PI ABAP Proxies versus RFC Web Services
I've been having an interesting conversation with one of my colleagues who works with PI. We've been talking about a standardised approach to eSOA from an SAP development perspective and got onto a bit of a sticky subject which I'm hoping someone can add some clarity to...
Basically, we're trying to understand where the PI ABAP Proxies fit into the eSOA world. That is to say, we can create a web service which wraps around a function group, function module, BAPI, etc... We cannot as far as we are aware create a web service that wraps directly around an ABAP object. PI ABAP Proxies appear to be ABAP objects published as a pseudo web service for the sole consumption of PI.
So, taking a long term view with the aim of service enabling a backend system function, if we wanted to create a sales order change service for example, I'd take the RFC function module and create a web service around it and publish it to the ESR. If PI wanted to change a sales order would they use the same web service? We are led to believe they should create an ABAP proxy to access the backend functionality. This effectively gives us two possible service points which I don't think is correct.
Any thoughts or suggestions will be most welcome.