public ActionResult Post([FromBody] FlightPlan fpDetails) { if (ModelState.IsValid) { string key = fpDetails.GenerateId(); cache.Set(key, fpDetails); // Updating the keys list with a new key. var keysList = (List <string>)cache.Get("keys"); keysList.Add(key); cache.Set("keys", keysList); // Save the flight id in the response headers (for testing it). HttpContext.Response.Headers["Location"] = key; var resp = CreatedAtAction(actionName: "Get", new { id = key }, fpDetails); return(resp); } return(BadRequest("Not a valid flight plan")); }