headers1.cs

[HttpGet]
[Route("products")]
public IHttpActionResult GetProducts([FromUri]string filter)
{
    string headerValue = null;
    IEnumerable headerValues;
    if (Request.Headers.TryGetValue("X-Secret-Penguin-Handshake", out headerValues))
    {
        headerValue = headerValues.FirstOrDefault();
    }
    if (string.IsNullOrEmpty(headerValue)) return BadRequest("Wenk!");
    var results = RunGetProductsQuery(filter);
    return Json(results);
}