Legacy operations vs. REST resources

Stefan Tilkov and Sean Gillies respond to my previous post about modelling operations in REST. There's also an interesting discussion on this on the rest-discuss yahoo group.

First of all, I think my example wasn't a good one. While the operations I had in mind were operations alright, they weren't state changing ones. I realize that my example definitely implies changing state. And I myself would advocate a PUT or at worst a POST in that case. The case I am making is for operations that don't change state but are like queries on a given resource.

I agree with both Stefan and Sean. "Resources, not Objects" as Sean puts it. In the REST world, a person does not walk but s/he reaches a location. And if I were designing a REST API for a new system I would most certainly use that approach.

But if I have existing APIs or SOAP web services such that the verbs talk and walk were firmly instilled in the verbiage of my user community, it might be a difficult proposition for me to suddenly introduce a new vocabulary for the same set of operations to my users. The user community sees them as operations and not in terms of the resulting resources (words and location). Legacy wins over technical correctness.