You never GET a resource
Resource vs representation vs message — the abstraction that makes content negotiation, caching, and ETags all make sense.
- Resource — whatever a URI names
- Representation — a serialization of its state
- How RFC 9110 defines it
A "representation" is information that is intended to reflect a past, current, or desired state of a given resource, in a format that can be
- Content negotiation — picking a representation
- Conditional requests — acting on a representation only if it hasn't changed