OnContextCreated may not always be called in renderer process

[cp3chao]

class CefClientApp : public CefApp,
public CefRenderProcessHandler {
public:
virtual CefRefPtr GetRenderProcessHandler()
override { return this; }

// CefRenderProcessHandler methods.
virtual void OnContextCreated(CefRefPtr<CefBrowser> browser,
	CefRefPtr<CefFrame> frame,
	CefRefPtr<CefV8Context> context) override;
     ........................................

}

the class CefClientApp inherits from Class CefRenderProcessHandler，I will register some methods in function OnContextCreated：

void CefClientApp::OnContextCreated(CefRefPtr browser,
CefRefPtr frame,
CefRefPtr context)
{
auto object = context->GetGlobal();
auto externalObj = CefV8Value::CreateObject(nullptr, nullptr);
object->SetValue("external", externalObj, V8_PROPERTY_ATTRIBUTE_NONE);
CefRefPtr cefV8Handler = new CefV8Client();
// the WebExtFunc:: is my defined functions list, the following method is registering the function
for (int i = 0; i < WebExtFunc::NameCount; i++)
{
externalObj->SetValue(WebExtFunc::Names[i], CefV8Value::CreateFunction(WebExtFunc::Names[i], cefV8Handler.get()), V8_PROPERTY_ATTRIBUTE_NONE);
}
}

A very random issue：
Sometimes it's difficult to reproduce even after opening the application many times, and sometimes it's easy to reproduce.
I opened the application multiple times and found that the function list registered under window.external was empty.

Expected behavior
Every time the application is opened, the function list in window.external can be registered normally in the renderer process.

Versions (please complete the following information):

• OS: Windows 11 -11th Gen Intel(R) Core(TM) i7-1185G7 @ 3.00GHz 3.00 GHz
• CEF Version: cef_binary_128.4.9+g9840ad9+chromium-128.0.6613.120

[cp3chao]

I see a similar problem, but it hasn't been resolved yet: OnContextCreated not always called when LoadUrl causes creation of new Renderer process · Issue #485 · cztomczak/cefpython · GitHub

[magreenblatt]

Sometimes it's difficult to reproduce even after opening the application many times, and sometimes it's easy to reproduce.

What URL are you loading? Is it the same URL every time?

[cp3chao]

Sometimes it's difficult to reproduce even after opening the application many times, and sometimes it's easy to reproduce.
What URL are you loading? Is it the same URL every time?

the URL is a website for our internal services. Yes, it is the same URL every time.

[magreenblatt]

OnContextCreated will only be called in cases where the frame source contains JavaScript code. When OnContextCreated is not called for you has your URL loaded correctly, and has it loaded/executed JavaScript code?

[cp3chao]

OnContextCreated will only be called in cases where the frame source contains JavaScript code. When OnContextCreated is not called for you has your URL loaded correctly, and has it loaded/executed JavaScript code?

Yes, the URL loaded correctly. The functions that should have been registered in Window. external in function OnContextCreated was not successfully registered, so I suspect that this OnContextCreated function has not been executed.

Functions registered in window.external under normal circumstances：

If there is a problem, this window.external is empty：

At present, the usage scenario of CEF is for login, and the operation is the same every time the application is opened. Normally, window.external has the function we registered, but in case of problems, it is empty. It's just strange.This problem occurs very randomly.

[magreenblatt]

Do you always create window.external (every call to OnContextCreated) or is it conditional?

[cp3chao]

Do you always create window.external (every call to OnContextCreated) or is it conditional?

yes, when opening my application, the OnContextCreated function should be called, and the window.external should be created every call. So It's just strange that the window.external is empty sometimes.

[cp3chao]

Hi, @magreenblatt
Is there any update? thanks!

[magreenblatt]

I'll leave this issue open, but it's unlikely to be addressed without clear and reliable reproduction steps.