MiniBrowser

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salvadordf
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Re: MiniBrowser

Post by salvadordf »

Read this :
https://stackoverflow.com/questions/39807377/how-to-get-windows-shutdown-event-in-fmx-project-as-wm-queryendsession-and-wm-en

Perhaps the second answer can help you.
Cantar
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Joined: Thu May 20, 2021 1:04 pm

Re: MiniBrowser

Post by Cantar »

Looking at the information on Google, it can be concluded that Chromium1,
that is, CEFWindowParent1,receives a WM_QUERYENDSESSION message,
but not the main form.
Can you implement a mechanism for passing these messages from Chromium1
to the main form VCL project?
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salvadordf
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Re: MiniBrowser

Post by salvadordf »

I just added this to the MiniBrowser demo to test this :

Code: Select all

protected
  procedure WMEndSession(var aMessage: TWMQueryEndSession); message WM_QUERYENDSESSION;

Code: Select all

procedure TMiniBrowserFrm.WMEndSession(var aMessage: TWMQueryEndSession);
var
  TempSL : TStringList;
begin
  TempSL := TStringList.Create;
  TempSL.Add('TMiniBrowserFrm.WMEndSession');
  TempSL.SaveToFile('1.txt');
  TempSL.Free;

  inherited;
end;
When I run the demo and closed the user session the demo created a file called 1.txt which means that the WM_QUERYENDSESSION message was received by the main form correctly. That message was not intercepted by Chromium.

Some other messages are intercepted by Chromium and you may get them in the TChromium.OnRenderCompMsg event.
Cantar
Posts: 16
Joined: Thu May 20, 2021 1:04 pm

Re: MiniBrowser

Post by Cantar »

Thanks.
Cantar
Posts: 16
Joined: Thu May 20, 2021 1:04 pm

Re: MiniBrowser

Post by Cantar »

When you click on the "Close" button, the application is quickly completed.
Below are the results of debugging the application closing.

Code: Select all

10.06.2021 19:37:54.872  FormCreated  
10.06.2021 19:37:55.028  Chromium1AfterCreated  CEF_AFTERCREATED
10.06.2021 20:23:11.638  FormCloseQuery 	CanClose 0
10.06.2021 20:23:11.674  Chromium1Close    	CEF_DESTROY cbaDelay
10.06.2021 20:23:11.678  BrowserDestroyMsg 	CEFWindowParent1 Free
10.06.2021 20:23:11.679  FormCloseQuery 	CanClose 1
10.06.2021 20:23:11.682  FormClose
However, when Win7 is turned off, and the form is not closed, the system requires
confirmation of the forced closing of the application. It is not very fast.
Project using third-party components. What's wrong?

Debug results of closing the application at session end.

Code: Select all

10.06.2021 19:50:44.872  FormCreated  
10.06.2021 19:50:45.028  Chromium1AfterCreated  CEF_AFTERCREATED
10.06.2021 20:23:21.530  FormCloseQuery 	CanClose 0
10.06.2021 20:23:21.532  Chromium1Close    	CEF_DESTROY cbaDelay
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salvadordf
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Re: MiniBrowser

Post by salvadordf »

If the application receives a WM_QUERYENDSESSION message then make sure it calls TChromium.CloseBrowser(TRUE);

The TRUE parameter will skip the JavaScript dialogs that ask the user for some confirmation before closing the browser.

I would also suggest that you send a WM_QUERYENDSESSION message manually while debugging your application in Delphi to see what could be the problem.
Cantar
Posts: 16
Joined: Thu May 20, 2021 1:04 pm

Re: MiniBrowser

Post by Cantar »

Thanks.
Yes I am calling TChromium.CloseBrowser (TRUE);
The cbaDelay parameter is set in the TChromium.Close event
When I manually send a WM_QUERYENDSESSION, the application immediately stops running.
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salvadordf
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Re: MiniBrowser

Post by salvadordf »

I read a few more pages about this and I can see clearly that I was wrong about the "end session" handling.

Chromium handles those two windows messages but the CEF source code don't :
https://source.chromium.org/search?q=WM_QUERYENDSESSION&ss=chromium
https://source.chromium.org/search?q=WM_ENDSESSION&ss=chromium

More information and guidelines from Microsoft :
https://docs.microsoft.com/en-us/windows/win32/rstmgr/guidelines-for-applications
https://docs.microsoft.com/en-us/windows/win32/shutdown/shutdown-changes-for-windows-vista
https://docs.microsoft.com/en-us/windows/win32/shutdown/wm-endsession
https://docs.microsoft.com/en-us/windows/win32/shutdown/wm-queryendsession

The CEF project maintainer gives this workaround :
https://magpcss.org/ceforum/viewtopic.php?f=6&t=15097

The are some interesting suggestions in this answer :
https://stackoverflow.com/questions/39807377/how-to-get-windows-shutdown-event-in-fmx-project-as-wm-queryendsession-and-wm-en

In addition to this, Delphi calls HALT when TApplication.WndProc receives a WM_ENDSESSION message.

I'll try to do more tests with all this information as soon as I have time... :oops:
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salvadordf
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Re: MiniBrowser

Post by salvadordf »

Please, download CEF4Delphi again.

I just added a workaround for this issue to the MiniBrowser demo.

TApplication calls HALT when it receives WM_ENDSESSION and we avoid that by returning False to WM_QUERYENDSESSION.
At that moment we can send WM_CLOSE to the main form to close it correctly but Windows may send WM_QUERYENDSESSION and WM_ENDSESSION to the CEF subprocesses before the main process. If that happens the CEF subprocesses will crash.

This is the new procedure in MiniBrowser :

Code: Select all

procedure TMiniBrowserFrm.WMQueryEndSession(var aMessage: TWMQueryEndSession);
begin
  // We return False (0) to close the browser correctly while we can.
  // This is not what Microsoft recommends doing when an application receives
  // WM_QUERYENDSESSION but at least we avoid TApplication calling HALT when
  // it receives WM_ENDSESSION.
  // The CEF subprocesses may receive WM_QUERYENDSESSION and WM_ENDSESSION
  // before the main process and they may crash before closing the main form.
  aMessage.Result := 0;
  PostMessage(Handle, WM_CLOSE, 0, 0);
end;
Cantar
Posts: 16
Joined: Thu May 20, 2021 1:04 pm

Re: MiniBrowser

Post by Cantar »

Thanks, It is Ok.
I upgraded my computer. Changed the hard disk on SSD
add 6 GB memory, installed Win10 64
and now the application shutdown immediatly.

Best regerd
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