How to use CefV8Context?

[eren]

So i'm using CEF3 and i need to do the following things:
1) wait until some HTML page is fully loaded;
2) then execute my own JavaScript function;
3) then read the result of this function into CefString.

I tried to use CefV8Context in ClientHandler::OnLoadEnd function.

Code: Select all

void ClientHandler::OnLoadEnd(CefRefPtr<CefBrowser> browser,
                       CefRefPtr<CefFrame> frame,
                       int httpStatusCode)
{
   if ((httpStatusCode != 0) && frame->IsMain())
   {
      CefRefPtr<CefV8Context> v8Context = frame->GetV8Context();
      CefRefPtr<CefV8Value> globalObj = v8Context->GetGlobal();
      
      CefRefPtr<CefV8Handler> handler = …;
      CefRefPtr<CefV8Value> func = CefV8Value::CreateFunction("myfunc", handler);

      CefV8ValueList args;
      CefRefPtr<CefV8Exception> exception;
      CefRefPtr<CefV8Value> retVal = evalFunc->ExecuteFunctionWithContext(v8Context, globalObj, args);
      CefString retValStr = retVal->GetStringValue();
   }
}


But application crashes on

CefRefPtr<CefV8Value> globalObj = v8Context->GetGlobal();

string.

What am i doing wrong?
And can this be made via CefRegisterExtension? Because I don't actually want to rewrite the native JavaScript code into CEF native implementation.

[magreenblatt]

V8 can only be used in the renderer process. ClientHandler::OnLoadEnd is probably called in the browser process. See https://code.google.com/p/chromiumembed ... h_Contexts.

[eren]

So how do i achieve this:

1) wait until some HTML page is fully loaded;
2) then execute my own JavaScript function;
3) then read the result of this function into CefString.

?
Do i need to call CefPostTask(TID_RENDERER, task) from ClientHandler::OnLoadEnd function? Or is there a better ways?

[magreenblatt]

1) wait until some HTML page is fully loaded;

Use document.onload via JS if you control the HTML contents or CefLoadHandler::OnLoadingStateChange via native code. CefLoadHandler is also supported in the renderer process with newer CEF versions via CefRenderProcessHandler::GetLoadHandler.

2) then execute my own JavaScript function;

Use any of the techniques described on the JavaScriptIntegration wiki page.

3) then read the result of this function into CefString.

What process do you need the result in? If the browser process then send a message from the renderer process after executing your JS function as described in https://code.google.com/p/chromiumembed ... e_Messages.

[eren]

Thank you, magreenblatt! This is exaclty what i was looking for.