Call .NET from JavaScript using CefGlue / CEF3

Question

There is an existing solution for CefGlue: Call .Net from javascript in CefSharp 1 - wpf

I want exactly this, but for CefGlue: I want to communicate with the App using JavaScript. So when I click a button in my HTML site, I want the application to handle this (for example: start a tcp server).

I tried to register an own CefV8Handler but without success, the Execute function on the handler is never called. Here is what I do right now

    protected override void OnWebKitInitialized()
    {
        Console.WriteLine("Registering testy extension");
        Xilium.CefGlue.CefRuntime.RegisterExtension("testy", "var testy;if (!testy)testy = {};(function() {testy.hello = function() {};})();", new V8Handler());
        base.OnWebKitInitialized();
    }

My V8Handler code looks as follows:

public class V8Handler : Xilium.CefGlue.CefV8Handler
{

    protected override bool Execute(string name, CefV8Value obj, CefV8Value[] arguments, out CefV8Value returnValue, out string exception)
    {

        if (name == "testy")
            Console.WriteLine("CALLED TESTY");
        else
            Console.WriteLine("CALLED SOMETHING WEIRED ({0})", name);

        returnValue = CefV8Value.CreateNull();
        exception = null;
        return true;

    }

}

I'm in multiprocess mode, no console window shows "CALLED TESTY" nor "CALLED SOMETHING WEIRED".

How are you calling testy from the Javascript side? – PhysicalEd Jun 16 '15 at 15:37 — PhysicalEd, Jun 16 '15 at 15:37

score 1 · Accepted Answer · answered Jun 16 '15 at 16:01

Found a solution for that. The trick is to create a CefV8Value (CreateFunction) and assign it to a V8Handler. Then assign this value to the global context. This is what it looks like:

internal class RenderProcessHandler : CefRenderProcessHandler
{

    protected override void OnContextCreated(CefBrowser browser, CefFrame frame, CefV8Context context)
    {
        CefV8Value global = context.GetGlobal();
        CefV8Value func = CefV8Value.CreateFunction("magic", new V8Handler());
        global.SetValue("magic", func, CefV8PropertyAttribute.None);
        base.OnContextCreated(browser, frame, context);
    }

}

Another problem came up: it was called in the renderer process, but I required the callback in the browser process. In the CefV8Handlers execute function i did this:

var browser = CefV8Context.GetCurrentContext().GetBrowser();
browser.SendProcessMessage(CefProcessId.Browser, CefProcessMessage.Create("ipc-js." + name));

This way I can retrive the message in the OnProcessMessageReceived function in the CefClient implementation.

Call .NET from JavaScript using CefGlue / CEF3

1 Answers1