BasicAuthAttribute - Attribute that validates the provided credentials in the XHR header of an AJAX request.

BasicAuthAttribute.cs

    /// <summary>
    /// Attribute that validates the provided credentials in the XHR header of an AJAX request.
    /// </summary>
    /// <example>
    /// Example call:
    /// http://stackoverflow.com/a/11960692/1039247
    /// </example>
    public class BasicAuthAttribute : ActionFilterAttribute
    {

        public override void OnActionExecuting(HttpActionContext actionContext)
        {
            // check if a header is available
            if (actionContext.Request.Headers.Authorization == null)
            {
                actionContext.Response = new System.Net.Http.HttpResponseMessage(System.Net.HttpStatusCode.Unauthorized);
            }
            else
            {
                // fetch the token
                var authToken = actionContext.Request.Headers.Authorization.Parameter;
                var decodedToken = Encoding.UTF8.GetString(Convert.FromBase64String(authToken));

                var username = decodedToken.Substring(0, decodedToken.IndexOf(":"));
                var password = decodedToken.Substring(decodedToken.IndexOf(":") + 1);

                // TODO: Validate username/password here
            }

            // finish executing the action
            base.OnActionExecuting(actionContext);
        }

    }