Web service differences between REST and RPC

Question

I have a web service that accepts JSON parameters and have specific URLs for methods, e.g.:

http://IP:PORT/API/getAllData?p={JSON}

This is definitely not REST as it is not stateless. It takes cookies into account and has its own session.

Is it RPC? What is the difference between RPC and REST?

Answer 1

I would argue thusly:

Does my entity hold/own the data? Then RPC: here is a copy of some of my data, manipulate the data copy I send to you and return to me a copy of your result.

Does the called entity hold/own the data? Then REST: either (1) show me a copy of some of your data or (2) manipulate some of your data.

Ultimately it is about which "side" of the action owns/holds the data. And yes, you can use REST verbiage to talk to an RPC-based system, but you will still be doing RPC activity when doing so.

Example 1: I have an object that is communicating to a relational database store (or any other type of data store) via a DAO. Makes sense to use REST style for that interaction between my object and the data access object which can exist as an API. My entity does not own/hold the data, the relational database (or non-relational data store) does.

Example 2: I need to do a lot of complex math. I don't want to load a bunch of math methods into my object, I just want to pass some values to something else that can do all kinds of math, and get a result. Then RPC style makes sense, because the math object/entity will expose to my object a whole bunch of operations. Note that these methods might all be exposed as individual APIs and I might call any of them with GET. I can even claim this is RESTful because I am calling via HTTP GET but really under the covers it is RPC. My entity owns/holds the data, the remote entity is just performing manipulations on the copies of the data that I sent to it.

Answer 2

Over HTTP they both end up being just HttpRequest objects and they both expect a HttpResponse object back. I think one can continue coding with that description and worry about something else.

Answer 3

REST is best described to work with the resources, where as RPC is more about the actions.

REST stands for Representational State Transfer. It is a simple way to organize interactions between independent systems. RESTful applications commonly use HTTP requests to post data (create and/or update), read data (e.g., make queries), and delete data. Thus, REST can use HTTP for all four CRUD (Create/Read/Update/Delete) operations.

RPC is basically used to communicate across the different modules to serve user requests. e.g. In openstack like how nova, glance and neutron work together when booting a virtual machine.