winforms: setting `remote-allow-origins` does not show remote origins on set port with Chrome bootstrap

[m-kovac]

Describe the bug

With CefSharp v126.2.70, CEF v126.0.6478.115 the remote-allow-origins parameter with set localhost:port stopped to have effect. This is connected to switch from Alloy bootstrap to Chrome bootstrap.

To Reproduce

1. Clone https://github.com/cefsharp/CefSharp.MinimalExample
2. Open solution CefSharp.MinimalExample.net472
3. Update CefSharp for CefSharp.MinimalExample.WinForms.net472 to v126.2.70
4. In CefSharp.MinimalExample.WinForms.net472 project Program.cs set following settings to CefSettings

settings.RemoteDebuggingPort = 1236; 
settings.CefCommandLineArgs.Add("remote-allow-origins", $"http://localhost:{settings.RemoteDebuggingPort}");

5. Start the project
6. Open new browser window and go to localhost:1236
7. Observe empty window
8. Stop the project
9. Add setting settings.ChromeRuntime = false; to CefSettings to change back to Alloy bootstrap
10. Start the project
11. Go to localhost:1236
12. Observe window with the link to "Google"

Expected behavior
The remote-allow-origins should work with Chrome bootstrap.

Screenshots

Missing link

Expected behavior

Versions (please complete the following information):

• OS: Windows 11
• CEF Version: v126.0.6478.115
• CefSharp Version: v126.2.70

[magreenblatt]

The remote-allow-origins flag is implemented in Chromium. I suggest that you test the behavior in Google Chrome.

[m-kovac]

Sorry, I don't understand. What should I test in Google Chrome?

[magreenblatt]

What should I test in Google Chrome?

You should test how the --remote-allow-origins flag behaves in Google Chrome. From the code:

// Enables web socket connections from the specified origins only. '*' allows
// any origin.

[magreenblatt]

Go to localhost:1236
Observe window with the link to "Google"

You should use chrome://inspect/ for connecting to remote debugging.

[magreenblatt]

Your "Missing link" and "Expected behavior" screenshots are also both showing Chrome style windows.

[magreenblatt]

Closing this issue as WontFix given that CEF has no special handling for the --remote-allow-origins flag, and there are better/preferred ways to access remote debugging if that is the intention.

[SiMoStro]

To be honest, we are facing the exact same problem starting from v126 and I don't get the "WontFix" reason; we were able to successfully use the "--remote-allow-origins" switch:

cefsharp/CefSharp#4894

this seems a regression to me, either in CEF or in CefSharp :-/

[jozefizso]

Opening the URL for the remote debugging port on previous CEF releases will load the JSON with list of active browser instances:

This no longer happens for the v126:

Requesting the JSON manually for v126 does work:

 curl http://localhost:1236/json/list?t=1722606942069
[ {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:1236/devtools/page/A4A02D4EEDF8E9EDB16F4C71237DB7FD",
   "id": "A4A02D4EEDF8E9EDB16F4C71237DB7FD",
   "title": "Slido",
   "type": "page",
   "url": "https://app.example.org/",
   "webSocketDebuggerUrl": "ws://localhost:1236/devtools/page/A4A02D4EEDF8E9EDB16F4C71237DB7FD"
} ]

And opening the devtoolsFrontendUrl in the browser will show the Dev Tools for the running CEF instance.