Which HTTP Method should I use for my REST Service method doing READ & WRITE?

Question

As per RESTful services guidelines we should use GET for reading a resource, POST for creating a new resource, DELETE for deleting an existing resource etc.

But assume I am developing a RESTFul webservice, say OrderProcessing. In placeOrder(Order) method I have to read some tables like inventory, product details etc, insert some new rows into tables like order and order details and do updates like reducing the inventory level etc. Then what HTTP method should I use for placeOrder() method.

At the very high level we are creating a new resource(Order), so I thought POST is correct HTTP method to use.

But in general what verb should be used for method doing read/create/update of data inside same method?

Answer 1

I agree with your thinking that POST is appropriate here. Even though you are doing multiple operations, you can view this as a single create of your Order resource. As for the other operations, I would view those as internal details that you are not exposing to the consumer of your service.

Edit - Taking this a step further, This assumes that you have defined Order as your resource, and the POST body contains a representation of this resource. And to be totally RESTful, if the POST results in the creation of a new Order, then HTTP 201 is the appropriate response code. See section 9.5 of http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html for more details.

Answer 2

Definitely POST. You can rule out GET and DELETE for obvious reasons, and you would only want to use PUT for an idempotent operation. Since you're reducing inventory, you can safely rule out PUT as a viable option.