I might have mentioned it before but my PBBG engine is basically a commands processor. In other words it accepts commands from the client, processes the information on the server and sends the response back to the clients as JSON. Not really different from a normal web request except it is specific to my PBBG engine and you don't request documents from the server you are telling the server you want your Character to "do" something.

My PBBG engine is essentially just the command processor and the classes surrounding processing commands. I have abstracted it completely from the data source. There are no data providers or data connections at all in the engine. Instead, if it needs to get data it raises events that a deriving library can handle and pass back the required data in the form of simple interfaces. Some assumptions I did make such as ID values defined in interfaces are int values rather than object since I don't design databases with primary keys other than int. :)

One of the things I also did for the CommandManager was to created an abstract Verb class that I can derive from to create command verbs such as move, say, attack, etc. These command verbs can be defined in the deriving library and set in the CommandManager when the game starts up. Another class to assist with commands was a generic Command<T> class where T has to be a derived Verb value. So I can create Command<Move>() and the call an Execute method on the class which in turn creates the Verb instance and executes the code in the Verb class.

This has been working pretty well so far and since the CommandManager raises an event each time if processes a command I can have any number of derived libraries executing their own commands.