How to implement HttpMessageHandler in Web API?

Question

In an ASP.NET 4.5 MVC 4 Web API project, I want to add a custom HttpMessageHandler. I\'ve changed WebApiConfig class (in \\App_Satrt\\WebApiConfig.

Answer 1

To write a custom message handler, you should derive from System.Net.Http.DelegatingHandler

class CustomMessageHandler : DelegatingHandler
{
    protected override Task 
      SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        IPrincipal principal = new GenericPrincipal(
            new GenericIdentity("myuser"), new string[] { "myrole" });
        Thread.CurrentPrincipal = principal;
        HttpContext.Current.User = principal;

        return base.SendAsync(request, cancellationToken);
    }
}

And call base.SendAsync to send the request to the inner handler.