[Development] Moving QDesktopServices from Gui to Core?

[Lars Knoll]

> On 6 May 2024, at 09:02, Marc Mutz via Development <development at qt-project.org> wrote:
> 
> Hi,
> 
> Juha is currently improving the OAuth implementation in QtNetworkAuth. 
> The protocol involves launching the system browser to get an access 
> code, in turn used to get access tokens with which services can then be 
> accessed.
> 
> OAuth therefore requires a UI to run the browser in, but not necessarily 
> a _G_UI (the system browser could be lynx). Even if a CLI tool like a 
> mail fetcher, backup program, or VPN client will eventually launch 
> Firefox or Chrome, I think it's too much to ask to link to QtGui just to 
> do the equivalent of exec xdf-open <url>.

I’d agree with that. And there’s no way to do OAuth without launching a browser during the authentication process.
> 
> I've looked at the implementation of openUrl(), and the only 
> Gui-dependency is on the platform helpers. The handler registration is 
> only using Core functionality.
> 
> I would therefore propose to move the services code from Gui to Core 
> (QTBUG-125085), so QtNetworkAuth can access it w/o incurring a Gui 
> dependency.
> 
> After a quick look, I can see two ways to do that:
> - keep the platform handling code in the platform helpers, incl. Gui 
> dependency, and only move the handler registration to Core
> - move the platform url handlers out of the platform helpers into (a 
> plugin for) Core
> 
> The first would enable users to write their own handlers w/o Gui 
> dependency, but has the disadvantage that the code behaves differently, 
> depending on whether QtGui is loaded or not.
> 
> The second would be more work, but with consistently better user experience.
> 
> Is there a reason other than history for the openUrl handlers to be in 
> the platform handlers? We have XDG-code in QtCore already (mime types), 
> so we should have all the information in Core already to implement the 
> functionality, should we not?

I believe the reason for this is mainly history. Moving this to Qt Core makes sense IMO.

I don’t think you need a separate plugin for Qt Core to implement this though. I’m a bit unsure about the windows code, but on Linux and macOS it’s simply launching ‘xdg-open’ or ‘open’. It would probably fit better to simply follow the usual pattern for Qt Core with a _platform.cpp implementation file.

Cheers,
Lars


> 
> Thanks,
> Marc
> 
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> 
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