Now that the server side of the Service Clients implementation has taken shape, it’s time to turn our attention to the design of the client side implementation, which is still somewhat immature.
The basic idea is that, now that the server is capable of dumbly passing messages and replies among clients, we can use that capability to model the actual Service Client functionality on the client-side. In other words, we want the clients to establish a protocol for remote procedure calls and introspection with the server, unaware of what is really going on, simply forwarding messages and replies back and forth between clients.
Our plan for the actual implementation will require, as expected, changes to libxmmsclient, but also the development of a new library, so far called libxmmsclient-sc. The new functionality added to libxmmsclient will merely facilitate message exchanging between clients, while the actual Service Client sugar will be laid on top of that in libxmmsclient-sc.
We already had some sketches for the client side of the implementation, most notably this one by nesciens, which gives a pretty good idea of where we are headed. Last week I published a sketch of my own, with an updated and slightly more concrete view of the implementation details now that we know what the server is capable of. It also contained a few more ideas.
While we have not yet throughly discussed these sketches and turned them into a more solid idea, they do provide a good basis we can work on refining over the next weeks.
One aspect of these sketches we had quite a lengthy discussion about was the alterations needed to accommodate the new message passing functionality in the asynchronous result mechanism in libxmmsclient. With valuable input from vdust, we reached a nice idea that I began implementing with this commit. It still needs some testing and polishing, which I will be doing in the next days.
