cefsharp/CefSharp

Losing access to bound object

Opened this issue · 4 comments

mstrattonHarris commented

Is there an existing issue for this?

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

CefSharp Version

126.2.180.0

Operating System

Windows 10

Architecture

x86

.Net Version

Net 4.8

Implementation

WinForms

Reproduction Steps

We have bound to the CefSharp browser using the sync "bound" object and everything works fine until the page has been idle for about 20 minutes. Then any access to the bound object fails and we have to force the browser to close without performing a save. I have searched high an low on how to prevent the "bound" object from being lost over long periods of time.

i have tried modifying IIS to have no timeouts, i have tried writing a "keepAlive" javascript call taht will go the server and pull down a json file and have been fighting this time out regardless of implementing it through sync or async calls.

The web page I am rendering is a 3rd party web page and it launches dialogs in our C# application when needing to create new information to be included on the page.

I dont have a way to provide you with a sample with all of the things involved but what i can say is we do the following:

/////////// I DECLARE IT WITH LegacyBindingEnabled - was seeing CefSharp.BrowserSubprocess error and this fixed it //////////
_browser = new ChromiumWebBrowser(_url)
{
Dock = DockStyle.Fill
};
_browser.JavascriptObjectRepository.Settings.LegacyBindingEnabled = true;

///////////////// I BIND IT WITH OUR CUSTOM OBJECT ///////////////////////

    if (_boundObject != null)
        {
            boundBrowser = new CustomBoundObject(_browser);
            _browser.JavascriptObjectRepository.Register("bound", _boundObject, false);
        }

/////////// I CAN CONFIRM IT BINDS ///////////////////

        _browser.JavascriptObjectRepository.ObjectBoundInJavascript += (sndr, evt) =>
        {
            _bObjectBounded = true;
            var name = evt.ObjectName;
            System.Diagnostics.Debug.WriteLine($"Object {name} was bound successfully.");
        };

All calls are good until what i suspect is a timeout occurs. I set IIS to 0 for timeout to make it indefinite and that did not help.

Expected behavior

I expect the bound object to be present.

Actual behavior

Bound object is present until time passes and then in dev tools, i set a break point where we will first access the bound object. In the watch window, it is still showing as an object until i invoke the call and then it goes to undefined.

Regression?

We upgraded from version 73.1.30 to 126.2.180. Original implementation I did not discover the IJavascritpCallback steps i needed to do and I implemented my changes asynchronously. That also lost its binding over time

Known Workarounds

None

Does this problem also occur in the CEF Sample Application

Not Tested

Other information

No response

mstrattonHarris commented

I will add that this is the exception i think i am getting: System.IO.PipeException: 'There was an error reading from the pipe: The pipe has been ended. (109, 0x6d).'

amaitland commented

What version are you using? Please only open an issue if you can reproduce the problem with version 130.1.90 or later.

As per https://github.com/cefsharp/CefSharp/blob/master/.github/ISSUE_TEMPLATE/bug_report.yml

CefSharp Version
126.2.180.0

Does your problem reproduce with the current supported version? M131 at time of writing.

mstrattonHarris commented
amaitland commented

Firstly thank you for the kind words!

Apologies on the delay, just getting back on top of things after being on holiday for a few weeks over Christmas.

I feel that this background is needed for you to understand that this is NOT a problem that any modern application should have. The application architecture has seen many developers over the years and it shows from old school DLL best practices, COM implementations, WPF and XAML.

Sounds like you are in for an interesting challenge! 😄 I can relate having worked on an application that's evolved greatly over the past decade!

The good news is we got it working to a point where the web page will not launch a new C# dialog but we can still save its current state allowing us to close and reopen the web page with a new instance of our BrowserForm dialog. To achieve this, we ultimately used the Cef.DoMessageLoopWork along with making the web page async and calling a synchronous call in the bound object.

Just to clarify are you still having an issue with losing access to the bound object?

M126 was the first version to switch over to using the Chrome Bootstrap. If you are still having problems you could try switching back to the Alloy bootstrap (which was removed upstream in M128).

#4835 (comment)