Friday, May 20, 2011

Calling contributors...

Recently Nokia announced the initial planning stages for Qt5, and looked to the community for ideas on how to improve Qt in a generally source-compatible way, meanwhile allowing extensions to be added and some things to be modified. All this, via the a mailing list - qt5 dash feedback at qt dot nokia dot com. There have been a number of great ideas that have come up - from additions to the QDateTime, time-zone support, enhancing the printing, integrating more from KDE, and lots more.

So why this blog? Well, I've been working with Qt professionally for just over 2 years now making a distributed network-based geometry measurement system for the railroad industry. The design uses a lot of service applications - which, use the QtService component add-on. Well, I'd very much like to see the QtService component become part of the Qt Core library in Qt5, but it needs a bit of love to get there.

Don't get me wrong - QtService is great. It works wonderfully, but it hasn't been updated in quite a while, and doesn't officially support Qt 4.6 or 4.7. Looking at Gitoroius, it's been put into the archives - i.e. its no longer going to be officially supported. Yet, I use this every day and I'm sure others do as well.

There are also a few other relatively minor problems with QtService:

1. It is template based. And this means that the base application from which you derive your own application can't use Qt's signals/slots to deliver the basic functionality. This is of greatest hindrance in the communications between the 'controller' portion of the application (which is provided for you) and your application. It also makes it very difficult to do things like delaying a service stop request (e.g. so you can unregister the application from a central server).

2. The command line is rather limited. That is, you get what they provide you and its very difficult (actually nearly impossible) to extend it to do other things - especially if those things are passing a parameter to your application (since there is NO signal you can send to it).

So, here I am now looking ahead to Qt5 and seeing that this nice component is not going to be supported. Meaning, I'm going to have to support it myself - and so is anyone else that wants to use it too, and I'm sure there are others out there.

Of course, since it is not a first-class citizen to the Qt Framework - and you have to explicitly pull it in and install it - then I'm sure that not everyone that really could make use of it does. So there are probably a lot more people out there that could make use of it and aren't simply because its too much work to install and use it, and you get those icky limitations that aren't very friendly to you either.

Fortunately, Qt is open source. And Nokia is moving Qt to open governance, especially with Qt5. This means that I, and everyone else, have the ability to contribute to Qt5 like never before. It also means if we can get a suitable new replacement for QtService written and on par with other parts of Qt then we stand a chance of having it become part of Qt itself - a first class citizen.

Well, time to wrap up my thoughts for this post...essentially, I have now joined gitorious ( and will be making a branch in the next week or so to star this work on. (Very exciting). Yes, I plan to "put my money where my mouth is" or so the old saying goes. I doubt my employer will let me do it on company time, but it'll be worth it if only so I don't have to maintain the other version in a lot less friendly and open manner. (Of course, that also means pushing my employer to use Qt5 when the time comes, which is quite a bit easier to do.)

So once I get back home, then I'll be finishing the setup of my gitorious account, and creating a branch, and possibly a team, for this effort. I very much do look forward to learning git in the process (I've been a staunch SVN user for years, but I mostly do work where centralized versioning makes sense; and community projects like this make better sense with a distributed versioning system.)

So, anyone else out there that is using QtService component, or would like to join in - please join us on the Qt5 Feedback mailing list mentioned above, and we'll get you plugged into the new work once I get it all setup.

And certainly look for more here as this endeavor continues. I'll certainly try to post more as it comes together.