novotnyllc / WinRtHttpClientHandler

WinRtHttpClientHandler

An HttpMessageHandler that lets you use the Windows Runtime IHttpFilter types

This could be used in a platform-specific factory method that returns a concrete HttpClient for your app's use.

The main motivation for this is due to the need for supporting invalid SSL certificates. While generally bad practice, there are some cases where you need to connect to an endpoint without a valid SSL certificate. In .NET, you can either use the WebRequestHandler or ServicePointManager to override SSL validation. Windows 8.1 does this with its new Windows.Web.HttpClient.

The problem occurs if you want to use Portable Class Libraries to share logic between platforms. In that case, you'll need to use the System.Net.Http.HttpClient, but unfortunately on Windows 8 and 8.1, there's no way for that class to override SSL Validation.

Thus this WinRtHttpClientHandler. You'll still need platform-specific factory libraries (see the Adaptation/Enlightenment patterns), but from there, you can return a System.Net.Http.HttpClient to your PCL.

Internally, the WinRtHttpClientHandler uses the "new" Windows 8.1 WinRT Windows.Web.HttpClient, so you can use any compatible IHttpFilter. The default one is HttpBaseProtocolFilter.

Installation

The easiest way to get started is to use the NuGet package.

Install-Package WinRtHttpClientHandler -pre

Sample usage in a PCL:

public interface IHttpClientCreator
{
    System.Net.Http.HttpClient Create();
}

public class MyWin81Factory : IHttpClientCreator
{
    public System.Net.HttpClient Create()
    {
        var filter = new HttpBaseProtocolFilter(); // do something with this
        filter.IgnorableServerCertificateErrors.Add(...)
        var client = new System.Net.Http.HttpClient(new WinRtHttpClientHandler(filter));
        return client;
    }
}

public class MyNetFxFactory : IHttpClientCreator
{
    static MyNetFxFactory()
    {
        ServicePointManager.ServerCertificateValidationCallback = ...
    }

    public HttpClient Create()
    {
        var client = new HttpClient();
    }
}