HeaderControllerSelector

public class HeaderControllerSelector : DefaultHttpControllerSelector
{
    public HeaderControllerSelector(HttpConfiguration configuration) : base(configuration)
    {
    }

    public override string GetControllerName(HttpRequestMessage request)
    {
        string controllerName = base.GetControllerName(request);

        if (!request.Headers.Contains("Accept"))
            return controllerName;

        IEnumerable<string> acceptHeaders = request.Headers.GetValues("Accept");

        string headerValue = GetVertionFromHeaders(acceptHeaders);

        if (string.IsNullOrWhiteSpace(headerValue) || headerValue == "1")
        {
            return controllerName;
        }

        int controllerVersion;

        if (!int.TryParse(headerValue, out controllerVersion))
        {
            return controllerName;
        }

        controllerName = string.Format("{0}v{1}", controllerName, controllerVersion);

        HttpControllerDescriptor controllerDesc = null;

        bool isVersionFound = GetControllerMapping().TryGetValue(controllerName, out controllerDesc);

        if (!isVersionFound)
        {
            string message = "No HTTP resource was found for specified request URI {0} and version {1}";

            throw new HttpResponseException(request.CreateErrorResponse(HttpStatusCode.NotFound, String.Format(message, request.RequestUri, controllerVersion)));
        }

        return controllerName;
    }

    private static string GetVertionFromHeaders(IEnumerable<string> acceptHeaders)
    {
        foreach (string header in acceptHeaders)
        {
            string[] sk = header.Split(';');

            foreach (string acceptDef in sk)
            {
                string[] def = acceptDef.Trim().Split('=');

                if (def.Length == 2 && def[0] == "version")
                {
                    return def[1];
                }
            }
        }

        return string.Empty;
    }
}