Conferences are useful: the WtDesktop case

You probably know I love Wt, the Qt-like C++ library for developing webapplications. I gave up on Ruby on Rails and PHP when I started using Wt about three years ago.

Koen and Wim, the authors of Wt, happen to be from Belgium and they attended aKademy 2008. I “arranged” a metting between Koen, Wim, Richard Dale (the KDEbindings man) and me. We talked about how great Wt is, how much the API ressembles Qt and how nice bindings to other languages would be. Guess what? A few months later, Richard had adapted SMOKE to Wt and had developed Wt::Ruby bindings. Impressive.

I attended last year’s FOSDEM and there we go again: over dinner we came with a new idea. Google Gears makes it possible to run webapplications like they were desktop applications. But it’s Python, it requires a Python interpreter an a load of libraries. Can’t we do the same thing with Wt and generate a single executable by statically linking everything? Can’t we? Of course we can! In theory, it would be very easy: start Wt with its own embedded server (wthttp) in a QThread, then load that in a QtWebKit-powered browser. Koen put that in writing as a “>GSoC idea but EmWeb (the company Koen and Wim founded to support Wt) was not accepted as a mentor in GSoC 2009.

It took me a long time to get started with WtDesktop because I was busy with other stuff but two weeks ago I finally started to cut the meat. And it turned out to be surprisingly easy! Yes, WtDesktop works! It’s not in Wt, it’s not finished yet, but I hope I will be able to work on it and have something very nice in a few weeks time (get WtDesktop Technology Preview 2 here; TP3 is in the works, clone this repository)

What will WtDesktop have in the future?

• Port autodiscovery (for now it’s hardcoded to run on port 9000, I’m having some trouble mixing Qt and Boost signals and slots to make it choose a new port automatically). This is almost done in TP3, which will be available soon.
• Call-outs: let the webapp go out of the web and add menus, toolbars, etc to the application when it’s linked against libwtdesktop.so. Yes, you read it correctly: if you link against libwthttp.so you get a webapp with its own embedded webserver, if you link against libwtfcgi.so you get a FastCGI module you can serve from Apache, IIS or whatever, and if you link against libwtdesktop.so you get a desktop appliation. No changes to your code at all! I’d like to have some declarative language like QML for this but that’ll take some time.
• Printing support. There is basic printing support (i. e. printing the whole page) already but I’d like to be able to connect buttons, frames, etc in the webapp to be able to print only some parts. This would require the above call-outs.
• Session-sharing and session-stealing. Wt has all the DOM tree for each session in memory, therefore it is able to send the same HTML, CSS, DOM tree, etc to some other address. Session-sharing would be like Remote Assistance on Windows: you can see what the other client is doing but you cannot touch. Session-stealing would be like Remote Desktop: you can click, type, etc and the other client would see a “this application is being used by XXX (IP address: X.Y.Z.T)”.

So yes, attending conferences is definitely fruitful. By the way, I’m attending FOSDEM 2010. Let’s see if I come with some other great idea!

UPDATE: Added git repository