I've been poking/investigating the GamersGate downloader through Wireshark and replicating the same behavior on python (hopefully moving it to C++/QT5) I got most of what I wanted honestly. I'm sort of having "second doubts" mostly because this is completely unofficial and I don't really know how GamersGate would feel about it. Honestly getting it working in WINE to download games I've paid would be GREAT in my opinion. I might leave a message tomorrow to them to see if I get the green flag.
Nice! I've never tried GamersGate client because I've never purchased games from them. Please let us know what you find out. here is some info on WineHQ: GamersGate download manager
Last screenshot. I was able to match the total content-length to the one GG Client gets. It took me a while, I won't work on it until I get word from GG. I only have one last challenge and most of it is regarding how to treat the downloading stream. I wish I could get some help in this department, I'm not really good managing bytes (yet). Practice I guess :] In simple terms to those who aren't in this field. I can now deduce the filename/size. This is I need more information.
In my case works good, from gamersgate, i have some games like as neverwinter nights diamond, total overdose, WRC 1, ford racing 2, ford racing 3, ford off road racing and download works without problem
No, I don't have the source code of their client. Think of it as reverse engineering. I just know how their application works.
Oh yea as for this, it became too painful to do follow-ups with gamersgate. I tried, sadly it felt like my answers just became more questions... Oh well!
As is this technical world we live in... Good effort on your part. I hope you learned something to take with you