I can't seem to find anything in the OpenRasta docs or tutorials that shows how to use arbitrary JSON objects (i.e. objects not predefined using C# classes) for both receiving from and responding back to the client.
One way to do it would be to use JsonValue and write a custom codec that would just use the (de)serialization features provided by JsonValue. That should be pretty straightforward and less than 50 lines of code, but I wondered if there isn't anything built into OpenRasta?
(One downside of JsonValue is that MS has not yet released it, so you can't yet deploy it to customers (see 1. "Additional Use Rights"). But in cases where that matters, any other Json library, like Json.NET can be used.)
I have written, like most people, a very simple codec that supports dynamics as inputs and outputs to handlers using json.net. You can also register that codec with an anonymous type and it works brilliantly. You end up with this:
public object Post(dynamic myCustomer) {
return new { response = myCustomer.Id };
}