func Handler(w http.ResponseWriter, r *http.Request) {
  request := new(MyRequest)
  
  if httpu.DecodeJsonOr400(w, r, request, "Could not decode request") {
    // http.StatusBadRequest has been written to the response, we can now exit the handler
    return
  }
  
  result, err := DoWork(request)
  
  if httpu.Write500IfErr(err, w, "Could not process request for: %v", request.Value) {
    // http.StatusInternalServerError has been written to the response
    return
  }
  
  httpu.EncodeJsonOr400(w, result, "Could not encode response json for: %v", result.Value)
}