Where to put the networking thread?

[Gergely Polonkai <gnome gergely polonkai eu>]

Hello List,

i’m about to create a new application that communicates via MQTT.  For MQTT itself i chose the paho-c library 
(if you have better alternatives at hand, especially if it’s already GLib “native”, i’m all ears.)

Paho-c doesn’t seem to play well with G(tk)Application, and i read somewhere that it’s generally considered 
bad design to do the network communication and GUI in the same thread anyway, so i decided to do the MQTT 
thing in a separate thread.

My first question is, where should i instantiate the GThead object? Should it be a separate entity (ie. a 
global value)? If so, wouldn’t that introduce a problem when i activate an already running instance of my 
app? Or should i make it a member of my application object? In that case, where should i create the thread? 
In the constructor or somewhere else?

The second question is, how and when should i start this thread? I currently load my settings from GSettings 
by binding them to my GtkApplicationʼs properties, and load the password from libsecret asynchronously. I 
guess i should somehow coordinate password loading (only start libsecret operations after GSettings are 
loaded), and start the MQTT connection only when the password is loaded. Is there a best practice for this?

And third, after that is done, i thought i will communicate using a GIO pipe between the MQTT and the GUI 
threads. Does that sound like a good idea? Is there something better/unwritten standard for this? The other 
option that came to mind is to send direct “commands” to my some GObjects i create based on the MQTT events 
flowing in, but iʼm not sure it would bode well between threads.

Thanks in advance!

Best,
Gergely