winforms - chromium - send custom header info on initial page load c#

Question

Or How to inject a custom header into the initial request to a site when new-ing up an instance of the ChromiumWebBrowser.

I'm a noob with Chromium and could really use some help. I have a winforms app with a CEF window. K, no prob so far. What I need to do is to call/load the initial url with a custom http-header that contains authentication info. Is this possible?

The following is essentially what is at play and all parts work except the custom header (Doh!)

Winform(CEF httpRequest(with custom header)) [never gets past this point]=> C# MVC web app => Owin_Authentication_Pipeline segment => MVC Response with populated Razor view => Shows up in Winform Chromium app.

Maybe this will help as well:

using CefSharp;
using CefSharp.WinForms;
...
private void Form1_Load(object sender, EventArgs e)
{
    Cef.Initialize();
    ChromiumWebBrowser myBrowser = new ChromiumWebBrowser("whatever.com");
    // ??How do i get a custom header be sent with the above line??

    myBrowser.Dock = DockStyle.Fill;
    //myBrowser.ShowDevTools();
    //myBrowser.RequestHandler = new DSRequestHander();
    //myBrowser.FrameLoadStart += myBrowser_FrameLoadStart;
    this.Controls.Add(myBrowser);
}

I Groggled this to death, looked, tried all the tricks in my toolbox and then some.

Any ideas, help or hints on how I might be able to solve or get around this boggler is greatly appreciated. Thanks in advance.

Answer 1

Updated to reflect major Chromium changes

Updated to reflect changes made in version 75 (should work in 75 and newer)

The method you're after should be OnBeforeResourceLoad, a basic example should look like:

public class CustomResourceRequestHandler : ResourceRequestHandler
{
    protected override CefReturnValue OnBeforeResourceLoad(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, IRequest request, IRequestCallback callback)
    {
        var headers = request.Headers;
        headers["User-Agent"] = "My User Agent";
        request.Headers = headers;

        return CefReturnValue.Continue;
    }
}

public class CustomRequestHandler : RequestHandler
{
    protected override IResourceRequestHandler GetResourceRequestHandler(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, IRequest request, bool isNavigation, bool isDownload, string requestInitiator, ref bool disableDefaultHandling)
    {
        return new CustomResourceRequestHandler();
    }
}

browser.RequestHandler = new CustomRequestHandler();

Using the IRequest.Headers property you must read the headers property, make changes then reassign it. It's now possible to use the SetHeaderByName/GetHeaderByName functions to get/set a single header.

• RequestHandler API Doc
• ResourceRequestHandler API Doc
• IRequest.GetHeaderByName API Doc
• IRequest.SetHeaderByName API Doc