What is the use case for the Ubuntu Download Manager
I the last few months I have been working on the Ubuntu Download Manager, one of The Big Rocks of August. The u-d-m provide a dbus service that allows applications to request downloads to be performed, to such download requests it adds some nice features that a user on a mobile phone, and probably a desktop, is interested to have. Some of those features are:
- Apparmor isolation per download. That means that only you application can interact with its downloads.
- Pause/Resume downloads
- Autodetect network connection.
- WIFI only downloads.
- Hash check support.
- Allow downloads to be performed while an application has been paused or killed.
- Group downloads, where a bunch of files are provided and the different downloads are performed as a single atomic operation.
A download might seem a simple action to perform, right? Well, as soon as you start supporting all the above a single download operation becomes a fairly complicated matter. The following is a state machine that identifies the states of a download that would support such features:
As you can see, it is a complicated matter and all these has to be tested and check by the QA team. By providing u-d-m (and later a client library to use approach in C and in the Ubuntu SDK, I’m terribly sorry but I did not have the time to finish it on time for the release) we are helping developers to perform simple downloads with robust code and do not worry about all the corner cases. Performing a download is as simple as requesting it and listen to the different signals. This kind of service is also provided by FirefoxOs, WEbOs and Tizan (but no in IOS or SailFish) but I believe we are doing a better job at exposing a richer API. Of course all this is open source and at least our friend at Jolla (and I really mean friends, I think they are doing an awesome work!!! and competition + collaboration is great).
In the following days I’ll be posting on hot to use the API via C, C++ and DBus.