[cookiecaper]

RPC is not fundamentally different from REST. REST is a form of RPC. (/me ducks tomatoes thrown among boos and hisses from the crowd)

The difference is that the processes behind REST speak with HTTP. You're still doing a "remote procedure call"; you're asking for a remote process to execute some function on your behalf and return the result. RPCs facilitate the same exact thing. How is this a "fundamental" difference?

[I'm speaking here of the practical difference, not some difference that was originally hypothesized in the dissertation.]

Thrift contains both an RPC and an IDL, but they don't necessarily have to be used together. Protobufs is just an IDL; gRPC is the RPC, which was released just a year or two ago.

You would layer Thrift and REST by putting a REST API over the top of an interface defined in the Thrift IDL. You could also run the Thrift RPC for Thrift-compatible clients.

[icebraining]

RPC doesn't have an Uniform Interface.

Say you have a user profile, which has a Gravatar associated. Sure you can have a getUserProfile() procedure that fetches the user information, but what about the image? You can write a getUserAvatar() procedure that proxies it, but that's wasteful.

In a RESTful system, you have a Resource Identifier (URL) that you can indicate as an hypermedia reference (link), with which the client can use a standard data fetching verb (GET) to retrieve it directly from the other server.

Of course, in a practical setting the getUserProfile() procedure would return the URL, but that's just an admission of the limitations of RPC vis-a-vis REST.

On the other hand, REST itself has its own problems and limitations, and is certainly not adequate for every use case, as Fielding's dissertation mentions at length.

[cookiecaper]

REST doesn't have a uniform interface in practice, either.

I haven't read the dissertation so I can't really comment on the hypothetical REST (though it is on my reading list now, and not that it really stops anyone else), I can only comment on what, in the real world, passes for a "REST API".

"REST" principles certainly sound nice on paper, but for the most part, it's clear that they're completely implausible to realize in a wide-scale, meaningful way. After over a decade of pro-REST propaganda, people still can't even tell if their interface is "RESTful" or not.

The parts of "REST" that have worked are the two simple basics of HTTP: GETting a resource to read it, or POSTing a resource to write it. Nothing else has really stuck or can be expected to have a uniform meaning (and even POST's behavior will vary, with some doing an upsert-style operation and some accepting it only for new writes and using PUT and/or PATCH for edits). 200 OK means it worked most of the time, but sometimes people will return a plaintext error with it. 404 might mean that the resource is not found, or it might mean that the route is not found/no longer valid (or that it was called with invalid or improperly encoded parameters). There are a bunch of esoteric codes that are used to mean a lot of different things, always depending on who the implementer is.

So the "uniform interface" is just that everyone is using HTTP, to mean all sorts of different things. In practical terms, it doesn't really amount to much, except a lot of blathering over whether something conforms with a theoretical ideal that everyone has already demonstrated they're unwilling to conform to.

[empthought]

REST APIs must be hypertext-driven[1].

The term "REST," like so many others, now "means" something totally different than what the inventor of the term intended.

[1]: http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hyperte...

[icebraining]

REST has been extremely successful, having scaled to billions of services, like the one we're using right now.

"RESTful APIs" have mostly been a failure, I fully agree with you on that. The difference is that I think it's a cultural problem; when people like Licklider sensibly thought about a future wherein computers would learn to talk to each other (of which REST is a first step), as static protocols obviously didn't scale, we proved him wrong by sheer brute force. Watching something like Bret Victor's The Future of Programming, it's hard to miss the giant indictment of our whole profession.

That said, since I know the term is hopelessly lost, I don't push for REST either. Our service uses XML/JSON-RPC.

[kelnos]

There is absolutely no reason why you can't implement the same REST concepts on top of another RPC mechanism.

[icebraining]

Of course you can. But x86 machine code doesn't have Monads just because Haskelll can be compiled to it. In both cases, the concepts have to be broken up to be implemented, as they are not meaningful at that level.

[godzilla82]

Can you please explain. Which REST concept cannot be implemented? I think the problems that REST/SOAP solve,is that the "levels" that you speak about, have already been implemented by someone else. I am talking of serialization, transport level details (e.g. SOAP over JMS) etc. If even transport level abstraction has been taken care of by the implementers, then which concept do you think, cannot be implemented.