Is RPC disguised as REST a bad idea?

Question

Our whole system is being designed around REST and are now considering how processes which are quite clearly RPC in intent can be mapped to RESTful resources without using verbs in the URL. Our remote procedure call is used to rebuild our search index when a content listing has been modified elsewhere.

What we are thinking about doing is this:

POST /index_updates

<indexUpdate><contentId>123</contentId></indexUpdate>

Nothing wrong with that in itself, but the smell is this resource which has been created does not return the URL of the newly created resource e.g. /index_updates/1234 which we can then access with a GET.

The indexing engine we are using does have a log mechanism, so in theory we could return a URL to a index_update resource so as to allow a GET to retrieve the resource, but to be honest we're not interested in the resource as this is nothing more than an RPC in disguise.

So my question is whether RESTfulness is expressed in structure or intent. I feel the structure of what I have outlined is restful, but the intent is not.

Does anyone have an comments or advice?

Thanks,

Chris

Answer 1

Use the right tool for the job. In this case, it definitely seems like the right tool is a pure remote procedure call, and there's no reason to pretend it's REST.

Answer 2

This is obviously a subjective field, but GET PUT POST DELETE is a rich enough vocabulary to describe anything. And when I go to non-English-speaking Asian countries I just point and they know what I mean since I don't speak the language... but it's hard to really get into a nice conversation with someone...

It's not a bad idea to disguise RPC as REST, since that's the whole exercise. Personally, I think SOAP has been bashed and hated while in fact it has many strengths (and with HTTP compression, HTTP/SSL, and cookies, many more strengths)... and your app is really exposing methods for the client to call. Why would you want to translate that to REST? I've never been convinced. SOAP lets you use a language that we know and love, that of the programming interface.

But to answer your question, is it a bad idea to disguise RPC as REST? No. Disguising RPC as REST and translating to the four basic operations is what the thing is about. Whether you think that's cool or not is a different story.

Answer 3

One reason you might return a new resource identifier from your POST /index_updates call is to monitor the status of the operation.

POST /index_updates
<contentId>123</contentId>

201 Created
Location: /index_updates/a9283b734e

GET /index_jobs/a9283b734e

 <index_update><percent_complete>89</percent_complete></index_update>