How to download update installation automatically

canid

hello，I want the program to download and install automatically. I can let the program download the installation file, but I don't know how to install it automatically in the background,How do I do that？thanks!

sierdzio

The answer depends heavily on the platform, on some it is impossible to update silently (Android for example). Check how Chrome and Firefox are doing it.

canid

@sierdzio
Yes, how to install silently in Windows, I see some games can be done, such as StarCraft 2, thank you

sierdzio

On Windows it should be enough to run the installer with QProcess, passing silent flag with it.

The problem is, of course, when the installer replaces the executable (which is in use). I don't know what is the recommended way to work around it. You probably need to start a detached QProcess, then programmatically exit the application, then the installer should re-open the app.

canid

@sierdzio
Yes，How does QProcess pass the silent flag? thanks

Bonnie

I think Firefox has a background service to do the silent installation.
Seems like that it will wait untill all of the Firefox instances are manually exited and then install the update files silently.
And I feel that must be very complicated...

sierdzio

@canid said in How to download update installation automatically:

@sierdzio
Yes，How does QProcess pass the silent flag? thanks

That's a question to your installer, not me :-) Each installer technology handles it differently. And you can cook up a custom installer, too.

canid

@sierdzio
I use QProcess:: Start () to get the upgrade installed automatically, but how do I get the callback to restart after it's installed

JonB

@canid
Do you mean you want to know when the QProcess is finished, or something else?

canid

@JonB
Yes, I had some difficulties writing code when qprocess is finished

JonB

@canid
OK, so search the doc page for finished, and you'll come across signal https://doc.qt.io/qt-5/qprocess.html#finished. Put a slot on that. When it's hit, the sub-process has finished.

Bonnie

Does your installing include upgrading this currently running executable file and other files being used by it like the dlls?
If yes you can't wait the process to be finished, but exit immediately after starting the process detached, otherwise those files can never be upgraded.

canid

@Bonnie
My code writes like this, the installation program also started, but did not output "started". What's wrong with it?

QProcess *process = new QProcess(this);
process->start("D:\\mysoft.exe", QStringList()<<"/SILENT");
connect(process,&QProcess::started,this,[](){
        qDebug()<<"started";
    });

Bonnie

@canid
You should connect the signal before you call start.