CefSharp 3 set proxy at Runtime

Question

I downloaded CEF (chromuim embedded framework) binary distributation that comes with (cefclient & cefsimple) c++ examples, And Realized that cefclient can change proxy settings on run-time.

And the key to do that is to Grab the RequestContext and call the function SetPreference.

on CefClient all works just nice.

but on CefSharp calling SetPreference always returns false, and also HasPreference returns false for the preference name "proxy".

Answer 1

thanks to amaitland the proper way to actively inforce changing the request-context prefrences, is to run the code on CEF UIThread as following:

    Cef.UIThreadTaskFactory.StartNew(delegate {
        var rc = this.browser.GetBrowser().GetHost().RequestContext;
        var v = new Dictionary<string, object>();
        v["mode"] = "fixed_servers";
        v["server"] = "scheme://host:port";
        string error;
        bool success = rc.SetPreference("proxy", v, out error);
        //success=true,error=""
    });

Answer 2

if anyone need any other soulition i found this solution.

Cef.UIThreadTaskFactory.StartNew(delegate
        {
            string ip = "ip or adress";
            string port = "port";
            var rc = this.browser.GetBrowser().GetHost().RequestContext;
            var dict = new Dictionary<string, object>();
            dict.Add("mode", "fixed_servers");
            dict.Add("server", "" + ip + ":" + port + "");
            string error;
            bool success = rc.SetPreference("proxy", dict, out error);

        });

Answer 3

I downloaded CefSharp.WinForms 65.0.0 and made class, that can help to start working with proxy:

public class ChromeTest
{
    public static ChromiumWebBrowser Create(WebProxy proxy = null, Action<ChromiumWebBrowser> onInited = null)
    {
       var result = default(ChromiumWebBrowser);
        var settings = new CefSettings();
        result = new ChromiumWebBrowser("about:blank");
        if (proxy != null)
            result.RequestHandler = new _requestHandler(proxy?.Credentials as NetworkCredential);

        result.IsBrowserInitializedChanged += (s, e) =>
        {
            if (!e.IsBrowserInitialized)
                return;

            var br = (ChromiumWebBrowser)s;
            if (proxy != null)
            {
                var v = new Dictionary<string, object>
                {
                    ["mode"] = "fixed_servers",
                    ["server"] = $"{proxy.Address.Scheme}://{proxy.Address.Host}:{proxy.Address.Port}"
                };
                if (!br.GetBrowser().GetHost().RequestContext.SetPreference("proxy", v, out string error))
                    MessageBox.Show(error);
            }

            onInited?.Invoke(br);
        };

        return result;
    }

    private class _requestHandler : DefaultRequestHandler
    {
        private NetworkCredential _credential;

        public _requestHandler(NetworkCredential credential = null) : base()
        {
            _credential = credential;
        }

        public override bool GetAuthCredentials(IWebBrowser browserControl, IBrowser browser, IFrame frame, bool isProxy, string host, int port, string realm, string scheme, IAuthCallback callback)
        {
            if (isProxy == true)
            {
                if (_credential == null)
                    throw new NullReferenceException("credential is null");

                callback.Continue(_credential.UserName, _credential.Password);
                return true;
            }

            return false;
        }
    }
}

Using:

        var p = new WebProxy("Scheme://Host:Port", true, new[] { "" }, new NetworkCredential("login", "pass"));
        var p1 = new WebProxy("Scheme://Host:Port", true, new[] { "" }, new NetworkCredential("login", "pass"));
        var p2 = new WebProxy("Scheme://Host:Port", true, new[] { "" }, new NetworkCredential("login", "pass"));

        wb1 = ChromeTest.Create(p1, b => b.Load("http://speed-tester.info/check_ip.php"));
        groupBox1.Controls.Add(wb1);
        wb1.Dock = DockStyle.Fill;

        wb2 = ChromeTest.Create(p2, b => b.Load("http://speed-tester.info/check_ip.php"));
        groupBox2.Controls.Add(wb2);
        wb2.Dock = DockStyle.Fill;

        wb3 = ChromeTest.Create(p, b => b.Load("http://speed-tester.info/check_ip.php"));
        groupBox3.Controls.Add(wb3);
        wb3.Dock = DockStyle.Fill;