gistfile1.cs

public class NotAcceptableConnegHandler : DelegatingHandler
{
	private const string allMediaTypesRange = "*/*";

	protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
	{
		var acceptHeader = request.Headers.Accept;
		if (!acceptHeader.Any(x => x.MediaType == allMediaTypesRange))
		{
			var hasFormetterForRequestedMediaType = GlobalConfiguration
								.Configuration
						                .Formatters
								.Any(formatter => acceptHeader.Any(mediaType => formatter.SupportedMediaTypes.Contains(mediaType)));

			if (!hasFormetterForRequestedMediaType)
				return Task<HttpResponseMessage>.Factory.StartNew(() => new HttpResponseMessage(HttpStatusCode.NotAcceptable));
		}
		return base.SendAsync(request, cancellationToken);
	}   
}