So HATEOAS is a hot topic. The discussions is about whether if its a good way of actually using it for an API or it should be the API. There are several things that concerns me.
Firstly there's no programming model for HATEOAS, such a like functional programming, procedural or like SQL type. Its representing something which there are no other mechanics for, so why would it be suitable for APIs?
Secondly the so called APIs, with exposing resources, requires a client which is dynamic enough to actually understand all of that data, and simple links to describe their relations. I haven't yet seen a language which does this natively so why would HATEOAS do this? SQL is pretty good at expressing relations and linking it together, however it doesn't understand what it is. Why would HATEOAS be so much better?
If HATEOAS is all of what you need to describe an API, why do I need a network to make use of it. Why isn't there a way of using it like a language? When there's a way of coding it and expression it as logical relations, I'd say it's something worth looking at.
I think all of those who think they need HATEOAS to describe an API have no idea of how to make one, it's simple like that. Yes you can create something which resembles an API, because you are exposing something which an consumer could use for something. BUT that's still not an API, simply because an API is so much more than how you relate resources to each other.
Most of the time when I see arguments for HATEOAS is the ability to extend without changing the client. The problems with having to change code because you update your API is a technical problem, not a API problem.
If there's any out there which could present me with a HATEOAS client which doesn't contain any code at all (!) and is able to understand what it can do with the API the client is exposed to and does everything the API exposes in a comprehensive matter which is useful, then I'd start think HATEOAS is a good thing.
Thing is, if you cannot show that you don't need a client which you have to translate the resources into something useful, HATEOAS is just another way for hipsters to mess up APIs.
Some links to read more about it: Jeff Knupp, Mule Soft,API Evangelist
