Javascript blocking execution and shutdown

[sflitter97]

Is there an existing issue for this?

• I have searched both open/closed issues, no issue already exists.

CefSharp Version

112.3.0

Operating System

Windows 10

Architecture

x64

.Net Version

.Net 4.7.2

Implementation

WinForms

Reproduction Steps

Go to Cefsharp.Offscreen.Example and replace TestUrlOne with "hxxps://meme-of-the-day-one[.]vercel[.]app/api/MemeOfTheDay" ("xx"s and brackets added so you don't accidentally navigate to this url). It's kind of malicious in that it tries to use up all your computer's memory.

Expected behavior

I would like to be able to navigate to this site, finish processing after some time (even if I had to set a timeout) and shut cef down.

Actual behavior

The javascript loop keeps running in the background, and in my application I end up calling Cef.Shutdown() and hanging bc that javascript is running. I have tried calling m_browser.Stop(); and var browser = webBrowser.GetBrowser(); browser.StopLoad();, but neither of those stops the javascript loop.

Basically, I cannot find a way to programmatically shut cef down instead of hanging infinitely.

Regression?

I don't think so. My application is running on an older version, and that's where I discovered this problem. I tried using Cefsharp.Offscreen.Example (newest version) to repro and that succeeded; so I don't think it's unique to a recent version of CefSharp.

Known Workarounds

none

Does this problem also occur in the CEF Sample Application

Yes using WPF/OffScreen command line args

Other information

Sorry if this isn't the right place for this question. I have searched the internet and asked chatgpt and found no results. This is significantly hurting our cloud app so I figured I'd reach out. If it's not the right place please let me know where I should be asking this :)

[amaitland]

If you are new to the project then please make sure to read the first few paragraphs of https://github.com/cefsharp/CefSharp/wiki/General-Usage

Sorry if this isn't the right place for this question.

Try asking on https://www.magpcss.org/ceforum/index.php to see if there's a way for CEF to gracefully handle this scenario.

I suspect that CEF would need code changes to gracefully close the browser.

[aimcosoftware]

I have only done a simple test on this, but you can close the browsersubprocess, without having to shutdown CEF.

[aimcosoftware]

I was interested in this for our project, so did some work on it.

You'll need to get the ProcessId from javascript, before the page loads:

Private ProcessId As Integer

Private Sub Browser_FrameLoadStart(sender As Object, e As FrameLoadStartEventArgs) Handles Browser.FrameLoadStart
  If e.Frame.IsMain Then
    e.Frame.ExecuteScriptAsync("CefSharp.PostMessage(CefSharp.RenderProcessId)")
  End If
End Sub

' Get the ProcessId
Sub Browser_JavascriptMessageReceived(sender As Object, e As JavascriptMessageReceivedEventArgs) Handles Browser.JavascriptMessageReceived
  ProcessId = e.Message
End Sub

Sub TerminateRenderProcess()
  If ProcessId Then
      Process.GetProcessById(ProcessId).Kill()
    End If
End Sub