CanExecuteJavascriptInMainFrame incorrectly false after loading page with different origin

[amaitland]

• What version of the product are you using?

79.1.310-pre

• What architecture x86 or x64?

Both

• On what operating system?

Win10

• Are you using WinForms, WPF or OffScreen?

WinForms/WPF/OffScreen

• What steps will reproduce the problem?

  • Open the WPF or WinForms example projects
  • Attach debugger breakpoint at https://github.com/cefsharp/CefSharp/blob/cefsharp/79/CefSharp.Core/Internals/ClientAdapter.cpp#L1049
  • Attach debugger breakpoint at https://github.com/cefsharp/CefSharp/blob/cefsharp/79/CefSharp.Core/Internals/ClientAdapter.cpp#L1073
  • Wait for google.com to load
  • Load a second web page with a different origin e.g. github.com

• What is the expected output? What do you see instead?

Expected
After loading google.com
SetCanExecuteJavascriptOnMainFrame(true)
After loading github.com
SetCanExecuteJavascriptOnMainFrame(true)
SetCanExecuteJavascriptOnMainFrame(false)

Actual
After loading google.com
SetCanExecuteJavascriptOnMainFrame(true);
After loading github.com
SetCanExecuteJavascriptOnMainFrame(false;
SetCanExecuteJavascriptOnMainFrame(true);

The order of the process messages from the render process is sent in a different order than expected after a render process switch.

[amaitland]

The options at this stage are

1. Remove CanExecuteJavascriptInMainFrame
2. Set CanExecuteJavascriptInMainFrame via a combination of FrameLoadStart/FrameLoadEnd/LoadingStateChanged

[amaitland]

The checks are only used in the extension methods, you can directly call the relevant IFrame methods and no checks will be performed.

• http://cefsharp.github.io/api/79.1.x/html/M_CefSharp_IFrame_EvaluateScriptAsync.htm
• http://cefsharp.github.io/api/79.1.x/html/M_CefSharp_IFrame_ExecuteJavaScriptAsync.htm

The extension methods execute on the main frame, call ChromiumWebBrowser.GetMainFrame() which will return an IFrame instance.

[amaitland]

From memory the frame identifier changes on render process switch, we might be able to use this to discard the second message.

[JogyBlack]

We have a similar issue, and a workaround that we implemented is to force a reload of the browser if CanExecuteJavascriptInMainFrame is false:

...
browser.LoadingStateChanged += Browser_LoadingStateChanged;
...
private void Browser_LoadingStateChanged(object sender, LoadingStateChangedEventArgs e)
{
  if (!e.IsLoading)
  {
    if (!browser.CanExecuteJavascriptInMainFrame)
      browser.Reload();
  }
}

The immediate reloading of the page is not very noticeable, and when the reloading finishes, CanExecuteJavascriptInMainFrame is true and we can execute JS on the page.

[amaitland]

• Ignore OnContextReleased that arrives after OnContextCreated when the frameId is greater.
• Add unit tests.

[amaitland]

The v81.3.20-pre packages are now on Nuget.org for anyone interested in testing this.

[Cloudmersive]

This was never fixed

[amaitland]

The test case added in commit 2a62f97 passes successfully. If you are having problems please provide a failing test case (Please create a pull request).