the aggregate root id and do not have to query the read store?

I suppose the first way is the correct way (not using GUIDs in forms) as then all my Gets and POSTS deal with identities of domain objects rather than GUIDSs which the client will not know.

I suppose this also allows me to build as REST based API which focuses on resources and their identities rather than system generated GUIDS. Please correct me if I am wrong

Answer 1

In my opinion you are on the right track here. The ui should rely solely on the read model and not really care about the aggregates. Then when you need to send a command you can use the read model to get the id of the aggregate you are interested in. The read model should be very fast to read from anyway (that's the whole reason behind using different models for reads and writes) and very easy to cache if you need to. This will also give you much nicer urls.