One common scenario when developing iPhone apps is that you have a desktop application of some sorts that you want your iPhone to pair with – be it to sync data, remote control one with the other, or establish any other kind of communication.

In this scenario, the desktop app would be the “server”, in RemObjects SDK terminology, and the iPhone would be the client.

For the next release of RemObjects SDK for OS X, coming next month, we’ve created a nice sample that illustrates how to easily achieve this, and i figured i would post a small screencast of the sample in action, below.

What you see is a desktop app written in Delphi (although .NET will do just fine, as well), which for sample purposes has a pretty minimal UI, but in real life would be your full-fledged desktop UI app. When the iPhone client is a launched, it automatically detects any instance of your desktop app running on the local network and shows them in a list.

(The UI for this would be up to the application designer, obviously; for simplicity we simply show them all in a UITableView. In real life, if only one server was found you’d probably want to forgo the list altogether and just ask the user if he wants to connect).

Once the user picks a server, communication is initiated, by the iPhone calling a service method and passing it a unique GUID it generated. Since this is the first time these two are talking to each other, the server rejects the phone, but displays a random 4-digit code in it’s UI (this code is not known to the phone, at this stage). The phone asks the user to enter the code and, once done, sends it to the server to confirm the pairing. Once successful, the server stores the client’s GUID for future reference – and any future calls (even after the phone app has been restarted) will work right away.

Of course instead of showing an UIAlertView, your application would instead commence doing it’s real work.

Here’s the app in action: